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  1. 29 5月, 2018 5 次提交
  3. 25 5月, 2018 1 次提交
    • M
      blk-mq: avoid starving tag allocation after allocating process migrates · e6fc4649
      由 Ming Lei 提交于 
      When the allocation process is scheduled back and the mapped hw queue is
changed, fake one extra wake up on previous queue for compensating wake
up miss, so other allocations on the previous queue won't be starved.

This patch fixes one request allocation hang issue, which can be
triggered easily in case of very low nr_request.

The race is as follows:

1) 2 hw queues, nr_requests are 2, and wake_batch is one

2) there are 3 waiters on hw queue 0

3) two in-flight requests in hw queue 0 are completed, and only two
   waiters of 3 are waken up because of wake_batch, but both the two
   waiters can be scheduled to another CPU and cause to switch to hw
   queue 1

4) then the 3rd waiter will wait for ever, since no in-flight request
   is in hw queue 0 any more.

5) this patch fixes it by the fake wakeup when waiter is scheduled to
   another hw queue

Cc: <stable@vger.kernel.org>
Reviewed-by: NOmar Sandoval <osandov@fb.com>
Signed-off-by: NMing Lei <ming.lei@redhat.com>

Modified commit message to make it clearer, and make it apply on
top of the 4.18 branch.
Signed-off-by: NJens Axboe <axboe@kernel.dk>
      e6fc4649
  5. 15 5月, 2018 6 次提交
  7. 14 5月, 2018 1 次提交
  9. 11 5月, 2018 1 次提交
  11. 09 5月, 2018 4 次提交
  13. 03 5月, 2018 1 次提交
  15. 29 4月, 2018 1 次提交
    • A
      <linux/stringhash.h>: fix end_name_hash() for 64bit long · 19b9ad67
      由 Amir Goldstein 提交于 
      The comment claims that this helper will try not to loose bits, but for
64bit long it looses the high bits before hashing 64bit long into 32bit
int.  Use the helper hash_long() to do the right thing for 64bit long.
For 32bit long, there is no change.

All the callers of end_name_hash() either assign the result to
qstr->hash, which is u32 or return the result as an int value (e.g.
full_name_hash()).  Change the helper return type to int to conform to
its users.

[ It took me a while to apply this, because my initial reaction to it
  was - incorrectly - that it could make for slower code.

  After having looked more at it, I take back all my complaints about
  the patch, Amir was right and I was mis-reading things or just being
  stupid.

  I also don't worry too much about the possible performance impact of
  this on 64-bit, since most architectures that actually care about
  performance end up not using this very much (the dcache code is the
  most performance-critical, but the word-at-a-time case uses its own
  hashing anyway).

  So this ends up being mostly used for filesystems that do their own
  degraded hashing (usually because they want a case-insensitive
  comparison function).

  A _tiny_ worry remains, in that not everybody uses DCACHE_WORD_ACCESS,
  and then this potentially makes things more expensive on 64-bit
  architectures with slow or lacking multipliers even for the normal
  case.

  That said, realistically the only such architecture I can think of is
  PA-RISC. Nobody really cares about performance on that, it's more of a
  "look ma, I've got warts^W an odd machine" platform.

  So the patch is fine, and all my initial worries were just misplaced
  from not looking at this properly.   - Linus ]
Signed-off-by: NAmir Goldstein <amir73il@gmail.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      19b9ad67
  17. 27 4月, 2018 2 次提交
  19. 26 4月, 2018 4 次提交
    • O
      blk-mq: fix sysfs inflight counter · bf0ddaba
      由 Omar Sandoval 提交于 
      When the blk-mq inflight implementation was added, /proc/diskstats was
converted to use it, but /sys/block/$dev/inflight was not. Fix it by
adding another helper to count in-flight requests by data direction.

Fixes: f299b7c7 ("blk-mq: provide internal in-flight variant")
Signed-off-by: NOmar Sandoval <osandov@fb.com>
Signed-off-by: NJens Axboe <axboe@kernel.dk>
      bf0ddaba
    • T
      Revert: Unify CLOCK_MONOTONIC and CLOCK_BOOTTIME · a3ed0e43
      由 Thomas Gleixner 提交于 
      Revert commits

92af4dcb ("tracing: Unify the "boot" and "mono" tracing clocks")
127bfa5f ("hrtimer: Unify MONOTONIC and BOOTTIME clock behavior")
7250a404 ("posix-timers: Unify MONOTONIC and BOOTTIME clock behavior")
d6c7270e ("timekeeping: Remove boot time specific code")
f2d6fdbf ("Input: Evdev - unify MONOTONIC and BOOTTIME clock behavior")
d6ed449a ("timekeeping: Make the MONOTONIC clock behave like the BOOTTIME clock")
72199320 ("timekeeping: Add the new CLOCK_MONOTONIC_ACTIVE clock")

As stated in the pull request for the unification of CLOCK_MONOTONIC and
CLOCK_BOOTTIME, it was clear that we might have to revert the change.

As reported by several folks systemd and other applications rely on the
documented behaviour of CLOCK_MONOTONIC on Linux and break with the above
changes. After resume daemons time out and other timeout related issues are
observed. Rafael compiled this list:

* systemd kills daemons on resume, after >WatchdogSec seconds
  of suspending (Genki Sky).  [Verified that that's because systemd uses
  CLOCK_MONOTONIC and expects it to not include the suspend time.]

* systemd-journald misbehaves after resume:
  systemd-journald[7266]: File /var/log/journal/016627c3c4784cd4812d4b7e96a34226/system.journal
corrupted or uncleanly shut down, renaming and replacing.
  (Mike Galbraith).

* NetworkManager reports "networking disabled" and networking is broken
  after resume 50% of the time (Pavel).  [May be because of systemd.]

* MATE desktop dims the display and starts the screensaver right after
  system resume (Pavel).

* Full system hang during resume (me).  [May be due to systemd or NM or both.]

That happens on debian and open suse systems.

It's sad, that these problems were neither catched in -next nor by those
folks who expressed interest in this change.
Reported-by: NRafael J. Wysocki <rjw@rjwysocki.net>
Reported-by: Genki Sky <sky@genki.is>,
Reported-by: NPavel Machek <pavel@ucw.cz>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Cc: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Cc: John Stultz <john.stultz@linaro.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Kevin Easton <kevin@guarana.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mark Salyzyn <salyzyn@android.com>
Cc: Michael Kerrisk <mtk.manpages@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Petr Mladek <pmladek@suse.com>
Cc: Prarit Bhargava <prarit@redhat.com>
Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
      a3ed0e43
    • A
      remoteproc: fix crashed parameter logic on stop call · fcd58037
      由 Arnaud Pouliquen 提交于 
      Fix rproc_add_subdev parameter name and inverse the crashed logic.

Fixes: 880f5b38 ("remoteproc: Pass type of shutdown to subdev remove")
Reviewed-by: NAlex Elder <elder@linaro.org>
Signed-off-by: NArnaud Pouliquen <arnaud.pouliquen@st.com>
Signed-off-by: NBjorn Andersson <bjorn.andersson@linaro.org>
      fcd58037
    • M
      virtio: add ability to iterate over vqs · 24a7e4d2
      由 Michael S. Tsirkin 提交于 
      For cleanup it's helpful to be able to simply scan all vqs and discard
all data. Add an iterator to do that.

Cc: stable@vger.kernel.org
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>
      24a7e4d2
  21. 25 4月, 2018 2 次提交
  23. 24 4月, 2018 3 次提交
  25. 23 4月, 2018 3 次提交
  27. 21 4月, 2018 3 次提交
    • A
      kasan: add no_sanitize attribute for clang builds · 12c8f25a
      由 Andrey Konovalov 提交于 
      KASAN uses the __no_sanitize_address macro to disable instrumentation of
particular functions.  Right now it's defined only for GCC build, which
causes false positives when clang is used.

This patch adds a definition for clang.

Note, that clang's revision 329612 or higher is required.

[andreyknvl@google.com: remove redundant #ifdef CONFIG_KASAN check]
  Link: http://lkml.kernel.org/r/c79aa31a2a2790f6131ed607c58b0dd45dd62a6c.1523967959.git.andreyknvl@google.com
Link: http://lkml.kernel.org/r/4ad725cc903f8534f8c8a60f0daade5e3d674f8d.1523554166.git.andreyknvl@google.comSigned-off-by: NAndrey Konovalov <andreyknvl@google.com>
Acked-by: NAndrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: David Woodhouse <dwmw@amazon.co.uk>
Cc: Andrey Konovalov <andreyknvl@google.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Paul Lawrence <paullawrence@google.com>
Cc: Sandipan Das <sandipan@linux.vnet.ibm.com>
Cc: Kees Cook <keescook@chromium.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      12c8f25a
    • G
      writeback: safer lock nesting · 2e898e4c
      由 Greg Thelen 提交于 
      lock_page_memcg()/unlock_page_memcg() use spin_lock_irqsave/restore() if
the page's memcg is undergoing move accounting, which occurs when a
process leaves its memcg for a new one that has
memory.move_charge_at_immigrate set.

unlocked_inode_to_wb_begin,end() use spin_lock_irq/spin_unlock_irq() if
the given inode is switching writeback domains.  Switches occur when
enough writes are issued from a new domain.

This existing pattern is thus suspicious:
    lock_page_memcg(page);
    unlocked_inode_to_wb_begin(inode, &locked);
    ...
    unlocked_inode_to_wb_end(inode, locked);
    unlock_page_memcg(page);

If both inode switch and process memcg migration are both in-flight then
unlocked_inode_to_wb_end() will unconditionally enable interrupts while
still holding the lock_page_memcg() irq spinlock.  This suggests the
possibility of deadlock if an interrupt occurs before unlock_page_memcg().

    truncate
    __cancel_dirty_page
    lock_page_memcg
    unlocked_inode_to_wb_begin
    unlocked_inode_to_wb_end
    <interrupts mistakenly enabled>
                                    <interrupt>
                                    end_page_writeback
                                    test_clear_page_writeback
                                    lock_page_memcg
                                    <deadlock>
    unlock_page_memcg

Due to configuration limitations this deadlock is not currently possible
because we don't mix cgroup writeback (a cgroupv2 feature) and
memory.move_charge_at_immigrate (a cgroupv1 feature).

If the kernel is hacked to always claim inode switching and memcg
moving_account, then this script triggers lockup in less than a minute:

  cd /mnt/cgroup/memory
  mkdir a b
  echo 1 > a/memory.move_charge_at_immigrate
  echo 1 > b/memory.move_charge_at_immigrate
  (
    echo $BASHPID > a/cgroup.procs
    while true; do
      dd if=/dev/zero of=/mnt/big bs=1M count=256
    done
  ) &
  while true; do
    sync
  done &
  sleep 1h &
  SLEEP=$!
  while true; do
    echo $SLEEP > a/cgroup.procs
    echo $SLEEP > b/cgroup.procs
  done

The deadlock does not seem possible, so it's debatable if there's any
reason to modify the kernel.  I suggest we should to prevent future
surprises.  And Wang Long said "this deadlock occurs three times in our
environment", so there's more reason to apply this, even to stable.
Stable 4.4 has minor conflicts applying this patch.  For a clean 4.4 patch
see "[PATCH for-4.4] writeback: safer lock nesting"
https://lkml.org/lkml/2018/4/11/146

Wang Long said "this deadlock occurs three times in our environment"

[gthelen@google.com: v4]
  Link: http://lkml.kernel.org/r/20180411084653.254724-1-gthelen@google.com
[akpm@linux-foundation.org: comment tweaks, struct initialization simplification]
Change-Id: Ibb773e8045852978f6207074491d262f1b3fb613
Link: http://lkml.kernel.org/r/20180410005908.167976-1-gthelen@google.com
Fixes: 682aa8e1 ("writeback: implement unlocked_inode_to_wb transaction and use it for stat updates")
Signed-off-by: NGreg Thelen <gthelen@google.com>
Reported-by: NWang Long <wanglong19@meituan.com>
Acked-by: NWang Long <wanglong19@meituan.com>
Acked-by: NMichal Hocko <mhocko@suse.com>
Reviewed-by: NAndrew Morton <akpm@linux-foundation.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Tejun Heo <tj@kernel.org>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: <stable@vger.kernel.org>	[v4.2+]
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      2e898e4c
    • K
      fork: unconditionally clear stack on fork · e01e8063
      由 Kees Cook 提交于 
      One of the classes of kernel stack content leaks[1] is exposing the
contents of prior heap or stack contents when a new process stack is
allocated.  Normally, those stacks are not zeroed, and the old contents
remain in place.  In the face of stack content exposure flaws, those
contents can leak to userspace.

Fixing this will make the kernel no longer vulnerable to these flaws, as
the stack will be wiped each time a stack is assigned to a new process.
There's not a meaningful change in runtime performance; it almost looks
like it provides a benefit.

Performing back-to-back kernel builds before:
	Run times: 157.86 157.09 158.90 160.94 160.80
	Mean: 159.12
	Std Dev: 1.54

and after:
	Run times: 159.31 157.34 156.71 158.15 160.81
	Mean: 158.46
	Std Dev: 1.46

Instead of making this a build or runtime config, Andy Lutomirski
recommended this just be enabled by default.

[1] A noisy search for many kinds of stack content leaks can be seen here:
https://cve.mitre.org/cgi-bin/cvekey.cgi?keyword=linux+kernel+stack+leak

I did some more with perf and cycle counts on running 100,000 execs of
/bin/true.

before:
Cycles: 218858861551 218853036130 214727610969 227656844122 224980542841
Mean:  221015379122.60
Std Dev: 4662486552.47

after:
Cycles: 213868945060 213119275204 211820169456 224426673259 225489986348
Mean:  217745009865.40
Std Dev: 5935559279.99

It continues to look like it's faster, though the deviation is rather
wide, but I'm not sure what I could do that would be less noisy.  I'm
open to ideas!

Link: http://lkml.kernel.org/r/20180221021659.GA37073@beastSigned-off-by: NKees Cook <keescook@chromium.org>
Acked-by: NMichal Hocko <mhocko@suse.com>
Reviewed-by: NAndrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Laura Abbott <labbott@redhat.com>
Cc: Rasmus Villemoes <rasmus.villemoes@prevas.dk>
Cc: Mel Gorman <mgorman@techsingularity.net>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      e01e8063
  29. 20 4月, 2018 1 次提交
    • R
      fsnotify: Fix fsnotify_mark_connector race · d90a10e2
      由 Robert Kolchmeyer 提交于 
      fsnotify() acquires a reference to a fsnotify_mark_connector through
the SRCU-protected pointer to_tell->i_fsnotify_marks. However, it
appears that no precautions are taken in fsnotify_put_mark() to
ensure that fsnotify() drops its reference to this
fsnotify_mark_connector before assigning a value to its 'destroy_next'
field. This can result in fsnotify_put_mark() assigning a value
to a connector's 'destroy_next' field right before fsnotify() tries to
traverse the linked list referenced by the connector's 'list' field.
Since these two fields are members of the same union, this behavior
results in a kernel panic.

This issue is resolved by moving the connector's 'destroy_next' field
into the object pointer union. This should work since the object pointer
access is protected by both a spinlock and the value of the 'flags'
field, and the 'flags' field is cleared while holding the spinlock in
fsnotify_put_mark() before 'destroy_next' is updated. It shouldn't be
possible for another thread to accidentally read from the object pointer
after the 'destroy_next' field is updated.

The offending behavior here is extremely unlikely; since
fsnotify_put_mark() removes references to a connector (specifically,
it ensures that the connector is unreachable from the inode it was
formerly attached to) before updating its 'destroy_next' field, a
sizeable chunk of code in fsnotify_put_mark() has to execute in the
short window between when fsnotify() acquires the connector reference
and saves the value of its 'list' field. On the HEAD kernel, I've only
been able to reproduce this by inserting a udelay(1) in fsnotify().
However, I've been able to reproduce this issue without inserting a
udelay(1) anywhere on older unmodified release kernels, so I believe
it's worth fixing at HEAD.

References: https://bugzilla.kernel.org/show_bug.cgi?id=199437
Fixes: 08991e83
CC: stable@vger.kernel.org
Signed-off-by: NRobert Kolchmeyer <rkolchmeyer@google.com>
Signed-off-by: NJan Kara <jack@suse.cz>
      d90a10e2
  31. 19 4月, 2018 2 次提交