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Filename Latest commit message Latest commit date
Guoqing Jiang d1d90147c9 md: always set THREAD_WAKEUP and wake up wqueue if thread existed
Since commit 4ad23a9764 ("MD: use per-cpu counter for writes_pending"),
the wait_queue is only got invoked if THREAD_WAKEUP is not set previously.

With above change, I can see process_metadata_update could always hang on
the wait queue, because mddev->thread could stay on 'D' status and the
THREAD_WAKEUP flag is not cleared since there are lots of place to wake up
mddev->thread. Then deadlock happened as follows:

linux175:~ # ps aux|grep md|grep D
root    20117   0.0 0.0         0   0 ? D   03:45   0:00 [md0_raid1]
root    20125   0.0 0.0         0   0 ? D   03:45   0:00 [md0_cluster_rec]
linux175:~ # cat /proc/20117/stack
[<ffffffffa0635604>] dlm_lock_sync+0x94/0xd0 [md_cluster]
[<ffffffffa0635674>] lock_token+0x34/0xd0 [md_cluster]
[<ffffffffa0635804>] metadata_update_start+0x64/0x110 [md_cluster]
[<ffffffffa04d985b>] md_update_sb.part.58+0x9b/0x860 [md_mod]
[<ffffffffa04da035>] md_update_sb+0x15/0x30 [md_mod]
[<ffffffffa04dc066>] md_check_recovery+0x266/0x490 [md_mod]
[<ffffffffa06450e2>] raid1d+0x42/0x810 [raid1]
[<ffffffffa04d2252>] md_thread+0x122/0x150 [md_mod]
[<ffffffff81091741>] kthread+0x101/0x140
linux175:~ # cat /proc/20125/stack
[<ffffffffa0636679>] recv_daemon+0x3f9/0x5c0 [md_cluster]
[<ffffffffa04d2252>] md_thread+0x122/0x150 [md_mod]
[<ffffffff81091741>] kthread+0x101/0x140

So let's revert the part of code in the commit to resovle the problem since
we can't get lots of benefits of previous change.

Fixes: 4ad23a9764 ("MD: use per-cpu counter for writes_pending")
Signed-off-by: Guoqing Jiang <gqjiang@suse.com>
Signed-off-by: Shaohua Li <shli@fb.com>
2017-10-08 20:36:39 -07:00
arch Merge branch 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2017-10-01 13:55:32 -07:00
block
certs
crypto
Documentation LED fixes for 4.14-rc3 2017-09-29 19:33:32 -07:00
drivers md: always set THREAD_WAKEUP and wake up wqueue if thread existed 2017-10-08 20:36:39 -07:00
firmware
fs Merge branch 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2017-10-01 12:10:02 -07:00
include Merge branch 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2017-10-01 13:03:16 -07:00
init
ipc
kernel Merge branch 'smp-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2017-10-01 12:34:42 -07:00
lib
mm
net
samples
scripts
security
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tools Merge branch 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2017-10-01 12:06:31 -07:00
usr
virt
.cocciconfig
.get_maintainer.ignore
.gitattributes
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COPYING
CREDITS
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MAINTAINERS LED fixes for 4.14-rc3 2017-09-29 19:33:32 -07:00
Makefile Linux 4.14-rc3 2017-10-01 14:54:54 -07:00
README

Linux kernel
============

This file was moved to Documentation/admin-guide/README.rst

Please notice that there are several guides for kernel developers and users.
These guides can be rendered in a number of formats, like HTML and PDF.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
See Documentation/00-INDEX for a list of what is contained in each file.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.