lkml.org 
[lkml]   [2018]   [Sep]   [5]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH v1] xen: avoid crash in disable_hotplug_cpu
Am Wed, 5 Sep 2018 12:55:58 +0200
schrieb Juergen Gross <jgross@suse.com>:

> Instead of trying to fight the symptoms, I think avoiding to offline
> the last cpu would make more sense.

Well, apparently the fix is to leave cpu#0 online because of a backtrace like that:

WARNING: CPU: 0 PID: 83 at kernel/sched/cpudeadline.c:159 cpudl_clear+0xa5/0xb0
Workqueue: events cpuset_hotplug_workfn
RIP: e030:cpudl_clear+0xa5/0xb0
Code: 8b 43 48 c7 44 28 0c ff ff ff ff e8 d5 fd ff ff 48 8d 43 08 f0 4c 0f ab 20 4c 89 ee 48 89 df 5b 5d 41 5c 41 5d e9 0b 3b 79 00 <0f> 0b e9 76 ff ff ff 0f 1f 40 00 66 66 66 66 90 41 56 49 89 d6 41
RSP: e02b:ffffc900411cbc40 EFLAGS: 00010086
RAX: ffffffff810d09a0 RBX: ffff880106f1a100 RCX: 0000000000000000
RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffff880106f1a100
RBP: 0000000000000000 R08: 0000000000000000 R09: ffff8801068989b0
R10: ffff8801068989d0 R11: 0000000000000008 R12: 0000000000000000
R13: ffff8801f3800200 R14: 0000000000000001 R15: ffff8801f3823240
FS: 00007fd40d7f08c0(0000) GS:ffff8801f3800000(0000) knlGS:0000000000000000
CS: e033 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055eff60fe098 CR3: 00000001edf24000 CR4: 0000000000002660
Call Trace:
rq_offline_dl+0x36/0x80
set_rq_offline+0x31/0x60
rq_attach_root+0x98/0xc0
cpu_attach_domain+0x107/0x320
partition_sched_domains+0x117/0x347
? cpus_read_lock+0x2d/0x50
rebuild_sched_domains_locked+0xe4/0x4e0
? __switch_to_asm+0x40/0x70
? xen_mc_flush+0x102/0x210
rebuild_sched_domains+0x16/0x30
cpuset_hotplug_workfn+0x45e/0xef0
? _raw_spin_unlock_irq+0x22/0x40
? finish_task_switch+0x75/0x250
process_one_work+0x1fd/0x3e0
worker_thread+0x2d/0x3d0
? rescuer_thread+0x340/0x340
kthread+0x112/0x130
? kthread_create_worker_on_cpu+0x40/0x40
ret_from_fork+0x3a/0x50

Initially I did not spot it because the kernel was booted with 'quiet'.

Olaf
[unhandled content-type:application/pgp-signature]
\
 
 \ /
  Last update: 2018-09-05 16:47    [W:0.079 / U:8.160 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site