Re: FAILED: patch "[PATCH] mm: revert "mm: shmem: fix data-race in shmem_getattr()"" failed to apply to 5.10-stable tree

[Hugh Dickins <hughd@google.com>]

On Sun, 17 Nov 2024, gregkh@linuxfoundation.org wrote:
> 
> The patch below does not apply to the 5.10-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-5.10.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 '2024111703-uncork-sincerity-4d6e@gregkh' --subject-prefix 'PATCH 5.10.y' HEAD^..

For 5.10 and 5.4 and 4.19 please use this replacement patch:

From 98dfa72dd24347bfcbb9a60ac65ad42130ff44f5 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()"

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>
---
 mm/shmem.c | 2 --
 1 file changed, 2 deletions(-)

diff --git a/mm/shmem.c b/mm/shmem.c
index 8239a0beb01c..e173d83b4448 100644
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -1077,9 +1077,7 @@ static int shmem_getattr(const struct path *path, struct kstat *stat,
 		shmem_recalc_inode(inode);
 		spin_unlock_irq(&info->lock);
 	}
-	inode_lock_shared(inode);
 	generic_fillattr(inode, stat);
-	inode_unlock_shared(inode);
 
 	if (is_huge_enabled(sb_info))
 		stat->blksize = HPAGE_PMD_SIZE;
-- 
2.47.0.338.g60cca15819-goog