Commit Graph

34072 Commits

Author SHA1 Message Date
Paul E. McKenney
4e025f52a1 rcu: IPI all CPUs at GP end for strict GPs
Currently, each CPU discovers the end of a given grace period on its
own time, which is again good for efficiency but bad for fast grace
periods, given that it is things like kfree() within the RCU callbacks
that will cause trouble for pointers leaked from RCU read-side critical
sections.  This commit therefore uses on_each_cpu() to IPI each CPU
after grace-period cleanup in order to inform each CPU of the end of
the old grace period in a timely manner, but only in kernels build with
CONFIG_RCU_STRICT_GRACE_PERIOD=y.

Reported-by Jann Horn <jannh@google.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2020-08-24 18:40:26 -07:00
Paul E. McKenney
933ada2c33 rcu: IPI all CPUs at GP start for strict GPs
Currently, each CPU discovers the beginning of a given grace period
on its own time, which is again good for efficiency but bad for fast
grace periods.  This commit therefore uses on_each_cpu() to IPI each
CPU after grace-period initialization in order to inform each CPU of
the new grace period in a timely manner, but only in kernels build with
CONFIG_RCU_STRICT_GRACE_PERIOD=y.

Reported-by Jann Horn <jannh@google.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2020-08-24 18:40:26 -07:00
Paul E. McKenney
1a2f5d57a3 rcu: Attempt QS when CPU discovers GP for strict GPs
A given CPU normally notes a new grace period during one RCU_SOFTIRQ,
but avoids reporting the corresponding quiescent state until some later
RCU_SOFTIRQ.  This leisurly approach improves efficiency by increasing
the number of update requests served by each grace period, but is not
what is needed for kernels built with CONFIG_RCU_STRICT_GRACE_PERIOD=y.

This commit therefore adds a new rcu_strict_gp_check_qs() function
which, in CONFIG_RCU_STRICT_GRACE_PERIOD=y kernels, simply enters and
immediately exist an RCU read-side critical section.  If the CPU is
in a quiescent state, the rcu_read_unlock() will attempt to report an
immediate quiescent state.  This rcu_strict_gp_check_qs() function is
invoked from note_gp_changes(), so that a CPU just noticing a new grace
period might immediately report a quiescent state for that grace period.

Reported-by Jann Horn <jannh@google.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2020-08-24 18:40:26 -07:00
Paul E. McKenney
44bad5b3cc rcu: Do full report for .need_qs for strict GPs
The rcu_preempt_deferred_qs_irqrestore() function is invoked at
the end of an RCU read-side critical section (for example, directly
from rcu_read_unlock()) and, if .need_qs is set, invokes rcu_qs() to
report the new quiescent state.  This works, except that rcu_qs() only
updates per-CPU state, leaving reporting of the actual quiescent state
to a later call to rcu_report_qs_rdp(), for example from within a later
RCU_SOFTIRQ instance.  Although this approach is exactly what you want if
you are more concerned about efficiency than about short grace periods,
in CONFIG_RCU_STRICT_GRACE_PERIOD=y kernels, short grace periods are
the name of the game.

This commit therefore makes rcu_preempt_deferred_qs_irqrestore() directly
invoke rcu_report_qs_rdp() in CONFIG_RCU_STRICT_GRACE_PERIOD=y, thus
shortening grace periods.

Historical note:  To the best of my knowledge, causing rcu_read_unlock()
to directly report a quiescent state first appeared in Jim Houston's
and Joe Korty's JRCU.  This is the second instance of a Linux-kernel RCU
feature being inspired by JRCU, the first being RCU callback offloading
(as in the RCU_NOCB_CPU Kconfig option).

Reported-by Jann Horn <jannh@google.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2020-08-24 18:40:25 -07:00
Paul E. McKenney
f19920e412 rcu: Always set .need_qs from __rcu_read_lock() for strict GPs
The ->rcu_read_unlock_special.b.need_qs field in the task_struct
structure indicates that the RCU core needs a quiscent state from the
corresponding task.  The __rcu_read_unlock() function checks this (via
an eventual call to rcu_preempt_deferred_qs_irqrestore()), and if set
reports a quiscent state immediately upon exit from the outermost RCU
read-side critical section.

Currently, this flag is only set when the scheduling-clock interrupt
decides that the current RCU grace period is too old, as in about
one full second too old.  But if the kernel has been built with
CONFIG_RCU_STRICT_GRACE_PERIOD=y, we clearly do not want to wait that
long.  This commit therefore sets the .need_qs field immediately at the
start of the RCU read-side critical section from within __rcu_read_lock()
in order to unconditionally enlist help from __rcu_read_unlock().

But note the additional check for rcu_state.gp_kthread, which prevents
attempts to awaken RCU's grace-period kthread during early boot before
there is a scheduler.  Leaving off this check results in early boot hangs.
So early that there is no console output.  Thus, this additional check
fails until such time as RCU's grace-period kthread has been created,
avoiding these empty-console hangs.

Reported-by Jann Horn <jannh@google.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2020-08-24 18:40:25 -07:00
Paul E. McKenney
29fc5f9332 rcu: Force DEFAULT_RCU_BLIMIT to 1000 for strict RCU GPs
The value of DEFAULT_RCU_BLIMIT is normally set to 10, the idea being to
avoid needless response-time degradation due to RCU callback invocation.
However, when CONFIG_RCU_STRICT_GRACE_PERIOD=y it is better to avoid
throttling callback execution in order to better detect pointer
leaks from RCU read-side critical sections.  This commit therefore
sets the value of DEFAULT_RCU_BLIMIT to 1000 in kernels built with
CONFIG_RCU_STRICT_GRACE_PERIOD=y.

Reported-by Jann Horn <jannh@google.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2020-08-24 18:40:24 -07:00
Paul E. McKenney
aecd34b976 rcu: Restrict default jiffies_till_first_fqs for strict RCU GPs
If there are idle CPUs, RCU's grace-period kthread will wait several
jiffies before even thinking about polling them.  This promotes
efficiency, which is normally a good thing, but when the kernel
has been built with CONFIG_RCU_STRICT_GRACE_PERIOD=y, we care more
about short grace periods.  This commit therefore restricts the
default jiffies_till_first_fqs value to zero in kernels built with
CONFIG_RCU_STRICT_GRACE_PERIOD=y, which causes RCU's grace-period kthread
to poll for idle CPUs immediately after starting a grace period.

Reported-by Jann Horn <jannh@google.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2020-08-24 18:40:24 -07:00
Paul E. McKenney
dc1269186b rcu: Reduce leaf fanout for strict RCU grace periods
Because strict RCU grace periods will complete more quickly, they will
experience greater lock contention on each leaf rcu_node structure's
->lock.  This commit therefore reduces the leaf fanout in order to reduce
this lock contention.

Note that this also has the effect of reducing the number of CPUs
supported to 16 in the case of CONFIG_RCU_FANOUT_LEAF=2 or 81 in the
case of CONFIG_RCU_FANOUT_LEAF=3.  However, greater numbers of CPUs are
probably a bad idea when using CONFIG_RCU_STRICT_GRACE_PERIOD=y.  Those
wishing to live dangerously are free to edit their kernel/rcu/Kconfig
files accordingly.

Reported-by Jann Horn <jannh@google.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2020-08-24 18:40:23 -07:00
Paul E. McKenney
8cbd0e38a9 rcu: Add Kconfig option for strict RCU grace periods
People running automated tests have asked for a way to make RCU minimize
grace-period duration in order to increase the probability of KASAN
detecting a pointer being improperly leaked from an RCU read-side critical
section, for example, like this:

	rcu_read_lock();
	p = rcu_dereference(gp);
	do_something_with(p); // OK
	rcu_read_unlock();
	do_something_else_with(p); // BUG!!!

The rcupdate.rcu_expedited boot parameter is a start in this direction,
given that it makes calls to synchronize_rcu() instead invoke the faster
(and more wasteful) synchronize_rcu_expedited().  However, this does
nothing to shorten RCU grace periods that are instead initiated by
call_rcu(), and RCU pointer-leak bugs can involve call_rcu() just as
surely as they can synchronize_rcu().

This commit therefore adds a RCU_STRICT_GRACE_PERIOD Kconfig option
that will be used to shorten normal (non-expedited) RCU grace periods.
This commit also dumps out a message when this option is in effect.
Later commits will actually shorten grace periods.

Reported-by Jann Horn <jannh@google.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2020-08-24 18:40:23 -07:00
Linus Torvalds
2cc3c4b3c2 io_uring-5.9-2020-08-15
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Merge tag 'io_uring-5.9-2020-08-15' of git://git.kernel.dk/linux-block

Pull io_uring fixes from Jens Axboe:
 "A few differerent things in here.

  Seems like syzbot got some more io_uring bits wired up, and we got a
  handful of reports and the associated fixes are in here.

  General fixes too, and a lot of them marked for stable.

  Lastly, a bit of fallout from the async buffered reads, where we now
  more easily trigger short reads. Some applications don't really like
  that, so the io_read() code now handles short reads internally, and
  got a cleanup along the way so that it's now easier to read (and
  documented). We're now passing tests that failed before"

* tag 'io_uring-5.9-2020-08-15' of git://git.kernel.dk/linux-block:
  io_uring: short circuit -EAGAIN for blocking read attempt
  io_uring: sanitize double poll handling
  io_uring: internally retry short reads
  io_uring: retain iov_iter state over io_read/io_write calls
  task_work: only grab task signal lock when needed
  io_uring: enable lookup of links holding inflight files
  io_uring: fail poll arm on queue proc failure
  io_uring: hold 'ctx' reference around task_work queue + execute
  fs: RWF_NOWAIT should imply IOCB_NOIO
  io_uring: defer file table grabbing request cleanup for locked requests
  io_uring: add missing REQ_F_COMP_LOCKED for nested requests
  io_uring: fix recursive completion locking on oveflow flush
  io_uring: use TWA_SIGNAL for task_work uncondtionally
  io_uring: account locked memory before potential error case
  io_uring: set ctx sq/cq entry count earlier
  io_uring: Fix NULL pointer dereference in loop_rw_iter()
  io_uring: add comments on how the async buffered read retry works
  io_uring: io_async_buf_func() need not test page bit
2020-08-16 10:55:12 -07:00
Linus Torvalds
5bbec3cfe3 Cleanup, SECCOMP_FILTER support, message printing fixes, and other
changes to arch/sh.
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Merge tag 'sh-for-5.9' of git://git.libc.org/linux-sh

Pull arch/sh updates from Rich Felker:
 "Cleanup, SECCOMP_FILTER support, message printing fixes, and other
  changes to arch/sh"

* tag 'sh-for-5.9' of git://git.libc.org/linux-sh: (34 commits)
  sh: landisk: Add missing initialization of sh_io_port_base
  sh: bring syscall_set_return_value in line with other architectures
  sh: Add SECCOMP_FILTER
  sh: Rearrange blocks in entry-common.S
  sh: switch to copy_thread_tls()
  sh: use the generic dma coherent remap allocator
  sh: don't allow non-coherent DMA for NOMMU
  dma-mapping: consolidate the NO_DMA definition in kernel/dma/Kconfig
  sh: unexport register_trapped_io and match_trapped_io_handler
  sh: don't include <asm/io_trapped.h> in <asm/io.h>
  sh: move the ioremap implementation out of line
  sh: move ioremap_fixed details out of <asm/io.h>
  sh: remove __KERNEL__ ifdefs from non-UAPI headers
  sh: sort the selects for SUPERH alphabetically
  sh: remove -Werror from Makefiles
  sh: Replace HTTP links with HTTPS ones
  arch/sh/configs: remove obsolete CONFIG_SOC_CAMERA*
  sh: stacktrace: Remove stacktrace_ops.stack()
  sh: machvec: Modernize printing of kernel messages
  sh: pci: Modernize printing of kernel messages
  ...
2020-08-15 18:50:32 -07:00
Linus Torvalds
50f6c7dbd9 Misc fixes and small updates all around the place:
- Fix mitigation state sysfs output
  - Fix an FPU xstate/sxave code assumption bug triggered by Architectural LBR support
  - Fix Lightning Mountain SoC TSC frequency enumeration bug
  - Fix kexec debug output
  - Fix kexec memory range assumption bug
  - Fix a boundary condition in the crash kernel code
 
  - Optimize porgatory.ro generation a bit
  - Enable ACRN guests to use X2APIC mode
  - Reduce a __text_poke() IRQs-off critical section for the benefit of PREEMPT_RT
 
 Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Merge tag 'x86-urgent-2020-08-15' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull x86 fixes from Ingo Molnar:
 "Misc fixes and small updates all around the place:

   - Fix mitigation state sysfs output

   - Fix an FPU xstate/sxave code assumption bug triggered by
     Architectural LBR support

   - Fix Lightning Mountain SoC TSC frequency enumeration bug

   - Fix kexec debug output

   - Fix kexec memory range assumption bug

   - Fix a boundary condition in the crash kernel code

   - Optimize porgatory.ro generation a bit

   - Enable ACRN guests to use X2APIC mode

   - Reduce a __text_poke() IRQs-off critical section for the benefit of
     PREEMPT_RT"

* tag 'x86-urgent-2020-08-15' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/alternatives: Acquire pte lock with interrupts enabled
  x86/bugs/multihit: Fix mitigation reporting when VMX is not in use
  x86/fpu/xstate: Fix an xstate size check warning with architectural LBRs
  x86/purgatory: Don't generate debug info for purgatory.ro
  x86/tsr: Fix tsc frequency enumeration bug on Lightning Mountain SoC
  kexec_file: Correctly output debugging information for the PT_LOAD ELF header
  kexec: Improve & fix crash_exclude_mem_range() to handle overlapping ranges
  x86/crash: Correct the address boundary of function parameters
  x86/acrn: Remove redundant chars from ACRN signature
  x86/acrn: Allow ACRN guest to use X2APIC mode
2020-08-15 10:38:03 -07:00
Linus Torvalds
1195d58f00 Two fixes: fix a new tracepoint's output value, and fix the formatting of show-state syslog printouts.
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Merge tag 'sched-urgent-2020-08-15' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull scheduler fixes from Ingo Molnar:
 "Two fixes: fix a new tracepoint's output value, and fix the formatting
  of show-state syslog printouts"

* tag 'sched-urgent-2020-08-15' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  sched/debug: Fix the alignment of the show-state debug output
  sched: Fix use of count for nr_running tracepoint
2020-08-15 10:36:40 -07:00
Linus Torvalds
7f5faaaa59 Misc fixes, an expansion of perf syscall access to CAP_PERFMON privileged tools,
plus a RAPL HW-enablement for Intel SPR platforms.
 
 Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Merge tag 'perf-urgent-2020-08-15' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull perf fixes from Ingo Molnar:
 "Misc fixes, an expansion of perf syscall access to CAP_PERFMON
  privileged tools, plus a RAPL HW-enablement for Intel SPR platforms"

* tag 'perf-urgent-2020-08-15' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  perf/x86/rapl: Add support for Intel SPR platform
  perf/x86/rapl: Support multiple RAPL unit quirks
  perf/x86/rapl: Fix missing psys sysfs attributes
  hw_breakpoint: Remove unused __register_perf_hw_breakpoint() declaration
  kprobes: Remove show_registers() function prototype
  perf/core: Take over CAP_SYS_PTRACE creds to CAP_PERFMON capability
2020-08-15 10:34:24 -07:00
Linus Torvalds
eb1319af41 A documentation fix and a 'fallthrough' macro update.
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Merge tag 'locking-urgent-2020-08-15' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull locking fixlets from Ingo Molnar:
 "A documentation fix and a 'fallthrough' macro update"

* tag 'locking-urgent-2020-08-15' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  futex: Convert to use the preferred 'fallthrough' macro
  Documentation/locking/locktypes: Fix a typo
2020-08-15 10:32:18 -07:00
Linus Torvalds
18737f4243 Merge branch 'akpm' (patches from Andrew)
Merge more updates from Andrew Morton:
 "Subsystems affected by this patch series: mm/hotfixes, lz4, exec,
  mailmap, mm/thp, autofs, sysctl, mm/kmemleak, mm/misc and lib"

* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (35 commits)
  virtio: pci: constify ioreadX() iomem argument (as in generic implementation)
  ntb: intel: constify ioreadX() iomem argument (as in generic implementation)
  rtl818x: constify ioreadX() iomem argument (as in generic implementation)
  iomap: constify ioreadX() iomem argument (as in generic implementation)
  sh: use generic strncpy()
  sh: clkfwk: remove r8/r16/r32
  include/asm-generic/vmlinux.lds.h: align ro_after_init
  mm: annotate a data race in page_zonenum()
  mm/swap.c: annotate data races for lru_rotate_pvecs
  mm/rmap: annotate a data race at tlb_flush_batched
  mm/mempool: fix a data race in mempool_free()
  mm/list_lru: fix a data race in list_lru_count_one
  mm/memcontrol: fix a data race in scan count
  mm/page_counter: fix various data races at memsw
  mm/swapfile: fix and annotate various data races
  mm/filemap.c: fix a data race in filemap_fault()
  mm/swap_state: mark various intentional data races
  mm/page_io: mark various intentional data races
  mm/frontswap: mark various intentional data races
  mm/kmemleak: silence KCSAN splats in checksum
  ...
2020-08-15 08:02:03 -07:00
Xiaoming Ni
88db0aa242 all arch: remove system call sys_sysctl
Since commit 61a47c1ad3 ("sysctl: Remove the sysctl system call"),
sys_sysctl is actually unavailable: any input can only return an error.

We have been warning about people using the sysctl system call for years
and believe there are no more users.  Even if there are users of this
interface if they have not complained or fixed their code by now they
probably are not going to, so there is no point in warning them any
longer.

So completely remove sys_sysctl on all architectures.

[nixiaoming@huawei.com: s390: fix build error for sys_call_table_emu]
 Link: http://lkml.kernel.org/r/20200618141426.16884-1-nixiaoming@huawei.com

Signed-off-by: Xiaoming Ni <nixiaoming@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Will Deacon <will@kernel.org>		[arm/arm64]
Acked-by: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Aleksa Sarai <cyphar@cyphar.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Bin Meng <bin.meng@windriver.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: chenzefeng <chenzefeng2@huawei.com>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: Christian Brauner <christian@brauner.io>
Cc: Chris Zankel <chris@zankel.net>
Cc: David Howells <dhowells@redhat.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Diego Elio Pettenò <flameeyes@flameeyes.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Dominik Brodowski <linux@dominikbrodowski.net>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Helge Deller <deller@gmx.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Iurii Zaikin <yzaikin@google.com>
Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Cc: James Bottomley <James.Bottomley@HansenPartnership.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Kars de Jong <jongk@linux-m68k.org>
Cc: Kees Cook <keescook@chromium.org>
Cc: Krzysztof Kozlowski <krzk@kernel.org>
Cc: Luis Chamberlain <mcgrof@kernel.org>
Cc: Marco Elver <elver@google.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Martin K. Petersen <martin.petersen@oracle.com>
Cc: Masahiro Yamada <yamada.masahiro@socionext.com>
Cc: Matt Turner <mattst88@gmail.com>
Cc: Max Filippov <jcmvbkbc@gmail.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Michal Simek <monstr@monstr.eu>
Cc: Miklos Szeredi <mszeredi@redhat.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Cc: Nick Piggin <npiggin@gmail.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Olof Johansson <olof@lixom.net>
Cc: Paul Burton <paulburton@kernel.org>
Cc: "Paul E. McKenney" <paulmck@kernel.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Ravi Bangoria <ravi.bangoria@linux.ibm.com>
Cc: Richard Henderson <rth@twiddle.net>
Cc: Rich Felker <dalias@libc.org>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Sami Tolvanen <samitolvanen@google.com>
Cc: Sargun Dhillon <sargun@sargun.me>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Sudeep Holla <sudeep.holla@arm.com>
Cc: Sven Schnelle <svens@stackframe.org>
Cc: Thiago Jung Bauermann <bauerman@linux.ibm.com>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Cc: Zhou Yanjie <zhouyanjie@wanyeetech.com>
Link: http://lkml.kernel.org/r/20200616030734.87257-1-nixiaoming@huawei.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-08-14 19:56:56 -07:00
Christoph Hellwig
846f9e1fb9 dma-mapping: consolidate the NO_DMA definition in kernel/dma/Kconfig
Have a single definition that architetures can select.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Rich Felker <dalias@libc.org>
2020-08-14 22:05:17 -04:00
Linus Torvalds
5848dc5b1b dma-debug: remove debug_dma_assert_idle() function
This remoes the code from the COW path to call debug_dma_assert_idle(),
which was added many years ago.

Google shows that it hasn't caught anything in the 6+ years we've had it
apart from a false positive, and Hugh just noticed how it had a very
unfortunate spinlock serialization in the COW path.

He fixed that issue the previous commit (a85ffd59bd: "dma-debug: fix
debug_dma_assert_idle(), use rcu_read_lock()"), but let's see if anybody
even notices when we remove this function entirely.

NOTE! We keep the dma tracking infrastructure that was added by the
commit that introduced it.  Partly to make it easier to resurrect this
debug code if we ever deside to, and partly because that tracking by pfn
and offset looks quite reasonable.

The problem with this debug code was simply that it was expensive and
didn't seem worth it, not that it was wrong per se.

Acked-by: Dan Williams <dan.j.williams@intel.com>
Acked-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-08-14 15:22:43 -07:00
Hugh Dickins
a85ffd59bd dma-debug: fix debug_dma_assert_idle(), use rcu_read_lock()
Since commit 2a9127fcf2 ("mm: rewrite wait_on_page_bit_common()
logic") improved unlock_page(), it has become more noticeable how
cow_user_page() in a kernel with CONFIG_DMA_API_DEBUG=y can create and
suffer from heavy contention on DMA debug's radix_lock in
debug_dma_assert_idle().

It is only doing a lookup: use rcu_read_lock() and rcu_read_unlock()
instead; though that does require the static ents[] to be moved
onstack...

...but, hold on, isn't that radix_tree_gang_lookup() and loop doing
quite the wrong thing: searching CACHELINES_PER_PAGE entries for an
exact match with the first cacheline of the page in question?
radix_tree_gang_lookup() is the right tool for the job, but we need
nothing more than to check the first entry it can find, reporting if
that falls anywhere within the page.

(Is RCU safe here? As safe as using the spinlock was. The entries are
never freed, so don't need to be freed by RCU. They may be reused, and
there is a faint chance of a race, with an offending entry reused while
printing its error info; but the spinlock did not prevent that either,
and I agree that it's not worth worrying about. ]

[ Side noe: this patch is a clear improvement to the status quo, but the
  next patch will be removing this debug function entirely.

  But just in case we decide we want to resurrect the debugging code
  some day, I'm first applying this improvement patch so that it doesn't
  get lost    - Linus ]

Fixes: 3b7a6418c7 ("dma debug: account for cachelines and read-only mappings in overlap tracking")
Signed-off-by: Hugh Dickins <hughd@google.com>
Acked-by: Dan Williams <dan.j.williams@intel.com>
Acked-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-08-14 15:16:03 -07:00
Linus Torvalds
b923f1247b A set oftimekeeping/VDSO updates:
- Preparatory work to allow S390 to switch over to the generic VDSO
    implementation.
 
    S390 requires that the VDSO data pointer is handed in to the counter
    read function when time namespace support is enabled. Adding the pointer
    is a NOOP for all other architectures because the compiler is supposed
    to optimize that out when it is unused in the architecture specific
    inline. The change also solved a similar problem for MIPS which
    fortunately has time namespaces not yet enabled.
 
    S390 needs to update clock related VDSO data independent of the
    timekeeping updates. This was solved so far with yet another sequence
    counter in the S390 implementation. A better solution is to utilize the
    already existing VDSO sequence count for this. The core code now exposes
    helper functions which allow to serialize against the timekeeper code
    and against concurrent readers.
 
    S390 needs extra data for their clock readout function. The initial
    common VDSO data structure did not provide a way to add that. It now has
    an embedded architecture specific struct embedded which defaults to an
    empty struct.
 
    Doing this now avoids tree dependencies and conflicts post rc1 and
    allows all other architectures which work on generic VDSO support to
    work from a common upstream base.
 
  - A trivial comment fix.
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Merge tag 'timers-urgent-2020-08-14' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull timekeeping updates from Thomas Gleixner:
 "A set of timekeeping/VDSO updates:

   - Preparatory work to allow S390 to switch over to the generic VDSO
     implementation.

     S390 requires that the VDSO data pointer is handed in to the
     counter read function when time namespace support is enabled.
     Adding the pointer is a NOOP for all other architectures because
     the compiler is supposed to optimize that out when it is unused in
     the architecture specific inline. The change also solved a similar
     problem for MIPS which fortunately has time namespaces not yet
     enabled.

     S390 needs to update clock related VDSO data independent of the
     timekeeping updates. This was solved so far with yet another
     sequence counter in the S390 implementation. A better solution is
     to utilize the already existing VDSO sequence count for this. The
     core code now exposes helper functions which allow to serialize
     against the timekeeper code and against concurrent readers.

     S390 needs extra data for their clock readout function. The initial
     common VDSO data structure did not provide a way to add that. It
     now has an embedded architecture specific struct embedded which
     defaults to an empty struct.

     Doing this now avoids tree dependencies and conflicts post rc1 and
     allows all other architectures which work on generic VDSO support
     to work from a common upstream base.

   - A trivial comment fix"

* tag 'timers-urgent-2020-08-14' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  time: Delete repeated words in comments
  lib/vdso: Allow to add architecture-specific vdso data
  timekeeping/vsyscall: Provide vdso_update_begin/end()
  vdso/treewide: Add vdso_data pointer argument to __arch_get_hw_counter()
2020-08-14 14:26:08 -07:00
Linus Torvalds
b6b178e38f A set of posix CPU timer changes which allows to defer the heavy work of
posix CPU timers into task work context. The tick interrupt is reduced to a
 quick check which queues the work which is doing the heavy lifting before
 returning to user space or going back to guest mode. Moving this out is
 deferring the signal delivery slightly but posix CPU timers are inaccurate
 by nature as they depend on the tick so there is no real damage. The
 relevant test cases all passed.
 
 This lifts the last offender for RT out of the hard interrupt context tick
 handler, but it also has the general benefit that the actual heavy work is
 accounted to the task/process and not to the tick interrupt itself.
 
 Further optimizations are possible to break long sighand lock hold and
 interrupt disabled (on !RT kernels) times when a massive amount of posix
 CPU timers (which are unpriviledged) is armed for a task/process.
 
 This is currently only enabled for x86 because the architecture has to
 ensure that task work is handled in KVM before entering a guest, which was
 just established for x86 with the new common entry/exit code which got
 merged post 5.8 and is not the case for other KVM architectures.
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Merge tag 'timers-core-2020-08-14' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull more timer updates from Thomas Gleixner:
 "A set of posix CPU timer changes which allows to defer the heavy work
  of posix CPU timers into task work context. The tick interrupt is
  reduced to a quick check which queues the work which is doing the
  heavy lifting before returning to user space or going back to guest
  mode. Moving this out is deferring the signal delivery slightly but
  posix CPU timers are inaccurate by nature as they depend on the tick
  so there is no real damage. The relevant test cases all passed.

  This lifts the last offender for RT out of the hard interrupt context
  tick handler, but it also has the general benefit that the actual
  heavy work is accounted to the task/process and not to the tick
  interrupt itself.

  Further optimizations are possible to break long sighand lock hold and
  interrupt disabled (on !RT kernels) times when a massive amount of
  posix CPU timers (which are unpriviledged) is armed for a
  task/process.

  This is currently only enabled for x86 because the architecture has to
  ensure that task work is handled in KVM before entering a guest, which
  was just established for x86 with the new common entry/exit code which
  got merged post 5.8 and is not the case for other KVM architectures"

* tag 'timers-core-2020-08-14' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86: Select POSIX_CPU_TIMERS_TASK_WORK
  posix-cpu-timers: Provide mechanisms to defer timer handling to task_work
  posix-cpu-timers: Split run_posix_cpu_timers()
2020-08-14 14:17:51 -07:00
Linus Torvalds
1d229a65b4 Two fixes in the core interrupt code which ensure that all error exits
unlock the descriptor lock.
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Merge tag 'irq-urgent-2020-08-14' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull irq fixes from Thomas Gleixner:
 "Two fixes in the core interrupt code which ensure that all error exits
  unlock the descriptor lock"

* tag 'irq-urgent-2020-08-14' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  genirq: Unlock irq descriptor after errors
  genirq/PM: Always unlock IRQ descriptor in rearm_wake_irq()
2020-08-14 14:14:28 -07:00
Linus Torvalds
0fd9cc6b0c Modules updates for v5.9
Summary of modules changes for the 5.9 merge window:
 
 - Have modules that use symbols from proprietary modules inherit the
   TAINT_PROPRIETARY_MODULE taint, in an effort to prevent GPL shim modules that
   are used to circumvent _GPL exports. These are modules that claim to be GPL
   licensed while also using symbols from proprietary modules. Such modules will
   be rejected while non-GPL modules will inherit the proprietary taint.
 
 - Module export space cleanup. Unexport symbols that are unused outside of
   module.c or otherwise used in only built-in code.
 
 Signed-off-by: Jessica Yu <jeyu@kernel.org>
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Merge tag 'modules-for-v5.9' of git://git.kernel.org/pub/scm/linux/kernel/git/jeyu/linux

Pull module updates from Jessica Yu:
 "The most important change would be Christoph Hellwig's patch
  implementing proprietary taint inheritance, in an effort to discourage
  the creation of GPL "shim" modules that interface between GPL symbols
  and proprietary symbols.

  Summary:

   - Have modules that use symbols from proprietary modules inherit the
     TAINT_PROPRIETARY_MODULE taint, in an effort to prevent GPL shim
     modules that are used to circumvent _GPL exports. These are modules
     that claim to be GPL licensed while also using symbols from
     proprietary modules. Such modules will be rejected while non-GPL
     modules will inherit the proprietary taint.

   - Module export space cleanup. Unexport symbols that are unused
     outside of module.c or otherwise used in only built-in code"

* tag 'modules-for-v5.9' of git://git.kernel.org/pub/scm/linux/kernel/git/jeyu/linux:
  modules: inherit TAINT_PROPRIETARY_MODULE
  modules: return licensing information from find_symbol
  modules: rename the licence field in struct symsearch to license
  modules: unexport __module_address
  modules: unexport __module_text_address
  modules: mark each_symbol_section static
  modules: mark find_symbol static
  modules: mark ref_module static
  modules: linux/moduleparam.h: drop duplicated word in a comment
2020-08-14 11:07:02 -07:00
Libing Zhou
cc172ff301 sched/debug: Fix the alignment of the show-state debug output
Current sysrq(t) output task fields name are not aligned with
actual task fields value, e.g.:

	kernel: sysrq: Show State
	kernel:  task                        PC stack   pid father
	kernel: systemd         S12456     1      0 0x00000000
	kernel: Call Trace:
	kernel: ? __schedule+0x240/0x740

To make it more readable, print fields name together with task fields
value in the same line, with fixed width:

	kernel: sysrq: Show State
	kernel: task:systemd         state:S stack:12920 pid:    1 ppid:     0 flags:0x00000000
	kernel: Call Trace:
	kernel: __schedule+0x282/0x620

Signed-off-by: Libing Zhou <libing.zhou@nokia-sbell.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20200814030236.37835-1-libing.zhou@nokia-sbell.com
2020-08-14 12:36:18 +02:00
Linus Torvalds
a1d21081a6 Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net
Pull networking fixes from David Miller:
 "Some merge window fallout, some longer term fixes:

   1) Handle headroom properly in lapbether and x25_asy drivers, from
      Xie He.

   2) Fetch MAC address from correct r8152 device node, from Thierry
      Reding.

   3) In the sw kTLS path we should allow MSG_CMSG_COMPAT in sendmsg,
      from Rouven Czerwinski.

   4) Correct fdputs in socket layer, from Miaohe Lin.

   5) Revert troublesome sockptr_t optimization, from Christoph Hellwig.

   6) Fix TCP TFO key reading on big endian, from Jason Baron.

   7) Missing CAP_NET_RAW check in nfc, from Qingyu Li.

   8) Fix inet fastreuse optimization with tproxy sockets, from Tim
      Froidcoeur.

   9) Fix 64-bit divide in new SFC driver, from Edward Cree.

  10) Add a tracepoint for prandom_u32 so that we can more easily
      perform usage analysis. From Eric Dumazet.

  11) Fix rwlock imbalance in AF_PACKET, from John Ogness"

* git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net: (49 commits)
  net: openvswitch: introduce common code for flushing flows
  af_packet: TPACKET_V3: fix fill status rwlock imbalance
  random32: add a tracepoint for prandom_u32()
  Revert "ipv4: tunnel: fix compilation on ARCH=um"
  net: accept an empty mask in /sys/class/net/*/queues/rx-*/rps_cpus
  net: ethernet: stmmac: Disable hardware multicast filter
  net: stmmac: dwmac1000: provide multicast filter fallback
  ipv4: tunnel: fix compilation on ARCH=um
  vsock: fix potential null pointer dereference in vsock_poll()
  sfc: fix ef100 design-param checking
  net: initialize fastreuse on inet_inherit_port
  net: refactor bind_bucket fastreuse into helper
  net: phy: marvell10g: fix null pointer dereference
  net: Fix potential memory leak in proto_register()
  net: qcom/emac: add missed clk_disable_unprepare in error path of emac_clks_phase1_init
  ionic_lif: Use devm_kcalloc() in ionic_qcq_alloc()
  net/nfc/rawsock.c: add CAP_NET_RAW check.
  hinic: fix strncpy output truncated compile warnings
  drivers/net/wan/x25_asy: Added needed_headroom and a skb->len check
  net/tls: Fix kmap usage
  ...
2020-08-13 20:03:11 -07:00
Miaohe Lin
405fa8ac89 futex: Convert to use the preferred 'fallthrough' macro
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20200813122117.51173-1-linmiaohe@huawei.com
2020-08-13 21:02:12 +02:00
Jens Axboe
ebf0d100df task_work: only grab task signal lock when needed
If JOBCTL_TASK_WORK is already set on the targeted task, then we need
not go through {lock,unlock}_task_sighand() to set it again and queue
a signal wakeup. This is safe as we're checking it _after_ adding the
new task_work with cmpxchg().

The ordering is as follows:

task_work_add()				get_signal()
--------------------------------------------------------------
STORE(task->task_works, new_work);	STORE(task->jobctl);
mb();					mb();
LOAD(task->jobctl);			LOAD(task->task_works);

This speeds up TWA_SIGNAL handling quite a bit, which is important now
that io_uring is relying on it for all task_work deliveries.

Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Jann Horn <jannh@google.com>
Acked-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-08-13 09:01:38 -06:00
Guenter Roeck
f107cee94b genirq: Unlock irq descriptor after errors
In irq_set_irqchip_state(), the irq descriptor is not unlocked after an
error is encountered. While that should never happen in practice, a buggy
driver may trigger it. This would result in a lockup, so fix it.

Fixes: 1d0326f352 ("genirq: Check irq_data_get_irq_chip() return value before use")
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20200811180012.80269-1-linux@roeck-us.net
2020-08-13 09:35:59 +02:00
Linus Torvalds
9ad57f6dfc Merge branch 'akpm' (patches from Andrew)
Merge more updates from Andrew Morton:

 - most of the rest of MM (memcg, hugetlb, vmscan, proc, compaction,
   mempolicy, oom-kill, hugetlbfs, migration, thp, cma, util,
   memory-hotplug, cleanups, uaccess, migration, gup, pagemap),

 - various other subsystems (alpha, misc, sparse, bitmap, lib, bitops,
   checkpatch, autofs, minix, nilfs, ufs, fat, signals, kmod, coredump,
   exec, kdump, rapidio, panic, kcov, kgdb, ipc).

* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (164 commits)
  mm/gup: remove task_struct pointer for all gup code
  mm: clean up the last pieces of page fault accountings
  mm/xtensa: use general page fault accounting
  mm/x86: use general page fault accounting
  mm/sparc64: use general page fault accounting
  mm/sparc32: use general page fault accounting
  mm/sh: use general page fault accounting
  mm/s390: use general page fault accounting
  mm/riscv: use general page fault accounting
  mm/powerpc: use general page fault accounting
  mm/parisc: use general page fault accounting
  mm/openrisc: use general page fault accounting
  mm/nios2: use general page fault accounting
  mm/nds32: use general page fault accounting
  mm/mips: use general page fault accounting
  mm/microblaze: use general page fault accounting
  mm/m68k: use general page fault accounting
  mm/ia64: use general page fault accounting
  mm/hexagon: use general page fault accounting
  mm/csky: use general page fault accounting
  ...
2020-08-12 11:24:12 -07:00
Peter Xu
64019a2e46 mm/gup: remove task_struct pointer for all gup code
After the cleanup of page fault accounting, gup does not need to pass
task_struct around any more.  Remove that parameter in the whole gup
stack.

Signed-off-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: John Hubbard <jhubbard@nvidia.com>
Link: http://lkml.kernel.org/r/20200707225021.200906-26-peterx@redhat.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-08-12 10:58:04 -07:00
Wei Yongjun
fed79d057d kcov: make some symbols static
Fix sparse build warnings:

kernel/kcov.c:99:1: warning:
 symbol '__pcpu_scope_kcov_percpu_data' was not declared. Should it be static?
kernel/kcov.c:778:6: warning:
 symbol 'kcov_remote_softirq_start' was not declared. Should it be static?
kernel/kcov.c:795:6: warning:
 symbol 'kcov_remote_softirq_stop' was not declared. Should it be static?

Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: Wei Yongjun <weiyongjun1@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Andrey Konovalov <andreyknvl@google.com>
Link: http://lkml.kernel.org/r/20200702115501.73077-1-weiyongjun1@huawei.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-08-12 10:58:02 -07:00
Marco Elver
31a1b9878c kcov: unconditionally add -fno-stack-protector to compiler options
Unconditionally add -fno-stack-protector to KCOV's compiler options, as
all supported compilers support the option.  This saves a compiler
invocation to determine if the option is supported.

Because Clang does not support -fno-conserve-stack, and
-fno-stack-protector was wrapped in the same cc-option, we were missing
-fno-stack-protector with Clang. Unconditionally adding this option
fixes this for Clang.

Suggested-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Marco Elver <elver@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Reviewed-by: Andrey Konovalov <andreyknvl@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Alexander Potapenko <glider@google.com>
Link: http://lkml.kernel.org/r/20200615184302.7591-1-elver@google.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-08-12 10:58:02 -07:00
Yue Hu
63037f7472 panic: make print_oops_end_marker() static
Since print_oops_end_marker() is not used externally, also remove it in
kernel.h at the same time.

Signed-off-by: Yue Hu <huyue2@yulong.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Kees Cook <keescook@chromium.org>
Link: http://lkml.kernel.org/r/20200724011516.12756-1-zbestahu@gmail.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-08-12 10:58:02 -07:00
Tiezhu Yang
79076e1241 kernel/panic.c: make oops_may_print() return bool
The return value of oops_may_print() is true or false, so change its type
to reflect that.

Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
Cc: Xuefeng Li <lixuefeng@loongson.cn>
Link: http://lkml.kernel.org/r/1591103358-32087-1-git-send-email-yangtiezhu@loongson.cn
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-08-12 10:58:01 -07:00
Vijay Balakrishna
0935288c6e kdump: append kernel build-id string to VMCOREINFO
Make kernel GNU build-id available in VMCOREINFO.  Having build-id in
VMCOREINFO facilitates presenting appropriate kernel namelist image with
debug information file to kernel crash dump analysis tools.  Currently
VMCOREINFO lacks uniquely identifiable key for crash analysis automation.

Regarding if this patch is necessary or matching of linux_banner and
OSRELEASE in VMCOREINFO employed by crash(8) meets the need -- IMO,
build-id approach more foolproof, in most instances it is a cryptographic
hash generated using internal code/ELF bits unlike kernel version string
upon which linux_banner is based that is external to the code.  I feel
each is intended for a different purpose.  Also OSRELEASE is not suitable
when two different kernel builds from same version with different features
enabled.

Currently for most linux (and non-linux) systems build-id can be extracted
using standard methods for file types such as user mode crash dumps,
shared libraries, loadable kernel modules etc., This is an exception for
linux kernel dump.  Having build-id in VMCOREINFO brings some uniformity
for automation tools.

Tyler said:

: I think this is a nice improvement over today's linux_banner approach for
: correlating vmlinux to a kernel dump.
:
: The elf notes parsing in this patch lines up with what is described in in
: the "Notes (Nhdr)" section of the elf(5) man page.
:
: BUILD_ID_MAX is sufficient to hold a sha1 build-id, which is the default
: build-id type today in GNU ld(2).  It is also sufficient to hold the
: "fast" build-id, which is the default build-id type today in LLVM lld(2).

Signed-off-by: Vijay Balakrishna <vijayb@linux.microsoft.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Tyler Hicks <tyhicks@linux.microsoft.com>
Acked-by: Baoquan He <bhe@redhat.com>
Cc: Dave Young <dyoung@redhat.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Link: http://lkml.kernel.org/r/1591849672-34104-1-git-send-email-vijayb@linux.microsoft.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-08-12 10:58:01 -07:00
Tiezhu Yang
6f9e148c21 kmod: remove redundant "be an" in the comment
There exists redundant "be an" in the comment, remove it.

Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Luis Chamberlain <mcgrof@kernel.org>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Christian Brauner <christian.brauner@ubuntu.com>
Cc: Chuck Lever <chuck.lever@oracle.com>
Cc: David Howells <dhowells@redhat.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jakub Kicinski <kuba@kernel.org>
Cc: James Morris <jmorris@namei.org>
Cc: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Cc: J. Bruce Fields <bfields@fieldses.org>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Josh Triplett <josh@joshtriplett.org>
Cc: Kees Cook <keescook@chromium.org>
Cc: Lars Ellenberg <lars.ellenberg@linbit.com>
Cc: Nikolay Aleksandrov <nikolay@cumulusnetworks.com>
Cc: Philipp Reisner <philipp.reisner@linbit.com>
Cc: Roopa Prabhu <roopa@cumulusnetworks.com>
Cc: "Serge E. Hallyn" <serge@hallyn.com>
Cc: Sergei Trofimovich <slyfox@gentoo.org>
Cc: Sergey Kvachonok <ravenexp@gmail.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Tony Vroon <chainsaw@gentoo.org>
Cc: Christoph Hellwig <hch@infradead.org>
Link: http://lkml.kernel.org/r/20200610154923.27510-3-mcgrof@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-08-12 10:58:01 -07:00
Christoph Hellwig
8043fc147a kernel: add a kernel_wait helper
Add a helper that waits for a pid and stores the status in the passed in
kernel pointer.  Use it to fix the usage of kernel_wait4 in
call_usermodehelper_exec_sync that only happens to work due to the
implicit set_fs(KERNEL_DS) for kernel threads.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Luis Chamberlain <mcgrof@kernel.org>
Link: http://lkml.kernel.org/r/20200721130449.5008-1-hch@lst.de
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-08-12 10:57:59 -07:00
Christoph Hellwig
fe81417596 exec: use force_uaccess_begin during exec and exit
Both exec and exit want to ensure that the uaccess routines actually do
access user pointers.  Use the newly added force_uaccess_begin helper
instead of an open coded set_fs for that to prepare for kernel builds
where set_fs() does not exist.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Nick Hu <nickhu@andestech.com>
Cc: Greentime Hu <green.hu@gmail.com>
Cc: Vincent Chen <deanbo422@gmail.com>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Link: http://lkml.kernel.org/r/20200710135706.537715-7-hch@lst.de
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-08-12 10:57:59 -07:00
Christoph Hellwig
3d13f313ce uaccess: add force_uaccess_{begin,end} helpers
Add helpers to wrap the get_fs/set_fs magic for undoing any damange done
by set_fs(KERNEL_DS).  There is no real functional benefit, but this
documents the intent of these calls better, and will allow stubbing the
functions out easily for kernels builds that do not allow address space
overrides in the future.

[hch@lst.de: drop two incorrect hunks, fix a commit log typo]
  Link: http://lkml.kernel.org/r/20200714105505.935079-6-hch@lst.de

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Acked-by: Greentime Hu <green.hu@gmail.com>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Nick Hu <nickhu@andestech.com>
Cc: Vincent Chen <deanbo422@gmail.com>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Link: http://lkml.kernel.org/r/20200710135706.537715-6-hch@lst.de
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-08-12 10:57:59 -07:00
Nitin Gupta
d34c0a7599 mm: use unsigned types for fragmentation score
Proactive compaction uses per-node/zone "fragmentation score" which is
always in range [0, 100], so use unsigned type of these scores as well as
for related constants.

Signed-off-by: Nitin Gupta <nigupta@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Baoquan He <bhe@redhat.com>
Cc: Luis Chamberlain <mcgrof@kernel.org>
Cc: Kees Cook <keescook@chromium.org>
Cc: Iurii Zaikin <yzaikin@google.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Link: http://lkml.kernel.org/r/20200618010319.13159-1-nigupta@nvidia.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-08-12 10:57:56 -07:00
Nitin Gupta
facdaa917c mm: proactive compaction
For some applications, we need to allocate almost all memory as hugepages.
However, on a running system, higher-order allocations can fail if the
memory is fragmented.  Linux kernel currently does on-demand compaction as
we request more hugepages, but this style of compaction incurs very high
latency.  Experiments with one-time full memory compaction (followed by
hugepage allocations) show that kernel is able to restore a highly
fragmented memory state to a fairly compacted memory state within <1 sec
for a 32G system.  Such data suggests that a more proactive compaction can
help us allocate a large fraction of memory as hugepages keeping
allocation latencies low.

For a more proactive compaction, the approach taken here is to define a
new sysctl called 'vm.compaction_proactiveness' which dictates bounds for
external fragmentation which kcompactd tries to maintain.

The tunable takes a value in range [0, 100], with a default of 20.

Note that a previous version of this patch [1] was found to introduce too
many tunables (per-order extfrag{low, high}), but this one reduces them to
just one sysctl.  Also, the new tunable is an opaque value instead of
asking for specific bounds of "external fragmentation", which would have
been difficult to estimate.  The internal interpretation of this opaque
value allows for future fine-tuning.

Currently, we use a simple translation from this tunable to [low, high]
"fragmentation score" thresholds (low=100-proactiveness, high=low+10%).
The score for a node is defined as weighted mean of per-zone external
fragmentation.  A zone's present_pages determines its weight.

To periodically check per-node score, we reuse per-node kcompactd threads,
which are woken up every 500 milliseconds to check the same.  If a node's
score exceeds its high threshold (as derived from user-provided
proactiveness value), proactive compaction is started until its score
reaches its low threshold value.  By default, proactiveness is set to 20,
which implies threshold values of low=80 and high=90.

This patch is largely based on ideas from Michal Hocko [2].  See also the
LWN article [3].

Performance data
================

System: x64_64, 1T RAM, 80 CPU threads.
Kernel: 5.6.0-rc3 + this patch

echo madvise | sudo tee /sys/kernel/mm/transparent_hugepage/enabled
echo madvise | sudo tee /sys/kernel/mm/transparent_hugepage/defrag

Before starting the driver, the system was fragmented from a userspace
program that allocates all memory and then for each 2M aligned section,
frees 3/4 of base pages using munmap.  The workload is mainly anonymous
userspace pages, which are easy to move around.  I intentionally avoided
unmovable pages in this test to see how much latency we incur when
hugepage allocations hit direct compaction.

1. Kernel hugepage allocation latencies

With the system in such a fragmented state, a kernel driver then allocates
as many hugepages as possible and measures allocation latency:

(all latency values are in microseconds)

- With vanilla 5.6.0-rc3

  percentile latency
  –––––––––– –––––––
	   5    7894
	  10    9496
	  25   12561
	  30   15295
	  40   18244
	  50   21229
	  60   27556
	  75   30147
	  80   31047
	  90   32859
	  95   33799

Total 2M hugepages allocated = 383859 (749G worth of hugepages out of 762G
total free => 98% of free memory could be allocated as hugepages)

- With 5.6.0-rc3 + this patch, with proactiveness=20

sysctl -w vm.compaction_proactiveness=20

  percentile latency
  –––––––––– –––––––
	   5       2
	  10       2
	  25       3
	  30       3
	  40       3
	  50       4
	  60       4
	  75       4
	  80       4
	  90       5
	  95     429

Total 2M hugepages allocated = 384105 (750G worth of hugepages out of 762G
total free => 98% of free memory could be allocated as hugepages)

2. JAVA heap allocation

In this test, we first fragment memory using the same method as for (1).

Then, we start a Java process with a heap size set to 700G and request the
heap to be allocated with THP hugepages.  We also set THP to madvise to
allow hugepage backing of this heap.

/usr/bin/time
 java -Xms700G -Xmx700G -XX:+UseTransparentHugePages -XX:+AlwaysPreTouch

The above command allocates 700G of Java heap using hugepages.

- With vanilla 5.6.0-rc3

17.39user 1666.48system 27:37.89elapsed

- With 5.6.0-rc3 + this patch, with proactiveness=20

8.35user 194.58system 3:19.62elapsed

Elapsed time remains around 3:15, as proactiveness is further increased.

Note that proactive compaction happens throughout the runtime of these
workloads.  The situation of one-time compaction, sufficient to supply
hugepages for following allocation stream, can probably happen for more
extreme proactiveness values, like 80 or 90.

In the above Java workload, proactiveness is set to 20.  The test starts
with a node's score of 80 or higher, depending on the delay between the
fragmentation step and starting the benchmark, which gives more-or-less
time for the initial round of compaction.  As t he benchmark consumes
hugepages, node's score quickly rises above the high threshold (90) and
proactive compaction starts again, which brings down the score to the low
threshold level (80).  Repeat.

bpftrace also confirms proactive compaction running 20+ times during the
runtime of this Java benchmark.  kcompactd threads consume 100% of one of
the CPUs while it tries to bring a node's score within thresholds.

Backoff behavior
================

Above workloads produce a memory state which is easy to compact.  However,
if memory is filled with unmovable pages, proactive compaction should
essentially back off.  To test this aspect:

- Created a kernel driver that allocates almost all memory as hugepages
  followed by freeing first 3/4 of each hugepage.
- Set proactiveness=40
- Note that proactive_compact_node() is deferred maximum number of times
  with HPAGE_FRAG_CHECK_INTERVAL_MSEC of wait between each check
  (=> ~30 seconds between retries).

[1] https://patchwork.kernel.org/patch/11098289/
[2] https://lore.kernel.org/linux-mm/20161230131412.GI13301@dhcp22.suse.cz/
[3] https://lwn.net/Articles/817905/

Signed-off-by: Nitin Gupta <nigupta@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Tested-by: Oleksandr Natalenko <oleksandr@redhat.com>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Reviewed-by: Khalid Aziz <khalid.aziz@oracle.com>
Reviewed-by: Oleksandr Natalenko <oleksandr@redhat.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Khalid Aziz <khalid.aziz@oracle.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Nitin Gupta <ngupta@nitingupta.dev>
Cc: Oleksandr Natalenko <oleksandr@redhat.com>
Link: http://lkml.kernel.org/r/20200616204527.19185-1-nigupta@nvidia.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-08-12 10:57:56 -07:00
Joonsoo Kim
b518154e59 mm/vmscan: protect the workingset on anonymous LRU
In current implementation, newly created or swap-in anonymous page is
started on active list.  Growing active list results in rebalancing
active/inactive list so old pages on active list are demoted to inactive
list.  Hence, the page on active list isn't protected at all.

Following is an example of this situation.

Assume that 50 hot pages on active list.  Numbers denote the number of
pages on active/inactive list (active | inactive).

1. 50 hot pages on active list
50(h) | 0

2. workload: 50 newly created (used-once) pages
50(uo) | 50(h)

3. workload: another 50 newly created (used-once) pages
50(uo) | 50(uo), swap-out 50(h)

This patch tries to fix this issue.  Like as file LRU, newly created or
swap-in anonymous pages will be inserted to the inactive list.  They are
promoted to active list if enough reference happens.  This simple
modification changes the above example as following.

1. 50 hot pages on active list
50(h) | 0

2. workload: 50 newly created (used-once) pages
50(h) | 50(uo)

3. workload: another 50 newly created (used-once) pages
50(h) | 50(uo), swap-out 50(uo)

As you can see, hot pages on active list would be protected.

Note that, this implementation has a drawback that the page cannot be
promoted and will be swapped-out if re-access interval is greater than the
size of inactive list but less than the size of total(active+inactive).
To solve this potential issue, following patch will apply workingset
detection similar to the one that's already applied to file LRU.

Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Hugh Dickins <hughd@google.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Minchan Kim <minchan@kernel.org>
Link: http://lkml.kernel.org/r/1595490560-15117-3-git-send-email-iamjoonsoo.kim@lge.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-08-12 10:57:55 -07:00
Guenter Roeck
e27b1636e9 genirq/PM: Always unlock IRQ descriptor in rearm_wake_irq()
rearm_wake_irq() does not unlock the irq descriptor if the interrupt
is not suspended or if wakeup is not enabled on it.

Restucture the exit conditions so the unlock is always ensured.

Fixes: 3a79bc63d9 ("PCI: irq: Introduce rearm_wake_irq()")
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20200811180001.80203-1-linux@roeck-us.net
2020-08-12 11:04:05 +02:00
Linus Torvalds
4bf5e36118 libnvdimm for 5.9
- Add 'Runtime Firmware Activation' support for NVDIMMs that advertise
   the relevant capability
 - Misc libnvdimm and DAX cleanups
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Merge tag 'libnvdimm-for-5.9' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm

Pull libnvdimm updayes from Vishal Verma:
 "You'd normally receive this pull request from Dan Williams, but he's
  busy watching a newborn (Congrats Dan!), so I'm watching libnvdimm
  this cycle.

  This adds a new feature in libnvdimm - 'Runtime Firmware Activation',
  and a few small cleanups and fixes in libnvdimm and DAX. I'd
  originally intended to make separate topic-based pull requests - one
  for libnvdimm, and one for DAX, but some of the DAX material fell out
  since it wasn't quite ready.

  Summary:

   - add 'Runtime Firmware Activation' support for NVDIMMs that
     advertise the relevant capability

   - misc libnvdimm and DAX cleanups"

* tag 'libnvdimm-for-5.9' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm:
  libnvdimm/security: ensure sysfs poll thread woke up and fetch updated attr
  libnvdimm/security: the 'security' attr never show 'overwrite' state
  libnvdimm/security: fix a typo
  ACPI: NFIT: Fix ARS zero-sized allocation
  dax: Fix incorrect argument passed to xas_set_err()
  ACPI: NFIT: Add runtime firmware activate support
  PM, libnvdimm: Add runtime firmware activation support
  libnvdimm: Convert to DEVICE_ATTR_ADMIN_RO()
  drivers/dax: Expand lock scope to cover the use of addresses
  fs/dax: Remove unused size parameter
  dax: print error message by pr_info() in __generic_fsdax_supported()
  driver-core: Introduce DEVICE_ATTR_ADMIN_{RO,RW}
  tools/testing/nvdimm: Emulate firmware activation commands
  tools/testing/nvdimm: Prepare nfit_ctl_test() for ND_CMD_CALL emulation
  tools/testing/nvdimm: Add command debug messages
  tools/testing/nvdimm: Cleanup dimm index passing
  ACPI: NFIT: Define runtime firmware activation commands
  ACPI: NFIT: Move bus_dsm_mask out of generic nvdimm_bus_descriptor
  libnvdimm: Validate command family indices
2020-08-11 10:59:19 -07:00
Linus Torvalds
97d052ea3f A set of locking fixes and updates:
- Untangle the header spaghetti which causes build failures in various
     situations caused by the lockdep additions to seqcount to validate that
     the write side critical sections are non-preemptible.
 
   - The seqcount associated lock debug addons which were blocked by the
     above fallout.
 
     seqcount writers contrary to seqlock writers must be externally
     serialized, which usually happens via locking - except for strict per
     CPU seqcounts. As the lock is not part of the seqcount, lockdep cannot
     validate that the lock is held.
 
     This new debug mechanism adds the concept of associated locks.
     sequence count has now lock type variants and corresponding
     initializers which take a pointer to the associated lock used for
     writer serialization. If lockdep is enabled the pointer is stored and
     write_seqcount_begin() has a lockdep assertion to validate that the
     lock is held.
 
     Aside of the type and the initializer no other code changes are
     required at the seqcount usage sites. The rest of the seqcount API is
     unchanged and determines the type at compile time with the help of
     _Generic which is possible now that the minimal GCC version has been
     moved up.
 
     Adding this lockdep coverage unearthed a handful of seqcount bugs which
     have been addressed already independent of this.
 
     While generaly useful this comes with a Trojan Horse twist: On RT
     kernels the write side critical section can become preemtible if the
     writers are serialized by an associated lock, which leads to the well
     known reader preempts writer livelock. RT prevents this by storing the
     associated lock pointer independent of lockdep in the seqcount and
     changing the reader side to block on the lock when a reader detects
     that a writer is in the write side critical section.
 
  - Conversion of seqcount usage sites to associated types and initializers.
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Merge tag 'locking-urgent-2020-08-10' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull locking updates from Thomas Gleixner:
 "A set of locking fixes and updates:

   - Untangle the header spaghetti which causes build failures in
     various situations caused by the lockdep additions to seqcount to
     validate that the write side critical sections are non-preemptible.

   - The seqcount associated lock debug addons which were blocked by the
     above fallout.

     seqcount writers contrary to seqlock writers must be externally
     serialized, which usually happens via locking - except for strict
     per CPU seqcounts. As the lock is not part of the seqcount, lockdep
     cannot validate that the lock is held.

     This new debug mechanism adds the concept of associated locks.
     sequence count has now lock type variants and corresponding
     initializers which take a pointer to the associated lock used for
     writer serialization. If lockdep is enabled the pointer is stored
     and write_seqcount_begin() has a lockdep assertion to validate that
     the lock is held.

     Aside of the type and the initializer no other code changes are
     required at the seqcount usage sites. The rest of the seqcount API
     is unchanged and determines the type at compile time with the help
     of _Generic which is possible now that the minimal GCC version has
     been moved up.

     Adding this lockdep coverage unearthed a handful of seqcount bugs
     which have been addressed already independent of this.

     While generally useful this comes with a Trojan Horse twist: On RT
     kernels the write side critical section can become preemtible if
     the writers are serialized by an associated lock, which leads to
     the well known reader preempts writer livelock. RT prevents this by
     storing the associated lock pointer independent of lockdep in the
     seqcount and changing the reader side to block on the lock when a
     reader detects that a writer is in the write side critical section.

   - Conversion of seqcount usage sites to associated types and
     initializers"

* tag 'locking-urgent-2020-08-10' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (25 commits)
  locking/seqlock, headers: Untangle the spaghetti monster
  locking, arch/ia64: Reduce <asm/smp.h> header dependencies by moving XTP bits into the new <asm/xtp.h> header
  x86/headers: Remove APIC headers from <asm/smp.h>
  seqcount: More consistent seqprop names
  seqcount: Compress SEQCNT_LOCKNAME_ZERO()
  seqlock: Fold seqcount_LOCKNAME_init() definition
  seqlock: Fold seqcount_LOCKNAME_t definition
  seqlock: s/__SEQ_LOCKDEP/__SEQ_LOCK/g
  hrtimer: Use sequence counter with associated raw spinlock
  kvm/eventfd: Use sequence counter with associated spinlock
  userfaultfd: Use sequence counter with associated spinlock
  NFSv4: Use sequence counter with associated spinlock
  iocost: Use sequence counter with associated spinlock
  raid5: Use sequence counter with associated spinlock
  vfs: Use sequence counter with associated spinlock
  timekeeping: Use sequence counter with associated raw spinlock
  xfrm: policy: Use sequence counters with associated lock
  netfilter: nft_set_rbtree: Use sequence counter with associated rwlock
  netfilter: conntrack: Use sequence counter with associated spinlock
  sched: tasks: Use sequence counter with associated spinlock
  ...
2020-08-10 19:07:44 -07:00
Randy Dunlap
b0294f3025 time: Delete repeated words in comments
Drop repeated words in kernel/time/.  {when, one, into}

Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: John Stultz <john.stultz@linaro.org>
Link: https://lore.kernel.org/r/20200807033248.8452-1-rdunlap@infradead.org
2020-08-10 22:14:07 +02:00
Linus Torvalds
fc80c51fd4 Kbuild updates for v5.9
- run the checker (e.g. sparse) after the compiler
 
  - remove unneeded cc-option tests for old compiler flags
 
  - fix tar-pkg to install dtbs
 
  - introduce ccflags-remove-y and asflags-remove-y syntax
 
  - allow to trace functions in sub-directories of lib/
 
  - introduce hostprogs-always-y and userprogs-always-y syntax
 
  - various Makefile cleanups
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Merge tag 'kbuild-v5.9' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild

Pull Kbuild updates from Masahiro Yamada:

 - run the checker (e.g. sparse) after the compiler

 - remove unneeded cc-option tests for old compiler flags

 - fix tar-pkg to install dtbs

 - introduce ccflags-remove-y and asflags-remove-y syntax

 - allow to trace functions in sub-directories of lib/

 - introduce hostprogs-always-y and userprogs-always-y syntax

 - various Makefile cleanups

* tag 'kbuild-v5.9' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild:
  kbuild: stop filtering out $(GCC_PLUGINS_CFLAGS) from cc-option base
  kbuild: include scripts/Makefile.* only when relevant CONFIG is enabled
  kbuild: introduce hostprogs-always-y and userprogs-always-y
  kbuild: sort hostprogs before passing it to ifneq
  kbuild: move host .so build rules to scripts/gcc-plugins/Makefile
  kbuild: Replace HTTP links with HTTPS ones
  kbuild: trace functions in subdirectories of lib/
  kbuild: introduce ccflags-remove-y and asflags-remove-y
  kbuild: do not export LDFLAGS_vmlinux
  kbuild: always create directories of targets
  powerpc/boot: add DTB to 'targets'
  kbuild: buildtar: add dtbs support
  kbuild: remove cc-option test of -ffreestanding
  kbuild: remove cc-option test of -fno-stack-protector
  Revert "kbuild: Create directory for target DTB"
  kbuild: run the checker after the compiler
2020-08-09 14:10:26 -07:00
Masahiro Yamada
15d5761ad3 kbuild: introduce ccflags-remove-y and asflags-remove-y
CFLAGS_REMOVE_<file>.o filters out flags when compiling a particular
object, but there is no convenient way to do that for every object in
a directory.

Add ccflags-remove-y and asflags-remove-y to make it easily.

Use ccflags-remove-y to clean up some Makefiles.

The add/remove order works as follows:

 [1] KBUILD_CFLAGS specifies compiler flags used globally

 [2] ccflags-y adds compiler flags for all objects in the
     current Makefile

 [3] ccflags-remove-y removes compiler flags for all objects in the
     current Makefile (New feature)

 [4] CFLAGS_<file> adds compiler flags per file.

 [5] CFLAGS_REMOVE_<file> removes compiler flags per file.

Having [3] before [4] allows us to remove flags from most (but not all)
objects in the current Makefile.

For example, kernel/trace/Makefile removes $(CC_FLAGS_FTRACE)
from all objects in the directory, then adds it back to
trace_selftest_dynamic.o and CFLAGS_trace_kprobe_selftest.o

The same applies to lib/livepatch/Makefile.

Please note ccflags-remove-y has no effect to the sub-directories.
In contrast, the previous notation got rid of compiler flags also from
all the sub-directories.

The following are not affected because they have no sub-directories:

  arch/arm/boot/compressed/
  arch/powerpc/xmon/
  arch/sh/
  kernel/trace/

However, lib/ has several sub-directories.

To keep the behavior, I added ccflags-remove-y to all Makefiles
in subdirectories of lib/, except the following:

  lib/vdso/Makefile        - Kbuild does not descend into this Makefile
  lib/raid/test/Makefile   - This is not used for the kernel build

I think commit 2464a609de ("ftrace: do not trace library functions")
excluded too much. In the next commit, I will remove ccflags-remove-y
from the sub-directories of lib/.

Suggested-by: Sami Tolvanen <samitolvanen@google.com>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Acked-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Acked-by: Michael Ellerman <mpe@ellerman.id.au> (powerpc)
Acked-by: Brendan Higgins <brendanhiggins@google.com> (KUnit)
Tested-by: Anders Roxell <anders.roxell@linaro.org>
2020-08-10 01:32:59 +09:00
Linus Torvalds
32663c78c1 Tracing updates for 5.9
- The biggest news in that the tracing ring buffer can now time events that
    interrupted other ring buffer events. Before this change, if an interrupt
    came in while recording another event, and that interrupt also had an
    event, those events would all have the same time stamp as the event it
    interrupted. Now, with the new design, those events will have a unique time
    stamp and rightfully display the time for those events that were recorded
    while interrupting another event.
 
  - Bootconfig how has an "override" operator that lets the users have a
    default config, but then add options to override the default.
 
  - A fix was made to properly filter function graph tracing to the ftrace
    PIDs. This came in at the end of the -rc cycle, and needs to be backported.
 
  - Several clean ups, performance updates, and minor fixes as well.
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Merge tag 'trace-v5.9' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace

Pull tracing updates from Steven Rostedt:

 - The biggest news in that the tracing ring buffer can now time events
   that interrupted other ring buffer events.

   Before this change, if an interrupt came in while recording another
   event, and that interrupt also had an event, those events would all
   have the same time stamp as the event it interrupted.

   Now, with the new design, those events will have a unique time stamp
   and rightfully display the time for those events that were recorded
   while interrupting another event.

 - Bootconfig how has an "override" operator that lets the users have a
   default config, but then add options to override the default.

 - A fix was made to properly filter function graph tracing to the
   ftrace PIDs. This came in at the end of the -rc cycle, and needs to
   be backported.

 - Several clean ups, performance updates, and minor fixes as well.

* tag 'trace-v5.9' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace: (39 commits)
  tracing: Add trace_array_init_printk() to initialize instance trace_printk() buffers
  kprobes: Fix compiler warning for !CONFIG_KPROBES_ON_FTRACE
  tracing: Use trace_sched_process_free() instead of exit() for pid tracing
  bootconfig: Fix to find the initargs correctly
  Documentation: bootconfig: Add bootconfig override operator
  tools/bootconfig: Add testcases for value override operator
  lib/bootconfig: Add override operator support
  kprobes: Remove show_registers() function prototype
  tracing/uprobe: Remove dead code in trace_uprobe_register()
  kprobes: Fix NULL pointer dereference at kprobe_ftrace_handler
  ftrace: Fix ftrace_trace_task return value
  tracepoint: Use __used attribute definitions from compiler_attributes.h
  tracepoint: Mark __tracepoint_string's __used
  trace : Have tracing buffer info use kvzalloc instead of kzalloc
  tracing: Remove outdated comment in stack handling
  ftrace: Do not let direct or IPMODIFY ftrace_ops be added to module and set trampolines
  ftrace: Setup correct FTRACE_FL_REGS flags for module
  tracing/hwlat: Honor the tracing_cpumask
  tracing/hwlat: Drop the duplicate assignment in start_kthread()
  tracing: Save one trace_event->type by using __TRACE_LAST_TYPE
  ...
2020-08-07 18:29:15 -07:00