Forwarded: [PATCH] xfs: take hm->lock in xfs_ioc_health_monitor() before insert

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Subject: [PATCH] xfs: take hm->lock in xfs_ioc_health_monitor() before insert
Author: kartikey406@gmail.com

#syz test: git://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git master

__xfs_healthmon_insert() asserts that hm->lock is held
(lockdep_assert_held), but xfs_ioc_health_monitor() called it right
after allocating hm, before ever taking the lock, triggering a
lockdep warning.

Take hm->lock around the call.

Reported-by: syzbot+ccdf3469f5f653bff7ac@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=ccdf3469f5f653bff7ac
Signed-off-by: Deepanshu Kartikey <kartikey406@gmail.com>
---
 fs/xfs/xfs_healthmon.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/fs/xfs/xfs_healthmon.c b/fs/xfs/xfs_healthmon.c
index 3ae5f4496ad1..2f762f90d329 100644
--- a/fs/xfs/xfs_healthmon.c
+++ b/fs/xfs/xfs_healthmon.c
@@ -1219,7 +1219,9 @@ xfs_ioc_health_monitor(
 	}
 	running_event->type = XFS_HEALTHMON_RUNNING;
 	running_event->domain = XFS_HEALTHMON_MOUNT;
+	mutex_lock(&hm->lock);
 	__xfs_healthmon_insert(hm, running_event);
+	mutex_unlock(&hm->lock);
 
 	/*
 	 * Preallocate the unmount event so that we can't fail to notify the
-- 
2.34.1