The patch titled
Subject: fs/dcache.c: re-add cond_resched() in shrink_dcache_parent()
has been added to the -mm tree. Its filename is
fs-dcachec-re-add-cond_resched-in-shrink_dcache_parent.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/fs-dcachec-re-add-cond_resched-in-shrink_dcache_parent.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/fs-dcachec-re-add-cond_resched-in-shrink_dcache_parent.patch
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------------------------------------------------------
From: Khazhismel Kumykov <khazhy@xxxxxxxxxx>
Subject: fs/dcache.c: re-add cond_resched() in shrink_dcache_parent()
shrink_dcache_parent() may spin waiting for a parallel
shrink_dentry_list(). In this case we may have 0 dentries to dispose, so
we will never schedule out while waiting for the parallel
shrink_dentry_list to complete.
Tested that this fixes syzbot reports of stalls in shrink_dcache_parent().
Link: http://lkml.kernel.org/r/20180413202823.204377-1-khazhy@xxxxxxxxxx
Fixes: 32785c0539b7 ("fs/dcache.c: add cond_resched() in shrink_dentry_list()")
Signed-off-by: Khazhismel Kumykov <khazhy@xxxxxxxxxx>
Reported-by: syzbot+ae80b790eb412884ca77@xxxxxxxxxxxxxxxxxxxxxxxxx
Cc: Nikolay Borisov <nborisov@xxxxxxxx>
Cc: David Rientjes <rientjes@xxxxxxxxxx>
Cc: Alexander Viro <viro@xxxxxxxxxxxxxxxxxx>
Cc: Goldwyn Rodrigues <rgoldwyn@xxxxxxx>
Cc: Jeff Mahoney <jeffm@xxxxxxxx>
Cc: Davidlohr Bueso <dave@xxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
fs/dcache.c | 1 +
1 file changed, 1 insertion(+)
diff -puN fs/dcache.c~fs-dcachec-re-add-cond_resched-in-shrink_dcache_parent fs/dcache.c
--- a/fs/dcache.c~fs-dcachec-re-add-cond_resched-in-shrink_dcache_parent
+++ a/fs/dcache.c
@@ -1488,6 +1488,7 @@ void shrink_dcache_parent(struct dentry
break;
shrink_dentry_list(&data.dispose);
+ cond_resched();
}
}
EXPORT_SYMBOL(shrink_dcache_parent);
_
Patches currently in -mm which might be from khazhy@xxxxxxxxxx are
fs-dcachec-re-add-cond_resched-in-shrink_dcache_parent.patch
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