FAILED: patch "[PATCH] mm: revert "mm: shmem: fix data-race in shmem_getattr()"" failed to apply to 4.19-stable tree

FAILED: patch "[PATCH] mm: revert "mm: shmem: fix data-race in shmem_getattr()"" failed to apply to 4.19-stable tree

[gregkh]

The patch below does not apply to the 4.19-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@vger.kernel.org>.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-4.19.y
git checkout FETCH_HEAD
git cherry-pick -x d1aa0c04294e29883d65eac6c2f72fe95cc7c049
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable@vger.kernel.org>' --in-reply-to '2024111704-operator-cusp-93c5@gregkh' --subject-prefix 'PATCH 4.19.y' HEAD^..

Possible dependencies:



thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From d1aa0c04294e29883d65eac6c2f72fe95cc7c049 Mon Sep 17 00:00:00 2001
From: Andrew Morton <akpm@linux-foundation.org>
Date: Fri, 15 Nov 2024 16:57:24 -0800
Subject: [PATCH] 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 [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>

diff --git a/mm/shmem.c b/mm/shmem.c
index e87f5d6799a7..568bb290bdce 100644
--- 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;