Re: PROBLEM: nfs? crash in Linux 5.3 (possible regression)

[Trond Myklebust]

On Fri, 2019-09-20 at 14:23 -0400, Nick Bowler wrote:
> Hi all,
> 
> I hit this oops on Linux 5.3 yesterday.  The crash itself occurred
> while
> compiling Linux (source and build dirs on NFS).  Afterwards, the
> system
> remained mostly alive but my NFS mounts became very busted with lots
> (but not all) I/O operations appearing to hang forever.
> 
> Not sure how reproducible this is.  Since I've never seen a crash
> like this before it may be a regression compared to, say, Linux 4.19
> but I am not certain because this particular machine is brand new so
> I don't have experience with older kernels on it...
> 
> Full dmesg is attached (gzipped).
> 
> Let me know if you need any more info.
> 
> [  796.050025] BUG: kernel NULL pointer dereference, address:
> 0000000000000014
> [  796.051280] #PF: supervisor read access in kernel mode
> [  796.053063] #PF: error_code(0x0000) - not-present page
> [  796.054636] PGD 0 P4D 0
> [  796.055688] Oops: 0000 [#1] PREEMPT SMP
> [  796.056768] CPU: 2 PID: 190 Comm: kworker/2:2 Tainted: G        W
>       5.3.0 #6
> [  796.057953] Hardware name: To Be Filled By O.E.M. To Be Filled By
> O.E.M./B450 Gaming-ITX/ac, BIOS P3.30 05/17/2019
> [  796.059329] Workqueue: events key_garbage_collector
> [  796.060623] RIP: 0010:keyring_gc_check_iterator+0x27/0x30

That would be the keyring garbage collector, not NFS.

Cced keyrings@xxxxxxxxxxxxxxx


> [  796.061845] Code: 44 00 00 48 83 e7 fc b8 01 00 00 00 f6 87 80 00
> 00 00 21 75 19 48 8b 57 58 48 39 16 7c 05 48 85 d2 7f 0b 48 8b 87 a0
> 00 00 00 <0f> b6 40 14 c3 0f 1f 40 00 48 83 e7 fc e9 27 eb ff ff 0f
> 1f
> 80 00
> [  796.064638] RSP: 0018:ffffb40fc0757df8 EFLAGS: 00010282
> [  796.066058] RAX: 0000000000000000 RBX: ffffa14338caed80 RCX:
> ffffb40fc0757e40
> [  796.067531] RDX: ffffa1433ae85558 RSI: ffffb40fc0757e40 RDI:
> ffffa1433ae85500
> [  796.069014] RBP: ffffb40fc0757e40 R08: 0000000000000000 R09:
> 000000000000000f
> [  796.070513] R10: 8080808080808080 R11: 0000000000000001 R12:
> ffffffffa4cd6180
> [  796.072025] R13: ffffa14338caee10 R14: ffffa14338caedf0 R15:
> ffffa1433ffeff00
> [  796.073567] FS:  0000000000000000(0000) GS:ffffa14340480000(0000)
> knlGS:0000000000000000
> [  796.075171] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> [  796.076785] CR2: 0000000000000014 CR3: 0000000747ce6000 CR4:
> 00000000003406e0
> [  796.078445] Call Trace:
> [  796.080091]  assoc_array_subtree_iterate+0x55/0x100
> [  796.081770]  keyring_gc+0x3f/0x80
> [  796.083447]  key_garbage_collector+0x330/0x3d0
> [  796.085155]  process_one_work+0x1cb/0x320
> [  796.086869]  worker_thread+0x28/0x3c0
> [  796.088603]  ? process_one_work+0x320/0x320
> [  796.090335]  kthread+0x106/0x120
> [  796.092053]  ? kthread_create_on_node+0x40/0x40
> [  796.093810]  ret_from_fork+0x1f/0x30
> [  796.095569] Modules linked in: sha1_ssse3 sha1_generic cbc cts
> rpcsec_gss_krb5 auth_rpcgss nfsv4 nfs lockd grace ext4 crc16 mbcache
> jbd2 iwlmvm mac80211 libarc4 amdgpu iwlwifi snd_hda_codec_realtek
> snd_hda_codec_generic kvm_amd gpu_sched kvm snd_hda_codec_hdmi
> drm_kms_helper irqbypass k10temp syscopyarea sysfillrect sysimgblt
> fb_sys_fops video ttm cfg80211 snd_hda_intel snd_hda_codec drm
> snd_hwdep rfkill snd_hda_core backlight snd_pcm evdev snd_timer snd
> soundcore efivarfs dm_crypt hid_generic igb hwmon i2c_algo_bit sr_mod
> cdrom sunrpc dm_mod
> [  796.104033] CR2: 0000000000000014
> [  796.106304] ---[ end trace 695aee10f9202347 ]---
> [  796.108585] RIP: 0010:keyring_gc_check_iterator+0x27/0x30
> [  796.110894] Code: 44 00 00 48 83 e7 fc b8 01 00 00 00 f6 87 80 00
> 00 00 21 75 19 48 8b 57 58 48 39 16 7c 05 48 85 d2 7f 0b 48 8b 87 a0
> 00 00 00 <0f> b6 40 14 c3 0f 1f 40 00 48 83 e7 fc e9 27 eb ff ff 0f
> 1f
> 80 00
> [  796.115773] RSP: 0018:ffffb40fc0757df8 EFLAGS: 00010282
> [  796.118209] RAX: 0000000000000000 RBX: ffffa14338caed80 RCX:
> ffffb40fc0757e40
> [  796.120683] RDX: ffffa1433ae85558 RSI: ffffb40fc0757e40 RDI:
> ffffa1433ae85500
> [  796.123176] RBP: ffffb40fc0757e40 R08: 0000000000000000 R09:
> 000000000000000f
> [  796.125668] R10: 8080808080808080 R11: 0000000000000001 R12:
> ffffffffa4cd6180
> [  796.128104] R13: ffffa14338caee10 R14: ffffa14338caedf0 R15:
> ffffa1433ffeff00
> [  796.130493] FS:  0000000000000000(0000) GS:ffffa14340480000(0000)
> knlGS:0000000000000000
> [  796.132923] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> [  796.135266] CR2: 0000000000000014 CR3: 0000000747ce6000 CR4:
> 00000000003406e0
> 
> Thanks,
>   Nick
-- 
Trond Myklebust
Linux NFS client maintainer, Hammerspace
trond.myklebust@xxxxxxxxxxxxxxx