Re: [btrfs] 3626a285f8: divide_error:#[##]

From: Oliver Sang
Date: Sun Mar 13 2022 - 22:06:24 EST


Hi Qu,

On Wed, Mar 09, 2022 at 04:42:41PM +0800, Qu Wenruo wrote:
>
>
> On 2022/3/9 15:49, Oliver Sang wrote:
> > Hi Qu,
> >
> > On Fri, Mar 04, 2022 at 03:26:19PM +0800, Qu Wenruo wrote:
> > >
> > >
> > > On 2022/3/2 16:44, Oliver Sang wrote:
> > > > Hi Qu,
> > > >
> > > > On Tue, Mar 01, 2022 at 03:47:38PM +0800, Qu Wenruo wrote:
> > > > >
> > > > >
> > > > > This is weird, the code is from simple_stripe_full_stripe_len(), which
> > > > > means the chunk map must be RAID0 or RAID10.
> > > > >
> > > > > In that case, their sub_stripes should be either 1 or 2, why we got 0 there?
> > > > >
> > > > > In fact, from volumes.c, all sub_stripes is from btrfs_raid_array[],
> > > > > which all have either 1 or 2 sub_stripes.
> > > > >
> > > > >
> > > > > Although the code is old, not the latest version, it should still not
> > > > > cause such problem.
> > > > >
> > > > > Mind to retest with my branch to see if it can be reproduced?
> > > > > https://github.com/adam900710/linux/tree/refactor_scrub
> > > >
> > > > we tested head of this branch:
> > > > d6e3a8c42f2fad btrfs: scrub: rename scrub_bio::pagev and related members
> > > > and:
> > > > fdad4a9615f180 btrfs: introduce dedicated helper to scrub simple-stripe based range
> > > > on this branch.
> > > >
> > > > by attached config.
> > > >
> > > > still reproduce the same issue.
> > > >
> > > > attached dmesgs FYI.
> > >
> > > Still failed to reproduce here.
> > >
> > > Those btrfs/07[0123] tests are already in scrub/replace group, thus I
> > > ran them almost hourly during the development.
> > >
> > >
> > > Although there are some ASSERT()s doing extra sanity checks, they should
> > > not affect the result anyway.
> > >
> > > Thus I pushed a branch with more explicit BUG_ON()s to catch the
> > > possible divide by zero bugs.
> > > (https://github.com/adam900710/linux/tree/refactor_scrub_testing)
> > >
> > > Mind to give it a try?
> >
> >
> > in our tests, it seems one BUG_ON you added is triggered
> > (full dmesg attached):
>
> What the heck...
>
> It's indeed some weird extent mapping has its sub-stripes as 0...
>
> I must be insane or there is something fundamental wrong.
>
> Mind to try that branch again? I have updated the branch, now it will
> trigger BUG_ON() as soon as it finds a chunk mapping with sub_stripes == 0.
>
> I'm wondering if it's old btrfs-progs involved (which may not properly
> initialize btrfs_chunk::sub_stripes) now.

below BUG print was caught by your new patch (detail dmesg attached):

[ 44.577527][ T1980] ------------[ cut here ]------------
[ 44.583552][ T335]
[ 44.583990][ T337] 512+0 records out
[ 44.583997][ T337]
[ 44.593932][ T1980] kernel BUG at fs/btrfs/volumes.c:7157!
[ 44.593940][ T1980] invalid opcode: 0000 [#1] SMP KASAN PTI
[ 44.598832][ T335] Data: single 8.00MiB
[ 44.603293][ T1980] CPU: 5 PID: 1980 Comm: mount Not tainted 5.17.0-rc4-00095-g7f159e82828e #1
[ 44.603297][ T1980] Hardware name: Dell Inc. OptiPlex 9020/0DNKMN, BIOS A05 12/05/2013
[ 44.603299][ T1980] RIP: 0010:read_one_chunk+0xa02/0xc80 [btrfs]
[ 44.605509][ T335]
[ 44.609168][ T1980] Code: 03 0f b6 14 02 4c 89 f0 83 e0 07 83 c0 03 38 d0 7c 08 84 d2 0f 85 14 01 00 00 48 8b 44 24 10 8b 50 1c 85 d2 0f 85 19 fb ff ff <0f> 0b 4c
89 c7 e8 f4 b0 fa ff 31 c0 e9 4d ff ff ff 48 8b 7c 24 78
[ 44.609171][ T1980] RSP: 0018:ffffc90002be76c8 EFLAGS: 00010246
[ 44.609175][ T1980] RAX: ffff888102c98e00 RBX: 0000000000000000 RCX: 0000000000000000
[ 44.609178][ T1980] RDX: 0000000000000000 RSI: 0000000000000008 RDI: fffff5200057ce75
[ 44.612227][ T335] Metadata: DUP 1.00GiB
[ 44.616871][ T1980] RBP: 000000000000033c R08: 000000000000005e R09: ffffed1034dd6791
[ 44.616873][ T1980] R10: ffff8881a6eb3c87 R11: ffffed1034dd6790 R12: ffff888214586b40
[ 44.616874][ T1980] R13: ffff888102c98e18 R14: ffff888102c98e1c R15: 0000000000000022
[ 44.616876][ T1980] FS: 00007fad1bd12100(0000) GS:ffff8881a6e80000(0000) knlGS:0000000000000000
[ 44.622475][ T335]
[ 44.628578][ T1980] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 44.628580][ T1980] CR2: 00007fff9d90df68 CR3: 00000001407fc003 CR4: 00000000001706e0
[ 44.628583][ T1980] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[ 44.628585][ T1980] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[ 44.628588][ T1980] Call Trace:
[ 44.638095][ T335] System: DUP 8.00MiB
[ 44.645166][ T1980] <TASK>
[ 44.645168][ T1980] ? _raw_spin_lock+0x81/0x100
[ 44.651206][ T335]
[ 44.653388][ T1980] ? _raw_spin_lock_bh+0x100/0x100
[ 44.653395][ T1980] ? __raw_callee_save___native_queued_spin_unlock+0x11/0x1e
[ 44.673370][ T335] SSD detected: no
[ 44.678876][ T1980] ? add_missing_dev+0x3c0/0x3c0 [btrfs]
[ 44.686756][ T335]
[ 44.694598][ T1980] ? btrfs_get_token_64+0x700/0x700 [btrfs]
[ 44.701187][ T335] Zoned device: no
[ 44.708574][ T1980] ? memcpy+0x39/0x80
[ 44.708581][ T1980] ? write_extent_buffer+0x192/0x240 [btrfs]
[ 44.716449][ T335]
[ 44.724294][ T1980] btrfs_read_sys_array+0x2c7/0x380 [btrfs]
[ 44.734138][ T335] Incompat features: extref, skinny-metadata, no-holes
[ 44.735313][ T1980] ? read_one_dev+0x13c0/0x13c0 [btrfs]
[ 44.741786][ T335]
[ 44.749628][ T1980] ? mutex_lock+0x80/0x100
[ 44.749634][ T1980] ? __mutex_lock_slowpath+0x40/0x40
[ 44.758164][ T335] Runtime features: free-space-tree
[ 44.765352][ T1980] ? btrfs_init_workqueues+0x4c1/0x7ba [btrfs]
[ 44.768515][ T335]
[ 44.774620][ T1980] open_ctree+0x16ac/0x2656 [btrfs]
[ 44.777966][ T335] Checksum: crc32c
[ 44.782064][ T1980] btrfs_mount_root.cold+0x13/0x192 [btrfs]
[ 44.784268][ T335]
[ 44.789241][ T1980] ? arch_stack_walk+0x9e/0x100
[ 44.789247][ T1980] ? parse_rescue_options+0x300/0x300 [btrfs]
[ 44.796977][ T335] Number of devices: 1
[ 44.800614][ T1980] ? vfs_parse_fs_param_source+0x3b/0x1c0
[ 44.806131][ T335]
[ 44.808314][ T1980] ? legacy_parse_param+0x6a/0x7c0
[ 44.808320][ T1980] ? parse_rescue_options+0x300/0x300 [btrfs]
[ 44.814273][ T335] Devices:
[ 44.818205][ T1980] legacy_get_tree+0xef/0x200
[ 44.818210][ T1980] vfs_get_tree+0x84/0x2c0
[ 44.822077][ T335]
[ 44.827928][ T1980] fc_mount+0xf/0x80
[ 44.827934][ T1980] vfs_kern_mount+0x71/0xc0
[ 44.830557][ T335] ID SIZE PATH
[ 44.835890][ T1980] btrfs_mount+0x1fc/0xa40 [btrfs]
[ 44.842730][ T335]
[ 44.848134][ T1980] ? kasan_save_stack+0x1e/0x40
[ 44.848149][ T1980] ? kasan_set_track+0x21/0x40
[ 44.850862][ T335] 1 300.00GiB /dev/sdb4
[ 44.854618][ T1980] ? kasan_set_free_info+0x20/0x40
[ 44.854624][ T1980] ? btrfs_show_options+0xf00/0xf00 [btrfs]
[ 44.859803][ T335]
[ 44.865032][ T1980] ? __x64_sys_mount+0x12c/0x1c0
[ 44.865036][ T1980] ? entry_SYSCALL_64_after_hwframe+0x44/0xae
[ 44.871101][ T335]
[ 44.873263][ T1980] ? terminate_walk+0x203/0x4c0
[ 44.873268][ T1980] ? vfs_parse_fs_param_source+0x3b/0x1c0
[ 44.878354][ T335]
[ 44.882803][ T1980] ? legacy_parse_param+0x6a/0x7c0
[ 44.882808][ T1980] ? vfs_parse_fs_string+0xd7/0x140
[ 44.889280][ T335] 2022-03-14 01:34:21 mkdir -p /fs/sdb1
[ 44.890770][ T1980] ? btrfs_show_options+0xf00/0xf00 [btrfs]
[ 44.895501][ T335]
[ 44.901430][ T1980] ? legacy_get_tree+0xef/0x200
[ 44.901435][ T1980] legacy_get_tree+0xef/0x200
[ 44.901448][ T1980] ? security_capable+0x56/0xc0
[ 44.905612][ T335] btrfs
[ 44.911057][ T1980] vfs_get_tree+0x84/0x2c0
[ 44.911062][ T1980] ? ns_capable_common+0x57/0x100
[ 44.913278][ T335]
[ 44.918247][ T1980] path_mount+0x7fc/0x1a40
[ 44.918252][ T1980] ? kasan_set_track+0x21/0x40
[ 44.925201][ T335] 2022-03-14 01:34:21 mount -t btrfs /dev/sdb1 /fs/sdb1
[ 44.927087][ T1980] ? finish_automount+0x600/0x600
[ 44.927092][ T1980] ? kmem_cache_free+0xa1/0x400
[ 44.931642][ T335]
[ 44.935926][ T1980] do_mount+0xca/0x100
[ 44.935931][ T1980] ? path_mount+0x1a40/0x1a40
[ 44.935933][ T1980] ? _copy_from_user+0x94/0x100
[ 44.938799][ T335] 2022-03-14 01:34:21 mkdir -p /fs/sdb2
[ 44.941885][ T1980] ? memdup_user+0x4e/0x80
[ 44.941890][ T1980] __x64_sys_mount+0x12c/0x1c0
[ 44.941893][ T1980] do_syscall_64+0x3b/0xc0
[ 44.946884][ T335]
[ 44.951068][ T1980] entry_SYSCALL_64_after_hwframe+0x44/0xae
[ 44.951074][ T1980] RIP: 0033:0x7fad1bf10fea
[ 44.951077][ T1980] Code: 48 8b 0d a9 0e 0c 00 f7 d8 64 89 01 48 83 c8 ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 49 89 ca b8 a5 00 00 00 0f 05 <48> 3d 01
f0 ff ff 73 01 c3 48 8b 0d 76 0e 0c 00 f7 d8 64 89 01 48
[ 44.956197][ T335] btrfs
[ 44.958245][ T1980] RSP: 002b:00007fff9d90f878 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
[ 44.958249][ T1980] RAX: ffffffffffffffda RBX: 00005628efc57970 RCX: 00007fad1bf10fea
[ 44.958251][ T1980] RDX: 00005628efc57b80 RSI: 00005628efc57bc0 RDI: 00005628efc57ba0
[ 44.958263][ T1980] RBP: 00007fad1c25e1c4 R08: 0000000000000000 R09: 00005628efc5a890
[ 44.958264][ T1980] R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
[ 44.962993][ T335]
[ 44.967613][ T1980] R13: 0000000000000000 R14: 00005628efc57ba0 R15: 00005628efc57b80
[ 44.967616][ T1980] </TASK>
[ 44.967617][ T1980] Modules linked in: dm_mod btrfs blake2b_generic xor raid6_pq
[ 44.973257][ T335] 2022-03-14 01:34:21 mount -t btrfs /dev/sdb2 /fs/sdb2
[ 44.977243][ T1980] zstd_compress libcrc32c sd_mod t10_pi sg
[ 44.983019][ T335]
[ 44.985203][ T1980] ipmi_devintf ata_generic ipmi_msghandler intel_rapl_msr intel_rapl_common x86_pkg_temp_thermal intel_powerclamp coretemp kvm_intel
[ 44.990720][ T335] 2022-03-14 01:34:21 mkdir -p /fs/sdb3
[ 44.995962][ T1980] i915 kvm intel_gtt ttm drm_kms_helper irqbypass crct10dif_pclmul crc32_pclmul crc32c_intel ghash_clmulni_intel syscopyarea sysfillrect
[ 44.998174][ T335]
[ 45.002882][ T1980] sysimgblt rapl mei_wdt fb_sys_fops ata_piix intel_cstate libata drm mei_me mei intel_uncore video ip_tables
[ 45.002919][ T1980] ---[ end trace 0000000000000000 ]---


>
> Thanks,
> Qu
>
> >
> >
> > [ 75.279958][ T3602] ------------[ cut here ]------------
> > [ 75.285221][ T3602] kernel BUG at fs/btrfs/scrub.c:3387!
> > [ 75.290490][ T3602] invalid opcode: 0000 [#1] SMP KASAN PTI
> > [ 75.296010][ T3602] CPU: 2 PID: 3602 Comm: btrfs Not tainted 5.17.0-rc4-00095-g6b837d4c40d5 #1
> > [ 75.304521][ T3602] Hardware name: Dell Inc. OptiPlex 9020/0DNKMN, BIOS A05 12/05/2013
> > [ 75.312344][ T3602] RIP: 0010:scrub_stripe+0xed3/0x1340 [btrfs]
> > [ 75.318250][ T3602] Code: 90 00 00 00 e8 0e f9 96 c0 e9 98 f3 ff ff e8 c4 f9 96 c0 e9 26 f3 ff ff 48 8b bc 24 80 00 00 00 e8 f2 f8 96 c0 e9 3b f4 ff ff <0f> 0b 0f
> > 0b 4c 8d a4 24 b8 01 00 00 31 f6 4c 8d bd 20 02 00 00 4c
> > [ 75.337480][ T3602] RSP: 0018:ffffc9000b47f550 EFLAGS: 00010246
> > [ 75.343340][ T3602] RAX: 0000000000000007 RBX: ffff88810231d600 RCX: ffff88810231d61c
> > [ 75.351074][ T3602] RDX: 0000000000000000 RSI: 0000000000000004 RDI: ffff8881023a2458
> > [ 75.358807][ T3602] RBP: ffff8881097ad800 R08: 0000000000000001 R09: ffffed102828100d
> > [ 75.366550][ T3602] R10: ffff888141408063 R11: ffffed102828100c R12: 0000000000000000
> > [ 75.374282][ T3602] R13: 0000000000100000 R14: ffff888141408000 R15: ffff888129c9c000
> > [ 75.382016][ T3602] FS: 00007f94c24ec8c0(0000) GS:ffff8881a6d00000(0000) knlGS:0000000000000000
> > [ 75.390691][ T3602] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> > [ 75.397054][ T3602] CR2: 00007ffe454aa8e8 CR3: 000000020a796004 CR4: 00000000001706e0
> > [ 75.404785][ T3602] Call Trace:
> > [ 75.407886][ T3602] <TASK>
> > [ 75.410645][ T3602] ? btrfs_wait_ordered_extents+0x9a1/0xe40 [btrfs]
> > [ 75.417049][ T3602] ? scrub_raid56_parity+0x5c0/0x5c0 [btrfs]
> > [ 75.422853][ T3602] ? btrfs_remove_ordered_extent+0xbc0/0xbc0 [btrfs]
> > [ 75.429341][ T3602] ? mutex_unlock+0x80/0x100
> > [ 75.433733][ T3602] ? __wake_up_common_lock+0xe3/0x140
> > [ 75.438897][ T3602] ? __lookup_extent_mapping+0x215/0x300 [btrfs]
> > [ 75.445037][ T3602] scrub_chunk+0x294/0x480 [btrfs]
> > [ 75.449984][ T3602] scrub_enumerate_chunks+0x643/0x1340 [btrfs]
> > [ 75.455962][ T3602] ? scrub_chunk+0x480/0x480 [btrfs]
> > [ 75.461083][ T3602] ? __scrub_blocked_if_needed+0xb9/0x200 [btrfs]
> > [ 75.467317][ T3602] ? scrub_checksum_data+0x4c0/0x4c0 [btrfs]
> > [ 75.473121][ T3602] ? down_read+0x137/0x240
> > [ 75.477339][ T3602] ? mutex_unlock+0x80/0x100
> > [ 75.481726][ T3602] ? __mutex_unlock_slowpath+0x300/0x300
> > [ 75.487743][ T3602] ? btrfs_find_device+0xac/0x240 [btrfs]
> > [ 75.493285][ T3602] btrfs_scrub_dev+0x535/0xc00 [btrfs]
> > [ 75.498578][ T3602] ? scrub_enumerate_chunks+0x1340/0x1340 [btrfs]
> > [ 75.504812][ T3602] ? btrfs_apply_pending_changes+0x80/0x80 [btrfs]
> > [ 75.511120][ T3602] ? btrfs_record_root_in_trans+0x4d/0x180 [btrfs]
> > [ 75.517428][ T3602] ? finish_wait+0x280/0x280
> > [ 75.521819][ T3602] btrfs_dev_replace_by_ioctl.cold+0x62c/0x720 [btrfs]
> > [ 75.528483][ T3602] ? btrfs_finish_block_group_to_copy+0x3c0/0x3c0 [btrfs]
> > [ 75.535440][ T3602] ? __raw_callee_save___native_queued_spin_unlock+0x11/0x1e
> > [ 75.542575][ T3602] btrfs_ioctl+0x37ee/0x51c0 [btrfs]
> > [ 75.547691][ T3602] ? fput_many+0xaa/0x140
> > [ 75.551823][ T3602] ? filp_close+0xef/0x140
> > [ 75.556041][ T3602] ? __x64_sys_close+0x2d/0x80
> > [ 75.560600][ T3602] ? do_syscall_64+0x3b/0xc0
> > [ 75.564991][ T3602] ? entry_SYSCALL_64_after_hwframe+0x44/0xae
> > [ 75.570838][ T3602] ? btrfs_ioctl_get_supported_features+0x40/0x40 [btrfs]
> > [ 75.577756][ T3602] ? _raw_spin_lock_irq+0x82/0xd2
> > [ 75.582572][ T3602] ? _raw_spin_lock+0x100/0x100
> > [ 75.587218][ T3602] ? fiemap_prep+0x200/0x200
> > [ 75.591607][ T3602] ? lockref_put_or_lock+0xc4/0x1c0
> > [ 75.596600][ T3602] ? do_sigaction+0x4b3/0x840
> > [ 75.601075][ T3602] ? __x64_sys_pidfd_send_signal+0x600/0x600
> > [ 75.606837][ T3602] ? __might_fault+0x4d/0x80
> > [ 75.611226][ T3602] ? __x64_sys_rt_sigaction+0x1d0/0x240
> > [ 75.616558][ T3602] ? __ia32_sys_signal+0x140/0x140
> > [ 75.621461][ T3602] ? __fget_light+0x57/0x540
> > [ 75.625854][ T3602] __x64_sys_ioctl+0x127/0x1c0
> > [ 75.630414][ T3602] do_syscall_64+0x3b/0xc0
> > [ 75.634633][ T3602] entry_SYSCALL_64_after_hwframe+0x44/0xae
> > [ 75.640307][ T3602] RIP: 0033:0x7f94c25df427
> > [ 75.644533][ T3602] Code: 00 00 90 48 8b 05 69 aa 0c 00 64 c7 00 26 00 00 00 48 c7 c0 ff ff ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 b8 10 00 00 00 0f 05 <48> 3d 01
> > f0 ff ff 73 01 c3 48 8b 0d 39 aa 0c 00 f7 d8 64 89 01 48
> > [ 75.663771][ T3602] RSP: 002b:00007ffd06a4acc8 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
> > [ 75.671937][ T3602] RAX: ffffffffffffffda RBX: 000055d51e9f72a0 RCX: 00007f94c25df427
> > [ 75.679671][ T3602] RDX: 00007ffd06a4b108 RSI: 00000000ca289435 RDI: 0000000000000004
> > [ 75.687404][ T3602] RBP: 00000000ffffffff R08: 0000000000000000 R09: 000055d51e9fa580
> > [ 75.695137][ T3602] R10: 0000000000000008 R11: 0000000000000246 R12: 00007ffd06a4e97a
> > [ 75.702868][ T3602] R13: 0000000000000004 R14: 0000000000000000 R15: 0000000000000005
> > [ 75.710600][ T3602] </TASK>
> > [ 75.713445][ T3602] Modules linked in: dm_mod btrfs blake2b_generic xor raid6_pq zstd_compress libcrc32c sd_mod t10_pi sg ata_generic ipmi_devintf ipmi_msghandler
> > intel_rapl_msr intel_rapl_common x86_pkg_temp_thermal intel_powerclamp coretemp i915 kvm_intel kvm intel_gtt ttm irqbypass crct10dif_pclmul crc32_pclmul crc32c_intel
> > ghash_clmulni_intel drm_kms_helper syscopyarea sysfillrect sysimgblt fb_sys_fops rapl ata_piix mei_wdt intel_cstate drm libata mei_me intel_uncore mei video ip_tables
> > [ 75.756460][ T3602] ---[ end trace 0000000000000000 ]---
> >
> >
> > >
> > > Thanks,
> > > Qu
> > >

Attachment: dmesg.xz
Description: application/xz