lkml.org 
[lkml]   [2007]   [May]   [29]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
Date
From
SubjectRe: [2.6.21.1] soft lockup when removing netconsole module
On Sat, 26 May 2007 17:40:12 +0200 Folkert van Heusden <folkert@vanheusden.com> wrote:

> When trying to remove the netconsole module, I got the following kernel
> output after a while (couple of minutes iirc):
>
> [525720.117293] BUG: soft lockup detected on CPU#1!
> [525720.117353] [<c1004d53>] show_trace_log_lvl+0x1a/0x30
> [525720.117439] [<c1004d7b>] show_trace+0x12/0x14
> [525720.117526] [<c1004e75>] dump_stack+0x16/0x18
> [525720.117613] [<c104dd5b>] softlockup_tick+0xa6/0xc2
> [525720.117694] [<c1026855>] run_local_timers+0x12/0x14
> [525720.117738] [<c1026669>] update_process_times+0x72/0xa1
> [525720.117744] [<c1038673>] tick_sched_timer+0x53/0xb6
> [525720.117748] [<c1033d62>] hrtimer_interrupt+0x189/0x1e3
> [525720.117753] [<c100e9e2>] local_apic_timer_interrupt+0x55/0x5b
> [525720.117761] [<c100ea12>] smp_apic_timer_interrupt+0x2a/0x39
> [525720.117766] [<c1004a3f>] apic_timer_interrupt+0x33/0x38
> [525720.117770] [<c120f4b1>] mutex_lock+0x8/0xa
> [525720.117775] [<c102d2f0>] flush_workqueue+0x2f/0x8f
> [525720.117780] [<c102d7a0>] cancel_rearming_delayed_workqueue+0x29/0x2b
> [525720.117785] [<c102d7b1>] cancel_rearming_delayed_work+0xf/0x11
> [525720.117790] [<c11be143>] netpoll_cleanup+0x75/0xa5
> [525720.117794] [<f893712d>] cleanup_netconsole+0x17/0x1a [netconsole]
> [525720.117804] [<c1041f11>] sys_delete_module+0x12f/0x14f
> [525720.117809] [<c1003f74>] syscall_call+0x7/0xb
> [525720.117812] =======================
>
> Also the rmmod hangs and would not exit even with kill -9. It also
> sucks up 100% cpu.

Jason recently posted a mystery patch without telling us what problem it
fixed.

It looks like you just found it: cancel_rearming_delayed_work() will hang
if the work isn't actually pending. Please test this:


From: Jason Wessel <jason.wessel@windriver.com>

Do not call cancel_rearming_delayed_work() if there is no
pending work.

Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

net/core/netpoll.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)

diff -puN net/core/netpoll.c~a net/core/netpoll.c
--- a/net/core/netpoll.c~a
+++ a/net/core/netpoll.c
@@ -784,8 +784,10 @@ void netpoll_cleanup(struct netpoll *np)
if (atomic_dec_and_test(&npinfo->refcnt)) {
skb_queue_purge(&npinfo->arp_tx);
skb_queue_purge(&npinfo->txq);
- cancel_rearming_delayed_work(&npinfo->tx_work);
- flush_scheduled_work();
+ if (delayed_work_pending(&npinfo->tx_work)) {
+ cancel_rearming_delayed_work(&npinfo->tx_work);
+ flush_scheduled_work();
+ }

kfree(npinfo);
}
_
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/

\
 
 \ /
  Last update: 2007-05-29 10:01    [W:0.470 / U:0.860 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site