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From: Hou Tao <houtao@huaweicloud.com>
To: linux-fsdevel@vger.kernel.org
Cc: Miklos Szeredi <miklos@szeredi.hu>,
	Zhao Chen <winters.zc@antgroup.com>,
	linux-kernel@vger.kernel.org,
	houtao1@huawei.com
Subject: [PATCH 1/2] fuse: set FR_PENDING atomically in fuse_resend()
Date: Thu,  9 May 2024 20:21:53 +0800
Message-Id: <20240509122154.782930-2-houtao@huaweicloud.com>
In-Reply-To: <20240509122154.782930-1-houtao@huaweicloud.com>
References: <20240509122154.782930-1-houtao@huaweicloud.com>
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From: Hou Tao <houtao1@huawei.com>

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: 760eac73f9f69 ("fuse: Introduce a new notification type for resend pending requests")
Signed-off-by: Hou Tao <houtao1@huawei.com>
---
 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;
 	}
-- 
2.29.2