4.14-stable review patch. If anyone has any objections, please let me know.
------------------ From: Will Deacon <[email protected]> [ 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 <[email protected]> Signed-off-by: Will Deacon <[email protected]> Signed-off-by: Al Viro <[email protected]> Signed-off-by: Sasha Levin <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]> --- 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;
