We've met problems that occasionally tasks with full cpumask
(e.g. by putting it into a cpuset or setting to full affinity)
were migrated to our isolated cpus in production environment.
After some analysis, we found that it is due to the current
select_idle_smt() not considering the sched_domain mask.
Steps to reproduce on my 31-CPU hyperthreads machine:
1. with boot parameter: "isolcpus=domain,2-31"
(thread lists: 0,16 and 1,17)
2. cgcreate -g cpu:test; cgexec -g cpu:test "test_threads"
3. some threads will be migrated to the isolated cpu16~17.
Fix it by checking the valid domain mask in select_idle_smt().
Fixes: 10e2f1acd0 ("sched/core: Rewrite and improve select_idle_siblings())
Reported-by: Wetp Zhang <wetp.zy@linux.alibaba.com>
Signed-off-by: Xunlei Pang <xlpang@linux.alibaba.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Jiang Biao <benbjiang@tencent.com>
Reviewed-by: Vincent Guittot <vincent.guittot@linaro.org>
Link: https://lkml.kernel.org/r/1600930127-76857-1-git-send-email-xlpang@linux.alibaba.com
The RT_RUNTIME_SHARE sched feature enables the sharing of rt_runtime
between CPUs, allowing a CPU to run a real-time task up to 100% of the
time while leaving more space for non-real-time tasks to run on the CPU
that lend rt_runtime.
The problem is that a CPU can easily borrow enough rt_runtime to allow
a spinning rt-task to run forever, starving per-cpu tasks like kworkers,
which are non-real-time by design.
This patch disables RT_RUNTIME_SHARE by default, avoiding this problem.
The feature will still be present for users that want to enable it,
though.
Signed-off-by: Daniel Bristot de Oliveira <bristot@redhat.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Wei Wang <wvw@google.com>
Link: https://lkml.kernel.org/r/b776ab46817e3db5d8ef79175fa0d71073c051c7.1600697903.git.bristot@redhat.com
When a boosted task gets throttled, what normally happens is that it's
immediately enqueued again with ENQUEUE_REPLENISH, which replenishes the
runtime and clears the dl_throttled flag. There is a special case however:
if the throttling happened on sched-out and the task has been deboosted in
the meantime, the replenish is skipped as the task will return to its
normal scheduling class. This leaves the task with the dl_throttled flag
set.
Now if the task gets boosted up to the deadline scheduling class again
while it is sleeping, it's still in the throttled state. The normal wakeup
however will enqueue the task with ENQUEUE_REPLENISH not set, so we don't
actually place it on the rq. Thus we end up with a task that is runnable,
but not actually on the rq and neither a immediate replenishment happens,
nor is the replenishment timer set up, so the task is stuck in
forever-throttled limbo.
Clear the dl_throttled flag before dropping back to the normal scheduling
class to fix this issue.
Signed-off-by: Lucas Stach <l.stach@pengutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Juri Lelli <juri.lelli@redhat.com>
Link: https://lkml.kernel.org/r/20200831110719.2126930-1-l.stach@pengutronix.de
Use runnable_avg to classify numa node state similarly to what is done for
normal load balancer. This helps to ensure that numa and normal balancers
use the same view of the state of the system.
Large arm64system: 2 nodes / 224 CPUs:
hackbench -l (256000/#grp) -g #grp
grp tip/sched/core +patchset improvement
1 14,008(+/- 4,99 %) 13,800(+/- 3.88 %) 1,48 %
4 4,340(+/- 5.35 %) 4.283(+/- 4.85 %) 1,33 %
16 3,357(+/- 0.55 %) 3.359(+/- 0.54 %) -0,06 %
32 3,050(+/- 0.94 %) 3.039(+/- 1,06 %) 0,38 %
64 2.968(+/- 1,85 %) 3.006(+/- 2.92 %) -1.27 %
128 3,290(+/-12.61 %) 3,108(+/- 5.97 %) 5.51 %
256 3.235(+/- 3.95 %) 3,188(+/- 2.83 %) 1.45 %
Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Mel Gorman <mgorman@suse.de>
Link: https://lkml.kernel.org/r/20200921072959.16317-1-vincent.guittot@linaro.org
The last sd_flag_debug shuffle inadvertently moved its definition within
an #ifdef CONFIG_SYSCTL region. While CONFIG_SYSCTL is indeed required to
produce the sched domain ctl interface (which uses sd_flag_debug to output
flag names), it isn't required to run any assertion on the sched_domain
hierarchy itself.
Move the definition of sd_flag_debug to a CONFIG_SCHED_DEBUG region of
topology.c.
Now at long last we have:
- sd_flag_debug declared in include/linux/sched/topology.h iff
CONFIG_SCHED_DEBUG=y
- sd_flag_debug defined in kernel/sched/topology.c, conditioned by:
- CONFIG_SCHED_DEBUG, with an explicit #ifdef block
- CONFIG_SMP, as a requirement to compile topology.c
With this change, all symbols pertaining to SD flag metadata (with the
exception of __SD_FLAG_CNT) are now defined exclusively within topology.c
Fixes: 8fca9494d4 ("sched/topology: Move sd_flag_debug out of linux/sched/topology.h")
Reported-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Valentin Schneider <valentin.schneider@arm.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20200908184956.23369-1-valentin.schneider@arm.com
sched_submit_work() is considered to be a hot path. The preempt_disable()
instruction is a compiler barrier and forces the compiler to load
task_struct::flags for the second comparison.
By using a local variable, the compiler can load the value once and keep it in
a register for the second comparison.
Verified on x86-64 with gcc-10.
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20200819200025.lqvmyefqnbok5i4f@linutronix.de
The code in reweight_entity() can be simplified.
For a sched entity on the rq, the entity accounting can be replaced by
cfs_rq instantaneous load updates currently called from within the
entity accounting.
Even though an entity on the rq can't represent a task in
reweight_entity() (a task is always dequeued before calling this
function) and so the numa task accounting and the rq->cfs_tasks list
management of the entity accounting are never called, the redundant
cfs_rq->nr_running decrement/increment will be avoided.
Signed-off-by: Jiang Biao <benbjiang@tencent.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Dietmar Eggemann <dietmar.eggemann@arm.com>
Reviewed-by: Vincent Guittot <vincent.guittot@linaro.org>
Link: https://lkml.kernel.org/r/20200811113209.34057-1-benbjiang@tencent.com
In find_energy_efficient_cpu() 'cpu_cap' could be less that 'util'.
It might be because of RT, DL (so higher sched class than CFS), irq or
thermal pressure signal, which reduce the capacity value.
In such situation the result of 'cpu_cap - util' might be negative but
stored in the unsigned long. Then it might be compared with other unsigned
long when uclamp_rq_util_with() reduced the 'util' such that is passes the
fits_capacity() check.
Prevent this situation and make the arithmetic more safe.
Fixes: 1d42509e47 ("sched/fair: Make EAS wakeup placement consider uclamp restrictions")
Signed-off-by: Lukasz Luba <lukasz.luba@arm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Valentin Schneider <valentin.schneider@arm.com>
Link: https://lkml.kernel.org/r/20200810083004.26420-1-lukasz.luba@arm.com
We currently set this flag *only* on domains whose topology level exactly
match the level where we detect asymmetry (as returned by
asym_cpu_capacity_level()). This is rather problematic.
Say there are two clusters in the system, one with a lone big CPU and the
other with a mix of big and LITTLE CPUs (as is allowed by DynamIQ):
DIE [ ]
MC [ ][ ]
0 1 2 3 4
L L B B B
asym_cpu_capacity_level() will figure out that the MC level is the one
where all CPUs can see a CPU of max capacity, and we will thus set
SD_ASYM_CPUCAPACITY at MC level for all CPUs.
That lone big CPU will degenerate its MC domain, since it would be alone in
there, and will end up with just a DIE domain. Since the flag was only set
at MC, this CPU ends up not seeing any SD with the flag set, which is
broken.
Rather than clearing dflags at every topology level, clear it before
entering the topology level loop. This will properly propagate upwards
flags that are set starting from a certain level.
Signed-off-by: Valentin Schneider <valentin.schneider@arm.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Quentin Perret <qperret@google.com>
Reviewed-by: Dietmar Eggemann <dietmar.eggemann@arm.com>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: https://lore.kernel.org/r/20200817113003.20802-11-valentin.schneider@arm.com
Decoding the output of /proc/sys/kernel/sched_domain/cpu*/domain*/flags has
always been somewhat annoying, as one needs to go fetch the bit -> name
mapping from the source code itself. This encoding can be saved in a script
somewhere, but that isn't safe from flags being added, removed or even
shuffled around.
What matters for debugging purposes is to get *which* flags are set in a
given domain, their associated value is pretty much meaningless.
Make the sd flags debug file output flag names.
Signed-off-by: Valentin Schneider <valentin.schneider@arm.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: https://lore.kernel.org/r/20200817113003.20802-7-valentin.schneider@arm.com
Pull networking fixes from David Miller:
"Another batch of fixes:
1) Remove nft_compat counter flush optimization, it generates warnings
from the refcount infrastructure. From Florian Westphal.
2) Fix BPF to search for build id more robustly, from Jiri Olsa.
3) Handle bogus getopt lengths in ebtables, from Florian Westphal.
4) Infoleak and other fixes to j1939 CAN driver, from Eric Dumazet and
Oleksij Rempel.
5) Reset iter properly on mptcp sendmsg() error, from Florian
Westphal.
6) Show a saner speed in bonding broadcast mode, from Jarod Wilson.
7) Various kerneldoc fixes in bonding and elsewhere, from Lee Jones.
8) Fix double unregister in bonding during namespace tear down, from
Cong Wang.
9) Disable RP filter during icmp_redirect selftest, from David Ahern"
* git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net: (75 commits)
otx2_common: Use devm_kcalloc() in otx2_config_npa()
net: qrtr: fix usage of idr in port assignment to socket
selftests: disable rp_filter for icmp_redirect.sh
Revert "net: xdp: pull ethernet header off packet after computing skb->protocol"
phylink: <linux/phylink.h>: fix function prototype kernel-doc warning
mptcp: sendmsg: reset iter on error redux
net: devlink: Remove overzealous WARN_ON with snapshots
tipc: not enable tipc when ipv6 works as a module
tipc: fix uninit skb->data in tipc_nl_compat_dumpit()
net: Fix potential wrong skb->protocol in skb_vlan_untag()
net: xdp: pull ethernet header off packet after computing skb->protocol
ipvlan: fix device features
bonding: fix a potential double-unregister
can: j1939: add rxtimer for multipacket broadcast session
can: j1939: abort multipacket broadcast session when timeout occurs
can: j1939: cancel rxtimer on multipacket broadcast session complete
can: j1939: fix support for multipacket broadcast message
net: fddi: skfp: cfm: Remove seemingly unused variable 'ID_sccs'
net: fddi: skfp: cfm: Remove set but unused variable 'oldstate'
net: fddi: skfp: smt: Remove seemingly unused variable 'ID_sccs'
...
Impose a limit on the number of watches that a user can hold so that
they can't use this mechanism to fill up all the available memory.
This is done by putting a counter in user_struct that's incremented when
a watch is allocated and decreased when it is released. If the number
exceeds the RLIMIT_NOFILE limit, the watch is rejected with EAGAIN.
This can be tested by the following means:
(1) Create a watch queue and attach it to fd 5 in the program given - in
this case, bash:
keyctl watch_session /tmp/nlog /tmp/gclog 5 bash
(2) In the shell, set the maximum number of files to, say, 99:
ulimit -n 99
(3) Add 200 keyrings:
for ((i=0; i<200; i++)); do keyctl newring a$i @s || break; done
(4) Try to watch all of the keyrings:
for ((i=0; i<200; i++)); do echo $i; keyctl watch_add 5 %:a$i || break; done
This should fail when the number of watches belonging to the user hits
99.
(5) Remove all the keyrings and all of those watches should go away:
for ((i=0; i<200; i++)); do keyctl unlink %:a$i; done
(6) Kill off the watch queue by exiting the shell spawned by
watch_session.
Fixes: c73be61ced ("pipe: Add general notification queue support")
Reported-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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
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
...
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
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
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
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
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
...
Daniel Borkmann says:
====================
pull-request: bpf 2020-08-15
The following pull-request contains BPF updates for your *net* tree.
We've added 23 non-merge commits during the last 4 day(s) which contain
a total of 32 files changed, 421 insertions(+), 141 deletions(-).
The main changes are:
1) Fix sock_ops ctx access splat due to register override, from John Fastabend.
2) Batch of various fixes to libbpf, bpftool, and selftests when testing build
in 32-bit mode, from Andrii Nakryiko.
3) Fix vmlinux.h generation on ARM by mapping GCC built-in types (__Poly*_t)
to equivalent ones clang can work with, from Jean-Philippe Brucker.
4) Fix build_id lookup in bpf_get_stackid() helper by walking all NOTE ELF
sections instead of just first, from Jiri Olsa.
5) Avoid use of __builtin_offsetof() in libbpf for CO-RE, from Yonghong Song.
6) Fix segfault in test_mmap due to inconsistent length params, from Jianlin Lv.
7) Don't override errno in libbpf when logging errors, from Toke Høiland-Jørgensen.
8) Fix v4_to_v6 sockaddr conversion in sk_lookup test, from Stanislav Fomichev.
9) Add link to bpf-helpers(7) man page to BPF doc, from Joe Stringer.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>
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>
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>
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()
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()
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()
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
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
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
...
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>
Currently when we look for build id within bpf_get_stackid helper
call, we check the first NOTE section and we fail if build id is
not there.
However on some system (Fedora) there can be multiple NOTE sections
in binaries and build id data is not always the first one, like:
$ readelf -a /usr/bin/ls
...
[ 2] .note.gnu.propert NOTE 0000000000000338 00000338
0000000000000020 0000000000000000 A 0 0 8358
[ 3] .note.gnu.build-i NOTE 0000000000000358 00000358
0000000000000024 0000000000000000 A 0 0 437c
[ 4] .note.ABI-tag NOTE 000000000000037c 0000037c
...
So the stack_map_get_build_id function will fail on build id retrieval
and fallback to BPF_STACK_BUILD_ID_IP.
This patch is changing the stack_map_get_build_id code to iterate
through all the NOTE sections and try to get build id data from
each of them.
When tracing on sched_switch tracepoint that does bpf_get_stackid
helper call kernel build, I can see about 60% increase of successful
build id retrieval. The rest seems fails on -EFAULT.
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Song Liu <songliubraving@fb.com>
Link: https://lore.kernel.org/bpf/20200812123102.20032-1-jolsa@kernel.org
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
...
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>
