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Author SHA1 Message Date
Linus Torvalds
3822a7c409 - Daniel Verkamp has contributed a memfd series ("mm/memfd: add 
F_SEAL_EXEC") which permits the setting of the memfd execute bit at
   memfd creation time, with the option of sealing the state of the X bit.
 
 - Peter Xu adds a patch series ("mm/hugetlb: Make huge_pte_offset()
   thread-safe for pmd unshare") which addresses a rare race condition
   related to PMD unsharing.
 
 - Several folioification patch serieses from Matthew Wilcox, Vishal
   Moola, Sidhartha Kumar and Lorenzo Stoakes
 
 - Johannes Weiner has a series ("mm: push down lock_page_memcg()") which
   does perform some memcg maintenance and cleanup work.
 
 - SeongJae Park has added DAMOS filtering to DAMON, with the series
   "mm/damon/core: implement damos filter".  These filters provide users
   with finer-grained control over DAMOS's actions.  SeongJae has also done
   some DAMON cleanup work.
 
 - Kairui Song adds a series ("Clean up and fixes for swap").
 
 - Vernon Yang contributed the series "Clean up and refinement for maple
   tree".
 
 - Yu Zhao has contributed the "mm: multi-gen LRU: memcg LRU" series.  It
   adds to MGLRU an LRU of memcgs, to improve the scalability of global
   reclaim.
 
 - David Hildenbrand has added some userfaultfd cleanup work in the
   series "mm: uffd-wp + change_protection() cleanups".
 
 - Christoph Hellwig has removed the generic_writepages() library
   function in the series "remove generic_writepages".
 
 - Baolin Wang has performed some maintenance on the compaction code in
   his series "Some small improvements for compaction".
 
 - Sidhartha Kumar is doing some maintenance work on struct page in his
   series "Get rid of tail page fields".
 
 - David Hildenbrand contributed some cleanup, bugfixing and
   generalization of pte management and of pte debugging in his series "mm:
   support __HAVE_ARCH_PTE_SWP_EXCLUSIVE on all architectures with swap
   PTEs".
 
 - Mel Gorman and Neil Brown have removed the __GFP_ATOMIC allocation
   flag in the series "Discard __GFP_ATOMIC".
 
 - Sergey Senozhatsky has improved zsmalloc's memory utilization with his
   series "zsmalloc: make zspage chain size configurable".
 
 - Joey Gouly has added prctl() support for prohibiting the creation of
   writeable+executable mappings.  The previous BPF-based approach had
   shortcomings.  See "mm: In-kernel support for memory-deny-write-execute
   (MDWE)".
 
 - Waiman Long did some kmemleak cleanup and bugfixing in the series
   "mm/kmemleak: Simplify kmemleak_cond_resched() & fix UAF".
 
 - T.J.  Alumbaugh has contributed some MGLRU cleanup work in his series
   "mm: multi-gen LRU: improve".
 
 - Jiaqi Yan has provided some enhancements to our memory error
   statistics reporting, mainly by presenting the statistics on a per-node
   basis.  See the series "Introduce per NUMA node memory error
   statistics".
 
 - Mel Gorman has a second and hopefully final shot at fixing a CPU-hog
   regression in compaction via his series "Fix excessive CPU usage during
   compaction".
 
 - Christoph Hellwig does some vmalloc maintenance work in the series
   "cleanup vfree and vunmap".
 
 - Christoph Hellwig has removed block_device_operations.rw_page() in ths
   series "remove ->rw_page".
 
 - We get some maple_tree improvements and cleanups in Liam Howlett's
   series "VMA tree type safety and remove __vma_adjust()".
 
 - Suren Baghdasaryan has done some work on the maintainability of our
   vm_flags handling in the series "introduce vm_flags modifier functions".
 
 - Some pagemap cleanup and generalization work in Mike Rapoport's series
   "mm, arch: add generic implementation of pfn_valid() for FLATMEM" and
   "fixups for generic implementation of pfn_valid()"
 
 - Baoquan He has done some work to make /proc/vmallocinfo and
   /proc/kcore better represent the real state of things in his series
   "mm/vmalloc.c: allow vread() to read out vm_map_ram areas".
 
 - Jason Gunthorpe rationalized the GUP system's interface to the rest of
   the kernel in the series "Simplify the external interface for GUP".
 
 - SeongJae Park wishes to migrate people from DAMON's debugfs interface
   over to its sysfs interface.  To support this, we'll temporarily be
   printing warnings when people use the debugfs interface.  See the series
   "mm/damon: deprecate DAMON debugfs interface".
 
 - Andrey Konovalov provided the accurately named "lib/stackdepot: fixes
   and clean-ups" series.
 
 - Huang Ying has provided a dramatic reduction in migration's TLB flush
   IPI rates with the series "migrate_pages(): batch TLB flushing".
 
 - Arnd Bergmann has some objtool fixups in "objtool warning fixes".
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Merge tag 'mm-stable-2023-02-20-13-37' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

Pull MM updates from Andrew Morton:

 - Daniel Verkamp has contributed a memfd series ("mm/memfd: add
   F_SEAL_EXEC") which permits the setting of the memfd execute bit at
   memfd creation time, with the option of sealing the state of the X
   bit.

 - Peter Xu adds a patch series ("mm/hugetlb: Make huge_pte_offset()
   thread-safe for pmd unshare") which addresses a rare race condition
   related to PMD unsharing.

 - Several folioification patch serieses from Matthew Wilcox, Vishal
   Moola, Sidhartha Kumar and Lorenzo Stoakes

 - Johannes Weiner has a series ("mm: push down lock_page_memcg()")
   which does perform some memcg maintenance and cleanup work.

 - SeongJae Park has added DAMOS filtering to DAMON, with the series
   "mm/damon/core: implement damos filter".

   These filters provide users with finer-grained control over DAMOS's
   actions. SeongJae has also done some DAMON cleanup work.

 - Kairui Song adds a series ("Clean up and fixes for swap").

 - Vernon Yang contributed the series "Clean up and refinement for maple
   tree".

 - Yu Zhao has contributed the "mm: multi-gen LRU: memcg LRU" series. It
   adds to MGLRU an LRU of memcgs, to improve the scalability of global
   reclaim.

 - David Hildenbrand has added some userfaultfd cleanup work in the
   series "mm: uffd-wp + change_protection() cleanups".

 - Christoph Hellwig has removed the generic_writepages() library
   function in the series "remove generic_writepages".

 - Baolin Wang has performed some maintenance on the compaction code in
   his series "Some small improvements for compaction".

 - Sidhartha Kumar is doing some maintenance work on struct page in his
   series "Get rid of tail page fields".

 - David Hildenbrand contributed some cleanup, bugfixing and
   generalization of pte management and of pte debugging in his series
   "mm: support __HAVE_ARCH_PTE_SWP_EXCLUSIVE on all architectures with
   swap PTEs".

 - Mel Gorman and Neil Brown have removed the __GFP_ATOMIC allocation
   flag in the series "Discard __GFP_ATOMIC".

 - Sergey Senozhatsky has improved zsmalloc's memory utilization with
   his series "zsmalloc: make zspage chain size configurable".

 - Joey Gouly has added prctl() support for prohibiting the creation of
   writeable+executable mappings.

   The previous BPF-based approach had shortcomings. See "mm: In-kernel
   support for memory-deny-write-execute (MDWE)".

 - Waiman Long did some kmemleak cleanup and bugfixing in the series
   "mm/kmemleak: Simplify kmemleak_cond_resched() & fix UAF".

 - T.J. Alumbaugh has contributed some MGLRU cleanup work in his series
   "mm: multi-gen LRU: improve".

 - Jiaqi Yan has provided some enhancements to our memory error
   statistics reporting, mainly by presenting the statistics on a
   per-node basis. See the series "Introduce per NUMA node memory error
   statistics".

 - Mel Gorman has a second and hopefully final shot at fixing a CPU-hog
   regression in compaction via his series "Fix excessive CPU usage
   during compaction".

 - Christoph Hellwig does some vmalloc maintenance work in the series
   "cleanup vfree and vunmap".

 - Christoph Hellwig has removed block_device_operations.rw_page() in
   ths series "remove ->rw_page".

 - We get some maple_tree improvements and cleanups in Liam Howlett's
   series "VMA tree type safety and remove __vma_adjust()".

 - Suren Baghdasaryan has done some work on the maintainability of our
   vm_flags handling in the series "introduce vm_flags modifier
   functions".

 - Some pagemap cleanup and generalization work in Mike Rapoport's
   series "mm, arch: add generic implementation of pfn_valid() for
   FLATMEM" and "fixups for generic implementation of pfn_valid()"

 - Baoquan He has done some work to make /proc/vmallocinfo and
   /proc/kcore better represent the real state of things in his series
   "mm/vmalloc.c: allow vread() to read out vm_map_ram areas".

 - Jason Gunthorpe rationalized the GUP system's interface to the rest
   of the kernel in the series "Simplify the external interface for
   GUP".

 - SeongJae Park wishes to migrate people from DAMON's debugfs interface
   over to its sysfs interface. To support this, we'll temporarily be
   printing warnings when people use the debugfs interface. See the
   series "mm/damon: deprecate DAMON debugfs interface".

 - Andrey Konovalov provided the accurately named "lib/stackdepot: fixes
   and clean-ups" series.

 - Huang Ying has provided a dramatic reduction in migration's TLB flush
   IPI rates with the series "migrate_pages(): batch TLB flushing".

 - Arnd Bergmann has some objtool fixups in "objtool warning fixes".

* tag 'mm-stable-2023-02-20-13-37' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (505 commits)
  include/linux/migrate.h: remove unneeded externs
  mm/memory_hotplug: cleanup return value handing in do_migrate_range()
  mm/uffd: fix comment in handling pte markers
  mm: change to return bool for isolate_movable_page()
  mm: hugetlb: change to return bool for isolate_hugetlb()
  mm: change to return bool for isolate_lru_page()
  mm: change to return bool for folio_isolate_lru()
  objtool: add UACCESS exceptions for __tsan_volatile_read/write
  kmsan: disable ftrace in kmsan core code
  kasan: mark addr_has_metadata __always_inline
  mm: memcontrol: rename memcg_kmem_enabled()
  sh: initialize max_mapnr
  m68k/nommu: add missing definition of ARCH_PFN_OFFSET
  mm: percpu: fix incorrect size in pcpu_obj_full_size()
  maple_tree: reduce stack usage with gcc-9 and earlier
  mm: page_alloc: call panic() when memoryless node allocation fails
  mm: multi-gen LRU: avoid futile retries
  migrate_pages: move THP/hugetlb migration support check to simplify code
  migrate_pages: batch flushing TLB
  migrate_pages: share more code between _unmap and _move
  ...
 2023-02-23 17:09:35 -08:00
Linus Torvalds
1f2d9ffc7a Scheduler updates in this cycle are: 
- Improve the scalability of the CFS bandwidth unthrottling logic
    with large number of CPUs.
 
  - Fix & rework various cpuidle routines, simplify interaction with
    the generic scheduler code. Add __cpuidle methods as noinstr to
    objtool's noinstr detection and fix boatloads of cpuidle bugs & quirks.
 
  - Add new ABI: introduce MEMBARRIER_CMD_GET_REGISTRATIONS,
    to query previously issued registrations.
 
  - Limit scheduler slice duration to the sysctl_sched_latency period,
    to improve scheduling granularity with a large number of SCHED_IDLE
    tasks.
 
  - Debuggability enhancement on sys_exit(): warn about disabled IRQs,
    but also enable them to prevent a cascade of followup problems and
    repeat warnings.
 
  - Fix the rescheduling logic in prio_changed_dl().
 
  - Micro-optimize cpufreq and sched-util methods.
 
  - Micro-optimize ttwu_runnable()
 
  - Micro-optimize the idle-scanning in update_numa_stats(),
    select_idle_capacity() and steal_cookie_task().
 
  - Update the RSEQ code & self-tests
 
  - Constify various scheduler methods
 
  - Remove unused methods
 
  - Refine __init tags
 
  - Documentation updates
 
  - ... Misc other cleanups, fixes
 
 Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Merge tag 'sched-core-2023-02-20' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull scheduler updates from Ingo Molnar:

 - Improve the scalability of the CFS bandwidth unthrottling logic with
   large number of CPUs.

 - Fix & rework various cpuidle routines, simplify interaction with the
   generic scheduler code. Add __cpuidle methods as noinstr to objtool's
   noinstr detection and fix boatloads of cpuidle bugs & quirks.

 - Add new ABI: introduce MEMBARRIER_CMD_GET_REGISTRATIONS, to query
   previously issued registrations.

 - Limit scheduler slice duration to the sysctl_sched_latency period, to
   improve scheduling granularity with a large number of SCHED_IDLE
   tasks.

 - Debuggability enhancement on sys_exit(): warn about disabled IRQs,
   but also enable them to prevent a cascade of followup problems and
   repeat warnings.

 - Fix the rescheduling logic in prio_changed_dl().

 - Micro-optimize cpufreq and sched-util methods.

 - Micro-optimize ttwu_runnable()

 - Micro-optimize the idle-scanning in update_numa_stats(),
   select_idle_capacity() and steal_cookie_task().

 - Update the RSEQ code & self-tests

 - Constify various scheduler methods

 - Remove unused methods

 - Refine __init tags

 - Documentation updates

 - Misc other cleanups, fixes

* tag 'sched-core-2023-02-20' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (110 commits)
  sched/rt: pick_next_rt_entity(): check list_entry
  sched/deadline: Add more reschedule cases to prio_changed_dl()
  sched/fair: sanitize vruntime of entity being placed
  sched/fair: Remove capacity inversion detection
  sched/fair: unlink misfit task from cpu overutilized
  objtool: mem*() are not uaccess safe
  cpuidle: Fix poll_idle() noinstr annotation
  sched/clock: Make local_clock() noinstr
  sched/clock/x86: Mark sched_clock() noinstr
  x86/pvclock: Improve atomic update of last_value in pvclock_clocksource_read()
  x86/atomics: Always inline arch_atomic64*()
  cpuidle: tracing, preempt: Squash _rcuidle tracing
  cpuidle: tracing: Warn about !rcu_is_watching()
  cpuidle: lib/bug: Disable rcu_is_watching() during WARN/BUG
  cpuidle: drivers: firmware: psci: Dont instrument suspend code
  KVM: selftests: Fix build of rseq test
  exit: Detect and fix irq disabled state in oops
  cpuidle, arm64: Fix the ARM64 cpuidle logic
  cpuidle: mvebu: Fix duplicate flags assignment
  sched/fair: Limit sched slice duration
  ...
 2023-02-20 17:41:08 -08:00
Suren Baghdasaryan
1c71222e5f mm: replace vma->vm_flags direct modifications with modifier calls 
Replace direct modifications to vma->vm_flags with calls to modifier
functions to be able to track flag changes and to keep vma locking
correctness.

[akpm@linux-foundation.org: fix drivers/misc/open-dice.c, per Hyeonggon Yoo]
Link: https://lkml.kernel.org/r/20230126193752.297968-5-surenb@google.com
Signed-off-by: Suren Baghdasaryan <surenb@google.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Mel Gorman <mgorman@techsingularity.net>
Acked-by: Mike Rapoport (IBM) <rppt@kernel.org>
Acked-by: Sebastian Reichel <sebastian.reichel@collabora.com>
Reviewed-by: Liam R. Howlett <Liam.Howlett@Oracle.com>
Reviewed-by: Hyeonggon Yoo <42.hyeyoo@gmail.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Arjun Roy <arjunroy@google.com>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: David Rientjes <rientjes@google.com>
Cc: Eric Dumazet <edumazet@google.com>
Cc: Greg Thelen <gthelen@google.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jann Horn <jannh@google.com>
Cc: Joel Fernandes <joelaf@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Kent Overstreet <kent.overstreet@linux.dev>
Cc: Laurent Dufour <ldufour@linux.ibm.com>
Cc: Lorenzo Stoakes <lstoakes@gmail.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Minchan Kim <minchan@google.com>
Cc: Paul E. McKenney <paulmck@kernel.org>
Cc: Peter Oskolkov <posk@google.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Punit Agrawal <punit.agrawal@bytedance.com>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Soheil Hassas Yeganeh <soheil@google.com>
Cc: Song Liu <songliubraving@fb.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2023-02-09 16:51:39 -08:00
Liam R. Howlett
cf51e86dfb mm/mmap: don't use __vma_adjust() in shift_arg_pages() 
Introduce shrink_vma() which uses the vma_prepare() and vma_complete()
functions to reduce the vma coverage.

Convert shift_arg_pages() to use expand_vma() and the new shrink_vma()
function.  Remove support from __vma_adjust() to reduce a vma size since
shift_arg_pages() is the only user that shrinks a VMA in this way.

Link: https://lkml.kernel.org/r/20230120162650.984577-46-Liam.Howlett@oracle.com
Signed-off-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2023-02-09 16:51:38 -08:00
Liam R. Howlett
b2b3b88673 mm: don't use __vma_adjust() in __split_vma() 
Use the abstracted locking and maple tree operations.  Since __split_vma()
is the only user of the __vma_adjust() function to use the insert
argument, drop that argument.  Remove the NULL passed through from
fs/exec's shift_arg_pages() and mremap() at the same time.

Link: https://lkml.kernel.org/r/20230120162650.984577-44-Liam.Howlett@oracle.com
Signed-off-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2023-02-09 16:51:37 -08:00
Liam R. Howlett
b373037fa9 mm: add vma iterator to vma_adjust() arguments 
Change the vma_adjust() function definition to accept the vma iterator and
pass it through to __vma_adjust().

Update fs/exec to use the new vma_adjust() function parameters.

Update mm/mremap to use the new vma_adjust() function parameters.

Revert the __split_vma() calls back from __vma_adjust() to vma_adjust()
and pass through the vma iterator.

Link: https://lkml.kernel.org/r/20230120162650.984577-37-Liam.Howlett@oracle.com
Signed-off-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2023-02-09 16:51:36 -08:00
Liam R. Howlett
2286a6914c mm: change mprotect_fixup to vma iterator 
Use the vma iterator so that the iterator can be invalidated or updated to
avoid each caller doing so.

Link: https://lkml.kernel.org/r/20230120162650.984577-18-Liam.Howlett@oracle.com
Signed-off-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2023-02-09 16:51:33 -08:00
Christian Brauner
e67fe63341
fs: port i_{g,u}id_into_vfs{g,u}id() to mnt_idmap 
Convert to struct mnt_idmap.
Remove legacy file_mnt_user_ns() and mnt_user_ns().

Last cycle we merged the necessary infrastructure in
256c8aed2b ("fs: introduce dedicated idmap type for mounts").
This is just the conversion to struct mnt_idmap.

Currently we still pass around the plain namespace that was attached to a
mount. This is in general pretty convenient but it makes it easy to
conflate namespaces that are relevant on the filesystem with namespaces
that are relevent on the mount level. Especially for non-vfs developers
without detailed knowledge in this area this can be a potential source for
bugs.

Once the conversion to struct mnt_idmap is done all helpers down to the
really low-level helpers will take a struct mnt_idmap argument instead of
two namespace arguments. This way it becomes impossible to conflate the two
eliminating the possibility of any bugs. All of the vfs and all filesystems
only operate on struct mnt_idmap.

Acked-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Christian Brauner (Microsoft) <brauner@kernel.org>
 2023-01-19 09:24:29 +01:00
Christian Brauner
9452e93e6d
fs: port privilege checking helpers to mnt_idmap 
Convert to struct mnt_idmap.

Last cycle we merged the necessary infrastructure in
256c8aed2b ("fs: introduce dedicated idmap type for mounts").
This is just the conversion to struct mnt_idmap.

Currently we still pass around the plain namespace that was attached to a
mount. This is in general pretty convenient but it makes it easy to
conflate namespaces that are relevant on the filesystem with namespaces
that are relevent on the mount level. Especially for non-vfs developers
without detailed knowledge in this area this can be a potential source for
bugs.

Once the conversion to struct mnt_idmap is done all helpers down to the
really low-level helpers will take a struct mnt_idmap argument instead of
two namespace arguments. This way it becomes impossible to conflate the two
eliminating the possibility of any bugs. All of the vfs and all filesystems
only operate on struct mnt_idmap.

Acked-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Christian Brauner (Microsoft) <brauner@kernel.org>
 2023-01-19 09:24:29 +01:00
Christian Brauner
4609e1f18e
fs: port ->permission() to pass mnt_idmap 
Convert to struct mnt_idmap.

Last cycle we merged the necessary infrastructure in
256c8aed2b ("fs: introduce dedicated idmap type for mounts").
This is just the conversion to struct mnt_idmap.

Currently we still pass around the plain namespace that was attached to a
mount. This is in general pretty convenient but it makes it easy to
conflate namespaces that are relevant on the filesystem with namespaces
that are relevent on the mount level. Especially for non-vfs developers
without detailed knowledge in this area this can be a potential source for
bugs.

Once the conversion to struct mnt_idmap is done all helpers down to the
really low-level helpers will take a struct mnt_idmap argument instead of
two namespace arguments. This way it becomes impossible to conflate the two
eliminating the possibility of any bugs. All of the vfs and all filesystems
only operate on struct mnt_idmap.

Acked-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Christian Brauner (Microsoft) <brauner@kernel.org>
 2023-01-19 09:24:28 +01:00
Mathieu Desnoyers
af7f588d8f sched: Introduce per-memory-map concurrency ID 
This feature allows the scheduler to expose a per-memory map concurrency
ID to user-space. This concurrency ID is within the possible cpus range,
and is temporarily (and uniquely) assigned while threads are actively
running within a memory map. If a memory map has fewer threads than
cores, or is limited to run on few cores concurrently through sched
affinity or cgroup cpusets, the concurrency IDs will be values close
to 0, thus allowing efficient use of user-space memory for per-cpu
data structures.

This feature is meant to be exposed by a new rseq thread area field.

The primary purpose of this feature is to do the heavy-lifting needed
by memory allocators to allow them to use per-cpu data structures
efficiently in the following situations:

- Single-threaded applications,
- Multi-threaded applications on large systems (many cores) with limited
  cpu affinity mask,
- Multi-threaded applications on large systems (many cores) with
  restricted cgroup cpuset per container.

One of the key concern from scheduler maintainers is the overhead
associated with additional spin locks or atomic operations in the
scheduler fast-path. This is why the following optimization is
implemented.

On context switch between threads belonging to the same memory map,
transfer the mm_cid from prev to next without any atomic ops. This
takes care of use-cases involving frequent context switch between
threads belonging to the same memory map.

Additional optimizations can be done if the spin locks added when
context switching between threads belonging to different memory maps end
up being a performance bottleneck. Those are left out of this patch
though. A performance impact would have to be clearly demonstrated to
justify the added complexity.

The credit goes to Paul Turner (Google) for the original virtual cpu id
idea. This feature is implemented based on the discussions with Paul
Turner and Peter Oskolkov (Google), but I took the liberty to implement
scheduler fast-path optimizations and my own NUMA-awareness scheme. The
rumor has it that Google have been running a rseq vcpu_id extension
internally in production for a year. The tcmalloc source code indeed has
comments hinting at a vcpu_id prototype extension to the rseq system
call [1].

The following benchmarks do not show any significant overhead added to
the scheduler context switch by this feature:

* perf bench sched messaging (process)

Baseline:                    86.5±0.3 ms
With mm_cid:                 86.7±2.6 ms

* perf bench sched messaging (threaded)

Baseline:                    84.3±3.0 ms
With mm_cid:                 84.7±2.6 ms

* hackbench (process)

Baseline:                    82.9±2.7 ms
With mm_cid:                 82.9±2.9 ms

* hackbench (threaded)

Baseline:                    85.2±2.6 ms
With mm_cid:                 84.4±2.9 ms

[1] https://github.com/google/tcmalloc/blob/master/tcmalloc/internal/linux_syscall_support.h#L26

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20221122203932.231377-8-mathieu.desnoyers@efficios.com
 2022-12-27 12:52:11 +01:00
Linus Torvalds
e1212e9b6f fs.vfsuid.conversion.v6.2 
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Merge tag 'fs.vfsuid.conversion.v6.2' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/idmapping

Pull vfsuid updates from Christian Brauner:
 "Last cycle we introduced the vfs{g,u}id_t types and associated helpers
  to gain type safety when dealing with idmapped mounts. That initial
  work already converted a lot of places over but there were still some
  left,

  This converts all remaining places that still make use of non-type
  safe idmapping helpers to rely on the new type safe vfs{g,u}id based
  helpers.

  Afterwards it removes all the old non-type safe helpers"

* tag 'fs.vfsuid.conversion.v6.2' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/idmapping:
  fs: remove unused idmapping helpers
  ovl: port to vfs{g,u}id_t and associated helpers
  fuse: port to vfs{g,u}id_t and associated helpers
  ima: use type safe idmapping helpers
  apparmor: use type safe idmapping helpers
  caps: use type safe idmapping helpers
  fs: use type safe idmapping helpers
  mnt_idmapping: add missing helpers
 2022-12-12 19:20:05 -08:00
Linus Torvalds
7fc035058e execve updates for v6.2-rc1 
- Add timens support (when switching mm). This version has survived
   in -next for the entire cycle (Andrei Vagin).
 
 - Various small bug fixes, refactoring, and readability improvements
   (Bernd Edlinger, Rolf Eike Beer, Bo Liu, Li Zetao Liu Shixin).
 
 - Remove FOLL_FORCE for stack setup (Kees Cook).
 
 - Whilespace cleanups (Rolf Eike Beer, Kees Cook).
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Merge tag 'execve-v6.2-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux

Pull execve updates from Kees Cook:
 "Most are small refactorings and bug fixes, but three things stand out:
  switching timens (which got reverted before) looks solid now,
  FOLL_FORCE has been removed (no failures seen yet across several weeks
  in -next), and some whitespace cleanups (which are long overdue).

   - Add timens support (when switching mm). This version has survived
     in -next for the entire cycle (Andrei Vagin)

   - Various small bug fixes, refactoring, and readability improvements
     (Bernd Edlinger, Rolf Eike Beer, Bo Liu, Li Zetao Liu Shixin)

   - Remove FOLL_FORCE for stack setup (Kees Cook)

   - Whitespace cleanups (Rolf Eike Beer, Kees Cook)"

* tag 'execve-v6.2-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux:
  binfmt_misc: fix shift-out-of-bounds in check_special_flags
  binfmt: Fix error return code in load_elf_fdpic_binary()
  exec: Remove FOLL_FORCE for stack setup
  binfmt_elf: replace IS_ERR() with IS_ERR_VALUE()
  binfmt_elf: simplify error handling in load_elf_phdrs()
  binfmt_elf: fix documented return value for load_elf_phdrs()
  exec: simplify initial stack size expansion
  binfmt: Fix whitespace issues
  exec: Add comments on check_unsafe_exec() fs counting
  ELF uapi: add spaces before '{'
  selftests/timens: add a test for vfork+exit
  fs/exec: switch timens when a task gets a new mm
 2022-12-12 08:42:29 -08:00
Kees Cook
cd57e44383 exec: Remove FOLL_FORCE for stack setup 
It does not appear that FOLL_FORCE should be needed for setting up the
stack pages. They are allocated using the nascent brpm->vma, which was
newly created with VM_STACK_FLAGS, which an arch can override, but they
all appear to include VM_WRITE | VM_MAYWRITE. Remove FOLL_FORCE.

Cc: Eric Biederman <ebiederm@xmission.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: linux-fsdevel@vger.kernel.org
Cc: linux-mm@kvack.org
Link: https://lore.kernel.org/lkml/202211171439.CDE720EAD@keescook/
Signed-off-by: Kees Cook <keescook@chromium.org>
 2022-11-17 16:31:55 -08:00
Linus Torvalds
3c339dbd13 23 hotfixes. 
Eight fix pre-6.0 bugs and the remainder address issues which were
 introduced in the 6.1-rc merge cycle, or address issues which aren't
 considered sufficiently serious to warrant a -stable backport.
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Merge tag 'mm-hotfixes-stable-2022-10-28' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

Pull misc hotfixes from Andrew Morton:
 "Eight fix pre-6.0 bugs and the remainder address issues which were
  introduced in the 6.1-rc merge cycle, or address issues which aren't
  considered sufficiently serious to warrant a -stable backport"

* tag 'mm-hotfixes-stable-2022-10-28' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (23 commits)
  mm: multi-gen LRU: move lru_gen_add_mm() out of IRQ-off region
  lib: maple_tree: remove unneeded initialization in mtree_range_walk()
  mmap: fix remap_file_pages() regression
  mm/shmem: ensure proper fallback if page faults
  mm/userfaultfd: replace kmap/kmap_atomic() with kmap_local_page()
  x86: fortify: kmsan: fix KMSAN fortify builds
  x86: asm: make sure __put_user_size() evaluates pointer once
  Kconfig.debug: disable CONFIG_FRAME_WARN for KMSAN by default
  x86/purgatory: disable KMSAN instrumentation
  mm: kmsan: export kmsan_copy_page_meta()
  mm: migrate: fix return value if all subpages of THPs are migrated successfully
  mm/uffd: fix vma check on userfault for wp
  mm: prep_compound_tail() clear page->private
  mm,madvise,hugetlb: fix unexpected data loss with MADV_DONTNEED on hugetlbfs
  mm/page_isolation: fix clang deadcode warning
  fs/ext4/super.c: remove unused `deprecated_msg'
  ipc/msg.c: fix percpu_counter use after free
  memory tier, sysfs: rename attribute "nodes" to "nodelist"
  MAINTAINERS: git://github.com -> https://github.com for nilfs2
  mm/kmemleak: prevent soft lockup in kmemleak_scan()'s object iteration loops
  ...
 2022-10-29 17:49:33 -07:00
Sebastian Andrzej Siewior
dda1c41a07 mm: multi-gen LRU: move lru_gen_add_mm() out of IRQ-off region 
lru_gen_add_mm() has been added within an IRQ-off region in the commit
mentioned below.  The other invocations of lru_gen_add_mm() are not within
an IRQ-off region.

The invocation within IRQ-off region is problematic on PREEMPT_RT because
the function is using a spin_lock_t which must not be used within
IRQ-disabled regions.

The other invocations of lru_gen_add_mm() occur while
task_struct::alloc_lock is acquired.  Move lru_gen_add_mm() after
interrupts are enabled and before task_unlock().

Link: https://lkml.kernel.org/r/20221026134830.711887-1-bigeasy@linutronix.de
Fixes: bd74fdaea1 ("mm: multi-gen LRU: support page table walks")
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Acked-by: Yu Zhao <yuzhao@google.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: "Eric W . Biederman" <ebiederm@xmission.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2022-10-28 13:37:23 -07:00
Christian Brauner
a2bd096fb2
fs: use type safe idmapping helpers 
We already ported most parts and filesystems over for v6.0 to the new
vfs{g,u}id_t type and associated helpers for v6.0. Convert the remaining
places so we can remove all the old helpers.
This is a non-functional change.

Reviewed-by: Seth Forshee (DigitalOcean) <sforshee@kernel.org>
Signed-off-by: Christian Brauner (Microsoft) <brauner@kernel.org>
 2022-10-26 10:02:34 +02:00
Rolf Eike Beer
bfb4a2b958 exec: simplify initial stack size expansion 
I had a hard time trying to understand completely why it is using vm_end in
one side of the expression and vm_start in the other one, and using
something in the "if" clause that is not an exact copy of what is used
below. The whole point is that the stack_size variable that was used in the
"if" clause is the difference between vm_start and vm_end, which is not far
away but makes this thing harder to read than it must be.

Signed-off-by: Rolf Eike Beer <eb@emlix.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/2017429.gqNitNVd0C@mobilepool36.emlix.com
 2022-10-25 15:19:48 -07:00
Kees Cook
8f6e3f9e5a binfmt: Fix whitespace issues 
Fix the annoying whitespace issues that have been following these files
around for years.

Cc: linux-fsdevel@vger.kernel.org
Signed-off-by: Kees Cook <keescook@chromium.org>
Acked-by: Christian Brauner (Microsoft) <brauner@kernel.org>
Link: https://lore.kernel.org/r/20221018071350.never.230-kees@kernel.org
 2022-10-25 15:17:23 -07:00
Kees Cook
275498a98b exec: Add comments on check_unsafe_exec() fs counting 
Add some comments about what the fs counting is doing in
check_unsafe_exec() and how it relates to the call graph.
Specifically, we can't force an unshare of the fs because
of at least Chrome:
https://lore.kernel.org/lkml/86CE201B-5632-4BB7-BCF6-7CB2C2895409@chromium.org/

Cc: Eric Biederman <ebiederm@xmission.com>
Cc: linux-fsdevel@vger.kernel.org
Signed-off-by: Kees Cook <keescook@chromium.org>
Acked-by: Christian Brauner (Microsoft) <brauner@kernel.org>
Link: https://lore.kernel.org/r/20221018071537.never.662-kees@kernel.org
 2022-10-25 15:17:08 -07:00
Andrei Vagin
2b5f9dad32 fs/exec: switch timens when a task gets a new mm 
Changing a time namespace requires remapping a vvar page, so we don't want
to allow doing that if any other tasks can use the same mm.

Currently, we install a time namespace when a task is created with a new
vm. exec() is another case when a task gets a new mm and so it can switch
a time namespace safely, but it isn't handled now.

One more issue of the current interface is that clone() with CLONE_VM isn't
allowed if the current task has unshared a time namespace
(timens_for_children doesn't match the current timens).

Both these issues make some inconvenience for users. For example, Alexey
and Florian reported that posix_spawn() uses vfork+exec and this pattern
doesn't work with time namespaces due to the both described issues.
LXC needed to workaround the exec() issue by calling setns.

In the commit 133e2d3e81 ("fs/exec: allow to unshare a time namespace on
vfork+exec"), we tried to fix these issues with minimal impact on UAPI. But
it adds extra complexity and some undesirable side effects. Eric suggested
fixing the issues properly because here are all the reasons to suppose that
there are no users that depend on the old behavior.

Cc: Alexey Izbyshev <izbyshev@ispras.ru>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Dmitry Safonov <0x7f454c46@gmail.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Florian Weimer <fweimer@redhat.com>
Cc: Kees Cook <keescook@chromium.org>
Suggested-by: "Eric W. Biederman" <ebiederm@xmission.com>
Origin-author: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Andrei Vagin <avagin@gmail.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20220921003120.209637-1-avagin@google.com
 2022-10-25 15:15:52 -07:00
Bernd Edlinger
5bf2fedca8 exec: Copy oldsighand->action under spin-lock 
unshare_sighand should only access oldsighand->action
while holding oldsighand->siglock, to make sure that
newsighand->action is in a consistent state.

Signed-off-by: Bernd Edlinger <bernd.edlinger@hotmail.de>
Cc: stable@vger.kernel.org
Fixes: 1da177e4c3 ("Linux-2.6.12-rc2")
Signed-off-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/AM8PR10MB470871DEBD1DED081F9CC391E4389@AM8PR10MB4708.EURPRD10.PROD.OUTLOOK.COM
 2022-10-25 15:05:58 -07:00
Linus Torvalds
27bc50fc90 - Yu Zhao's Multi-Gen LRU patches are here. They've been under test in 
linux-next for a couple of months without, to my knowledge, any negative
   reports (or any positive ones, come to that).
 
 - Also the Maple Tree from Liam R.  Howlett.  An overlapping range-based
   tree for vmas.  It it apparently slight more efficient in its own right,
   but is mainly targeted at enabling work to reduce mmap_lock contention.
 
   Liam has identified a number of other tree users in the kernel which
   could be beneficially onverted to mapletrees.
 
   Yu Zhao has identified a hard-to-hit but "easy to fix" lockdep splat
   (https://lkml.kernel.org/r/CAOUHufZabH85CeUN-MEMgL8gJGzJEWUrkiM58JkTbBhh-jew0Q@mail.gmail.com).
   This has yet to be addressed due to Liam's unfortunately timed
   vacation.  He is now back and we'll get this fixed up.
 
 - Dmitry Vyukov introduces KMSAN: the Kernel Memory Sanitizer.  It uses
   clang-generated instrumentation to detect used-unintialized bugs down to
   the single bit level.
 
   KMSAN keeps finding bugs.  New ones, as well as the legacy ones.
 
 - Yang Shi adds a userspace mechanism (madvise) to induce a collapse of
   memory into THPs.
 
 - Zach O'Keefe has expanded Yang Shi's madvise(MADV_COLLAPSE) to support
   file/shmem-backed pages.
 
 - userfaultfd updates from Axel Rasmussen
 
 - zsmalloc cleanups from Alexey Romanov
 
 - cleanups from Miaohe Lin: vmscan, hugetlb_cgroup, hugetlb and memory-failure
 
 - Huang Ying adds enhancements to NUMA balancing memory tiering mode's
   page promotion, with a new way of detecting hot pages.
 
 - memcg updates from Shakeel Butt: charging optimizations and reduced
   memory consumption.
 
 - memcg cleanups from Kairui Song.
 
 - memcg fixes and cleanups from Johannes Weiner.
 
 - Vishal Moola provides more folio conversions
 
 - Zhang Yi removed ll_rw_block() :(
 
 - migration enhancements from Peter Xu
 
 - migration error-path bugfixes from Huang Ying
 
 - Aneesh Kumar added ability for a device driver to alter the memory
   tiering promotion paths.  For optimizations by PMEM drivers, DRM
   drivers, etc.
 
 - vma merging improvements from Jakub Matěn.
 
 - NUMA hinting cleanups from David Hildenbrand.
 
 - xu xin added aditional userspace visibility into KSM merging activity.
 
 - THP & KSM code consolidation from Qi Zheng.
 
 - more folio work from Matthew Wilcox.
 
 - KASAN updates from Andrey Konovalov.
 
 - DAMON cleanups from Kaixu Xia.
 
 - DAMON work from SeongJae Park: fixes, cleanups.
 
 - hugetlb sysfs cleanups from Muchun Song.
 
 - Mike Kravetz fixes locking issues in hugetlbfs and in hugetlb core.
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Merge tag 'mm-stable-2022-10-08' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

Pull MM updates from Andrew Morton:

 - Yu Zhao's Multi-Gen LRU patches are here. They've been under test in
   linux-next for a couple of months without, to my knowledge, any
   negative reports (or any positive ones, come to that).

 - Also the Maple Tree from Liam Howlett. An overlapping range-based
   tree for vmas. It it apparently slightly more efficient in its own
   right, but is mainly targeted at enabling work to reduce mmap_lock
   contention.

   Liam has identified a number of other tree users in the kernel which
   could be beneficially onverted to mapletrees.

   Yu Zhao has identified a hard-to-hit but "easy to fix" lockdep splat
   at [1]. This has yet to be addressed due to Liam's unfortunately
   timed vacation. He is now back and we'll get this fixed up.

 - Dmitry Vyukov introduces KMSAN: the Kernel Memory Sanitizer. It uses
   clang-generated instrumentation to detect used-unintialized bugs down
   to the single bit level.

   KMSAN keeps finding bugs. New ones, as well as the legacy ones.

 - Yang Shi adds a userspace mechanism (madvise) to induce a collapse of
   memory into THPs.

 - Zach O'Keefe has expanded Yang Shi's madvise(MADV_COLLAPSE) to
   support file/shmem-backed pages.

 - userfaultfd updates from Axel Rasmussen

 - zsmalloc cleanups from Alexey Romanov

 - cleanups from Miaohe Lin: vmscan, hugetlb_cgroup, hugetlb and
   memory-failure

 - Huang Ying adds enhancements to NUMA balancing memory tiering mode's
   page promotion, with a new way of detecting hot pages.

 - memcg updates from Shakeel Butt: charging optimizations and reduced
   memory consumption.

 - memcg cleanups from Kairui Song.

 - memcg fixes and cleanups from Johannes Weiner.

 - Vishal Moola provides more folio conversions

 - Zhang Yi removed ll_rw_block() :(

 - migration enhancements from Peter Xu

 - migration error-path bugfixes from Huang Ying

 - Aneesh Kumar added ability for a device driver to alter the memory
   tiering promotion paths. For optimizations by PMEM drivers, DRM
   drivers, etc.

 - vma merging improvements from Jakub Matěn.

 - NUMA hinting cleanups from David Hildenbrand.

 - xu xin added aditional userspace visibility into KSM merging
   activity.

 - THP & KSM code consolidation from Qi Zheng.

 - more folio work from Matthew Wilcox.

 - KASAN updates from Andrey Konovalov.

 - DAMON cleanups from Kaixu Xia.

 - DAMON work from SeongJae Park: fixes, cleanups.

 - hugetlb sysfs cleanups from Muchun Song.

 - Mike Kravetz fixes locking issues in hugetlbfs and in hugetlb core.

Link: https://lkml.kernel.org/r/CAOUHufZabH85CeUN-MEMgL8gJGzJEWUrkiM58JkTbBhh-jew0Q@mail.gmail.com [1]

* tag 'mm-stable-2022-10-08' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (555 commits)
  hugetlb: allocate vma lock for all sharable vmas
  hugetlb: take hugetlb vma_lock when clearing vma_lock->vma pointer
  hugetlb: fix vma lock handling during split vma and range unmapping
  mglru: mm/vmscan.c: fix imprecise comments
  mm/mglru: don't sync disk for each aging cycle
  mm: memcontrol: drop dead CONFIG_MEMCG_SWAP config symbol
  mm: memcontrol: use do_memsw_account() in a few more places
  mm: memcontrol: deprecate swapaccounting=0 mode
  mm: memcontrol: don't allocate cgroup swap arrays when memcg is disabled
  mm/secretmem: remove reduntant return value
  mm/hugetlb: add available_huge_pages() func
  mm: remove unused inline functions from include/linux/mm_inline.h
  selftests/vm: add selftest for MADV_COLLAPSE of uffd-minor memory
  selftests/vm: add file/shmem MADV_COLLAPSE selftest for cleared pmd
  selftests/vm: add thp collapse shmem testing
  selftests/vm: add thp collapse file and tmpfs testing
  selftests/vm: modularize thp collapse memory operations
  selftests/vm: dedup THP helpers
  mm/khugepaged: add tracepoint to hpage_collapse_scan_file()
  mm/madvise: add file and shmem support to MADV_COLLAPSE
  ...
 2022-10-10 17:53:04 -07:00
Linus Torvalds
493ffd6605 ucounts: Split rlimit and ucount values and max values 
After the ucount rlimit code was merged a bunch of small but
 siginificant bugs were found and fixed.  At the time it was realized
 that part of the problem was that while the ucount rlimits were very
 similar to the oridinary ucounts (in being nested counts with limits)
 the semantics were slightly different and the code would be less error
 prone if there was less sharing.  This is the long awaited cleanup
 that should hopefully keep things more comprehensible and less error
 prone for whoever needs to touch that code next.
 
 Alexey Gladkov (1):
       ucounts: Split rlimit and ucount values and max values
 
  fs/exec.c                      |  2 +-
  fs/proc/array.c                |  2 +-
  include/linux/user_namespace.h | 35 ++++++++++++++++++++++-------------
  kernel/fork.c                  | 12 ++++++------
  kernel/sys.c                   |  2 +-
  kernel/ucount.c                | 34 +++++++++++++++-------------------
  kernel/user_namespace.c        | 10 +++++-----
  7 files changed, 51 insertions(+), 46 deletions(-)
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Merge tag 'ucount-rlimits-cleanups-for-v5.19' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace

Pull ucounts update from Eric Biederman:
 "Split rlimit and ucount values and max values

  After the ucount rlimit code was merged a bunch of small but
  siginificant bugs were found and fixed. At the time it was realized
  that part of the problem was that while the ucount rlimits were very
  similar to the oridinary ucounts (in being nested counts with limits)
  the semantics were slightly different and the code would be less error
  prone if there was less sharing.

  This is the long awaited cleanup that should hopefully keep things
  more comprehensible and less error prone for whoever needs to touch
  that code next"

* tag 'ucount-rlimits-cleanups-for-v5.19' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace:
  ucounts: Split rlimit and ucount values and max values
 2022-10-09 16:24:05 -07:00
Linus Torvalds
ab29622157 whack-a-mole: cropped up open-coded file_inode() uses... 
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Merge tag 'pull-file_inode' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs

Pull file_inode() updates from Al Vrio:
 "whack-a-mole: cropped up open-coded file_inode() uses..."

* tag 'pull-file_inode' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  orangefs: use ->f_mapping
  _nfs42_proc_copy(): use ->f_mapping instead of file_inode()->i_mapping
  dma_buf: no need to bother with file_inode()->i_mapping
  nfs_finish_open(): don't open-code file_inode()
  bprm_fill_uid(): don't open-code file_inode()
  sgx: use ->f_mapping...
  exfat_iterate(): don't open-code file_inode(file)
  ibmvmc: don't open-code file_inode()
 2022-10-06 17:22:11 -07:00
Eric W. Biederman
987f20a9dc a.out: Remove the a.out implementation 
In commit 19e8b701e2 ("a.out: Stop building a.out/osf1 support on
alpha and m68k") the last users of a.out were disabled.

As nothing has turned up to cause this change to be reverted, let's
remove the code implementing a.out support as well.

There may be userspace users of the uapi bits left so the uapi
headers have been left untouched.

Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Acked-by: Arnd Bergmann <arnd@arndb.de> # arm defconfigs
Signed-off-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/871qrx3hq3.fsf@email.froward.int.ebiederm.org
 2022-09-27 07:11:02 -07:00
Matthew Wilcox (Oracle)
19066e5868 exec: use VMA iterator instead of linked list 
Remove a use of the vm_next list by doing the initial lookup with the VMA
iterator and then using it to find the next entry.

Link: https://lkml.kernel.org/r/20220906194824.2110408-42-Liam.Howlett@oracle.com
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Liam R. Howlett <Liam.Howlett@Oracle.com>
Tested-by: Yu Zhao <yuzhao@google.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: SeongJae Park <sj@kernel.org>
Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2022-09-26 19:46:21 -07:00
Liam R. Howlett
7964cf8caa mm: remove vmacache 
By using the maple tree and the maple tree state, the vmacache is no
longer beneficial and is complicating the VMA code.  Remove the vmacache
to reduce the work in keeping it up to date and code complexity.

Link: https://lkml.kernel.org/r/20220906194824.2110408-26-Liam.Howlett@oracle.com
Signed-off-by: Liam R. Howlett <Liam.Howlett@Oracle.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Tested-by: Yu Zhao <yuzhao@google.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org>
Cc: SeongJae Park <sj@kernel.org>
Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2022-09-26 19:46:18 -07:00
Yu Zhao
bd74fdaea1 mm: multi-gen LRU: support page table walks 
To further exploit spatial locality, the aging prefers to walk page tables
to search for young PTEs and promote hot pages.  A kill switch will be
added in the next patch to disable this behavior.  When disabled, the
aging relies on the rmap only.

NB: this behavior has nothing similar with the page table scanning in the
2.4 kernel [1], which searches page tables for old PTEs, adds cold pages
to swapcache and unmaps them.

To avoid confusion, the term "iteration" specifically means the traversal
of an entire mm_struct list; the term "walk" will be applied to page
tables and the rmap, as usual.

An mm_struct list is maintained for each memcg, and an mm_struct follows
its owner task to the new memcg when this task is migrated.  Given an
lruvec, the aging iterates lruvec_memcg()->mm_list and calls
walk_page_range() with each mm_struct on this list to promote hot pages
before it increments max_seq.

When multiple page table walkers iterate the same list, each of them gets
a unique mm_struct; therefore they can run concurrently.  Page table
walkers ignore any misplaced pages, e.g., if an mm_struct was migrated,
pages it left in the previous memcg will not be promoted when its current
memcg is under reclaim.  Similarly, page table walkers will not promote
pages from nodes other than the one under reclaim.

This patch uses the following optimizations when walking page tables:
1. It tracks the usage of mm_struct's between context switches so that
   page table walkers can skip processes that have been sleeping since
   the last iteration.
2. It uses generational Bloom filters to record populated branches so
   that page table walkers can reduce their search space based on the
   query results, e.g., to skip page tables containing mostly holes or
   misplaced pages.
3. It takes advantage of the accessed bit in non-leaf PMD entries when
   CONFIG_ARCH_HAS_NONLEAF_PMD_YOUNG=y.
4. It does not zigzag between a PGD table and the same PMD table
   spanning multiple VMAs. IOW, it finishes all the VMAs within the
   range of the same PMD table before it returns to a PGD table. This
   improves the cache performance for workloads that have large
   numbers of tiny VMAs [2], especially when CONFIG_PGTABLE_LEVELS=5.

Server benchmark results:
  Single workload:
    fio (buffered I/O): no change

  Single workload:
    memcached (anon): +[8, 10]%
                Ops/sec      KB/sec
      patch1-7: 1147696.57   44640.29
      patch1-8: 1245274.91   48435.66

  Configurations:
    no change

Client benchmark results:
  kswapd profiles:
    patch1-7
      48.16%  lzo1x_1_do_compress (real work)
       8.20%  page_vma_mapped_walk (overhead)
       7.06%  _raw_spin_unlock_irq
       2.92%  ptep_clear_flush
       2.53%  __zram_bvec_write
       2.11%  do_raw_spin_lock
       2.02%  memmove
       1.93%  lru_gen_look_around
       1.56%  free_unref_page_list
       1.40%  memset

    patch1-8
      49.44%  lzo1x_1_do_compress (real work)
       6.19%  page_vma_mapped_walk (overhead)
       5.97%  _raw_spin_unlock_irq
       3.13%  get_pfn_folio
       2.85%  ptep_clear_flush
       2.42%  __zram_bvec_write
       2.08%  do_raw_spin_lock
       1.92%  memmove
       1.44%  alloc_zspage
       1.36%  memset

  Configurations:
    no change

Thanks to the following developers for their efforts [3].
  kernel test robot <lkp@intel.com>

[1] https://lwn.net/Articles/23732/
[2] https://llvm.org/docs/ScudoHardenedAllocator.html
[3] https://lore.kernel.org/r/202204160827.ekEARWQo-lkp@intel.com/

Link: https://lkml.kernel.org/r/20220918080010.2920238-9-yuzhao@google.com
Signed-off-by: Yu Zhao <yuzhao@google.com>
Acked-by: Brian Geffon <bgeffon@google.com>
Acked-by: Jan Alexander Steffens (heftig) <heftig@archlinux.org>
Acked-by: Oleksandr Natalenko <oleksandr@natalenko.name>
Acked-by: Steven Barrett <steven@liquorix.net>
Acked-by: Suleiman Souhlal <suleiman@google.com>
Tested-by: Daniel Byrne <djbyrne@mtu.edu>
Tested-by: Donald Carr <d@chaos-reins.com>
Tested-by: Holger Hoffstätte <holger@applied-asynchrony.com>
Tested-by: Konstantin Kharlamov <Hi-Angel@yandex.ru>
Tested-by: Shuang Zhai <szhai2@cs.rochester.edu>
Tested-by: Sofia Trinh <sofia.trinh@edi.works>
Tested-by: Vaibhav Jain <vaibhav@linux.ibm.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Cc: Barry Song <baohua@kernel.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Hillf Danton <hdanton@sina.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Michael Larabel <Michael@MichaelLarabel.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Mike Rapoport <rppt@linux.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Qi Zheng <zhengqi.arch@bytedance.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2022-09-26 19:46:09 -07:00
Andrei Vagin
33a2d6bc34 Revert "fs/exec: allow to unshare a time namespace on vfork+exec" 
This reverts commit 133e2d3e81.

Alexey pointed out a few undesirable side effects of the reverted change.
First, it doesn't take into account that CLONE_VFORK can be used with
CLONE_THREAD. Second, a child process doesn't enter a target time name-space,
if its parent dies before the child calls exec. It happens because the parent
clears vfork_done.

Eric W. Biederman suggests installing a time namespace as a task gets a new mm.
It includes all new processes cloned without CLONE_VM and all tasks that call
exec(). This is an user API change, but we think there aren't users that depend
on the old behavior.

It is too late to make such changes in this release, so let's roll back
this patch and introduce the right one in the next release.

Cc: Alexey Izbyshev <izbyshev@ispras.ru>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Dmitry Safonov <0x7f454c46@gmail.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Florian Weimer <fweimer@redhat.com>
Cc: Kees Cook <keescook@chromium.org>
Signed-off-by: Andrei Vagin <avagin@gmail.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20220913102551.1121611-3-avagin@google.com
 2022-09-13 10:38:43 -07:00
Al Viro
e6ae438124 bprm_fill_uid(): don't open-code file_inode() 
Reviewed-by: Christian Brauner (Microsoft) <brauner@kernel.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
 2022-09-01 17:44:38 -04:00
Linus Torvalds
50cd95ac46 execve fix for v6.0-rc2 
- Replace remaining kmap() uses with kmap_local_page() (Fabio M. De Francesco)
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Merge tag 'execve-v6.0-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux

Pull execve fix from Kees Cook:

 - Replace remaining kmap() uses with kmap_local_page() (Fabio M. De
   Francesco)

* tag 'execve-v6.0-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux:
  exec: Replace kmap{,_atomic}() with kmap_local_page()
 2022-08-19 14:02:24 -07:00
Fabio M. De Francesco
3a608cfee9 exec: Replace kmap{,_atomic}() with kmap_local_page() 
The use of kmap() and kmap_atomic() are being deprecated in favor of
kmap_local_page().

There are two main problems with kmap(): (1) It comes with an overhead as
mapping space is restricted and protected by a global lock for
synchronization and (2) it also requires global TLB invalidation when the
kmap’s pool wraps and it might block when the mapping space is fully
utilized until a slot becomes available.

With kmap_local_page() the mappings are per thread, CPU local, can take
page faults, and can be called from any context (including interrupts).
It is faster than kmap() in kernels with HIGHMEM enabled. Furthermore,
the tasks can be preempted and, when they are scheduled to run again, the
kernel virtual addresses are restored and are still valid.

Since the use of kmap_local_page() in exec.c is safe, it should be
preferred everywhere in exec.c.

As said, since kmap_local_page() can be also called from atomic context,
and since remove_arg_zero() doesn't (and shouldn't ever) rely on an
implicit preempt_disable(), this function can also safely replace
kmap_atomic().

Therefore, replace kmap() and kmap_atomic() with kmap_local_page() in
fs/exec.c.

Tested with xfstests on a QEMU/KVM x86_32 VM, 6GB RAM, booting a kernel
with HIGHMEM64GB enabled.

Cc: Eric W. Biederman <ebiederm@xmission.com>
Suggested-by: Ira Weiny <ira.weiny@intel.com>
Reviewed-by: Ira Weiny <ira.weiny@intel.com>
Signed-off-by: Fabio M. De Francesco <fmdefrancesco@gmail.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20220803182856.28246-1-fmdefrancesco@gmail.com
 2022-08-16 12:11:27 -07:00
Thadeu Lima de Souza Cascardo
e362359ace posix-cpu-timers: Cleanup CPU timers before freeing them during exec 
Commit 55e8c8eb2c ("posix-cpu-timers: Store a reference to a pid not a
task") started looking up tasks by PID when deleting a CPU timer.

When a non-leader thread calls execve, it will switch PIDs with the leader
process. Then, as it calls exit_itimers, posix_cpu_timer_del cannot find
the task because the timer still points out to the old PID.

That means that armed timers won't be disarmed, that is, they won't be
removed from the timerqueue_list. exit_itimers will still release their
memory, and when that list is later processed, it leads to a
use-after-free.

Clean up the timers from the de-threaded task before freeing them. This
prevents a reported use-after-free.

Fixes: 55e8c8eb2c ("posix-cpu-timers: Store a reference to a pid not a task")
Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@canonical.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Cc: <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/20220809170751.164716-1-cascardo@canonical.com
 2022-08-09 20:02:13 +02:00
Linus Torvalds
d7b767b508 execve updates for v5.20-rc1 
- Allow unsharing time namespace on vfork+exec (Andrei Vagin)
 
 - Replace usage of deprecated kmap APIs (Fabio M. De Francesco)
 
 - Fix spelling mistake (Zhang Jiaming)
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Merge tag 'execve-v5.20-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux

Pull execve updates from Kees Cook:

 - Allow unsharing time namespace on vfork+exec (Andrei Vagin)

 - Replace usage of deprecated kmap APIs (Fabio M. De Francesco)

 - Fix spelling mistake (Zhang Jiaming)

* tag 'execve-v5.20-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux:
  exec: Call kmap_local_page() in copy_string_kernel()
  exec: Fix a spelling mistake
  selftests/timens: add a test for vfork+exit
  fs/exec: allow to unshare a time namespace on vfork+exec
 2022-08-02 14:36:19 -07:00
Fabio M. De Francesco
c6e8e36c6a exec: Call kmap_local_page() in copy_string_kernel() 
The use of kmap_atomic() is being deprecated in favor of kmap_local_page().

With kmap_local_page(), the mappings are per thread, CPU local and not
globally visible. Furthermore, the mappings can be acquired from any
context (including interrupts).

Therefore, replace kmap_atomic() with kmap_local_page() in
copy_string_kernel(). Instead of open-coding local mapping + memcpy(),
use memcpy_to_page(). Delete a redundant call to flush_dcache_page().

Tested with xfstests on a QEMU/ KVM x86_32 VM, 6GB RAM, booting a kernel
with HIGHMEM64GB enabled.

Suggested-by: Ira Weiny <ira.weiny@intel.com>
Signed-off-by: Fabio M. De Francesco <fmdefrancesco@gmail.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20220724212523.13317-1-fmdefrancesco@gmail.com
 2022-07-27 14:15:09 -07:00
Oleg Nesterov
d5b36a4dbd fix race between exit_itimers() and /proc/pid/timers 
As Chris explains, the comment above exit_itimers() is not correct,
we can race with proc_timers_seq_ops. Change exit_itimers() to clear
signal->posix_timers with ->siglock held.

Cc: <stable@vger.kernel.org>
Reported-by: chris@accessvector.net
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2022-07-11 09:52:59 -07:00
Zhang Jiaming
5036793d7d exec: Fix a spelling mistake 
Change 'wont't' to 'won't'.

Signed-off-by: Zhang Jiaming <jiaming@nfschina.com>
Reviewed-by: Souptick Joarder (HPE) <jrdr.linux@gmail.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20220629072932.27506-1-jiaming@nfschina.com
 2022-07-01 15:06:14 -07:00
Andrei Vagin
133e2d3e81 fs/exec: allow to unshare a time namespace on vfork+exec 
Right now, a new process can't be forked in another time namespace
if it shares mm with its parent. It is prohibited, because each time
namespace has its own vvar page that is mapped into a process address
space.

When a process calls exec, it gets a new mm and so it could be "legal"
to switch time namespace in that case. This was not implemented and
now if we want to do this, we need to add another clone flag to not
break backward compatibility.

We don't have any user requests to switch times on exec except the
vfork+exec combination, so there is no reason to add a new clone flag.
As for vfork+exec, this should be safe to allow switching timens with
the current clone flag. Right now, vfork (CLONE_VFORK | CLONE_VM) fails
if a child is forked into another time namespace. With this change,
vfork creates a new process in parent's timens, and the following exec
does the actual switch to the target time namespace.

Suggested-by: Florian Weimer <fweimer@redhat.com>
Signed-off-by: Andrei Vagin <avagin@gmail.com>
Acked-by: Christian Brauner (Microsoft) <brauner@kernel.org>
Signed-off-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20220613060723.197407-1-avagin@gmail.com
 2022-06-15 07:58:04 -07:00
Linus Torvalds
1ec6574a3c This set of changes updates init and user mode helper tasks to be 
ordinary user mode tasks.
 
 In commit 40966e316f ("kthread: Ensure struct kthread is present for
 all kthreads") caused init and the user mode helper threads that call
 kernel_execve to have struct kthread allocated for them.  This struct
 kthread going away during execve in turned made a use after free of
 struct kthread possible.
 
 The commit 343f4c49f2 ("kthread: Don't allocate kthread_struct for
 init and umh") is enough to fix the use after free and is simple enough
 to be backportable.
 
 The rest of the changes pass struct kernel_clone_args to clean things
 up and cause the code to make sense.
 
 In making init and the user mode helpers tasks purely user mode tasks
 I ran into two complications.  The function task_tick_numa was
 detecting tasks without an mm by testing for the presence of
 PF_KTHREAD.  The initramfs code in populate_initrd_image was using
 flush_delayed_fput to ensuere the closing of all it's file descriptors
 was complete, and flush_delayed_fput does not work in a userspace thread.
 
 I have looked and looked and more complications and in my code review
 I have not found any, and neither has anyone else with the code sitting
 in linux-next.
 
 Link: https://lkml.kernel.org/r/87mtfu4up3.fsf@email.froward.int.ebiederm.org
 
 Eric W. Biederman (8):
       kthread: Don't allocate kthread_struct for init and umh
       fork: Pass struct kernel_clone_args into copy_thread
       fork: Explicity test for idle tasks in copy_thread
       fork: Generalize PF_IO_WORKER handling
       init: Deal with the init process being a user mode process
       fork: Explicitly set PF_KTHREAD
       fork: Stop allowing kthreads to call execve
       sched: Update task_tick_numa to ignore tasks without an mm
 
  arch/alpha/kernel/process.c      | 13 ++++++------
  arch/arc/kernel/process.c        | 13 ++++++------
  arch/arm/kernel/process.c        | 12 ++++++-----
  arch/arm64/kernel/process.c      | 12 ++++++-----
  arch/csky/kernel/process.c       | 15 ++++++-------
  arch/h8300/kernel/process.c      | 10 ++++-----
  arch/hexagon/kernel/process.c    | 12 ++++++-----
  arch/ia64/kernel/process.c       | 15 +++++++------
  arch/m68k/kernel/process.c       | 12 ++++++-----
  arch/microblaze/kernel/process.c | 12 ++++++-----
  arch/mips/kernel/process.c       | 13 ++++++------
  arch/nios2/kernel/process.c      | 12 ++++++-----
  arch/openrisc/kernel/process.c   | 12 ++++++-----
  arch/parisc/kernel/process.c     | 18 +++++++++-------
  arch/powerpc/kernel/process.c    | 15 +++++++------
  arch/riscv/kernel/process.c      | 12 ++++++-----
  arch/s390/kernel/process.c       | 12 ++++++-----
  arch/sh/kernel/process_32.c      | 12 ++++++-----
  arch/sparc/kernel/process_32.c   | 12 ++++++-----
  arch/sparc/kernel/process_64.c   | 12 ++++++-----
  arch/um/kernel/process.c         | 15 +++++++------
  arch/x86/include/asm/fpu/sched.h |  2 +-
  arch/x86/include/asm/switch_to.h |  8 +++----
  arch/x86/kernel/fpu/core.c       |  4 ++--
  arch/x86/kernel/process.c        | 18 +++++++++-------
  arch/xtensa/kernel/process.c     | 17 ++++++++-------
  fs/exec.c                        |  8 ++++---
  include/linux/sched/task.h       |  8 +++++--
  init/initramfs.c                 |  2 ++
  init/main.c                      |  2 +-
  kernel/fork.c                    | 46 +++++++++++++++++++++++++++++++++-------
  kernel/sched/fair.c              |  2 +-
  kernel/umh.c                     |  6 +++---
  33 files changed, 234 insertions(+), 160 deletions(-)
 
 Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
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Merge tag 'kthread-cleanups-for-v5.19' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace

Pull kthread updates from Eric Biederman:
 "This updates init and user mode helper tasks to be ordinary user mode
  tasks.

  Commit 40966e316f ("kthread: Ensure struct kthread is present for
  all kthreads") caused init and the user mode helper threads that call
  kernel_execve to have struct kthread allocated for them. This struct
  kthread going away during execve in turned made a use after free of
  struct kthread possible.

  Here, commit 343f4c49f2 ("kthread: Don't allocate kthread_struct for
  init and umh") is enough to fix the use after free and is simple
  enough to be backportable.

  The rest of the changes pass struct kernel_clone_args to clean things
  up and cause the code to make sense.

  In making init and the user mode helpers tasks purely user mode tasks
  I ran into two complications. The function task_tick_numa was
  detecting tasks without an mm by testing for the presence of
  PF_KTHREAD. The initramfs code in populate_initrd_image was using
  flush_delayed_fput to ensuere the closing of all it's file descriptors
  was complete, and flush_delayed_fput does not work in a userspace
  thread.

  I have looked and looked and more complications and in my code review
  I have not found any, and neither has anyone else with the code
  sitting in linux-next"

* tag 'kthread-cleanups-for-v5.19' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace:
  sched: Update task_tick_numa to ignore tasks without an mm
  fork: Stop allowing kthreads to call execve
  fork: Explicitly set PF_KTHREAD
  init: Deal with the init process being a user mode process
  fork: Generalize PF_IO_WORKER handling
  fork: Explicity test for idle tasks in copy_thread
  fork: Pass struct kernel_clone_args into copy_thread
  kthread: Don't allocate kthread_struct for init and umh
 2022-06-03 16:03:05 -07:00
Alexey Gladkov
de399236e2 ucounts: Split rlimit and ucount values and max values 
Since the semantics of maximum rlimit values are different, it would be
better not to mix ucount and rlimit values. This will prevent the error
of using inc_count/dec_ucount for rlimit parameters.

This patch also renames the functions to emphasize the lack of
connection between rlimit and ucount.

v3:
- Fix BUG:KASAN:use-after-free_in_dec_ucount.

v2:
- Fix the array-index-out-of-bounds that was found by the lkp project.

Reported-by: kernel test robot <oliver.sang@intel.com>
Signed-off-by: Alexey Gladkov <legion@kernel.org>
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Link: https://lkml.kernel.org/r/20220518171730.l65lmnnjtnxnftpq@example.org
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
 2022-05-18 18:24:57 -05:00
Nadav Amit
4a18419f71 mm/mprotect: use mmu_gather 
Patch series "mm/mprotect: avoid unnecessary TLB flushes", v6.

This patchset is intended to remove unnecessary TLB flushes during
mprotect() syscalls.  Once this patch-set make it through, similar and
further optimizations for MADV_COLD and userfaultfd would be possible.

Basically, there are 3 optimizations in this patch-set:

1. Use TLB batching infrastructure to batch flushes across VMAs and do
   better/fewer flushes.  This would also be handy for later userfaultfd
   enhancements.

2. Avoid unnecessary TLB flushes.  This optimization is the one that
   provides most of the performance benefits.  Unlike previous versions,
   we now only avoid flushes that would not result in spurious
   page-faults.

3. Avoiding TLB flushes on change_huge_pmd() that are only needed to
   prevent the A/D bits from changing.

Andrew asked for some benchmark numbers.  I do not have an easy
determinate macrobenchmark in which it is easy to show benefit.  I
therefore ran a microbenchmark: a loop that does the following on
anonymous memory, just as a sanity check to see that time is saved by
avoiding TLB flushes.  The loop goes:

	mprotect(p, PAGE_SIZE, PROT_READ)
	mprotect(p, PAGE_SIZE, PROT_READ|PROT_WRITE)
	*p = 0; // make the page writable

The test was run in KVM guest with 1 or 2 threads (the second thread was
busy-looping).  I measured the time (cycles) of each operation:

		1 thread		2 threads
		mmots	+patch		mmots	+patch
PROT_READ	3494	2725 (-22%)	8630	7788 (-10%)
PROT_READ|WRITE	3952	2724 (-31%)	9075	2865 (-68%)

[ mmots = v5.17-rc6-mmots-2022-03-06-20-38 ]

The exact numbers are really meaningless, but the benefit is clear.  There
are 2 interesting results though.  

(1) PROT_READ is cheaper, while one can expect it not to be affected. 
This is presumably due to TLB miss that is saved

(2) Without memory access (*p = 0), the speedup of the patch is even
greater.  In that scenario mprotect(PROT_READ) also avoids the TLB flush. 
As a result both operations on the patched kernel take roughly ~1500
cycles (with either 1 or 2 threads), whereas on mmotm their cost is as
high as presented in the table.


This patch (of 3):

change_pXX_range() currently does not use mmu_gather, but instead
implements its own deferred TLB flushes scheme.  This both complicates the
code, as developers need to be aware of different invalidation schemes,
and prevents opportunities to avoid TLB flushes or perform them in finer
granularity.

The use of mmu_gather for modified PTEs has benefits in various scenarios
even if pages are not released.  For instance, if only a single page needs
to be flushed out of a range of many pages, only that page would be
flushed.  If a THP page is flushed, on x86 a single TLB invlpg instruction
can be used instead of 512 instructions (or a full TLB flush, which would
Linux would actually use by default).  mprotect() over multiple VMAs
requires a single flush.

Use mmu_gather in change_pXX_range().  As the pages are not released, only
record the flushed range using tlb_flush_pXX_range().

Handle THP similarly and get rid of flush_cache_range() which becomes
redundant since tlb_start_vma() calls it when needed.

Link: https://lkml.kernel.org/r/20220401180821.1986781-1-namit@vmware.com
Link: https://lkml.kernel.org/r/20220401180821.1986781-2-namit@vmware.com
Signed-off-by: Nadav Amit <namit@vmware.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Andrew Cooper <andrew.cooper3@citrix.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Will Deacon <will@kernel.org>
Cc: Yu Zhao <yuzhao@google.com>
Cc: Nick Piggin <npiggin@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2022-05-13 07:20:05 -07:00
Eric W. Biederman
1b2552cbdb fork: Stop allowing kthreads to call execve 
Now that kernel_execve is no longer called from kernel threads stop
supporting kernel threads calling kernel_execve.

Remove the code for converting a kthread to a normal thread in execve.

Document the restriction that kthreads may not call kernel_execve by
having kernel_execve fail if called by a kthread.

Link: https://lkml.kernel.org/r/20220506141512.516114-7-ebiederm@xmission.com
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
 2022-05-07 09:01:59 -05:00
Eric W. Biederman
343f4c49f2 kthread: Don't allocate kthread_struct for init and umh 
If kthread_is_per_cpu runs concurrently with free_kthread_struct the
kthread_struct that was just freed may be read from.

This bug was introduced by commit 40966e316f ("kthread: Ensure
struct kthread is present for all kthreads").  When kthread_struct
started to be allocated for all tasks that have PF_KTHREAD set.  This
in turn required the kthread_struct to be freed in kernel_execve and
violated the assumption that kthread_struct will have the same
lifetime as the task.

Looking a bit deeper this only applies to callers of kernel_execve
which is just the init process and the user mode helper processes.
These processes really don't want to be kernel threads but are for
historical reasons.  Mostly that copy_thread does not know how to take
a kernel mode function to the process with for processes without
PF_KTHREAD or PF_IO_WORKER set.

Solve this by not allocating kthread_struct for the init process and
the user mode helper processes.

This is done by adding a kthread member to struct kernel_clone_args.
Setting kthread in fork_idle and kernel_thread.  Adding
user_mode_thread that works like kernel_thread except it does not set
kthread.  In fork only allocating the kthread_struct if .kthread is set.

I have looked at kernel/kthread.c and since commit 40966e316f
("kthread: Ensure struct kthread is present for all kthreads") there
have been no assumptions added that to_kthread or __to_kthread will
not return NULL.

There are a few callers of to_kthread or __to_kthread that assume a
non-NULL struct kthread pointer will be returned.  These functions are
kthread_data(), kthread_parmme(), kthread_exit(), kthread(),
kthread_park(), kthread_unpark(), kthread_stop().  All of those functions
can reasonably expected to be called when it is know that a task is a
kthread so that assumption seems reasonable.

Cc: stable@vger.kernel.org
Fixes: 40966e316f ("kthread: Ensure struct kthread is present for all kthreads")
Reported-by: Максим Кутявин <maximkabox13@gmail.com>
Link: https://lkml.kernel.org/r/20220506141512.516114-1-ebiederm@xmission.com
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
 2022-05-06 14:49:44 -05:00
Linus Torvalds
1930a6e739 ptrace: Cleanups for v5.18 
This set of changes removes tracehook.h, moves modification of all of
 the ptrace fields inside of siglock to remove races, adds a missing
 permission check to ptrace.c
 
 The removal of tracehook.h is quite significant as it has been a major
 source of confusion in recent years.  Much of that confusion was
 around task_work and TIF_NOTIFY_SIGNAL (which I have now decoupled
 making the semantics clearer).
 
 For people who don't know tracehook.h is a vestiage of an attempt to
 implement uprobes like functionality that was never fully merged, and
 was later superseeded by uprobes when uprobes was merged.  For many
 years now we have been removing what tracehook functionaly a little
 bit at a time.  To the point where now anything left in tracehook.h is
 some weird strange thing that is difficult to understand.
 
 Eric W. Biederman (15):
       ptrace: Move ptrace_report_syscall into ptrace.h
       ptrace/arm: Rename tracehook_report_syscall report_syscall
       ptrace: Create ptrace_report_syscall_{entry,exit} in ptrace.h
       ptrace: Remove arch_syscall_{enter,exit}_tracehook
       ptrace: Remove tracehook_signal_handler
       task_work: Remove unnecessary include from posix_timers.h
       task_work: Introduce task_work_pending
       task_work: Call tracehook_notify_signal from get_signal on all architectures
       task_work: Decouple TIF_NOTIFY_SIGNAL and task_work
       signal: Move set_notify_signal and clear_notify_signal into sched/signal.h
       resume_user_mode: Remove #ifdef TIF_NOTIFY_RESUME in set_notify_resume
       resume_user_mode: Move to resume_user_mode.h
       tracehook: Remove tracehook.h
       ptrace: Move setting/clearing ptrace_message into ptrace_stop
       ptrace: Return the signal to continue with from ptrace_stop
 
 Jann Horn (1):
       ptrace: Check PTRACE_O_SUSPEND_SECCOMP permission on PTRACE_SEIZE
 
 Yang Li (1):
       ptrace: Remove duplicated include in ptrace.c
 
  MAINTAINERS                          |   1 -
  arch/Kconfig                         |   5 +-
  arch/alpha/kernel/ptrace.c           |   5 +-
  arch/alpha/kernel/signal.c           |   4 +-
  arch/arc/kernel/ptrace.c             |   5 +-
  arch/arc/kernel/signal.c             |   4 +-
  arch/arm/kernel/ptrace.c             |  12 +-
  arch/arm/kernel/signal.c             |   4 +-
  arch/arm64/kernel/ptrace.c           |  14 +--
  arch/arm64/kernel/signal.c           |   4 +-
  arch/csky/kernel/ptrace.c            |   5 +-
  arch/csky/kernel/signal.c            |   4 +-
  arch/h8300/kernel/ptrace.c           |   5 +-
  arch/h8300/kernel/signal.c           |   4 +-
  arch/hexagon/kernel/process.c        |   4 +-
  arch/hexagon/kernel/signal.c         |   1 -
  arch/hexagon/kernel/traps.c          |   6 +-
  arch/ia64/kernel/process.c           |   4 +-
  arch/ia64/kernel/ptrace.c            |   6 +-
  arch/ia64/kernel/signal.c            |   1 -
  arch/m68k/kernel/ptrace.c            |   5 +-
  arch/m68k/kernel/signal.c            |   4 +-
  arch/microblaze/kernel/ptrace.c      |   5 +-
  arch/microblaze/kernel/signal.c      |   4 +-
  arch/mips/kernel/ptrace.c            |   5 +-
  arch/mips/kernel/signal.c            |   4 +-
  arch/nds32/include/asm/syscall.h     |   2 +-
  arch/nds32/kernel/ptrace.c           |   5 +-
  arch/nds32/kernel/signal.c           |   4 +-
  arch/nios2/kernel/ptrace.c           |   5 +-
  arch/nios2/kernel/signal.c           |   4 +-
  arch/openrisc/kernel/ptrace.c        |   5 +-
  arch/openrisc/kernel/signal.c        |   4 +-
  arch/parisc/kernel/ptrace.c          |   7 +-
  arch/parisc/kernel/signal.c          |   4 +-
  arch/powerpc/kernel/ptrace/ptrace.c  |   8 +-
  arch/powerpc/kernel/signal.c         |   4 +-
  arch/riscv/kernel/ptrace.c           |   5 +-
  arch/riscv/kernel/signal.c           |   4 +-
  arch/s390/include/asm/entry-common.h |   1 -
  arch/s390/kernel/ptrace.c            |   1 -
  arch/s390/kernel/signal.c            |   5 +-
  arch/sh/kernel/ptrace_32.c           |   5 +-
  arch/sh/kernel/signal_32.c           |   4 +-
  arch/sparc/kernel/ptrace_32.c        |   5 +-
  arch/sparc/kernel/ptrace_64.c        |   5 +-
  arch/sparc/kernel/signal32.c         |   1 -
  arch/sparc/kernel/signal_32.c        |   4 +-
  arch/sparc/kernel/signal_64.c        |   4 +-
  arch/um/kernel/process.c             |   4 +-
  arch/um/kernel/ptrace.c              |   5 +-
  arch/x86/kernel/ptrace.c             |   1 -
  arch/x86/kernel/signal.c             |   5 +-
  arch/x86/mm/tlb.c                    |   1 +
  arch/xtensa/kernel/ptrace.c          |   5 +-
  arch/xtensa/kernel/signal.c          |   4 +-
  block/blk-cgroup.c                   |   2 +-
  fs/coredump.c                        |   1 -
  fs/exec.c                            |   1 -
  fs/io-wq.c                           |   6 +-
  fs/io_uring.c                        |  11 +-
  fs/proc/array.c                      |   1 -
  fs/proc/base.c                       |   1 -
  include/asm-generic/syscall.h        |   2 +-
  include/linux/entry-common.h         |  47 +-------
  include/linux/entry-kvm.h            |   2 +-
  include/linux/posix-timers.h         |   1 -
  include/linux/ptrace.h               |  81 ++++++++++++-
  include/linux/resume_user_mode.h     |  64 ++++++++++
  include/linux/sched/signal.h         |  17 +++
  include/linux/task_work.h            |   5 +
  include/linux/tracehook.h            | 226 -----------------------------------
  include/uapi/linux/ptrace.h          |   2 +-
  kernel/entry/common.c                |  19 +--
  kernel/entry/kvm.c                   |   9 +-
  kernel/exit.c                        |   3 +-
  kernel/livepatch/transition.c        |   1 -
  kernel/ptrace.c                      |  47 +++++---
  kernel/seccomp.c                     |   1 -
  kernel/signal.c                      |  62 +++++-----
  kernel/task_work.c                   |   4 +-
  kernel/time/posix-cpu-timers.c       |   1 +
  mm/memcontrol.c                      |   2 +-
  security/apparmor/domain.c           |   1 -
  security/selinux/hooks.c             |   1 -
  85 files changed, 372 insertions(+), 495 deletions(-)
 
 Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
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Merge tag 'ptrace-cleanups-for-v5.18' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace

Pull ptrace cleanups from Eric Biederman:
 "This set of changes removes tracehook.h, moves modification of all of
  the ptrace fields inside of siglock to remove races, adds a missing
  permission check to ptrace.c

  The removal of tracehook.h is quite significant as it has been a major
  source of confusion in recent years. Much of that confusion was around
  task_work and TIF_NOTIFY_SIGNAL (which I have now decoupled making the
  semantics clearer).

  For people who don't know tracehook.h is a vestiage of an attempt to
  implement uprobes like functionality that was never fully merged, and
  was later superseeded by uprobes when uprobes was merged. For many
  years now we have been removing what tracehook functionaly a little
  bit at a time. To the point where anything left in tracehook.h was
  some weird strange thing that was difficult to understand"

* tag 'ptrace-cleanups-for-v5.18' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace:
  ptrace: Remove duplicated include in ptrace.c
  ptrace: Check PTRACE_O_SUSPEND_SECCOMP permission on PTRACE_SEIZE
  ptrace: Return the signal to continue with from ptrace_stop
  ptrace: Move setting/clearing ptrace_message into ptrace_stop
  tracehook: Remove tracehook.h
  resume_user_mode: Move to resume_user_mode.h
  resume_user_mode: Remove #ifdef TIF_NOTIFY_RESUME in set_notify_resume
  signal: Move set_notify_signal and clear_notify_signal into sched/signal.h
  task_work: Decouple TIF_NOTIFY_SIGNAL and task_work
  task_work: Call tracehook_notify_signal from get_signal on all architectures
  task_work: Introduce task_work_pending
  task_work: Remove unnecessary include from posix_timers.h
  ptrace: Remove tracehook_signal_handler
  ptrace: Remove arch_syscall_{enter,exit}_tracehook
  ptrace: Create ptrace_report_syscall_{entry,exit} in ptrace.h
  ptrace/arm: Rename tracehook_report_syscall report_syscall
  ptrace: Move ptrace_report_syscall into ptrace.h
 2022-03-28 17:29:53 -07:00
Linus Torvalds
194dfe88d6 asm-generic updates for 5.18 
There are three sets of updates for 5.18 in the asm-generic tree:
 
  - The set_fs()/get_fs() infrastructure gets removed for good. This
    was already gone from all major architectures, but now we can
    finally remove it everywhere, which loses some particularly
    tricky and error-prone code.
    There is a small merge conflict against a parisc cleanup, the
    solution is to use their new version.
 
  - The nds32 architecture ends its tenure in the Linux kernel. The
    hardware is still used and the code is in reasonable shape, but
    the mainline port is not actively maintained any more, as all
    remaining users are thought to run vendor kernels that would never
    be updated to a future release.
    There are some obvious conflicts against changes to the removed
    files.
 
  - A series from Masahiro Yamada cleans up some of the uapi header
    files to pass the compile-time checks.
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Merge tag 'asm-generic-5.18' of git://git.kernel.org/pub/scm/linux/kernel/git/arnd/asm-generic

Pull asm-generic updates from Arnd Bergmann:
 "There are three sets of updates for 5.18 in the asm-generic tree:

   - The set_fs()/get_fs() infrastructure gets removed for good.

     This was already gone from all major architectures, but now we can
     finally remove it everywhere, which loses some particularly tricky
     and error-prone code. There is a small merge conflict against a
     parisc cleanup, the solution is to use their new version.

   - The nds32 architecture ends its tenure in the Linux kernel.

     The hardware is still used and the code is in reasonable shape, but
     the mainline port is not actively maintained any more, as all
     remaining users are thought to run vendor kernels that would never
     be updated to a future release.

   - A series from Masahiro Yamada cleans up some of the uapi header
     files to pass the compile-time checks"

* tag 'asm-generic-5.18' of git://git.kernel.org/pub/scm/linux/kernel/git/arnd/asm-generic: (27 commits)
  nds32: Remove the architecture
  uaccess: remove CONFIG_SET_FS
  ia64: remove CONFIG_SET_FS support
  sh: remove CONFIG_SET_FS support
  sparc64: remove CONFIG_SET_FS support
  lib/test_lockup: fix kernel pointer check for separate address spaces
  uaccess: generalize access_ok()
  uaccess: fix type mismatch warnings from access_ok()
  arm64: simplify access_ok()
  m68k: fix access_ok for coldfire
  MIPS: use simpler access_ok()
  MIPS: Handle address errors for accesses above CPU max virtual user address
  uaccess: add generic __{get,put}_kernel_nofault
  nios2: drop access_ok() check from __put_user()
  x86: use more conventional access_ok() definition
  x86: remove __range_not_ok()
  sparc64: add __{get,put}_kernel_nofault()
  nds32: fix access_ok() checks in get/put_user
  uaccess: fix nios2 and microblaze get_user_8()
  sparc64: fix building assembly files
  ...
 2022-03-23 18:03:08 -07:00
Eric W. Biederman
355f841a3f tracehook: Remove tracehook.h 
Now that all of the definitions have moved out of tracehook.h into
ptrace.h, sched/signal.h, resume_user_mode.h there is nothing left in
tracehook.h so remove it.

Update the few files that were depending upon tracehook.h to bring in
definitions to use the headers they need directly.

Reviewed-by: Kees Cook <keescook@chromium.org>
Link: https://lkml.kernel.org/r/20220309162454.123006-13-ebiederm@xmission.com
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
 2022-03-10 16:51:51 -06:00
Tom Rix
b452722e6f exec: cleanup comments 
Remove the second 'from'.
Replace 'backwords' with 'backwards'.
Replace 'visibile' with 'visible'.

Signed-off-by: Tom Rix <trix@redhat.com>
Acked-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20220211160940.2516243-1-trix@redhat.com
 2022-03-01 16:16:27 -08:00
Kees Cook
dcd46d897a exec: Force single empty string when argv is empty 
Quoting[1] Ariadne Conill:

"In several other operating systems, it is a hard requirement that the
second argument to execve(2) be the name of a program, thus prohibiting
a scenario where argc < 1. POSIX 2017 also recommends this behaviour,
but it is not an explicit requirement[2]:

    The argument arg0 should point to a filename string that is
    associated with the process being started by one of the exec
    functions.
...
Interestingly, Michael Kerrisk opened an issue about this in 2008[3],
but there was no consensus to support fixing this issue then.
Hopefully now that CVE-2021-4034 shows practical exploitative use[4]
of this bug in a shellcode, we can reconsider.

This issue is being tracked in the KSPP issue tracker[5]."

While the initial code searches[6][7] turned up what appeared to be
mostly corner case tests, trying to that just reject argv == NULL
(or an immediately terminated pointer list) quickly started tripping[8]
existing userspace programs.

The next best approach is forcing a single empty string into argv and
adjusting argc to match. The number of programs depending on argc == 0
seems a smaller set than those calling execve with a NULL argv.

Account for the additional stack space in bprm_stack_limits(). Inject an
empty string when argc == 0 (and set argc = 1). Warn about the case so
userspace has some notice about the change:

    process './argc0' launched './argc0' with NULL argv: empty string added

Additionally WARN() and reject NULL argv usage for kernel threads.

[1] https://lore.kernel.org/lkml/20220127000724.15106-1-ariadne@dereferenced.org/
[2] https://pubs.opengroup.org/onlinepubs/9699919799/functions/exec.html
[3] https://bugzilla.kernel.org/show_bug.cgi?id=8408
[4] https://www.qualys.com/2022/01/25/cve-2021-4034/pwnkit.txt
[5] https://github.com/KSPP/linux/issues/176
[6] https://codesearch.debian.net/search?q=execve%5C+*%5C%28%5B%5E%2C%5D%2B%2C+*NULL&literal=0
[7] https://codesearch.debian.net/search?q=execlp%3F%5Cs*%5C%28%5B%5E%2C%5D%2B%2C%5Cs*NULL&literal=0
[8] https://lore.kernel.org/lkml/20220131144352.GE16385@xsang-OptiPlex-9020/

Reported-by: Ariadne Conill <ariadne@dereferenced.org>
Reported-by: Michael Kerrisk <mtk.manpages@gmail.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Rich Felker <dalias@libc.org>
Cc: Eric Biederman <ebiederm@xmission.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: linux-fsdevel@vger.kernel.org
Cc: stable@vger.kernel.org
Signed-off-by: Kees Cook <keescook@chromium.org>
Acked-by: Christian Brauner <brauner@kernel.org>
Acked-by: Ariadne Conill <ariadne@dereferenced.org>
Acked-by: Andy Lutomirski <luto@kernel.org>
Link: https://lore.kernel.org/r/20220201000947.2453721-1-keescook@chromium.org
 2022-03-01 16:16:26 -08:00
Arnd Bergmann
967747bbc0 uaccess: remove CONFIG_SET_FS 
There are no remaining callers of set_fs(), so CONFIG_SET_FS
can be removed globally, along with the thread_info field and
any references to it.

This turns access_ok() into a cheaper check against TASK_SIZE_MAX.

As CONFIG_SET_FS is now gone, drop all remaining references to
set_fs()/get_fs(), mm_segment_t, user_addr_max() and uaccess_kernel().

Acked-by: Sam Ravnborg <sam@ravnborg.org> # for sparc32 changes
Acked-by: "Eric W. Biederman" <ebiederm@xmission.com>
Tested-by: Sergey Matyukevich <sergey.matyukevich@synopsys.com> # for arc changes
Acked-by: Stafford Horne <shorne@gmail.com> # [openrisc, asm-generic]
Acked-by: Dinh Nguyen <dinguyen@kernel.org>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
 2022-02-25 09:36:06 +01:00