From: Sasha Levin <sashal@kernel.org>
To: Lu Fengqi <lufq.fnst@cn.fujitsu.com>
Cc: stable@vger.kernel.org, David Sterba <dsterba@suse.com>
Subject: Re: [PATCH 4.9] btrfs: fix pinned underflow after transaction aborted
Date: Fri, 23 Nov 2018 14:33:37 -0500 [thread overview]
Message-ID: <20181123193337.GI1917@sasha-vm> (raw)
In-Reply-To: <20181120031732.15435-1-lufq.fnst@cn.fujitsu.com>
On Tue, Nov 20, 2018 at 11:17:32AM +0800, Lu Fengqi wrote:
>commit fcd5e74288f7d36991b1f0fb96b8c57079645e38 upstream.
>
>When running generic/475, we may get the following warning in dmesg:
>
>[ 6902.102154] WARNING: CPU: 3 PID: 18013 at fs/btrfs/extent-tree.c:9776 btrfs_free_block_groups+0x2af/0x3b0 [btrfs]
>[ 6902.109160] CPU: 3 PID: 18013 Comm: umount Tainted: G W O 4.19.0-rc8+ #8
>[ 6902.110971] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 0.0.0 02/06/2015
>[ 6902.112857] RIP: 0010:btrfs_free_block_groups+0x2af/0x3b0 [btrfs]
>[ 6902.118921] RSP: 0018:ffffc9000459bdb0 EFLAGS: 00010286
>[ 6902.120315] RAX: ffff880175050bb0 RBX: ffff8801124a8000 RCX: 0000000000170007
>[ 6902.121969] RDX: 0000000000000002 RSI: 0000000000170007 RDI: ffffffff8125fb74
>[ 6902.123716] RBP: ffff880175055d10 R08: 0000000000000000 R09: 0000000000000000
>[ 6902.125417] R10: 0000000000000000 R11: 0000000000000000 R12: ffff880175055d88
>[ 6902.127129] R13: ffff880175050bb0 R14: 0000000000000000 R15: dead000000000100
>[ 6902.129060] FS: 00007f4507223780(0000) GS:ffff88017ba00000(0000) knlGS:0000000000000000
>[ 6902.130996] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
>[ 6902.132558] CR2: 00005623599cac78 CR3: 000000014b700001 CR4: 00000000003606e0
>[ 6902.134270] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
>[ 6902.135981] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
>[ 6902.137836] Call Trace:
>[ 6902.138939] close_ctree+0x171/0x330 [btrfs]
>[ 6902.140181] ? kthread_stop+0x146/0x1f0
>[ 6902.141277] generic_shutdown_super+0x6c/0x100
>[ 6902.142517] kill_anon_super+0x14/0x30
>[ 6902.143554] btrfs_kill_super+0x13/0x100 [btrfs]
>[ 6902.144790] deactivate_locked_super+0x2f/0x70
>[ 6902.146014] cleanup_mnt+0x3b/0x70
>[ 6902.147020] task_work_run+0x9e/0xd0
>[ 6902.148036] do_syscall_64+0x470/0x600
>[ 6902.149142] ? trace_hardirqs_off_thunk+0x1a/0x1c
>[ 6902.150375] entry_SYSCALL_64_after_hwframe+0x49/0xbe
>[ 6902.151640] RIP: 0033:0x7f45077a6a7b
>[ 6902.157324] RSP: 002b:00007ffd589f3e68 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6
>[ 6902.159187] RAX: 0000000000000000 RBX: 000055e8eec732b0 RCX: 00007f45077a6a7b
>[ 6902.160834] RDX: 0000000000000001 RSI: 0000000000000000 RDI: 000055e8eec73490
>[ 6902.162526] RBP: 0000000000000000 R08: 000055e8eec734b0 R09: 00007ffd589f26c0
>[ 6902.164141] R10: 0000000000000000 R11: 0000000000000246 R12: 000055e8eec73490
>[ 6902.165815] R13: 00007f4507ac61a4 R14: 0000000000000000 R15: 00007ffd589f40d8
>[ 6902.167553] irq event stamp: 0
>[ 6902.168998] hardirqs last enabled at (0): [<0000000000000000>] (null)
>[ 6902.170731] hardirqs last disabled at (0): [<ffffffff810cd810>] copy_process.part.55+0x3b0/0x1f00
>[ 6902.172773] softirqs last enabled at (0): [<ffffffff810cd810>] copy_process.part.55+0x3b0/0x1f00
>[ 6902.174671] softirqs last disabled at (0): [<0000000000000000>] (null)
>[ 6902.176407] ---[ end trace 463138c2986b275c ]---
>[ 6902.177636] BTRFS info (device dm-3): space_info 4 has 273465344 free, is not full
>[ 6902.179453] BTRFS info (device dm-3): space_info total=276824064, used=4685824, pinned=18446744073708158976, reserved=0, may_use=0, readonly=65536
>
>In the above line there's "pinned=18446744073708158976" which is an
>unsigned u64 value of -1392640, an obvious underflow.
>
>When transaction_kthread is running cleanup_transaction(), another
>fsstress is running btrfs_commit_transaction(). The
>btrfs_finish_extent_commit() may get the same range as
>btrfs_destroy_pinned_extent() got, which causes the pinned underflow.
>
>Fixes: d4b450cd4b33 ("Btrfs: fix race between transaction commit and empty block group removal")
>CC: stable@vger.kernel.org # 4.4+
>Reviewed-by: Josef Bacik <josef@toxicpanda.com>
>Signed-off-by: Lu Fengqi <lufq.fnst@cn.fujitsu.com>
>Reviewed-by: David Sterba <dsterba@suse.com>
>Signed-off-by: David Sterba <dsterba@suse.com>
Queued both patches to their respective branches, thank you.
--
Thanks,
Sasha
prev parent reply other threads:[~2018-11-24 6:19 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-11-20 3:17 [PATCH 4.9] btrfs: fix pinned underflow after transaction aborted Lu Fengqi
2018-11-23 19:33 ` Sasha Levin [this message]
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