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  1. 27 Jan, 2015 32 commits
  3. 16 Jan, 2015 8 commits
    • Greg Kroah-Hartman's avatar
      Linux 3.14.29 · a2ab9187
      Greg Kroah-Hartman authored
      a2ab9187
    • Linus Torvalds's avatar
      mm: Don't count the stack guard page towards RLIMIT_STACK · 1bec714a
      Linus Torvalds authored 
      commit 690eac53 upstream.

Commit fee7e49d ("mm: propagate error from stack expansion even for
guard page") made sure that we return the error properly for stack
growth conditions.  It also theorized that counting the guard page
towards the stack limit might break something, but also said "Let's see
if anybody notices".

Somebody did notice.  Apparently android-x86 sets the stack limit very
close to the limit indeed, and including the guard page in the rlimit
check causes the android 'zygote' process problems.

So this adds the (fairly trivial) code to make the stack rlimit check be
against the actual real stack size, rather than the size of the vma that
includes the guard page.
Reported-and-tested-by: default avatarChih-Wei Huang <cwhuang@android-x86.org>
Cc: Jay Foad <jay.foad@gmail.com>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      1bec714a
    • Linus Torvalds's avatar
      mm: propagate error from stack expansion even for guard page · 11e4f3bf
      Linus Torvalds authored 
      commit fee7e49d upstream.

Jay Foad reports that the address sanitizer test (asan) sometimes gets
confused by a stack pointer that ends up being outside the stack vma
that is reported by /proc/maps.

This happens due to an interaction between RLIMIT_STACK and the guard
page: when we do the guard page check, we ignore the potential error
from the stack expansion, which effectively results in a missing guard
page, since the expected stack expansion won't have been done.

And since /proc/maps explicitly ignores the guard page (commit
d7824370: "mm: fix up some user-visible effects of the stack guard
page"), the stack pointer ends up being outside the reported stack area.

This is the minimal patch: it just propagates the error.  It also
effectively makes the guard page part of the stack limit, which in turn
measn that the actual real stack is one page less than the stack limit.

Let's see if anybody notices.  We could teach acct_stack_growth() to
allow an extra page for a grow-up/grow-down stack in the rlimit test,
but I don't want to add more complexity if it isn't needed.
Reported-and-tested-by: default avatarJay Foad <jay.foad@gmail.com>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      11e4f3bf
    • Vlastimil Babka's avatar
      mm, vmscan: prevent kswapd livelock due to pfmemalloc-throttled process being killed · 18d9304b
      Vlastimil Babka authored 
      commit 9e5e3661 upstream.

Charles Shirron and Paul Cassella from Cray Inc have reported kswapd
stuck in a busy loop with nothing left to balance, but
kswapd_try_to_sleep() failing to sleep.  Their analysis found the cause
to be a combination of several factors:

1. A process is waiting in throttle_direct_reclaim() on pgdat->pfmemalloc_wait

2. The process has been killed (by OOM in this case), but has not yet been
   scheduled to remove itself from the waitqueue and die.

3. kswapd checks for throttled processes in prepare_kswapd_sleep():

        if (waitqueue_active(&pgdat->pfmemalloc_wait)) {
                wake_up(&pgdat->pfmemalloc_wait);
		return false; // kswapd will not go to sleep
	}

   However, for a process that was already killed, wake_up() does not remove
   the process from the waitqueue, since try_to_wake_up() checks its state
   first and returns false when the process is no longer waiting.

4. kswapd is running on the same CPU as the only CPU that the process is
   allowed to run on (through cpus_allowed, or possibly single-cpu system).

5. CONFIG_PREEMPT_NONE=y kernel is used. If there's nothing to balance, kswapd
   encounters no voluntary preemption points and repeatedly fails
   prepare_kswapd_sleep(), blocking the process from running and removing
   itself from the waitqueue, which would let kswapd sleep.

So, the source of the problem is that we prevent kswapd from going to
sleep until there are processes waiting on the pfmemalloc_wait queue,
and a process waiting on a queue is guaranteed to be removed from the
queue only when it gets scheduled.  This was done to make sure that no
process is left sleeping on pfmemalloc_wait when kswapd itself goes to
sleep.

However, it isn't necessary to postpone kswapd sleep until the
pfmemalloc_wait queue actually empties.  To prevent processes from being
left sleeping, it's actually enough to guarantee that all processes
waiting on pfmemalloc_wait queue have been woken up by the time we put
kswapd to sleep.

This patch therefore fixes this issue by substituting 'wake_up' with
'wake_up_all' and removing 'return false' in the code snippet from
prepare_kswapd_sleep() above.  Note that if any process puts itself in
the queue after this waitqueue_active() check, or after the wake up
itself, it means that the process will also wake up kswapd - and since
we are under prepare_to_wait(), the wake up won't be missed.  Also we
update the comment prepare_kswapd_sleep() to hopefully more clearly
describe the races it is preventing.

Fixes: 5515061d ("mm: throttle direct reclaimers if PF_MEMALLOC reserves are low and swap is backed by network storage")
Signed-off-by: default avatarVlastimil Babka <vbabka@suse.cz>
Signed-off-by: default avatarVladimir Davydov <vdavydov@parallels.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: default avatarMichal Hocko <mhocko@suse.cz>
Acked-by: default avatarRik van Riel <riel@redhat.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      18d9304b
    • Krzysztof Kozlowski's avatar
      mmc: sdhci: Fix sleep in atomic after inserting SD card · b36cd20d
      Krzysztof Kozlowski authored 
      commit 2836766a upstream.

Sleep in atomic context happened on Trats2 board after inserting or
removing SD card because mmc_gpio_get_cd() was called under spin lock.

Fix this by moving card detection earlier, before acquiring spin lock.
The mmc_gpio_get_cd() call does not have to be protected by spin lock
because it does not access any sdhci internal data.
The sdhci_do_get_cd() call access host flags (SDHCI_DEVICE_DEAD). After
moving it out side of spin lock it could theoretically race with driver
removal but still there is no actual protection against manual card
eject.

Dmesg after inserting SD card:
[   41.663414] BUG: sleeping function called from invalid context at drivers/gpio/gpiolib.c:1511
[   41.670469] in_atomic(): 1, irqs_disabled(): 128, pid: 30, name: kworker/u8:1
[   41.677580] INFO: lockdep is turned off.
[   41.681486] irq event stamp: 61972
[   41.684872] hardirqs last  enabled at (61971): [<c0490ee0>] _raw_spin_unlock_irq+0x24/0x5c
[   41.693118] hardirqs last disabled at (61972): [<c04907ac>] _raw_spin_lock_irq+0x18/0x54
[   41.701190] softirqs last  enabled at (61648): [<c0026fd4>] __do_softirq+0x234/0x2c8
[   41.708914] softirqs last disabled at (61631): [<c00273a0>] irq_exit+0xd0/0x114
[   41.716206] Preemption disabled at:[<  (null)>]   (null)
[   41.721500]
[   41.722985] CPU: 3 PID: 30 Comm: kworker/u8:1 Tainted: G        W      3.18.0-rc5-next-20141121 #883
[   41.732111] Workqueue: kmmcd mmc_rescan
[   41.735945] [<c0014d2c>] (unwind_backtrace) from [<c0011c80>] (show_stack+0x10/0x14)
[   41.743661] [<c0011c80>] (show_stack) from [<c0489d14>] (dump_stack+0x70/0xbc)
[   41.750867] [<c0489d14>] (dump_stack) from [<c0228b74>] (gpiod_get_raw_value_cansleep+0x18/0x30)
[   41.759628] [<c0228b74>] (gpiod_get_raw_value_cansleep) from [<c03646e8>] (mmc_gpio_get_cd+0x38/0x58)
[   41.768821] [<c03646e8>] (mmc_gpio_get_cd) from [<c036d378>] (sdhci_request+0x50/0x1a4)
[   41.776808] [<c036d378>] (sdhci_request) from [<c0357934>] (mmc_start_request+0x138/0x268)
[   41.785051] [<c0357934>] (mmc_start_request) from [<c0357cc8>] (mmc_wait_for_req+0x58/0x1a0)
[   41.793469] [<c0357cc8>] (mmc_wait_for_req) from [<c0357e68>] (mmc_wait_for_cmd+0x58/0x78)
[   41.801714] [<c0357e68>] (mmc_wait_for_cmd) from [<c0361c00>] (mmc_io_rw_direct_host+0x98/0x124)
[   41.810480] [<c0361c00>] (mmc_io_rw_direct_host) from [<c03620f8>] (sdio_reset+0x2c/0x64)
[   41.818641] [<c03620f8>] (sdio_reset) from [<c035a3d8>] (mmc_rescan+0x254/0x2e4)
[   41.826028] [<c035a3d8>] (mmc_rescan) from [<c003a0e0>] (process_one_work+0x180/0x3f4)
[   41.833920] [<c003a0e0>] (process_one_work) from [<c003a3bc>] (worker_thread+0x34/0x4b0)
[   41.841991] [<c003a3bc>] (worker_thread) from [<c003fed8>] (kthread+0xe4/0x104)
[   41.849285] [<c003fed8>] (kthread) from [<c000f268>] (ret_from_fork+0x14/0x2c)
[   42.038276] mmc0: new high speed SDHC card at address 1234
Signed-off-by: default avatarKrzysztof Kozlowski <k.kozlowski@samsung.com>
Fixes: 94144a46 ("mmc: sdhci: add get_cd() implementation")
Signed-off-by: default avatarUlf Hansson <ulf.hansson@linaro.org>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      b36cd20d
    • Stefan Roese's avatar
      spi: fsl: Fix problem with multi message transfers · 2937d5ac
      Stefan Roese authored 
      commit 4302a596 upstream.

When used via spidev with more than one messages to tranfer via
SPI_IOC_MESSAGE the current implementation would return with
-EINVAL, since bits_per_word and speed_hz are set in all
transfer structs. And in the 2nd loop status will stay at
-EINVAL as its not overwritten again via fsl_spi_setup_transfer().

This patch changes this behavious by first checking if one of
the messages uses different settings. If this is the case
the function will return with -EINVAL. If not, the messages
are transferred correctly.
Signed-off-by: default avatarStefan Roese <sr@denx.de>
Signed-off-by: default avatarMark Brown <broonie@linaro.org>
Cc: Esben Haabendal <esbenhaabendal@gmail.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      2937d5ac
    • Jiri Olsa's avatar
      perf session: Do not fail on processing out of order event · ceaefcdf
      Jiri Olsa authored 
      commit f61ff6c0 upstream.

Linus reported perf report command being interrupted due to processing
of 'out of order' event, with following error:

  Timestamp below last timeslice flush
  0x5733a8 [0x28]: failed to process type: 3

I could reproduce the issue and in my case it was caused by one CPU
(mmap) being behind during record and userspace mmap reader seeing the
data after other CPUs data were already stored.

This is expected under some circumstances because we need to limit the
number of events that we queue for reordering when we receive a
PERF_RECORD_FINISHED_ROUND or when we force flush due to memory
pressure.
Reported-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: default avatarJiri Olsa <jolsa@kernel.org>
Acked-by: default avatarIngo Molnar <mingo@kernel.org>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Matt Fleming <matt.fleming@intel.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/r/1417016371-30249-1-git-send-email-jolsa@kernel.orgSigned-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
[zhangzhiqiang: backport to 3.10:
 - adjust context
 - commit f61ff6c0 struct events_stats was defined in tools/perf/util/event.h
   while 3.10 stable defined in tools/perf/util/hist.h.
 - 3.10 stable there is no pr_oe_time() which used for debug.
 - After the above adjustments, becomes same to the original patch:
   https://github.com/torvalds/linux/commit/f61ff6c06dc8f32c7036013ad802c899ec590607
]
Signed-off-by: default avatarZhiqiang Zhang <zhangzhiqiang.zhang@huawei.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      ceaefcdf
    • Jiri Olsa's avatar
      perf: Fix events installation during moving group · c8af8989
      Jiri Olsa authored 
      commit 9fc81d87 upstream.

We allow PMU driver to change the cpu on which the event
should be installed to. This happened in patch:

  e2d37cd2 ("perf: Allow the PMU driver to choose the CPU on which to install events")

This patch also forces all the group members to follow
the currently opened events cpu if the group happened
to be moved.

This and the change of event->cpu in perf_install_in_context()
function introduced in:

  0cda4c02 ("perf: Introduce perf_pmu_migrate_context()")

forces group members to change their event->cpu,
if the currently-opened-event's PMU changed the cpu
and there is a group move.

Above behaviour causes problem for breakpoint events,
which uses event->cpu to touch cpu specific data for
breakpoints accounting. By changing event->cpu, some
breakpoints slots were wrongly accounted for given
cpu.

Vinces's perf fuzzer hit this issue and caused following
WARN on my setup:

   WARNING: CPU: 0 PID: 20214 at arch/x86/kernel/hw_breakpoint.c:119 arch_install_hw_breakpoint+0x142/0x150()
   Can't find any breakpoint slot
   [...]

This patch changes the group moving code to keep the event's
original cpu.
Reported-by: default avatarVince Weaver <vince@deater.net>
Signed-off-by: default avatarJiri Olsa <jolsa@redhat.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Vince Weaver <vince@deater.net>
Cc: Yan, Zheng <zheng.z.yan@intel.com>
Link: http://lkml.kernel.org/r/1418243031-20367-3-git-send-email-jolsa@kernel.orgSigned-off-by: default avatarIngo Molnar <mingo@kernel.org>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      c8af8989
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