Messages in this thread Patch in this message | | | From | Greg Kroah-Hartman <> | Subject | [PATCH 4.14 139/496] fs: dcache: Use READ_ONCE when accessing i_dir_seq | Date | Mon, 28 May 2018 11:58:44 +0200 |
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4.14-stable review patch. If anyone has any objections, please let me know.
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From: Will Deacon <will.deacon@arm.com>
[ Upstream commit 8cc07c808c9d595e81cbe5aad419b7769eb2e5c9 ]
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> Signed-off-by: Sasha Levin <alexander.levin@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> --- fs/dcache.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
--- a/fs/dcache.c +++ b/fs/dcache.c @@ -2510,7 +2510,7 @@ 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;
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