Skip to content

K
kernel_linux

OpenHarmony / kernel_linux
上一次同步 4 年多

通知 15
Star 8
Fork 2
K
kernel_linux
切换分支/标签
  1. 06 11月, 2013 23 次提交
  3. 29 8月, 2013 3 次提交
    • H
      cgroup: fix rmdir EBUSY regression in 3.11 · bb78a92f
      由 Hugh Dickins 提交于 
      On 3.11-rc we are seeing cgroup directories left behind when they should
have been removed.  Here's a trivial reproducer:

cd /sys/fs/cgroup/memory
mkdir parent parent/child; rmdir parent/child parent
rmdir: failed to remove `parent': Device or resource busy

It's because cgroup_destroy_locked() (step 1 of destruction) leaves
cgroup on parent's children list, letting cgroup_offline_fn() (step 2 of
destruction) remove it; but step 2 is run by work queue, which may not
yet have removed the children when parent destruction checks the list.

Fix that by checking through a non-empty list of children: if every one
of them has already been marked CGRP_DEAD, then it's safe to proceed:
those children are invisible to userspace, and should not obstruct rmdir.

(I didn't see any reason to keep the cgrp->children checks under the
unrelated css_set_lock, so moved them out.)

tj: Flattened nested ifs a bit and updated comment so that it's
    correct on both for-3.11-fixes and for-3.12.
Signed-off-by: NHugh Dickins <hughd@google.com>
Signed-off-by: NTejun Heo <tj@kernel.org>
      bb78a92f
    • T
      workqueue: cond_resched() after processing each work item · b22ce278
      由 Tejun Heo 提交于 
      If !PREEMPT, a kworker running work items back to back can hog CPU.
This becomes dangerous when a self-requeueing work item which is
waiting for something to happen races against stop_machine.  Such
self-requeueing work item would requeue itself indefinitely hogging
the kworker and CPU it's running on while stop_machine would wait for
that CPU to enter stop_machine while preventing anything else from
happening on all other CPUs.  The two would deadlock.

Jamie Liu reports that this deadlock scenario exists around
scsi_requeue_run_queue() and libata port multiplier support, where one
port may exclude command processing from other ports.  With the right
timing, scsi_requeue_run_queue() can end up requeueing itself trying
to execute an IO which is asked to be retried while another device has
an exclusive access, which in turn can't make forward progress due to
stop_machine.

Fix it by invoking cond_resched() after executing each work item.
Signed-off-by: NTejun Heo <tj@kernel.org>
Reported-by: NJamie Liu <jamieliu@google.com>
References: http://thread.gmane.org/gmane.linux.kernel/1552567
Cc: stable@vger.kernel.org
--
 kernel/workqueue.c |    9 +++++++++
 1 file changed, 9 insertions(+)
      b22ce278
    • N
      timer_list: correct the iterator for timer_list · 84a78a65
      由 Nathan Zimmer 提交于 
      Correct an issue with /proc/timer_list reported by Holger.

When reading from the proc file with a sufficiently small buffer, 2k so
not really that small, there was one could get hung trying to read the
file a chunk at a time.

The timer_list_start function failed to account for the possibility that
the offset was adjusted outside the timer_list_next.
Signed-off-by: NNathan Zimmer <nzimmer@sgi.com>
Reported-by: NHolger Hans Peter Freyther <holger@freyther.de>
Cc: John Stultz <john.stultz@linaro.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Berke Durak <berke.durak@xiphos.com>
Cc: Jeff Layton <jlayton@redhat.com>
Tested-by: NAl Viro <viro@zeniv.linux.org.uk>
Cc: <stable@vger.kernel.org> # 3.10.x
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      84a78a65
  5. 28 8月, 2013 1 次提交
  7. 21 8月, 2013 1 次提交
    • L
      cpuset: fix a regression in validating config change · 1c09b195
      由 Li Zefan 提交于 
      It's not allowed to clear masks of a cpuset if there're tasks in it,
but it's broken:

  # mkdir /cgroup/sub
  # echo 0 > /cgroup/sub/cpuset.cpus
  # echo 0 > /cgroup/sub/cpuset.mems
  # echo $$ > /cgroup/sub/tasks
  # echo > /cgroup/sub/cpuset.cpus
  (should fail)

This bug was introduced by commit 88fa523b
("cpuset: allow to move tasks to empty cpusets").

tj: Dropped temp bool variables and nestes the conditionals directly.
Signed-off-by: NLi Zefan <lizefan@huawei.com>
Signed-off-by: NTejun Heo <tj@kernel.org>
      1c09b195
  9. 20 8月, 2013 1 次提交
  11. 14 8月, 2013 2 次提交
    • M
      microblaze: fix clone syscall · dfa9771a
      由 Michal Simek 提交于 
      Fix inadvertent breakage in the clone syscall ABI for Microblaze that
was introduced in commit f3268edb ("microblaze: switch to generic
fork/vfork/clone").

The Microblaze syscall ABI for clone takes the parent tid address in the
4th argument; the third argument slot is used for the stack size.  The
incorrectly-used CLONE_BACKWARDS type assigned parent tid to the 3rd
slot.

This commit restores the original ABI so that existing userspace libc
code will work correctly.

All kernel versions from v3.8-rc1 were affected.
Signed-off-by: NMichal Simek <michal.simek@xilinx.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      dfa9771a
    • S
      PM / QoS: Fix workqueue deadlock when using pm_qos_update_request_timeout() · 40fea92f
      由 Stephen Boyd 提交于 
      pm_qos_update_request_timeout() updates a qos and then schedules
a delayed work item to bring the qos back down to the default
after the timeout. When the work item runs, pm_qos_work_fn() will
call pm_qos_update_request() and deadlock because it tries to
cancel itself via cancel_delayed_work_sync(). Future callers of
that qos will also hang waiting to cancel the work that is
canceling itself. Let's extract the little bit of code that does
the real work of pm_qos_update_request() and call it from the
work function so that we don't deadlock.

Before ed1ac6e9 (PM: don't use [delayed_]work_pending()) this didn't
happen because the work function wouldn't try to cancel itself.
Signed-off-by: NStephen Boyd <sboyd@codeaurora.org>
Reviewed-by: NTejun Heo <tj@kernel.org>
Cc: 3.9+ <stable@vger.kernel.org> # 3.9+
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>
      40fea92f
  13. 13 8月, 2013 2 次提交
    • O
      sched: fix the theoretical signal_wake_up() vs schedule() race · e0acd0a6
      由 Oleg Nesterov 提交于 
      This is only theoretical, but after try_to_wake_up(p) was changed
to check p->state under p->pi_lock the code like

	__set_current_state(TASK_INTERRUPTIBLE);
	schedule();

can miss a signal. This is the special case of wait-for-condition,
it relies on try_to_wake_up/schedule interaction and thus it does
not need mb() between __set_current_state() and if(signal_pending).

However, this __set_current_state() can move into the critical
section protected by rq->lock, now that try_to_wake_up() takes
another lock we need to ensure that it can't be reordered with
"if (signal_pending(current))" check inside that section.

The patch is actually one-liner, it simply adds smp_wmb() before
spin_lock_irq(rq->lock). This is what try_to_wake_up() already
does by the same reason.

We turn this wmb() into the new helper, smp_mb__before_spinlock(),
for better documentation and to allow the architectures to change
the default implementation.

While at it, kill smp_mb__after_lock(), it has no callers.

Perhaps we can also add smp_mb__before/after_spinunlock() for
prepare_to_wait().
Signed-off-by: NOleg Nesterov <oleg@redhat.com>
Acked-by: NPeter Zijlstra <peterz@infradead.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      e0acd0a6
    • L
      cpuset: fix the return value of cpuset_write_u64() · a903f086
      由 Li Zefan 提交于 
      Writing to this file always returns -ENODEV:

  # echo 1 > cpuset.memory_pressure_enabled
  -bash: echo: write error: No such device
Signed-off-by: NLi Zefan <lizefan@huawei.com>
Cc: <stable@vger.kernel.org> # 3.9+
Signed-off-by: NTejun Heo <tj@kernel.org>
      a903f086
  15. 09 8月, 2013 1 次提交
  17. 07 8月, 2013 3 次提交
  19. 03 8月, 2013 3 次提交