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authorWill Deacon <will.deacon@arm.com>2018-02-19 14:55:55 +0000
committerAl Viro <viro@zeniv.linux.org.uk>2018-02-25 12:51:10 -0500
commit8cc07c808c9d595e81cbe5aad419b7769eb2e5c9 (patch)
treeb67b43888c8f559aba6365fd2a9965584d626f41
parent015555fd4d2930bc0c86952c46ad88b3392f66e4 (diff)
downloadlinux-8cc07c808c9d595e81cbe5aad419b7769eb2e5c9.tar.bz2
fs: dcache: Use READ_ONCE when accessing i_dir_seq
i_dir_seq is subject to concurrent modification by a cmpxchg or store-release operation, so ensure that the relaxed access in d_alloc_parallel uses READ_ONCE. Reported-by: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Will Deacon <will.deacon@arm.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
-rw-r--r--fs/dcache.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/fs/dcache.c b/fs/dcache.c
index bde3b6662601..8945e6cabd93 100644
--- a/fs/dcache.c
+++ b/fs/dcache.c
@@ -2507,7 +2507,7 @@ retry:
}
hlist_bl_lock(b);
- if (unlikely(parent->d_inode->i_dir_seq != seq)) {
+ if (unlikely(READ_ONCE(parent->d_inode->i_dir_seq) != seq)) {
hlist_bl_unlock(b);
rcu_read_unlock();
goto retry;