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| author |   Wei Fang <fangwei1@huawei.com> | 2016-07-06 11:32:20 +0800 |
|---|---|---|
| committer |   Al Viro <viro@zeniv.linux.org.uk> | 2016-07-24 16:37:16 -0400 |
| commit | 47be61845c775643f1aa4d2a54343549f943c94c (patch) | |
| tree | 7bc3d07cecb30116a51bdf11dfa0540bfacc4e43 /Documentation/filesystems/Locking | |
| parent | vfs: new d_init method (diff) | |
| download | linux-dev-47be61845c775643f1aa4d2a54343549f943c94c.tar.xz linux-dev-47be61845c775643f1aa4d2a54343549f943c94c.zip | |
fs/dcache.c: avoid soft-lockup in dput()
We triggered soft-lockup under stress test which
open/access/write/close one file concurrently on more than
five different CPUs:
WARN: soft lockup - CPU#0 stuck for 11s! [who:30631]
...
[<ffffffc0003986f8>] dput+0x100/0x298
[<ffffffc00038c2dc>] terminate_walk+0x4c/0x60
[<ffffffc00038f56c>] path_lookupat+0x5cc/0x7a8
[<ffffffc00038f780>] filename_lookup+0x38/0xf0
[<ffffffc000391180>] user_path_at_empty+0x78/0xd0
[<ffffffc0003911f4>] user_path_at+0x1c/0x28
[<ffffffc00037d4fc>] SyS_faccessat+0xb4/0x230
->d_lock trylock may failed many times because of concurrently
operations, and dput() may execute a long time.
Fix this by replacing cpu_relax() with cond_resched().
dput() used to be sleepable, so make it sleepable again
should be safe.
Cc: <stable@vger.kernel.org>
Signed-off-by: Wei Fang <fangwei1@huawei.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Diffstat (limited to 'Documentation/filesystems/Locking')
0 files changed, 0 insertions, 0 deletions