Messages in this thread | | | Date | Tue, 10 Mar 2015 12:42:37 +0100 | From | Markus Trippelsdorf <> | Subject | Re: WARNING: CPU: 2 PID: 32343 at fs/btrfs/inode.c:8693 btrfs_destroy_inode+0x278/0x2a0() |
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On 2015.03.07 at 09:35 +0000, Filipe David Manana wrote: > On Tue, Mar 3, 2015 at 2:13 PM, Markus Trippelsdorf > <markus@trippelsdorf.de> wrote: > > On 2015.03.02 at 14:29 +0100, Markus Trippelsdorf wrote: > >> On 2015.03.02 at 12:07 +0000, Filipe David Manana wrote: > >> > >> [83159.038708] ------------[ cut here ]------------ > >> > >> [83159.038716] WARNING: CPU: 2 PID: 32343 at fs/btrfs/inode.c:8693 btrfs_destroy_inode+0x278/0x2a0() > >> > >> [83159.038718] CPU: 2 PID: 32343 Comm: rm Tainted: G W 4.0.0-rc1-dirty #104 > >> > >> [83159.038719] Hardware name: System manufacturer System Product Name/M4A78T-E, BIOS 3503 04/13/2011 > >> > >> [83159.038720] 0000000000000000 ffffffff8199990f ffffffff8168d723 0000000000000000 > >> > >> [83159.038722] ffffffff8106d2d2 0000000000000000 ffff88005756edf0 ffff880215805800 > >> > >> [83159.038723] ffff880169477eb8 ffff88005756edf0 ffffffff8121bab8 ffff880100675000 > >> > >> [83159.038725] Call Trace: > >> > >> [83159.038728] [<ffffffff8168d723>] ? dump_stack+0x40/0x50 > >> > >> [83159.038731] [<ffffffff8106d2d2>] ? warn_slowpath_common+0x72/0xc0 > >> > >> [83159.038732] [<ffffffff8121bab8>] ? btrfs_destroy_inode+0x278/0x2a0 > >> > >> [83159.038735] [<ffffffff8111f747>] ? do_unlinkat+0x1a7/0x2e0 > >> > >> [83159.038737] [<ffffffff81083974>] ? task_work_run+0xb4/0x100 > >> > >> [83159.038740] [<ffffffff8103b9a9>] ? do_notify_resume+0x69/0x80 > >> > >> [83159.038742] [<ffffffff81694092>] ? system_call_fastpath+0x12/0x17 > >> > >> [83159.038743] ---[ end trace 3b7c45c6e46fe8dd ]--- > >> > >> [83159.038744] ------------[ cut here ]------------ > >> > >> [83159.038745] WARNING: CPU: 2 PID: 32343 at fs/btrfs/inode.c:8694 btrfs_destroy_inode+0x1f2/0x2a0() > >> > >> [83159.038746] CPU: 2 PID: 32343 Comm: rm Tainted: G W 4.0.0-rc1-dirty #104 > >> > >> [83159.038747] Hardware name: System manufacturer System Product Name/M4A78T-E, BIOS 3503 04/13/2011 > >> > >> [83159.038747] 0000000000000000 ffffffff8199990f ffffffff8168d723 0000000000000000 > >> > >> [83159.038749] ffffffff8106d2d2 0000000000000000 ffff88005756edf0 ffff880215805800 > >> > >> [83159.038750] ffff880169477eb8 ffff88005756edf0 ffffffff8121ba32 ffff880100675000 > >> > >> [83159.038751] Call Trace: > >> > >> [83159.038753] [<ffffffff8168d723>] ? dump_stack+0x40/0x50 > >> > >> [83159.038754] [<ffffffff8106d2d2>] ? warn_slowpath_common+0x72/0xc0 > >> > >> [83159.038755] [<ffffffff8121ba32>] ? btrfs_destroy_inode+0x1f2/0x2a0 > >> > >> [83159.038757] [<ffffffff8111f747>] ? do_unlinkat+0x1a7/0x2e0 > >> > >> [83159.038758] [<ffffffff81083974>] ? task_work_run+0xb4/0x100 > >> > >> [83159.038760] [<ffffffff8103b9a9>] ? do_notify_resume+0x69/0x80 > >> > >> [83159.038761] [<ffffffff81694092>] ? system_call_fastpath+0x12/0x17 > >> > >> [83159.038762] ---[ end trace 3b7c45c6e46fe8de ]--- > >> > > > >> > > Unfortunately the issue isn't 100% reproducible, so I unfortunately > >> > > cannot bisect. > >> > > >> > You probably don't need to bisect. The warning is related to the > >> > outstanding_extents counter being != 0: > >> > > >> > https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/tree/fs/btrfs/inode.c?id=refs/tags/v4.0-rc1#n8693 > >> > > >> > The only change in 4.0 that changes updates to that counter is: > >> > > >> > https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=3e05bde8c3c2dd761da4d52944a087907955a53c > >> > > >> > So that's likely the change you would find with a bisect. > >> > >> OK, thank you. I will revert the commit and see if it fixes the issue. > > > > No. Reverting 3e05bde8c3 does _not_ fix the issue. It still happens. > > Ok, so I ran into this as well, and identified the following patch as > the source of the problem: > > https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=dcab6a3b2ae657a2017637083c28ee303b6b1b8e > > It's actually very easy to trigger. The following fio job config triggers it: > > [global] > ioengine=sync > direct=0 > bssplit=130M/100 > fallocate=none > filename=foobar > > [job1] > numjobs=1 > size=1G > rw=randwrite > > Then run these steps: > > mkfs.btrfs -f /dev/sdd > mount /dev/sdd /mnt > cd /mnt > fio fio_job.ini > cd .. > umount /mnt > (see dmesg) > > The important part is that the writes need to be larger than 128Mb. > With btrfs assertions enabled (CONFIG_BTRFS_ASSERT=y) you'll get a > BUG_ON() immediately: > > [211158.555563] BTRFS: assertion failed: > BTRFS_I(inode)->outstanding_extents >= num_extents, file: > fs/btrfs/extent-tree.c, line: 4983 > [211158.557901] ------------[ cut here ]------------ > [211158.558666] kernel BUG at fs/btrfs/ctree.h:4013! > [211158.559660] invalid opcode: 0000 [#1] SMP DEBUG_PAGEALLOC > (....) > [211158.561837] Call Trace: > [211158.561837] [<ffffffffa0474666>] drop_outstanding_extent+0x3d/0x6d [btrfs] > [211158.561837] [<ffffffffa047a5b8>] > btrfs_delalloc_release_metadata+0x53/0xfc [btrfs] > (....) > > Otherwise only the warnings you reported during inode eviction. > > This happens for both direct IO and buffered writes (direct=0). At > least for the direct IO case, the issue happens due to underflows when > decrementing the inode's outstanding_extents counter (after the very > first write we get outstanding_extents = (unsigned)1 - 2 = > 4294967295).
Josef?
-- Markus
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