mm: revert "mm: shmem: fix data-race in shmem_getattr()"

Revert d949d1d14fa2 ("mm: shmem: fix data-race in shmem_getattr()") as
suggested by Chuck [1].  It is causing deadlocks when accessing tmpfs over
NFS.

As Hugh commented, "added just to silence a syzbot sanitizer splat: added
where there has never been any practical problem".

Link: https://lkml.kernel.org/r/ZzdxKF39VEmXSSyN@tissot.1015granger.net
Fixes: d949d1d14fa2 ("mm: shmem: fix data-race in shmem_getattr()")
Acked-by: Hugh Dickins <hughd@google.com>
Cc: Chuck Lever <chuck.lever@oracle.com>
Cc: Jeongjun Park <aha310510@gmail.com>
Cc: Yu Zhao <yuzhao@google.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/mm/shmem.c b/mm/shmem.c
index e87f5d6799a7bbff935d33da4ea6a9d2809066b2..568bb290bdce3e11ad0ba6e467360b5fb2cccda6 100644 (file)
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -1166,9 +1166,7 @@ static int shmem_getattr(struct mnt_idmap *idmap,
        stat->attributes_mask |= (STATX_ATTR_APPEND |
                        STATX_ATTR_IMMUTABLE |
                        STATX_ATTR_NODUMP);
-       inode_lock_shared(inode);
        generic_fillattr(idmap, request_mask, inode, stat);
-       inode_unlock_shared(inode);
 
        if (shmem_huge_global_enabled(inode, 0, 0, false, NULL, 0))
                stat->blksize = HPAGE_PMD_SIZE;