Re: [BUG]:bad unlock balance detected!

[Liu Bo <bo.li.liu@oracle.com>]

Hi,

Would you please try the following patch?

-liubo

From: Liu Bo <bo.li.liu@oracle.com>
Subject: [PATCH] Btrfs: fix to use the right trans for async commit

@trans has been freed and is undefined, and we should use the trans
handle created for async commit instead.

Signed-off-by: Liu Bo <bo.li.liu@oracle.com>
---
 fs/btrfs/transaction.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/btrfs/transaction.c b/fs/btrfs/transaction.c
index 8c81bdc..648d839 100644
--- a/fs/btrfs/transaction.c
+++ b/fs/btrfs/transaction.c
@@ -1494,7 +1494,7 @@ int btrfs_commit_transaction_async(struct
btrfs_trans_handle *trans,
 	 * Tell lockdep we've released the freeze rwsem, since the
 	 * async commit thread will be the one to unlock it.
 	 */
-	if (trans->type < TRANS_JOIN_NOLOCK)
+	if (ac->newtrans->type < TRANS_JOIN_NOLOCK)
 		rwsem_release(
 			&root->fs_info->sb->s_writers.lock_map[SB_FREEZE_FS-1],
 			1, _THIS_IP_);
-- 
1.8.1.4

On Tue, Nov 05, 2013 at 09:34:01AM +0800, majianpeng wrote:
> On the mainline linux tree, the head of git is :be408cd3e1fef73e9408b196a7.
> 
> [ 2372.462131] 
> [ 2372.462147] =====================================
> [ 2372.462171] [ BUG: bad unlock balance detected! ]
> [ 2372.462191] 3.12.0+ #32 Tainted: G        W   
> [ 2372.462209] -------------------------------------
> [ 2372.462228] ceph-osd/14048 is trying to release lock (sb_internal) at:
> [ 2372.462275] [<ffffffffa022cb10>] btrfs_commit_transaction_async+0x1b0/0x2a0 [btrfs]
> [ 2372.462305] but there are no more locks to release!
> [ 2372.462324] 
> [ 2372.462324] other info that might help us debug this:
> [ 2372.462349] no locks held by ceph-osd/14048.
> [ 2372.462367] 
> [ 2372.462367] stack backtrace:
> [ 2372.462386] CPU: 2 PID: 14048 Comm: ceph-osd Tainted: G        W    3.12.0+ #32
> [ 2372.462414] Hardware name: To Be Filled By O.E.M. To Be Filled By O.E.M./To be filled by O.E.M., BIOS 080015  11/09/2011
> [ 2372.462455]  ffffffffa022cb10 ffff88007490fd28 ffffffff816f094a ffff8800378aa320
> [ 2372.462491]  ffff88007490fd50 ffffffff810adf4c ffff8800378aa320 ffff88009af97650
> [ 2372.462526]  ffffffffa022cb10 ffff88007490fd88 ffffffff810b01ee ffff8800898c0000
> [ 2372.462562] Call Trace:
> [ 2372.462584]  [<ffffffffa022cb10>] ? btrfs_commit_transaction_async+0x1b0/0x2a0 [btrfs]
> [ 2372.462619]  [<ffffffff816f094a>] dump_stack+0x45/0x56
> [ 2372.462642]  [<ffffffff810adf4c>] print_unlock_imbalance_bug+0xec/0x100
> [ 2372.462677]  [<ffffffffa022cb10>] ? btrfs_commit_transaction_async+0x1b0/0x2a0 [btrfs]
> [ 2372.462710]  [<ffffffff810b01ee>] lock_release+0x18e/0x210
> [ 2372.462742]  [<ffffffffa022cb36>] btrfs_commit_transaction_async+0x1d6/0x2a0 [btrfs]
> [ 2372.462783]  [<ffffffffa025a7ce>] btrfs_ioctl_start_sync+0x3e/0xc0 [btrfs]
> [ 2372.462822]  [<ffffffffa025f1d3>] btrfs_ioctl+0x4c3/0x1f70 [btrfs]
> [ 2372.462849]  [<ffffffff812c0321>] ? avc_has_perm+0x121/0x1b0
> [ 2372.462873]  [<ffffffff812c0224>] ? avc_has_perm+0x24/0x1b0
> [ 2372.462897]  [<ffffffff8107ecc8>] ? sched_clock_cpu+0xa8/0x100
> [ 2372.462922]  [<ffffffff8117b145>] do_vfs_ioctl+0x2e5/0x4e0
> [ 2372.462946]  [<ffffffff812c19e6>] ? file_has_perm+0x86/0xa0
> [ 2372.462969]  [<ffffffff8117b3c1>] SyS_ioctl+0x81/0xa0
> [ 2372.462991]  [<ffffffff817045a4>] tracesys+0xdd/0xe2
> [ 2709.388375] btrfs: device fsid 983de968-d6a9-4ca9-bd27-2be472d15b9b devid 1 transid 26 /dev/sdb
> [ 2709.394532] btrfs: disk space caching is enabled