linux-kernel - [PATCH] fs/gfs2:lock a spinlock always before returning from do

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Date:   Tue, 28 Apr 2020 11:29:05 +0800
From:   Wu Bo <wubo40@...wei.com>
To:     <rpeterso@...hat.com>, <agruenba@...hat.com>
CC:     <cluster-devel@...hat.com>, <linux-kernel@...r.kernel.org>,
        <liuzhiqiang26@...wei.com>, <linfeilong@...wei.com>,
        <wubo40@...wei.com>
Subject: [PATCH] fs/gfs2:lock a spinlock always before returning from do_xmote()

The call stack is as follows:
finish_xmote()
        ...
        spin_lock(&gl->gl_lockref.lock);
        ...
	--> do_xmote()
            spin_unlock(&gl->gl_lockref.lock);
            ...
            return;
        ...
        spin_unlock(&gl->gl_lockref.lock);
           
do_xmote function needs to be locked before returning,
Otherwise, there will be a double release lock in finish_xmote() function.

Signed-off-by: Wu Bo <wubo40@...wei.com>
---
 fs/gfs2/glock.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/fs/gfs2/glock.c b/fs/gfs2/glock.c
index 29f9b66..7129d10 100644
--- a/fs/gfs2/glock.c
+++ b/fs/gfs2/glock.c
@@ -613,6 +613,7 @@ static void do_xmote(struct gfs2_glock *gl, struct gfs2_holder *gh, unsigned int
 				fs_err(sdp, "Error %d syncing glock \n", ret);
 				gfs2_dump_glock(NULL, gl, true);
 			}
+			spin_lock(&gl->gl_lockref.lock);
 			return;
 		}
 	}
-- 
1.8.3.1