| Commit message (Collapse) | Author | Age | Files | Lines |
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git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull perf fixes from Thomas Gleixner:
"A few fixes from the perf departement
- prevent a imbalanced preemption disable in the events teardown code
- prevent out of bound acces in perf userspace
- make perf tools compile with UCLIBC again
- a fix for the userspace unwinder utility"
* 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
perf/core: Use this_cpu_ptr() when stopping AUX events
perf evsel: Do not access outside hw cache name arrays
tools lib: Reinstate strlcpy() header guard with __UCLIBC__
perf unwind: Use addr_location::addr instead of ip for entries
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When tearing down an AUX buf for an event via perf_mmap_close(),
__perf_event_output_stop() is called on the event's CPU to ensure that
trace generation is halted before the process of unmapping and
freeing the buffer pages begins.
The callback is performed via cpu_function_call(), which ensures that it
runs with interrupts disabled and is therefore not preemptible.
Unfortunately, the current code grabs the per-cpu context pointer using
get_cpu_ptr(), which unnecessarily disables preemption and doesn't pair
the call with put_cpu_ptr(), leading to a preempt_count() imbalance and
a BUG when freeing the AUX buffer later on:
WARNING: CPU: 1 PID: 2249 at kernel/events/ring_buffer.c:539 __rb_free_aux+0x10c/0x120
Modules linked in:
[...]
Call Trace:
[<ffffffff813379dd>] dump_stack+0x4f/0x72
[<ffffffff81059ff6>] __warn+0xc6/0xe0
[<ffffffff8105a0c8>] warn_slowpath_null+0x18/0x20
[<ffffffff8112761c>] __rb_free_aux+0x10c/0x120
[<ffffffff81128163>] rb_free_aux+0x13/0x20
[<ffffffff8112515e>] perf_mmap_close+0x29e/0x2f0
[<ffffffff8111da30>] ? perf_iterate_ctx+0xe0/0xe0
[<ffffffff8115f685>] remove_vma+0x25/0x60
[<ffffffff81161796>] exit_mmap+0x106/0x140
[<ffffffff8105725c>] mmput+0x1c/0xd0
[<ffffffff8105cac3>] do_exit+0x253/0xbf0
[<ffffffff8105e32e>] do_group_exit+0x3e/0xb0
[<ffffffff81068d49>] get_signal+0x249/0x640
[<ffffffff8101c273>] do_signal+0x23/0x640
[<ffffffff81905f42>] ? _raw_write_unlock_irq+0x12/0x30
[<ffffffff81905f69>] ? _raw_spin_unlock_irq+0x9/0x10
[<ffffffff81901896>] ? __schedule+0x2c6/0x710
[<ffffffff810022a4>] exit_to_usermode_loop+0x74/0x90
[<ffffffff81002a56>] prepare_exit_to_usermode+0x26/0x30
[<ffffffff81906d1b>] retint_user+0x8/0x10
This patch uses this_cpu_ptr() instead of get_cpu_ptr(), since preemption is
already disabled by the caller.
Signed-off-by: Will Deacon <will.deacon@arm.com>
Reviewed-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Fixes: 95ff4ca26c49 ("perf/core: Free AUX pages in unmap path")
Link: http://lkml.kernel.org/r/20160824091905.GA16944@arm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull irq fixes from Thomas Gleixner:
"This lot provides:
- plug a hotplug race in the new affinity infrastructure
- a fix for the trigger type of chained interrupts
- plug a potential memory leak in the core code
- a few fixes for ARM and MIPS GICs"
* 'irq-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
irqchip/mips-gic: Implement activate op for device domain
irqchip/mips-gic: Cleanup chip and handler setup
genirq/affinity: Use get/put_online_cpus around cpumask operations
genirq: Fix potential memleak when failing to get irq pm
irqchip/gicv3-its: Disable the ITS before initializing it
irqchip/gicv3: Remove disabling redistributor and group1 non-secure interrupts
irqchip/gic: Allow self-SGIs for SMP on UP configurations
genirq: Correctly configure the trigger on chained interrupts
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Without locking out CPU mask operations we might end up with an inconsistent
view of the cpumask in the function.
Fixes: 5e385a6ef31f: "genirq: Add a helper to spread an affinity mask for MSI/MSI-X vectors"
Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: http://lkml.kernel.org/r/1470924405-25728-1-git-send-email-hch@lst.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
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Obviously we should free action here if irq_chip_pm_get failed.
Fixes: be45beb2df69: "genirq: Add runtime power management support for IRQ chips"
Signed-off-by: Shawn Lin <shawn.lin@rock-chips.com>
Cc: Jon Hunter <jonathanh@nvidia.com>
Cc: Marc Zyngier <marc.zyngier@arm.com>
Link: http://lkml.kernel.org/r/1471854112-13006-1-git-send-email-shawn.lin@rock-chips.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
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Commit 1e2a7d78499e ("irqdomain: Don't set type when mapping an IRQ")
moved the trigger configuration call from the irqdomain mapping to
the interrupt being actually requested.
This patch failed to handle the case where we configure a chained
interrupt, which doesn't get requested through the usual path.
In order to solve this, let's call __irq_set_trigger just before
starting the cascade interrupt. Special care must be taken to
make the flow handler stick, as the .irq_set_type method could
have reset it (it doesn't know we're dealing with a chained
interrupt).
Based on an initial patch by Jon Hunter.
Fixes: 1e2a7d78499e ("irqdomain: Don't set type when mapping an IRQ")
Reported-by: John Stultz <john.stultz@linaro.org>
Reported-by: Linus Walleij <linus.walleij@linaro.org>
Tested-by: John Stultz <john.stultz@linaro.org>
Acked-by: Jon Hunter <jonathanh@nvidia.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
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git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull timer fixes from Thomas Gleixner:
"A few updates for timers & co:
- prevent a livelock in the timekeeping code when debugging is
enabled
- prevent out of bounds access in the timekeeping debug code
- various fixes in clocksource drivers
- a new maintainers entry"
* 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
clocksource/drivers/sun4i: Clear interrupts after stopping timer in probe function
drivers/clocksource/pistachio: Fix memory corruption in init
clocksource/drivers/timer-atmel-pit: Enable mck clock
clocksource/drivers/pxa: Fix include files for compilation
MAINTAINERS: Add ARM ARCHITECTED TIMER entry
timekeeping: Cap array access in timekeeping_debug
timekeeping: Avoid taking lock in NMI path with CONFIG_DEBUG_TIMEKEEPING
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It was reported that hibernation could fail on the 2nd attempt, where the
system hangs at hibernate() -> syscore_resume() -> i8237A_resume() ->
claim_dma_lock(), because the lock has already been taken.
However there is actually no other process would like to grab this lock on
that problematic platform.
Further investigation showed that the problem is triggered by setting
/sys/power/pm_trace to 1 before the 1st hibernation.
Since once pm_trace is enabled, the rtc becomes unmeaningful after suspend,
and meanwhile some BIOSes would like to adjust the 'invalid' RTC (e.g, smaller
than 1970) to the release date of that motherboard during POST stage, thus
after resumed, it may seem that the system had a significant long sleep time
which is a completely meaningless value.
Then in timekeeping_resume -> tk_debug_account_sleep_time, if the bit31 of the
sleep time happened to be set to 1, fls() returns 32 and we add 1 to
sleep_time_bin[32], which causes an out of bounds array access and therefor
memory being overwritten.
As depicted by System.map:
0xffffffff81c9d080 b sleep_time_bin
0xffffffff81c9d100 B dma_spin_lock
the dma_spin_lock.val is set to 1, which caused this problem.
This patch adds a sanity check in tk_debug_account_sleep_time()
to ensure we don't index past the sleep_time_bin array.
[jstultz: Problem diagnosed and original patch by Chen Yu, I've solved the
issue slightly differently, but borrowed his excelent explanation of the
issue here.]
Fixes: 5c83545f24ab "power: Add option to log time spent in suspend"
Reported-by: Janek Kozicki <cosurgi@gmail.com>
Reported-by: Chen Yu <yu.c.chen@intel.com>
Signed-off-by: John Stultz <john.stultz@linaro.org>
Cc: linux-pm@vger.kernel.org
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Xunlei Pang <xpang@redhat.com>
Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Cc: stable <stable@vger.kernel.org>
Cc: Zhang Rui <rui.zhang@intel.com>
Link: http://lkml.kernel.org/r/1471993702-29148-3-git-send-email-john.stultz@linaro.org
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
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When I added some extra sanity checking in timekeeping_get_ns() under
CONFIG_DEBUG_TIMEKEEPING, I missed that the NMI safe __ktime_get_fast_ns()
method was using timekeeping_get_ns().
Thus the locking added to the debug checks broke the NMI-safety of
__ktime_get_fast_ns().
This patch open-codes the timekeeping_get_ns() logic for
__ktime_get_fast_ns(), so can avoid any deadlocks in NMI.
Fixes: 4ca22c2648f9 "timekeeping: Add warnings when overflows or underflows are observed"
Reported-by: Steven Rostedt <rostedt@goodmis.org>
Reported-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: John Stultz <john.stultz@linaro.org>
Cc: stable <stable@vger.kernel.org>
Link: http://lkml.kernel.org/r/1471993702-29148-2-git-send-email-john.stultz@linaro.org
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
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Merge fixes from Andrew Morton:
"11 fixes"
* emailed patches from Andrew Morton <akpm@linux-foundation.org>:
mm: silently skip readahead for DAX inodes
dax: fix device-dax region base
fs/seq_file: fix out-of-bounds read
mm: memcontrol: avoid unused function warning
mm: clarify COMPACTION Kconfig text
treewide: replace config_enabled() with IS_ENABLED() (2nd round)
printk: fix parsing of "brl=" option
soft_dirty: fix soft_dirty during THP split
sysctl: handle error writing UINT_MAX to u32 fields
get_maintainer: quiet noisy implicit -f vcs_file_exists checking
byteswap: don't use __builtin_bswap*() with sparse
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Commit bbeddf52adc1 ("printk: move braille console support into separate
braille.[ch] files") moved the parsing of braille-related options into
_braille_console_setup(), changing the type of variable str from char*
to char**. In this commit, memcmp(str, "brl,", 4) was correctly updated
to memcmp(*str, "brl,", 4) but not memcmp(str, "brl=", 4).
Update the code to make "brl=" option work again and replace memcmp()
with strncmp() to make the compiler able to detect such an issue.
Fixes: bbeddf52adc1 ("printk: move braille console support into separate braille.[ch] files")
Link: http://lkml.kernel.org/r/20160823165700.28952-1-nicolas.iooss_linux@m4x.org
Signed-off-by: Nicolas Iooss <nicolas.iooss_linux@m4x.org>
Cc: Joe Perches <joe@perches.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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We have scripts which write to certain fields on 3.18 kernels but this
seems to be failing on 4.4 kernels. An entry which we write to here is
xfrm_aevent_rseqth which is u32.
echo 4294967295 > /proc/sys/net/core/xfrm_aevent_rseqth
Commit 230633d109e3 ("kernel/sysctl.c: detect overflows when converting
to int") prevented writing to sysctl entries when integer overflow
occurs. However, this does not apply to unsigned integers.
Heinrich suggested that we introduce a new option to handle 64 bit
limits and set min as 0 and max as UINT_MAX. This might not work as it
leads to issues similar to __do_proc_doulongvec_minmax. Alternatively,
we would need to change the datatype of the entry to 64 bit.
static int __do_proc_doulongvec_minmax(void *data, struct ctl_table
{
i = (unsigned long *) data; //This cast is causing to read beyond the size of data (u32)
vleft = table->maxlen / sizeof(unsigned long); //vleft is 0 because maxlen is sizeof(u32) which is lesser than sizeof(unsigned long) on x86_64.
Introduce a new proc handler proc_douintvec. Individual proc entries
will need to be updated to use the new handler.
[akpm@linux-foundation.org: coding-style fixes]
Fixes: 230633d109e3 ("kernel/sysctl.c:detect overflows when converting to int")
Link: http://lkml.kernel.org/r/1471479806-5252-1-git-send-email-subashab@codeaurora.org
Signed-off-by: Subash Abhinov Kasiviswanathan <subashab@codeaurora.org>
Cc: Heinrich Schuchardt <xypron.glpk@gmx.de>
Cc: Kees Cook <keescook@chromium.org>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Ingo Molnar <mingo@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Pull block fixes from Jens Axboe:
"Here's a set of block fixes for the current 4.8-rc release. This
contains:
- a fix for a secure erase regression, from Adrian.
- a fix for an mmc use-after-free bug regression, also from Adrian.
- potential zero pointer deference in bdev freezing, from Andrey.
- a race fix for blk_set_queue_dying() from Bart.
- a set of xen blkfront fixes from Bob Liu.
- three small fixes for bcache, from Eric and Kent.
- a fix for a potential invalid NVMe state transition, from Gabriel.
- blk-mq CPU offline fix, preventing us from issuing and completing a
request on the wrong queue. From me.
- revert two previous floppy changes, since they caused a user
visibile regression. A better fix is in the works.
- ensure that we don't send down bios that have more than 256
elements in them. Fixes a crash with bcache, for example. From
Ming.
- a fix for deferencing an error pointer with cgroup writeback.
Fixes a regression. From Vegard"
* 'for-linus' of git://git.kernel.dk/linux-block:
mmc: fix use-after-free of struct request
Revert "floppy: refactor open() flags handling"
Revert "floppy: fix open(O_ACCMODE) for ioctl-only open"
fs/block_dev: fix potential NULL ptr deref in freeze_bdev()
blk-mq: improve warning for running a queue on the wrong CPU
blk-mq: don't overwrite rq->mq_ctx
block: make sure a big bio is split into at most 256 bvecs
nvme: Fix nvme_get/set_features() with a NULL result pointer
bdev: fix NULL pointer dereference
xen-blkfront: free resources if xlvbd_alloc_gendisk fails
xen-blkfront: introduce blkif_set_queue_limits()
xen-blkfront: fix places not updated after introducing 64KB page granularity
bcache: pr_err: more meaningful error message when nr_stripes is invalid
bcache: RESERVE_PRIO is too small by one when prio_buckets() is a power of two.
bcache: register_bcache(): call blkdev_put() when cache_alloc() fails
block: Fix race triggered by blk_set_queue_dying()
block: Fix secure erase
nvme: Prevent controller state invalid transition
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Commit 288dab8a35a0 ("block: add a separate operation type for secure
erase") split REQ_OP_SECURE_ERASE from REQ_OP_DISCARD without considering
all the places REQ_OP_DISCARD was being used to mean either. Fix those.
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Fixes: 288dab8a35a0 ("block: add a separate operation type for secure erase")
Signed-off-by: Jens Axboe <axboe@fb.com>
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git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull scheduler fixes from Ingo Molnar:
"Two cputime fixes - hopefully the last ones"
* 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
sched/cputime: Resync steal time when guest & host lose sync
sched/cputime: Fix NO_HZ_FULL getrusage() monotonicity regression
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Commit:
57430218317e ("sched/cputime: Count actually elapsed irq & softirq time")
... fixed a bug but also triggered a regression:
On an i5 laptop, 4 pCPUs, 4vCPUs for one full dynticks guest, there are four
CPU hog processes(for loop) running in the guest, I hot-unplug the pCPUs
on host one by one until there is only one left, then observe CPU utilization
via 'top' in the guest, it shows:
100% st for cpu0(housekeeping)
75% st for other CPUs (nohz full mode)
However, w/o this commit it shows the correct 75% for all four CPUs.
When a guest is interrupted for a longer amount of time, missed clock ticks
are not redelivered later. Because of that, we should not limit the amount
of steal time accounted to the amount of time that the calling functions
think have passed.
However, the interval returned by account_other_time() is NOT rounded down
to the nearest jiffy, while the base interval in get_vtime_delta() it is
subtracted from is, so the max cputime limit is required to avoid underflow.
This patch fixes the regression by limiting the account_other_time() from
get_vtime_delta() to avoid underflow, and lets the other three call sites
(in account_other_time() and steal_account_process_time()) account however
much steal time the host told us elapsed.
Suggested-by: Rik van Riel <riel@redhat.com>
Suggested-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Wanpeng Li <wanpeng.li@hotmail.com>
Reviewed-by: Rik van Riel <riel@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Radim Krcmar <rkrcmar@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: kvm@vger.kernel.org
Link: http://lkml.kernel.org/r/1471399546-4069-1-git-send-email-wanpeng.li@hotmail.com
[ Improved the changelog. ]
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Mike reports:
Roughly 10% of the time, ltp testcase getrusage04 fails:
getrusage04 0 TINFO : Expected timers granularity is 4000 us
getrusage04 0 TINFO : Using 1 as multiply factor for max [us]time increment (1000+4000us)!
getrusage04 0 TINFO : utime: 0us; stime: 179us
getrusage04 0 TINFO : utime: 3751us; stime: 0us
getrusage04 1 TFAIL : getrusage04.c:133: stime increased > 5000us:
And tracked it down to the case where the task simply doesn't get
_any_ [us]time ticks.
Update the code to assume all rtime is utime when we lack information,
thus ensuring a task that elides the tick gets time accounted.
Reported-by: Mike Galbraith <umgwanakikbuti@gmail.com>
Tested-by: Mike Galbraith <umgwanakikbuti@gmail.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Fredrik Markstrom <fredrik.markstrom@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Radim <rkrcmar@redhat.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Cc: Wanpeng Li <wanpeng.li@hotmail.com>
Cc: stable@vger.kernel.org # 4.3+
Fixes: 9d7fb0427648 ("sched/cputime: Guarantee stime + utime == rtime")
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull perf fixes from Ingo Molnar:
"Mostly tooling fixes, but also start/stop filter related fixes, a perf
event read() fix, a fix uncovered by fuzzing, and an uprobes leak fix"
* 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
perf/core: Check return value of the perf_event_read() IPI
perf/core: Enable mapping of the stop filters
perf/core: Update filters only on executable mmap
perf/core: Fix file name handling for start/stop filters
perf/core: Fix event_function_local()
uprobes: Fix the memcg accounting
perf intel-pt: Fix occasional decoding errors when tracing system-wide
tools: Sync kvm related header files for arm64 and s390
perf probe: Release resources on error when handling exit paths
perf probe: Check for dup and fdopen failures
perf symbols: Fix annotation of objects with debuginfo files
perf script: Don't disable use_callchain if input is pipe
perf script: Show proper message when failed list scripts
perf jitdump: Add the right header to get the major()/minor() definitions
perf ppc64le: Fix build failure when libelf is not present
perf tools mem: Fix -t store option for record command
perf intel-pt: Fix ip compression
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The call to smp_call_function_single in perf_event_read() may fail if
an invalid or not online CPU index is passed. Warn user if such bug is
present and return error.
Signed-off-by: David Carrillo-Cisneros <davidcc@google.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Kan Liang <kan.liang@intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul Turner <pjt@google.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vegard Nossum <vegard.nossum@gmail.com>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Link: http://lkml.kernel.org/r/1471467307-61171-2-git-send-email-davidcc@google.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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At this time the perf_addr_filter_needs_mmap() function will _not_
return true on a user space 'stop' filter. But stop filters need
exactly the same kind of mapping that range and start filters get.
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Link: http://lkml.kernel.org/r/1468860187-318-4-git-send-email-mathieu.poirier@linaro.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Function perf_event_mmap() is called by the MM subsystem each time
part of a binary is loaded in memory. There can be several mapping
for a binary, many times unrelated to the code section.
Each time a section of a binary is mapped address filters are
updated, event when the map doesn't pertain to the code section.
The end result is that filters are configured based on the last map
event that was received rather than the last mapping of the code
segment.
For example if we have an executable 'main' that calls library
'libcstest.so.1.0', and that we want to collect traces on code
that is in that library. The perf cmd line for this scenario
would be:
perf record -e cs_etm// --filter 'filter 0x72c/0x40@/opt/lib/libcstest.so.1.0' --per-thread ./main
Resulting in binaries being mapped this way:
root@linaro-nano:~# cat /proc/1950/maps
00400000-00401000 r-xp 00000000 08:02 33169 /home/linaro/main
00410000-00411000 r--p 00000000 08:02 33169 /home/linaro/main
00411000-00412000 rw-p 00001000 08:02 33169 /home/linaro/main
7fa2464000-7fa2474000 rw-p 00000000 00:00 0
7fa2474000-7fa25a4000 r-xp 00000000 08:02 543 /lib/aarch64-linux-gnu/libc-2.21.so
7fa25a4000-7fa25b3000 ---p 00130000 08:02 543 /lib/aarch64-linux-gnu/libc-2.21.so
7fa25b3000-7fa25b7000 r--p 0012f000 08:02 543 /lib/aarch64-linux-gnu/libc-2.21.so
7fa25b7000-7fa25b9000 rw-p 00133000 08:02 543 /lib/aarch64-linux-gnu/libc-2.21.so
7fa25b9000-7fa25bd000 rw-p 00000000 00:00 0
7fa25bd000-7fa25be000 r-xp 00000000 08:02 38308 /opt/lib/libcstest.so.1.0
7fa25be000-7fa25cd000 ---p 00001000 08:02 38308 /opt/lib/libcstest.so.1.0
7fa25cd000-7fa25ce000 r--p 00000000 08:02 38308 /opt/lib/libcstest.so.1.0
7fa25ce000-7fa25cf000 rw-p 00001000 08:02 38308 /opt/lib/libcstest.so.1.0
7fa25cf000-7fa25eb000 r-xp 00000000 08:02 574 /lib/aarch64-linux-gnu/ld-2.21.so
7fa25ef000-7fa25f2000 rw-p 00000000 00:00 0
7fa25f7000-7fa25f9000 rw-p 00000000 00:00 0
7fa25f9000-7fa25fa000 r--p 00000000 00:00 0 [vvar]
7fa25fa000-7fa25fb000 r-xp 00000000 00:00 0 [vdso]
7fa25fb000-7fa25fc000 r--p 0001c000 08:02 574 /lib/aarch64-linux-gnu/ld-2.21.so
7fa25fc000-7fa25fe000 rw-p 0001d000 08:02 574 /lib/aarch64-linux-gnu/ld-2.21.so
7ff2ea8000-7ff2ec9000 rw-p 00000000 00:00 0 [stack]
root@linaro-nano:~#
Before 'main()' can execute 'libcstest.so.1.0' has to be loaded in
memory. Once that has been done perf_event_mmap() has been called
4 times, with the last map starting at address 0x7fa25ce000 and
the address filter configured to start filtering when the
IP has passed over address 0x0x7fa25ce72c (0x7fa25ce000 + 0x72c).
But that is wrong since the code segment for library 'libcstest.so.1.0'
as been mapped at 0x7fa25bd000, resulting in traces not being
collected.
This patch corrects the situation by requesting that address
filters be updated only if the mapped event is for a code
segment.
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Link: http://lkml.kernel.org/r/1468860187-318-3-git-send-email-mathieu.poirier@linaro.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Binary file names have to be supplied for both range and start/stop
filters but the current code only processes the filename if an
address range filter is specified. This code adds processing of
the filename for start/stop filters.
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Link: http://lkml.kernel.org/r/1468860187-318-2-git-send-email-mathieu.poirier@linaro.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Vincent reported triggering the WARN_ON_ONCE() in event_function_local().
While thinking through cases I noticed that by using event_function()
directly, we miss the inactive case usually handled by
event_function_call().
Therefore construct a blend of event_function_call() and
event_function() that handles the cases relevant to
event_function_local().
Reported-by: Vince Weaver <vincent.weaver@maine.edu>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: stable@vger.kernel.org # 4.5+
Fixes: fae3fde65138 ("perf: Collapse and fix event_function_call() users")
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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__replace_page() wronlgy calls mem_cgroup_cancel_charge() in "success" path,
it should only do this if page_check_address() fails.
This means that every enable/disable leads to unbalanced mem_cgroup_uncharge()
from put_page(old_page), it is trivial to underflow the page_counter->count
and trigger OOM.
Reported-and-tested-by: Brenden Blanco <bblanco@plumgrid.com>
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Reviewed-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Michal Hocko <mhocko@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Alexei Starovoitov <alexei.starovoitov@gmail.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vladimir Davydov <vdavydov@virtuozzo.com>
Cc: stable@vger.kernel.org # 3.17+
Fixes: 00501b531c47 ("mm: memcontrol: rewrite charge API")
Link: http://lkml.kernel.org/r/20160817153629.GB29724@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm
Pull power management fixes from Rafael Wysocki:
"More hibernation-related material: one fix for a recent regression in
the core, one small cleanup of the x86-64 resume code and a
documentation update.
Specifics:
- Fix a hibernate core regression resulting from uncovering a latent
bug in its implementation of memory bitmaps by a recent commit
(James Morse).
- Use __pa() to compute a physical address in the x86-64 code
finalizing resume from hibernation (Rafael Wysocki).
- Update power management documentation related to system sleep
states to remove outdated information from it and to add a
description of a recently introduced hibernation debug feature to
it (Rafael Wysocki)"
* tag 'pm-4.8-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
PM / hibernate: Fix rtree_next_node() to avoid walking off list ends
x86/power/64: Use __pa() for physical address computation
PM / sleep: Update some system sleep documentation
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* pm-sleep:
PM / hibernate: Fix rtree_next_node() to avoid walking off list ends
x86/power/64: Use __pa() for physical address computation
PM / sleep: Update some system sleep documentation
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rtree_next_node() walks the linked list of leaf nodes to find the next
block of pages in the struct memory_bitmap. If it walks off the end of
the list of nodes, it walks the list of memory zones to find the next
region of memory. If it walks off the end of the list of zones, it
returns false.
This leaves the struct bm_position's node and zone pointers pointing
at their respective struct list_heads in struct mem_zone_bm_rtree.
memory_bm_find_bit() uses struct bm_position's node and zone pointers
to avoid walking lists and trees if the next bit appears in the same
node/zone. It handles these values being stale.
Swap rtree_next_node()s 'step then test' to 'test-next then step',
this means if we reach the end of memory we return false and leave
the node and zone pointers as they were.
This fixes a panic on resume using AMD Seattle with 64K pages:
[ 6.868732] Freezing user space processes ... (elapsed 0.000 seconds) done.
[ 6.875753] Double checking all user space processes after OOM killer disable... (elapsed 0.000 seconds)
[ 6.896453] PM: Using 3 thread(s) for decompression.
[ 6.896453] PM: Loading and decompressing image data (5339 pages)...
[ 7.318890] PM: Image loading progress: 0%
[ 7.323395] Unable to handle kernel paging request at virtual address 00800040
[ 7.330611] pgd = ffff000008df0000
[ 7.334003] [00800040] *pgd=00000083fffe0003, *pud=00000083fffe0003, *pmd=00000083fffd0003, *pte=0000000000000000
[ 7.344266] Internal error: Oops: 96000005 [#1] PREEMPT SMP
[ 7.349825] Modules linked in:
[ 7.352871] CPU: 2 PID: 1 Comm: swapper/0 Tainted: G W I 4.8.0-rc1 #4737
[ 7.360512] Hardware name: AMD Overdrive/Supercharger/Default string, BIOS ROD1002C 04/08/2016
[ 7.369109] task: ffff8003c0220000 task.stack: ffff8003c0280000
[ 7.375020] PC is at set_bit+0x18/0x30
[ 7.378758] LR is at memory_bm_set_bit+0x24/0x30
[ 7.383362] pc : [<ffff00000835bbc8>] lr : [<ffff0000080faf18>] pstate: 60000045
[ 7.390743] sp : ffff8003c0283b00
[ 7.473551]
[ 7.475031] Process swapper/0 (pid: 1, stack limit = 0xffff8003c0280020)
[ 7.481718] Stack: (0xffff8003c0283b00 to 0xffff8003c0284000)
[ 7.800075] Call trace:
[ 7.887097] [<ffff00000835bbc8>] set_bit+0x18/0x30
[ 7.891876] [<ffff0000080fb038>] duplicate_memory_bitmap.constprop.38+0x54/0x70
[ 7.899172] [<ffff0000080fcc40>] snapshot_write_next+0x22c/0x47c
[ 7.905166] [<ffff0000080fe1b4>] load_image_lzo+0x754/0xa88
[ 7.910725] [<ffff0000080ff0a8>] swsusp_read+0x144/0x230
[ 7.916025] [<ffff0000080fa338>] load_image_and_restore+0x58/0x90
[ 7.922105] [<ffff0000080fa660>] software_resume+0x2f0/0x338
[ 7.927752] [<ffff000008083350>] do_one_initcall+0x38/0x11c
[ 7.933314] [<ffff000008b40cc0>] kernel_init_freeable+0x14c/0x1ec
[ 7.939395] [<ffff0000087ce564>] kernel_init+0x10/0xfc
[ 7.944520] [<ffff000008082e90>] ret_from_fork+0x10/0x40
[ 7.949820] Code: d2800022 8b400c21 f9800031 9ac32043 (c85f7c22)
[ 7.955909] ---[ end trace 0024a5986e6ff323 ]---
[ 7.960529] Kernel panic - not syncing: Attempted to kill init! exitcode=0x0000000b
Here struct mem_zone_bm_rtree's start_pfn has been returned instead of
struct rtree_node's addr as the node/zone pointers are corrupt after
we walked off the end of the lists during mark_unsafe_pages().
This behaviour was exposed by commit 6dbecfd345a6 ("PM / hibernate:
Simplify mark_unsafe_pages()"), which caused mark_unsafe_pages() to call
duplicate_memory_bitmap(), which uses memory_bm_find_bit() after walking
off the end of the memory bitmap.
Fixes: 3a20cb177961 (PM / Hibernate: Implement position keeping in radix tree)
Signed-off-by: James Morse <james.morse@arm.com>
[ rjw: Subject ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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Pull networking fixes from David Miller:
1) Buffers powersave frame test is reversed in cfg80211, fix from Felix
Fietkau.
2) Remove bogus WARN_ON in openvswitch, from Jarno Rajahalme.
3) Fix some tg3 ethtool logic bugs, and one that would cause no
interrupts to be generated when rx-coalescing is set to 0. From
Satish Baddipadige and Siva Reddy Kallam.
4) QLCNIC mailbox corruption and napi budget handling fix from Manish
Chopra.
5) Fix fib_trie logic when walking the trie during /proc/net/route
output than can access a stale node pointer. From David Forster.
6) Several sctp_diag fixes from Phil Sutter.
7) PAUSE frame handling fixes in mlxsw driver from Ido Schimmel.
8) Checksum fixup fixes in bpf from Daniel Borkmann.
9) Memork leaks in nfnetlink, from Liping Zhang.
10) Use after free in rxrpc, from David Howells.
11) Use after free in new skb_array code of macvtap driver, from Jason
Wang.
12) Calipso resource leak, from Colin Ian King.
13) mediatek bug fixes (missing stats sync init, etc.) from Sean Wang.
14) Fix bpf non-linear packet write helpers, from Daniel Borkmann.
15) Fix lockdep splats in macsec, from Sabrina Dubroca.
16) hv_netvsc bug fixes from Vitaly Kuznetsov, mostly to do with VF
handling.
17) Various tc-action bug fixes, from CONG Wang.
* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net: (116 commits)
net_sched: allow flushing tc police actions
net_sched: unify the init logic for act_police
net_sched: convert tcf_exts from list to pointer array
net_sched: move tc offload macros to pkt_cls.h
net_sched: fix a typo in tc_for_each_action()
net_sched: remove an unnecessary list_del()
net_sched: remove the leftover cleanup_a()
mlxsw: spectrum: Allow packets to be trapped from any PG
mlxsw: spectrum: Unmap 802.1Q FID before destroying it
mlxsw: spectrum: Add missing rollbacks in error path
mlxsw: reg: Fix missing op field fill-up
mlxsw: spectrum: Trap loop-backed packets
mlxsw: spectrum: Add missing packet traps
mlxsw: spectrum: Mark port as active before registering it
mlxsw: spectrum: Create PVID vPort before registering netdevice
mlxsw: spectrum: Remove redundant errors from the code
mlxsw: spectrum: Don't return upon error in removal path
i40e: check for and deal with non-contiguous TCs
ixgbe: Re-enable ability to toggle VLAN filtering
ixgbe: Force VLNCTRL.VFE to be set in all VMDq paths
...
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While hashing out BPF's current_task_under_cgroup helper bits, it came
to discussion that the skb_in_cgroup helper name was suboptimally chosen.
Tejun says:
So, I think in_cgroup should mean that the object is in that
particular cgroup while under_cgroup in the subhierarchy of that
cgroup. Let's rename the other subhierarchy test to under too. I
think that'd be a lot less confusing going forward.
[...]
It's more intuitive and gives us the room to implement the real
"in" test if ever necessary in the future.
Since this touches uapi bits, we need to change this as long as v4.8
is not yet officially released. Thus, change the helper enum and rename
related bits.
Fixes: 4a482f34afcc ("cgroup: bpf: Add bpf_skb_in_cgroup_proto")
Reference: http://patchwork.ozlabs.org/patch/658500/
Suggested-by: Sargun Dhillon <sargun@sargun.me>
Suggested-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Alexei Starovoitov <ast@kernel.org>
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The introduction of pre-allocated hash elements inadvertently broke
the behavior of bpf hash maps where users expected to call
bpf_map_update_elem() without considering that the map can be full.
Some programs do:
old_value = bpf_map_lookup_elem(map, key);
if (old_value) {
... prepare new_value on stack ...
bpf_map_update_elem(map, key, new_value);
}
Before pre-alloc the update() for existing element would work even
in 'map full' condition. Restore this behavior.
The above program could have updated old_value in place instead of
update() which would be faster and most programs use that approach,
but sometimes the values are large and the programs use update()
helper to do atomic replacement of the element.
Note we cannot simply update element's value in-place like percpu
hash map does and have to allocate extra num_possible_cpu elements
and use this extra reserve when the map is full.
Fixes: 6c9059817432 ("bpf: pre-allocate hash map elements")
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Using per-register incrementing ID can lead to
find_good_pkt_pointers() confusing registers which
have completely different values. Consider example:
0: (bf) r6 = r1
1: (61) r8 = *(u32 *)(r6 +76)
2: (61) r0 = *(u32 *)(r6 +80)
3: (bf) r7 = r8
4: (07) r8 += 32
5: (2d) if r8 > r0 goto pc+9
R0=pkt_end R1=ctx R6=ctx R7=pkt(id=0,off=0,r=32) R8=pkt(id=0,off=32,r=32) R10=fp
6: (bf) r8 = r7
7: (bf) r9 = r7
8: (71) r1 = *(u8 *)(r7 +0)
9: (0f) r8 += r1
10: (71) r1 = *(u8 *)(r7 +1)
11: (0f) r9 += r1
12: (07) r8 += 32
13: (2d) if r8 > r0 goto pc+1
R0=pkt_end R1=inv56 R6=ctx R7=pkt(id=0,off=0,r=32) R8=pkt(id=1,off=32,r=32) R9=pkt(id=1,off=0,r=32) R10=fp
14: (71) r1 = *(u8 *)(r9 +16)
15: (b7) r7 = 0
16: (bf) r0 = r7
17: (95) exit
We need to get a UNKNOWN_VALUE with imm to force id
generation so lines 0-5 make r7 a valid packet pointer.
We then read two different bytes from the packet and
add them to copies of the constructed packet pointer.
r8 (line 9) and r9 (line 11) will get the same id of 1,
independently. When either of them is validated (line
13) - find_good_pkt_pointers() will also mark the other
as safe. This leads to access on line 14 being mistakenly
considered safe.
Fixes: 969bf05eb3ce ("bpf: direct packet access")
Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
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git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm
Pull power management fixes from Rafael Wysocki:
"Two hibernation fixes allowing it to work with the recently added
randomization of the kernel identity mapping base on x86-64 and one
cpufreq driver regression fix.
Specifics:
- Fix the x86 identity mapping creation helpers to avoid the
assumption that the base address of the mapping will always be
aligned at the PGD level, as it may be aligned at the PUD level if
address space randomization is enabled (Rafael Wysocki).
- Fix the hibernation core to avoid executing tracing functions
before restoring the processor state completely during resume
(Thomas Garnier).
- Fix a recently introduced regression in the powernv cpufreq driver
that causes it to crash due to an out-of-bounds array access
(Akshay Adiga)"
* tag 'pm-4.8-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
PM / hibernate: Restore processor state before using per-CPU variables
x86/power/64: Always create temporary identity mapping correctly
cpufreq: powernv: Fix crash in gpstate_timer_handler()
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* pm-sleep:
PM / hibernate: Restore processor state before using per-CPU variables
x86/power/64: Always create temporary identity mapping correctly
* pm-cpufreq:
cpufreq: powernv: Fix crash in gpstate_timer_handler()
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Restore the processor state before calling any other functions to
ensure per-CPU variables can be used with KASLR memory randomization.
Tracing functions use per-CPU variables (GS based on x86) and one was
called just before restoring the processor state fully. It resulted
in a double fault when both the tracing & the exception handler
functions tried to use a per-CPU variable.
Fixes: bb3632c6101b (PM / sleep: trace events for suspend/resume)
Reported-and-tested-by: Borislav Petkov <bp@suse.de>
Reported-by: Jiri Kosina <jikos@kernel.org>
Tested-by: Rafael J. Wysocki <rafael@kernel.org>
Tested-by: Jiri Kosina <jkosina@suse.cz>
Signed-off-by: Thomas Garnier <thgarnie@google.com>
Acked-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull timer fixes from Ingo Molnar:
"Misc fixes: a /dev/rtc regression fix, two APIC timer period
calibration fixes, an ARM clocksource driver fix and a NOHZ
power use regression fix"
* 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/hpet: Fix /dev/rtc breakage caused by RTC cleanup
x86/timers/apic: Inform TSC deadline clockevent device about recalibration
x86/timers/apic: Fix imprecise timer interrupts by eliminating TSC clockevents frequency roundoff error
timers: Fix get_next_timer_interrupt() computation
clocksource/arm_arch_timer: Force per-CPU interrupt to be level-triggered
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Signed-off-by: Ingo Molnar <mingo@kernel.org>
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The tick_nohz_stop_sched_tick() routine is not properly
canceling the sched timer when nothing is pending, because
get_next_timer_interrupt() is no longer returning KTIME_MAX in
that case. This causes periodic interrupts when none are needed.
When determining the next interrupt time, we first use
__next_timer_interrupt() to get the first expiring timer in the
timer wheel. If no timer is found, we return the base clock value
plus NEXT_TIMER_MAX_DELTA to indicate there is no timer in the
timer wheel.
Back in get_next_timer_interrupt(), we set the "expires" value
by converting the timer wheel expiry (in ticks) to a nsec value.
But we don't want to do this if the timer wheel expiry value
indicates no timer; we want to return KTIME_MAX.
Prior to commit 500462a9de65 ("timers: Switch to a non-cascading
wheel") we checked base->active_timers to see if any timers
were active, and if not, we didn't touch the expiry value and so
properly returned KTIME_MAX. Now we don't have active_timers.
To fix this, we now just check the timer wheel expiry value to
see if it is "now + NEXT_TIMER_MAX_DELTA", and if it is, we don't
try to compute a new value based on it, but instead simply let the
KTIME_MAX value in expires remain.
Fixes: 500462a9de65 "timers: Switch to a non-cascading wheel"
Signed-off-by: Chris Metcalf <cmetcalf@mellanox.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: John Stultz <john.stultz@linaro.org>
Link: http://lkml.kernel.org/r/1470688147-22287-1-git-send-email-cmetcalf@mellanox.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
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git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull scheduler fixes from Ingo Molnar:
"Misc fixes: cputime fixes, two deadline scheduler fixes and a cgroups
scheduling fix"
* 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
sched/cputime: Fix omitted ticks passed in parameter
sched/cputime: Fix steal time accounting
sched/deadline: Fix lock pinning warning during CPU hotplug
sched/cputime: Mitigate performance regression in times()/clock_gettime()
sched/fair: Fix typo in sync_throttle()
sched/deadline: Fix wrap-around in DL heap
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Commit:
f9bcf1e0e014 ("sched/cputime: Fix steal time accounting")
... fixes a leak on steal time accounting but forgets to account
the ticks passed in parameters, assuming there is only one to
take into account.
Let's consider that parameter back.
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Acked-by: Wanpeng Li <kernellwp@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Radim <rkrcmar@redhat.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Wanpeng Li <wanpeng.li@hotmail.com>
Cc: linux-tip-commits@vger.kernel.org
Link: http://lkml.kernel.org/r/20160811125822.GB4214@lerouge
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Commit:
57430218317 ("sched/cputime: Count actually elapsed irq & softirq time")
... didn't take steal time into consideration with passing the noirqtime
kernel parameter.
As Paolo pointed out before:
| Why not? If idle=poll, for example, any time the guest is suspended (and
| thus cannot poll) does count as stolen time.
This patch fixes it by reducing steal time from idle time accounting when
the noirqtime parameter is true. The average idle time drops from 56.8%
to 54.75% for nohz idle kvm guest(noirqtime, idle=poll, four vCPUs running
on one pCPU).
Signed-off-by: Wanpeng Li <wanpeng.li@hotmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Radim <rkrcmar@redhat.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1470893795-3527-1-git-send-email-wanpeng.li@hotmail.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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The following warning can be triggered by hot-unplugging the CPU
on which an active SCHED_DEADLINE task is running on:
WARNING: CPU: 0 PID: 0 at kernel/locking/lockdep.c:3531 lock_release+0x690/0x6a0
releasing a pinned lock
Call Trace:
dump_stack+0x99/0xd0
__warn+0xd1/0xf0
? dl_task_timer+0x1a1/0x2b0
warn_slowpath_fmt+0x4f/0x60
? sched_clock+0x13/0x20
lock_release+0x690/0x6a0
? enqueue_pushable_dl_task+0x9b/0xa0
? enqueue_task_dl+0x1ca/0x480
_raw_spin_unlock+0x1f/0x40
dl_task_timer+0x1a1/0x2b0
? push_dl_task.part.31+0x190/0x190
WARNING: CPU: 0 PID: 0 at kernel/locking/lockdep.c:3649 lock_unpin_lock+0x181/0x1a0
unpinning an unpinned lock
Call Trace:
dump_stack+0x99/0xd0
__warn+0xd1/0xf0
warn_slowpath_fmt+0x4f/0x60
lock_unpin_lock+0x181/0x1a0
dl_task_timer+0x127/0x2b0
? push_dl_task.part.31+0x190/0x190
As per the comment before this code, its safe to drop the RQ lock
here, and since we (potentially) change rq, unpin and repin to avoid
the splat.
Signed-off-by: Wanpeng Li <wanpeng.li@hotmail.com>
[ Rewrote changelog. ]
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Juri Lelli <juri.lelli@arm.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Luca Abeni <luca.abeni@unitn.it>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1470274940-17976-1-git-send-email-wanpeng.li@hotmail.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Commit:
6e998916dfe3 ("sched/cputime: Fix clock_nanosleep()/clock_gettime() inconsistency")
fixed a problem whereby clock_nanosleep() followed by clock_gettime() could
allow a task to wake early. It addressed the problem by calling the scheduling
classes update_curr() when the cputimer starts.
Said change induced a considerable performance regression on the syscalls
times() and clock_gettimes(CLOCK_PROCESS_CPUTIME_ID). There are some
debuggers and applications that monitor their own performance that
accidentally depend on the performance of these specific calls.
This patch mitigates the performace loss by prefetching data in the CPU
cache, as stalls due to cache misses appear to be where most time is spent
in our benchmarks.
Here are the performance gain of this patch over v4.7-rc7 on a Sandy Bridge
box with 32 logical cores and 2 NUMA nodes. The test is repeated with a
variable number of threads, from 2 to 4*num_cpus; the results are in
seconds and correspond to the average of 10 runs; the percentage gain is
computed with (before-after)/before so a positive value is an improvement
(it's faster). The improvement varies between a few percents for 5-20
threads and more than 10% for 2 or >20 threads.
pound_clock_gettime:
threads 4.7-rc7 patched 4.7-rc7
[num] [secs] [secs (percent)]
2 3.48 3.06 ( 11.83%)
5 3.33 3.25 ( 2.40%)
8 3.37 3.26 ( 3.30%)
12 3.32 3.37 ( -1.60%)
21 4.01 3.90 ( 2.74%)
30 3.63 3.36 ( 7.41%)
48 3.71 3.11 ( 16.27%)
79 3.75 3.16 ( 15.74%)
110 3.81 3.25 ( 14.80%)
128 3.88 3.31 ( 14.76%)
pound_times:
threads 4.7-rc7 patched 4.7-rc7
[num] [secs] [secs (percent)]
2 3.65 3.25 ( 11.03%)
5 3.45 3.17 ( 7.92%)
8 3.52 3.22 ( 8.69%)
12 3.29 3.36 ( -2.04%)
21 4.07 3.92 ( 3.78%)
30 3.87 3.40 ( 12.17%)
48 3.79 3.16 ( 16.61%)
79 3.88 3.28 ( 15.42%)
110 3.90 3.38 ( 13.35%)
128 4.00 3.38 ( 15.45%)
pound_clock_gettime and pound_clock_gettime are two benchmarks included in
the MMTests framework. They launch a given number of threads which
repeatedly call times() or clock_gettimes(). The results above can be
reproduced with cloning MMTests from github.com and running the "poundtime"
workload:
$ git clone https://github.com/gormanm/mmtests.git
$ cd mmtests
$ cp configs/config-global-dhp__workload_poundtime config
$ ./run-mmtests.sh --run-monitor $(uname -r)
The above will run "poundtime" measuring the kernel currently running on
the machine; Once a new kernel is installed and the machine rebooted,
running again
$ cd mmtests
$ ./run-mmtests.sh --run-monitor $(uname -r)
will produce results to compare with. A comparison table will be output
with:
$ cd mmtests/work/log
$ ../../compare-kernels.sh
the table will contain a lot of entries; grepping for "Amean" (as in
"arithmetic mean") will give the tables presented above. The source code
for the two benchmarks is reported at the end of this changelog for
clairity.
The cache misses addressed by this patch were found using a combination of
`perf top`, `perf record` and `perf annotate`. The incriminated lines were
found to be
struct sched_entity *curr = cfs_rq->curr;
and
delta_exec = now - curr->exec_start;
in the function update_curr() from kernel/sched/fair.c. This patch
prefetches the data from memory just before update_curr is called in the
interested execution path.
A comparison of the total number of cycles before and after the patch
follows; the data is obtained using `perf stat -r 10 -ddd <program>`
running over the same sequence of number of threads used above (a positive
gain is an improvement):
threads cycles before cycles after gain
2 19,699,563,964 +-1.19% 17,358,917,517 +-1.85% 11.88%
5 47,401,089,566 +-2.96% 45,103,730,829 +-0.97% 4.85%
8 80,923,501,004 +-3.01% 71,419,385,977 +-0.77% 11.74%
12 112,326,485,473 +-0.47% 110,371,524,403 +-0.47% 1.74%
21 193,455,574,299 +-0.72% 180,120,667,904 +-0.36% 6.89%
30 315,073,519,013 +-1.64% 271,222,225,950 +-1.29% 13.92%
48 321,969,515,332 +-1.48% 273,353,977,321 +-1.16% 15.10%
79 337,866,003,422 +-0.97% 289,462,481,538 +-1.05% 14.33%
110 338,712,691,920 +-0.78% 290,574,233,170 +-0.77% 14.21%
128 348,384,794,006 +-0.50% 292,691,648,206 +-0.66% 15.99%
A comparison of cache miss vs total cache loads ratios, before and after
the patch (again from the `perf stat -r 10 -ddd <program>` tables):
threads L1 misses/total*100 L1 misses/total*100 gain
before after
2 7.43 +-4.90% 7.36 +-4.70% 0.94%
5 13.09 +-4.74% 13.52 +-3.73% -3.28%
8 13.79 +-5.61% 12.90 +-3.27% 6.45%
12 11.57 +-2.44% 8.71 +-1.40% 24.72%
21 12.39 +-3.92% 9.97 +-1.84% 19.53%
30 13.91 +-2.53% 11.73 +-2.28% 15.67%
48 13.71 +-1.59% 12.32 +-1.97% 10.14%
79 14.44 +-0.66% 13.40 +-1.06% 7.20%
110 15.86 +-0.50% 14.46 +-0.59% 8.83%
128 16.51 +-0.32% 15.06 +-0.78% 8.78%
As a final note, the following shows the evolution of performance figures
in the "poundtime" benchmark and pinpoints commit 6e998916dfe3
("sched/cputime: Fix clock_nanosleep()/clock_gettime() inconsistency") as a
major source of degradation, mostly unaddressed to this day (figures
expressed in seconds).
pound_clock_gettime:
threads parent of 6e998916dfe3 4.7-rc7
6e998916dfe3 itself
2 2.23 3.68 ( -64.56%) 3.48 (-55.48%)
5 2.83 3.78 ( -33.42%) 3.33 (-17.43%)
8 2.84 4.31 ( -52.12%) 3.37 (-18.76%)
12 3.09 3.61 ( -16.74%) 3.32 ( -7.17%)
21 3.14 4.63 ( -47.36%) 4.01 (-27.71%)
30 3.28 5.75 ( -75.37%) 3.63 (-10.80%)
48 3.02 6.05 (-100.56%) 3.71 (-22.99%)
79 2.88 6.30 (-118.90%) 3.75 (-30.26%)
110 2.95 6.46 (-119.00%) 3.81 (-29.24%)
128 3.05 6.42 (-110.08%) 3.88 (-27.04%)
pound_times:
threads parent of 6e998916dfe3 4.7-rc7
6e998916dfe3 itself
2 2.27 3.73 ( -64.71%) 3.65 (-61.14%)
5 2.78 3.77 ( -35.56%) 3.45 (-23.98%)
8 2.79 4.41 ( -57.71%) 3.52 (-26.05%)
12 3.02 3.56 ( -17.94%) 3.29 ( -9.08%)
21 3.10 4.61 ( -48.74%) 4.07 (-31.34%)
30 3.33 5.75 ( -72.53%) 3.87 (-16.01%)
48 2.96 6.06 (-105.04%) 3.79 (-28.10%)
79 2.88 6.24 (-116.83%) 3.88 (-34.81%)
110 2.98 6.37 (-114.08%) 3.90 (-31.12%)
128 3.10 6.35 (-104.61%) 4.00 (-28.87%)
The source code of the two benchmarks follows. To compile the two:
NR_THREADS=42
for FILE in pound_times pound_clock_gettime; do
gcc -lrt -O2 -lpthread -DNUM_THREADS=$NR_THREADS $FILE.c -o $FILE
done
==== BEGIN pound_times.c ====
struct tms start;
void *pound (void *threadid)
{
struct tms end;
int oldutime = 0;
int utime;
int i;
for (i = 0; i < 5000000 / NUM_THREADS; i++) {
times(&end);
utime = ((int)end.tms_utime - (int)start.tms_utime);
if (oldutime > utime) {
printf("utime decreased, was %d, now %d!\n", oldutime, utime);
}
oldutime = utime;
}
pthread_exit(NULL);
}
int main()
{
pthread_t th[NUM_THREADS];
long i;
times(&start);
for (i = 0; i < NUM_THREADS; i++) {
pthread_create (&th[i], NULL, pound, (void *)i);
}
pthread_exit(NULL);
return 0;
}
==== END pound_times.c ====
==== BEGIN pound_clock_gettime.c ====
void *pound (void *threadid)
{
struct timespec ts;
int rc, i;
unsigned long prev = 0, this = 0;
for (i = 0; i < 5000000 / NUM_THREADS; i++) {
rc = clock_gettime(CLOCK_PROCESS_CPUTIME_ID, &ts);
if (rc < 0)
perror("clock_gettime");
this = (ts.tv_sec * 1000000000) + ts.tv_nsec;
if (0 && this < prev)
printf("%lu ns timewarp at iteration %d\n", prev - this, i);
prev = this;
}
pthread_exit(NULL);
}
int main()
{
pthread_t th[NUM_THREADS];
long rc, i;
pid_t pgid;
for (i = 0; i < NUM_THREADS; i++) {
rc = pthread_create(&th[i], NULL, pound, (void *)i);
if (rc < 0)
perror("pthread_create");
}
pthread_exit(NULL);
return 0;
}
==== END pound_clock_gettime.c ====
Suggested-by: Mike Galbraith <mgalbraith@suse.de>
Signed-off-by: Giovanni Gherdovich <ggherdovich@suse.cz>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stanislaw Gruszka <sgruszka@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1470385316-15027-2-git-send-email-ggherdovich@suse.cz
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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We should update cfs_rq->throttled_clock_task, not
pcfs_rq->throttle_clock_task.
The effects of this bug was probably occasionally erratic
group scheduling, particularly in cgroups-intense workloads.
Signed-off-by: Xunlei Pang <xlpang@redhat.com>
[ Added changelog. ]
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Fixes: 55e16d30bd99 ("sched/fair: Rework throttle_count sync")
Link: http://lkml.kernel.org/r/1468050862-18864-1-git-send-email-xlpang@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Current code in cpudeadline.c has a bug in re-heapifying when adding a
new element at the end of the heap, because a deadline value of 0 is
temporarily set in the new elem, then cpudl_change_key() is called
with the actual elem deadline as param.
However, the function compares the new deadline to set with the one
previously in the elem, which is 0. So, if current absolute deadlines
grew so much to have negative values as s64, the comparison in
cpudl_change_key() makes the wrong decision. Instead, as from
dl_time_before(), the kernel should handle correctly abs deadlines
wrap-arounds.
This patch fixes the problem with a minimally invasive change that
forces cpudl_change_key() to heapify up in this case.
Signed-off-by: Tommaso Cucinotta <tommaso.cucinotta@sssup.it>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Luca Abeni <luca.abeni@unitn.it>
Cc: Juri Lelli <juri.lelli@arm.com>
Cc: Juri Lelli <juri.lelli@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1468921493-10054-2-git-send-email-tommaso.cucinotta@sssup.it
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull perf fixes from Ingo Molnar:
"Mostly tooling fixes, plus two uncore-PMU fixes, an uprobes fix, a
perf-cgroups fix and an AUX events fix"
* 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
perf/x86/intel/uncore: Add enable_box for client MSR uncore
perf/x86/intel/uncore: Fix uncore num_counters
uprobes/x86: Fix RIP-relative handling of EVEX-encoded instructions
perf/core: Set cgroup in CPU contexts for new cgroup events
perf/core: Fix sideband list-iteration vs. event ordering NULL pointer deference crash
perf probe ppc64le: Fix probe location when using DWARF
perf probe: Add function to post process kernel trace events
tools: Sync cpufeatures headers with the kernel
toops: Sync tools/include/uapi/linux/bpf.h with the kernel
tools: Sync cpufeatures.h and vmx.h with the kernel
perf probe: Support signedness casting
perf stat: Avoid skew when reading events
perf probe: Fix module name matching
perf probe: Adjust map->reloc offset when finding kernel symbol from map
perf hists: Trim libtraceevent trace_seq buffers
perf script: Add 'bpf-output' field to usage message
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There's a perf stat bug easy to observer on a machine with only one cgroup:
$ perf stat -e cycles -I 1000 -C 0 -G /
# time counts unit events
1.000161699 <not counted> cycles /
2.000355591 <not counted> cycles /
3.000565154 <not counted> cycles /
4.000951350 <not counted> cycles /
We'd expect some output there.
The underlying problem is that there is an optimization in
perf_cgroup_sched_{in,out}() that skips the switch of cgroup events
if the old and new cgroups in a task switch are the same.
This optimization interacts with the current code in two ways
that cause a CPU context's cgroup (cpuctx->cgrp) to be NULL even if a
cgroup event matches the current task. These are:
1. On creation of the first cgroup event in a CPU: In current code,
cpuctx->cpu is only set in perf_cgroup_sched_in, but due to the
aforesaid optimization, perf_cgroup_sched_in will run until the next
cgroup switches in that CPU. This may happen late or never happen,
depending on system's number of cgroups, CPU load, etc.
2. On deletion of the last cgroup event in a cpuctx: In list_del_event,
cpuctx->cgrp is set NULL. Any new cgroup event will not be sched in
because cpuctx->cgrp == NULL until a cgroup switch occurs and
perf_cgroup_sched_in is executed (updating cpuctx->cgrp).
This patch fixes both problems by setting cpuctx->cgrp in list_add_event,
mirroring what list_del_event does when removing a cgroup event from CPU
context, as introduced in:
commit 68cacd29167b ("perf_events: Fix stale ->cgrp pointer in update_cgrp_time_from_cpuctx()")
With this patch, cpuctx->cgrp is always set/clear when installing/removing
the first/last cgroup event in/from the CPU context. With cpuctx->cgrp
correctly set, event_filter_match works as intended when events are
sched in/out.
After the fix, the output is as expected:
$ perf stat -e cycles -I 1000 -a -G /
# time counts unit events
1.004699159 627342882 cycles /
2.007397156 615272690 cycles /
3.010019057 616726074 cycles /
Signed-off-by: David Carrillo-Cisneros <davidcc@google.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Kan Liang <kan.liang@intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul Turner <pjt@google.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vegard Nossum <vegard.nossum@gmail.com>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Link: http://lkml.kernel.org/r/1470124092-113192-1-git-send-email-davidcc@google.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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deference crash
Vegard Nossum reported that perf fuzzing generates a NULL
pointer dereference crash:
> Digging a bit deeper into this, it seems the event itself is getting
> created by perf_event_open() and it gets added to the pmu_event_list
> through:
>
> perf_event_open()
> - perf_event_alloc()
> - account_event()
> - account_pmu_sb_event()
> - attach_sb_event()
>
> so at this point the event is being attached but its ->ctx is still
> NULL. It seems like ->ctx is set just a bit later in
> perf_event_open(), though.
>
> But before that, __schedule() comes along and creates a stack trace
> similar to the one above:
>
> __schedule()
> - __perf_event_task_sched_out()
> - perf_iterate_sb()
> - perf_iterate_sb_cpu()
> - event_filter_match()
> - perf_cgroup_match()
> - __get_cpu_context()
> - (dereference ctx which is NULL)
>
> So I guess the question is... should the event be attached (= put on
> the list) before ->ctx gets set? Or should the cgroup code check for a
> NULL ->ctx?
The latter seems like the simplest solution. Moving the list-add later
creates a bit of a mess.
Reported-by: Vegard Nossum <vegard.nossum@gmail.com>
Tested-by: Vegard Nossum <vegard.nossum@gmail.com>
Tested-by: Vince Weaver <vincent.weaver@maine.edu>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: David Carrillo-Cisneros <davidcc@google.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Kan Liang <kan.liang@intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Fixes: f2fb6bef9251 ("perf/core: Optimize side-band event delivery")
Link: http://lkml.kernel.org/r/20160804123724.GN6862@twins.programming.kicks-ass.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull locking fixes from Ingo Molnar:
"Misc fixes: lockstat fix, futex fix on !MMU systems, big endian fix
for qrwlocks and a race fix for pvqspinlocks"
* 'locking-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
locking/pvqspinlock: Fix a bug in qstat_read()
locking/pvqspinlock: Fix double hash race
locking/qrwlock: Fix write unlock bug on big endian systems
futex: Assume all mappings are private on !MMU systems
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It's obviously wrong to set stat to NULL. So lets remove it.
Otherwise it is always zero when we check the latency of kick/wake.
Signed-off-by: Pan Xinhui <xinhui.pan@linux.vnet.ibm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Waiman Long <Waiman.Long@hpe.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1468405414-3700-1-git-send-email-xinhui.pan@linux.vnet.ibm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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When the lock holder vCPU is racing with the queue head:
CPU 0 (lock holder) CPU1 (queue head)
=================== =================
spin_lock(); spin_lock();
pv_kick_node(): pv_wait_head_or_lock():
if (!lp) {
lp = pv_hash(lock, pn);
xchg(&l->locked, _Q_SLOW_VAL);
}
WRITE_ONCE(pn->state, vcpu_halted);
cmpxchg(&pn->state,
vcpu_halted, vcpu_hashed);
WRITE_ONCE(l->locked, _Q_SLOW_VAL);
(void)pv_hash(lock, pn);
In this case, lock holder inserts the pv_node of queue head into the
hash table and set _Q_SLOW_VAL unnecessary. This patch avoids it by
restoring/setting vcpu_hashed state after failing adaptive locking
spinning.
Signed-off-by: Wanpeng Li <wanpeng.li@hotmail.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Pan Xinhui <xinhui.pan@linux.vnet.ibm.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Waiman Long <Waiman.Long@hpe.com>
Link: http://lkml.kernel.org/r/1468484156-4521-1-git-send-email-wanpeng.li@hotmail.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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