Re: Bug 215605 - [5.14 regression] BUG: unable to handle page fault while running badblocks (fsck.ext4 -c) on a raid5 md array

[Song Liu <song@kernel.org>]

On Mon, Feb 28, 2022 at 1:43 AM Thorsten Leemhuis
<regressions@leemhuis.info> wrote:
>
> [CCing Jens]
>
> Hi, this is your Linux kernel regression tracker. Top-posting for once,
> to make this easily accessible to everyone.
>
> What's up here? Below regression was reported two weeks ago and I
> forwarded it nearly a week ago, nevertheless the reporter afaics didn't
> get a single reply. Is the issue discussed somewhere else and I just
> missed it? Is the report not accurate for some reason or missing
> something important? Or did the report fall throug the cracks?

Sorry for the late reply. I was on vacation last week.

>
> Ciao, Thorsten (wearing his 'the Linux kernel's regression tracker' hat)
>
> P.S.: As the Linux kernel's regression tracker I'm getting a lot of
> reports on my table. I can only look briefly into most of them and lack
> knowledge about most of the areas they concern. I thus unfortunately
> will sometimes get things wrong or miss something important. I hope
> that's not the case here; if you think it is, don't hesitate to tell me
> in a public reply, it's in everyone's interest to set the public record
> straight.
>
> #regzbot poke
>
> On 22.02.22 09:59, Thorsten Leemhuis wrote:
> > Hi, this is your Linux kernel regression tracker.
> >
> > I noticed a regression report in bugzilla.kernel.org that afaics nobody
> > acted upon since it was reported about a week ago, that's why I decided
> > to forward it to the lists and add a few relevant people to the CC. To
> > quote from https://bugzilla.kernel.org/show_bug.cgi?id=215605
> >
> >>  Dominik Mierzejewski 2022-02-14 10:36:36 UTC
> >>
> >> Created attachment 300450 [details]
> >> kernel-5.16.8 dmesg with crash
> >>
> >> I'm experiencing kernel crash when running badblocks (fsck.ext4 -c) on a raid5 md array in my Intel Atom-based NAS box (Thecus N5550):
> >> [  720.911993] kernel: BUG: unable to handle page fault for address: ffffdbc681023bc8
> >> [  720.912073] kernel: #PF: supervisor read access in kernel mode
> >> [  720.912120] kernel: #PF: error_code(0x0000) - not-present page
> >> [  720.912166] kernel: PGD 11ffc6067 P4D 11ffc6067 PUD 0
> >> [  720.912213] kernel: Oops: 0000 [#1] PREEMPT SMP NOPTI
> >> [  720.912256] kernel: CPU: 1 PID: 1406 Comm: badblocks Not tainted 5.16.8-200.fc35.x86_64 #1
> >> [  720.912321] kernel: Hardware name: Intel Corporation Milstead Platform/Granite Well, BIOS CDV W Series 05 08/27/2015
> >> [  720.912400] kernel: RIP: 0010:kfree+0x58/0x3e0
> >> [  720.912449] kernel: Code: 80 4c 01 e5 0f 82 84 03 00 00 48 c7 c0 00 00 00 80 48 2b 05 4a 96 3b 01 48 01 c5 48 c1 ed 0c 48 c1 e5 06 48 03 2d 28 96 3b 01 <48> 8b 45 08 48 8d 50 ff a8 01 48 0f 45 ea 4
> >> 8 8b 55 08 48 8d 42 ff
> >> [  720.912598] kernel: RSP: 0018:ffff9db4008efaf8 EFLAGS: 00010286
> >> [  720.912648] kernel: RAX: 00006d7bc0000000 RBX: ffff9284c5214800 RCX: ffff9284c3758ff8
> >> [  720.912708] kernel: RDX: ffff9283c1102740 RSI: ffffffffc07af091 RDI: ffff9db4008efd58
> >> [  720.912767] kernel: RBP: ffffdbc681023bc0 R08: ffff9db4008efb88 R09: ffff9284c3759000
> >> [  720.912826] kernel: R10: 0000000000000028 R11: ffff9284c213db48 R12: ffff9db4008efd58
> >> [  720.912885] kernel: R13: ffff9284c213da00 R14: ffff9284c375f000 R15: ffff9db4008efd58
> >> [  720.912945] kernel: FS:  00007f73e6669740(0000) GS:ffff9284dbc80000(0000) knlGS:0000000000000000
> >> [  720.913012] kernel: CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> >> [  720.913062] kernel: CR2: ffffdbc681023bc8 CR3: 000000005c2cc000 CR4: 00000000000006e0
> >> [  720.913122] kernel: Call Trace:
> >> [  720.913150] kernel:  <TASK>
> >> [  720.913179] kernel:  raid5_make_request+0xb31/0xb90 [raid456]
> >> [  720.913247] kernel:  ? do_wait_intr_irq+0xa0/0xa0
> >> [  720.913292] kernel:  ? __blk_queue_split+0x30a/0x470
> >> [  720.913339] kernel:  md_handle_request+0x119/0x180
> >> [  720.913386] kernel:  md_submit_bio+0x67/0xa0
> >> [  720.913425] kernel:  __submit_bio_fops+0x91/0x160
> >> [  720.913468] kernel:  submit_bio_noacct+0xd7/0x2c0
> >> [  720.913510] kernel:  __blkdev_direct_IO_simple+0x198/0x290
> >> [  720.913576] kernel:  ? __fpu_restore_sig+0x193/0x570
> >> [  720.913623] kernel:  ? sysvec_apic_timer_interrupt+0xaf/0xd0
> >> [  720.913676] kernel:  ? __blkdev_direct_IO_simple+0x290/0x290
> >> [  720.913728] kernel:  generic_file_read_iter+0x9b/0x160
> >> [  720.913775] kernel:  new_sync_read+0x105/0x180
> >> [  720.913820] kernel:  vfs_read+0xf1/0x190
> >> [  720.913858] kernel:  ksys_read+0x4f/0xc0
> >> [  720.913896] kernel:  do_syscall_64+0x38/0x90
> >> [  720.913936] kernel:  entry_SYSCALL_64_after_hwframe+0x44/0xae
> >> [  720.913985] kernel: RIP: 0033:0x7f73e676d772
> >> [  720.914024] kernel: Code: c0 e9 b2 fe ff ff 50 48 8d 3d da 2e 0c 00 e8 b5 f9 01 00 0f 1f 44 00 00 f3 0f 1e fa 64 8b 04 25 18 00 00 00 85 c0 75 10 0f 05 <48> 3d 00 f0 ff ff 77 56 c3 0f 1f 44 00 00 48 83 ec 28 48 89 54 24
> >> [  720.914166] kernel: RSP: 002b:00007fff1b8fcbb8 EFLAGS: 00000246 ORIG_RAX: 0000000000000000
> >> [  720.914231] kernel: RAX: ffffffffffffffda RBX: 0000000000000040 RCX: 00007f73e676d772
> >> [  720.917149] kernel: RDX: 0000000000040000 RSI: 00007f73e65d3000 RDI: 0000000000000004
> >> [  720.920078] kernel: RBP: 0000000000001000 R08: 00000000015105c0 R09: 0000000000000080
> >> [  720.922980] kernel: R10: 00007fff1b8fca00 R11: 0000000000000246 R12: 00000015105c0000
> >> [  720.925875] kernel: R13: 0000000000000004 R14: 00007f73e65d3000 R15: 0000000000040000
> >> [  720.928795] kernel:  </TASK>
> >> [  720.931704] kernel: Modules linked in: sctp ip6_udp_tunnel udp_tunnel rpcrdma rdma_cm iw_cm ib_cm ib_core sit tunnel4 ip_tunnel rfkill ipt_REJECT nf_reject_ipv4 iptable_filter xt_nat iptable_nat nf_nat iptable_mangle nf_conntrack_pptp xt_CT iptable_raw xt_multiport xt_set ip6t_REJECT nf_reject_ipv6 xt_LOG nf_log_syslog xt_limit xt_state xt_conntrack nf_conntrack nf_defrag_ipv6 nf_defrag_ipv4 ip6table_filter ip6_tables ip_set_hash_netport ip_set_hash_net ip_set drivetemp it87 nfnetlink hwmon_vid vfat fat iTCO_wdt intel_pmc_bxt iTCO_vendor_support at24 raid456 async_raid6_recov async_memcpy async_pq async_xor async_tx intel_powerclamp raid1 coretemp snd_hda_codec_realtek snd_hda_codec_generic ledtrig_audio snd_hda_codec_hdmi snd_hda_intel snd_intel_dspcfg snd_intel_sdw_acpi snd_hda_codec snd_hda_core snd_usb_audio i2c_i801 gma500_gfx i2c_smbus snd_usbmidi_lib joydev snd_hwdep snd_rawmidi snd_seq_device mc snd_pcm lpc_ich i2c_algo_bit snd_timer drm_kms_helper snd cec soundcore nfsd auth_rpcgss
> >> [  720.931885] kernel:  nfs_acl lockd grace drm fuse sunrpc zram ip_tables hid_logitech_hidpp serio_raw r8152 sata_sil24 video mii hid_jabra e1000e hid_logitech_dj
> >> [  720.952122] kernel: CR2: ffffdbc681023bc8
> >> [  720.955651] kernel: ---[ end trace de2c3d5b971ae71d ]---
> >> [  720.959186] kernel: RIP: 0010:kfree+0x58/0x3e0
> >> [  720.962723] kernel: Code: 80 4c 01 e5 0f 82 84 03 00 00 48 c7 c0 00 00 00 80 48 2b 05 4a 96 3b 01 48 01 c5 48 c1 ed 0c 48 c1 e5 06 48 03 2d 28 96 3b 01 <48> 8b 45 08 48 8d 50 ff a8 01 48 0f 45 ea 48 8b 55 08 48 8d 42 ff
> >> [  720.966472] kernel: RSP: 0018:ffff9db4008efaf8 EFLAGS: 00010286
> >> [  720.970238] kernel: RAX: 00006d7bc0000000 RBX: ffff9284c5214800 RCX: ffff9284c3758ff8
> >> [  720.973993] kernel: RDX: ffff9283c1102740 RSI: ffffffffc07af091 RDI: ffff9db4008efd58
> >> [  720.977723] kernel: RBP: ffffdbc681023bc0 R08: ffff9db4008efb88 R09: ffff9284c3759000
> >> [  720.981464] kernel: R10: 0000000000000028 R11: ffff9284c213db48 R12: ffff9db4008efd58
> >> [  720.985228] kernel: R13: ffff9284c213da00 R14: ffff9284c375f000 R15: ffff9db4008efd58
> >> [  720.988995] kernel: FS:  00007f73e6669740(0000) GS:ffff9284dbc80000(0000) knlGS:0000000000000000
> >> [  720.992774] kernel: CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> >> [  720.996535] kernel: CR2: ffffdbc681023bc8 CR3: 000000005c2cc000 CR4: 00000000000006e0

I tried a few things (injecting badblocks, etc.) but still could not
reproduce this issue.

Hi Dominik,

Could you please share more information about the array?

   mdadm --detail /dev/mdXXX
   mdadm --examine /dev/<devices>

Thanks,
Song

> >>
> >> There was a crash earlier which caused the array to become degraded, but I wasn't able to capture the backtrace due to journal corruption. After resyncing the array I tried running fsck on the filesystem and it's causing a kernel crash each time.
> >>
> >> I've reproduced the crash with the following kernels:
> >> 5.16.8-200.fc35.x86_64
> >> 5.15.18-200.fc35.x86_64
> >> 5.14.10-300.fc35.x86_64
> >>
> >> It doesn't happen with 5.13 kernels. I've been running fsck.ext4 -c on the array for the last 10 hours without a crash. It found 27 read errors which it corrected.
> >>
> >> Steps to reproduce:
> >> 1. fsck.ext4 -c -v /dev/md126
> >> 2. crash
> >>
> >> The array was degraded as a result of a previous crash, but it recovered itself with no errors reported. Obviously, there remained some read errors which badblocks found and which the kernel tripped over.
> >>
> >> Crash with 5.14.10 looks different:
> >> Feb 13 17:55:06 kernel: general protection fault, probably for non-canonical address 0xef6dfcf53c7d6fc3: 0000 [#1] SMP NOPTI
> >> Feb 13 17:55:06 kernel: CPU: 2 PID: 831 Comm: md126_raid5 Not tainted 5.14.10-300.fc35.x86_64 #1
> >> Feb 13 17:55:06 kernel: Hardware name: Intel Corporation Milstead Platform/Granite Well, BIOS CDV W Series 05 08/27/2015
> >> Feb 13 17:55:06 kernel: RIP: 0010:bio_endio+0x87/0x130
> >> Feb 13 17:55:06 kernel: Code: 02 00 48 8b 45 08 48 85 c0 74 09 0f b7 55 14 f6 c6 01 75 2f 48 81 7d 38 50 48 5e bb 75 38 0f b6 45 1a 48 8b 5d 40 84 c0 74 09 <80> 7b 1a 00 75 03 88 43 1a 48 89 ef 48 89 dd e8 d5 fe ff ff e9 6a
> >> Feb 13 17:55:06 kernel: RSP: 0000:ffffa5bb80597b48 EFLAGS: 00010206
> >> Feb 13 17:55:06 kernel: RAX: 000000000000000a RBX: ef6dfcf53c7d6fa9 RCX: ffff92b840865b50
> >> Feb 13 17:55:06 kernel: RDX: 0000000000000082 RSI: ffff92b8497f46c0 RDI: ffff92b84881f180
> >> Feb 13 17:55:06 kernel: RBP: ffff92b8497f46c0 R08: 0000000000000001 R09: 0000000000000000
> >> Feb 13 17:55:06 kernel: R10: ffff92b74a722c01 R11: 0000000000000001 R12: 0000000000000000
> >> Feb 13 17:55:06 kernel: R13: 0000000000000000 R14: ffff92b74a722cd0 R15: ffff92b844748860
> >> Feb 13 17:55:06 kernel: FS:  0000000000000000(0000) GS:ffff92b85bd00000(0000) knlGS:0000000000000000
> >> Feb 13 17:55:06 kernel: CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> >> Feb 13 17:55:06 kernel: CR2: 0000557d787a2028 CR3: 000000003c194000 CR4: 00000000000006e0
> >> Feb 13 17:55:06 kernel: Call Trace:
> >> Feb 13 17:55:06 kernel:  ops_complete_biofill+0x98/0xe0 [raid456]
> >> Feb 13 17:55:06 kernel:  async_trigger_callback+0x7d/0xc1 [async_tx]
> >> Feb 13 17:55:06 kernel:  raid_run_ops+0x98c/0x15b0 [raid456]
> >> Feb 13 17:55:06 kernel:  ? handle_stripe_clean_event+0x400/0x400 [raid456]
> >> Feb 13 17:55:06 kernel:  handle_stripe+0xe91/0x1dc0 [raid456]
> >> Feb 13 17:55:06 kernel:  handle_active_stripes.constprop.0+0x390/0x560 [raid456]
> >> Feb 13 17:55:06 kernel:  raid5d+0x39d/0x5d0 [raid456]
> >> Feb 13 17:55:06 kernel:  ? prepare_to_wait_event+0x5d/0x170
> >> Feb 13 17:55:06 kernel:  md_thread+0x98/0x140
> >> Feb 13 17:55:06 kernel:  ? finish_wait+0x80/0x80
> >> Feb 13 17:55:06 kernel:  ? md_write_inc+0x50/0x50
> >> Feb 13 17:55:06 kernel:  kthread+0x124/0x150
> >> Feb 13 17:55:06 kernel:  ? set_kthread_struct+0x40/0x40
> >> Feb 13 17:55:06 kernel:  ret_from_fork+0x1f/0x30
> >> Feb 13 17:55:06 kernel: Modules linked in: rpcrdma rdma_cm iw_cm ib_cm ib_core rfkill ip6t_REJECT nf_reject_ipv6 ip6table_filter ip6_tables xt_set ipt_REJECT nf_reject_ipv4 xt_LOG nf_log_syslog xt_limit xt_multiport xt_state xt_conntrack iptable_filter xt_nat iptable_nat nf_nat iptable_mangle nf_conntrack_pptp xt_CT nf_conntrack nf_defrag_ipv6 nf_defrag_ipv4 iptable_raw ip_set_hash_netport ip_set_hash_net ip_set drivetemp it87 nfnetlink hwmon_vid vfat fat snd_hda_codec_realtek snd_hda_codec_generic ledtrig_audio snd_hda_codec_hdmi iTCO_wdt snd_hda_intel intel_pmc_bxt snd_intel_dspcfg iTCO_vendor_support raid456 snd_intel_sdw_acpi snd_hda_codec async_raid6_recov at24 async_memcpy async_pq async_xor async_tx snd_hda_core gma500_gfx snd_hwdep i2c_algo_bit drm_kms_helper snd_pcm intel_powerclamp i2c_i801 snd_timer coretemp i2c_smbus snd cec soundcore lpc_ich nfsd auth_rpcgss nfs_acl lockd drm grace fuse sunrpc ip_tables raid1 serio_raw video sata_sil24 e1000e
> >> Feb 13 17:55:06 kernel: ---[ end trace 97447bed31e596e0 ]---
> >> Feb 13 17:55:06 kernel: RIP: 0010:bio_endio+0x87/0x130
> >> Feb 13 17:55:06 kernel: Code: 02 00 48 8b 45 08 48 85 c0 74 09 0f b7 55 14 f6 c6 01 75 2f 48 81 7d 38 50 48 5e bb 75 38 0f b6 45 1a 48 8b 5d 40 84 c0 74 09 <80> 7b 1a 00 75 03 88 43 1a 48 89 ef 48 89 dd e8 d5 fe ff ff e9 6a
> >> Feb 13 17:55:06 kernel: RSP: 0000:ffffa5bb80597b48 EFLAGS: 00010206
> >> Feb 13 17:55:06 kernel: RAX: 000000000000000a RBX: ef6dfcf53c7d6fa9 RCX: ffff92b840865b50
> >> Feb 13 17:55:06 kernel: RDX: 0000000000000082 RSI: ffff92b8497f46c0 RDI: ffff92b84881f180
> >> Feb 13 17:55:06 kernel: RBP: ffff92b8497f46c0 R08: 0000000000000001 R09: 0000000000000000
> >> Feb 13 17:55:06 kernel: R10: ffff92b74a722c01 R11: 0000000000000001 R12: 0000000000000000
> >> Feb 13 17:55:06 kernel: R13: 0000000000000000 R14: ffff92b74a722cd0 R15: ffff92b844748860
> >> Feb 13 17:55:06 kernel: FS:  0000000000000000(0000) GS:ffff92b85bd00000(0000) knlGS:0000000000000000
> >> Feb 13 17:55:06 kernel: CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> >> Feb 13 17:55:06 kernel: CR2: 0000557d787a2028 CR3: 000000003c194000 CR4: 00000000000006e0
> >> Feb 13 17:55:06 kernel: ------------[ cut here ]------------
> >> Feb 13 17:55:06 kernel: WARNING: CPU: 2 PID: 831 at kernel/exit.c:739 do_exit+0x37/0xa90
> >> Feb 13 17:55:06 kernel: Modules linked in: rpcrdma rdma_cm iw_cm ib_cm ib_core rfkill ip6t_REJECT nf_reject_ipv6 ip6table_filter ip6_tables xt_set ipt_REJECT nf_reject_ipv4 xt_LOG nf_log_syslog xt_limit xt_multiport xt_state xt_conntrack iptable_filter xt_nat iptable_nat nf_nat iptable_mangle nf_conntrack_pptp xt_CT nf_conntrack nf_defrag_ipv6 nf_defrag_ipv4 iptable_raw ip_set_hash_netport ip_set_hash_net ip_set drivetemp it87 nfnetlink hwmon_vid vfat fat snd_hda_codec_realtek snd_hda_codec_generic ledtrig_audio snd_hda_codec_hdmi iTCO_wdt snd_hda_intel intel_pmc_bxt snd_intel_dspcfg iTCO_vendor_support raid456 snd_intel_sdw_acpi snd_hda_codec async_raid6_recov at24 async_memcpy async_pq async_xor async_tx snd_hda_core gma500_gfx snd_hwdep i2c_algo_bit drm_kms_helper snd_pcm intel_powerclamp i2c_i801 snd_timer coretemp i2c_smbus snd cec soundcore lpc_ich nfsd auth_rpcgss nfs_acl lockd drm grace fuse sunrpc ip_tables raid1 serio_raw video sata_sil24 e1000e
> >> Feb 13 17:55:06 kernel: CPU: 2 PID: 831 Comm: md126_raid5 Tainted: G      D           5.14.10-300.fc35.x86_64 #1
> >> Feb 13 17:55:06 kernel: Hardware name: Intel Corporation Milstead Platform/Granite Well, BIOS CDV W Series 05 08/27/2015
> >> Feb 13 17:55:06 kernel: RIP: 0010:do_exit+0x37/0xa90
> >> Feb 13 17:55:06 kernel: Code: 55 48 89 fd 53 65 48 8b 1c 25 c0 7b 01 00 48 83 ec 28 48 8b 83 a8 0c 00 00 48 85 c0 74 0e 48 8b 10 48 39 d0 0f 84 56 04 00 00 <0f> 0b 65 8b 0d a0 2c f3 44 89 c8 25 00 ff ff 00 89 44 24 0c 0f 85
> >> Feb 13 17:55:06 kernel: RSP: 0000:ffffa5bb80597ef8 EFLAGS: 00010212
> >> Feb 13 17:55:06 kernel: RAX: ffffa5bb80597e50 RBX: ffff92b8437d8000 RCX: 0000000000000000
> >> Feb 13 17:55:06 kernel: RDX: ffff92b844217548 RSI: ffff92b85bd18a00 RDI: 000000000000000b
> >> Feb 13 17:55:06 kernel: RBP: 000000000000000b R08: 0000000000000000 R09: ffffa5bb805977a0
> >> Feb 13 17:55:06 kernel: R10: ffffa5bb80597798 R11: ffffffffbcf47468 R12: 000000000000000b
> >> Feb 13 17:55:06 kernel: R13: 0000000000000000 R14: ffff92b8437d8000 R15: 0000000000000000
> >> Feb 13 17:55:06 kernel: FS:  0000000000000000(0000) GS:ffff92b85bd00000(0000) knlGS:0000000000000000
> >> Feb 13 17:55:06 kernel: CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> >> Feb 13 17:55:06 kernel: CR2: 0000557d787a2028 CR3: 000000003c194000 CR4: 00000000000006e0
> >> Feb 13 17:55:06 kernel: Call Trace:
> >> Feb 13 17:55:06 kernel:  ? kthread+0x124/0x150
> >> Feb 13 17:55:06 kernel:  rewind_stack_do_exit+0x17/0x20
> >> Feb 13 17:55:06 kernel: RIP: 0000:0x0
> >> Feb 13 17:55:06 kernel: Code: Unable to access opcode bytes at RIP 0xffffffffffffffd6.
> >> Feb 13 17:55:06 kernel: RSP: 0000:0000000000000000 EFLAGS: 00000000 ORIG_RAX: 0000000000000000
> >> Feb 13 17:55:06 kernel: RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000
> >> Feb 13 17:55:06 kernel: RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
> >> Feb 13 17:55:06 kernel: RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
> >> Feb 13 17:55:06 kernel: R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
> >> Feb 13 17:55:06 kernel: R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
> >> Feb 13 17:55:06 kernel: ---[ end trace 97447bed31e596e1 ]---
> >>
> >> Downstream bug report: https://bugzilla.redhat.com/show_bug.cgi?id=2053936 .
> >
> > Could somebody take a look into this? Or was this discussed somewhere
> > else already? Or even fixed?
> >
> > FWIW, I searched the list and wondered if these might be related, but I
> > was unable to tell for sure:
> >
> > https://lore.kernel.org/all/164244747275.86917.2623783912687807916@richardiv.omgwallhack.org/
> > https://lore.kernel.org/all/20211216145222.15370-4-mariusz.tkaczyk@linux.intel.com/
> >
> > Anyway, to get this tracked:
> >
> > #regzbot introduced: v5.13..v5.14.10
> > #regzbot from: Dominik Mierzejewski <dominik@greysector.net>
> > #regzbot title: md: unable to handle page fault while running badblocks
> > (fsck.ext4 -c) on a raid5 md array
> > #regzbot link: https://bugzilla.kernel.org/show_bug.cgi?id=215605
> >
> > Ciao, Thorsten (wearing his 'the Linux kernel's regression tracker' hat)
> >
> > P.S.: As the Linux kernel's regression tracker I'm getting a lot of
> > reports on my table. I can only look briefly into most of them and lack
> > knowledge about most of the areas they concern. I thus unfortunately
> > will sometimes get things wrong or miss something important. I hope
> > that's not the case here; if you think it is, don't hesitate to tell me
> > in a public reply, it's in everyone's interest to set the public record
> > straight.
> >