From: Andrew Morton <akpm@linux-foundation.org>
Date: Sat, 16 Nov 2024 00:57:24 +0000 (-0800)
Subject: mm: revert "mm: shmem: fix data-race in shmem_getattr()"
X-Git-Url: http://git.hungrycats.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=5874c1150e77296565ad6e495ef41fbf87570d14;p=linux

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

commit d1aa0c04294e29883d65eac6c2f72fe95cc7c049 upstream.

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 [1]
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>
Signed-off-by: Hugh Dickins <hughd@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---

diff --git a/mm/shmem.c b/mm/shmem.c
index 0e1fbc53717d..f7c08e169e42 100644
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -1086,9 +1086,7 @@ static int shmem_getattr(struct user_namespace *mnt_userns,
 	stat->attributes_mask |= (STATX_ATTR_APPEND |
 			STATX_ATTR_IMMUTABLE |
 			STATX_ATTR_NODUMP);
-	inode_lock_shared(inode);
 	generic_fillattr(&init_user_ns, inode, stat);
-	inode_unlock_shared(inode);
 
 	if (shmem_is_huge(NULL, inode, 0, false))
 		stat->blksize = HPAGE_PMD_SIZE;