[PATCH 6.9 112/374] fuse: set FR_PENDING atomically in fuse_resend()

Greg Kroah-Hartman
2024-06-06T14:09:09Z

From: Hou Tao <houtao1@huawei.com>

[ Upstream commit 42815f8ac54c5113bf450ec4b7ccc5b62af0f6a7 ]

When fuse_resend() moves the requests from processing lists to pending
list, it uses __set_bit() to set FR_PENDING bit in req->flags.

Using __set_bit() is not safe, because other functions may update
req->flags concurrently (e.g., request_wait_answer() may call
set_bit(FR_INTERRUPTED, &flags)).

Fix it by using set_bit() instead.

Fixes: 760eac73f9f6 ("fuse: Introduce a new notification type for resend pending requests")
Signed-off-by: Hou Tao <houtao1@huawei.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
fs/fuse/dev.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/fuse/dev.c b/fs/fuse/dev.c
index 3ec8bb5e68ff5..8eb2ce7c0b012 100644
--- a/fs/fuse/dev.c
+++ b/fs/fuse/dev.c
@@ -1813,7 +1813,7 @@ static void fuse_resend(struct fuse_conn *fc)
spin_unlock(&fc->lock);

list_for_each_entry_safe(req, next, &to_queue, list) {
- __set_bit(FR_PENDING, &req->flags);
+ set_bit(FR_PENDING, &req->flags);
/* mark the request as resend request */
req->in.h.unique |= FUSE_UNIQUE_RESEND;
}
--
2.43.0