From: Ingo Molnar <mingo@elte.hu>
To: Kamalesh Babulal <kamalesh@linux.vnet.ibm.com>
Cc: Dhaval Giani <dhaval@linux.vnet.ibm.com>,
Jens Axboe <jens.axboe@oracle.com>,
Srivatsa Vaddagiri <vatsa@linux.vnet.ibm.com>,
LKML <linux-kernel@vger.kernel.org>,
linuxppc-dev@ozlabs.org, Balbir Singh <balbir@linux.vnet.ibm.com>
Subject: Re: [BUG] 2.6.25-rc1-git1 softlockup while bootup on powerpc
Date: Tue, 12 Feb 2008 08:58:12 +0100 [thread overview]
Message-ID: <20080212075812.GC11775@elte.hu> (raw)
In-Reply-To: <47B1463E.1070809@linux.vnet.ibm.com>
* Kamalesh Babulal <kamalesh@linux.vnet.ibm.com> wrote:
> While booting with the 2.6.25-rc1-git1 kernel on the powerbox the
> softlockup is seen, with following trace.
> BUG: soft lockup - CPU#1 stuck for 61s! [insmod:377]
> TASK = c00000077cb2f0e0[377] 'insmod' THREAD: c00000077cb28000 CPU: 1
> NIP [c0000000001b172c] .radix_tree_gang_lookup+0xdc/0x1e4
> LR [c0000000001a6f00] .call_for_each_cic+0x50/0x10c
> Call Trace:
> [c00000077cb2bb20] [c0000000001a6f60] .call_for_each_cic+0xb0/0x10c (unreliable)
> [c00000077cb2bc60] [c00000000019ecd8] .exit_io_context+0xf0/0x110
> [c00000077cb2bcf0] [c00000000006254c] .do_exit+0x820/0x850
> [c00000077cb2bda0] [c000000000062648] .do_group_exit+0xcc/0xe8
> [c00000077cb2be30] [c00000000000872c] syscall_exit+0x0/0x40
this call_for_each_cic/radix_tree_gang_lookup locked up, and all other
CPUs deadlocked in stopmachine, due to this one.
call_for_each_cic is in ./block/cfq-iosched.c uses RCU, but you've got
classic-RCU:
CONFIG_CLASSIC_RCU=y
# CONFIG_PREEMPT_RCU is not set
so it's not related to the preempt-RCU changes either.
It is this part that locks up:
do {
...
nr = radix_tree_gang_lookup(&ioc->radix_root, (void **) cics,
index, CIC_GANG_NR);
...
} while (nr == CIC_GANG_NR);
...
it seems the radix tree will yield new entries again and again. Either
it got corrupted, or some other CPU is filling it faster than we can
deplete it [unlikely i think].
Ingo
next prev parent reply other threads:[~2008-02-12 7:58 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-02-12 7:09 [BUG] 2.6.25-rc1-git1 softlockup while bootup on powerpc Kamalesh Babulal
2008-02-12 7:58 ` Ingo Molnar [this message]
2008-02-14 9:59 ` Kamalesh Babulal
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20080212075812.GC11775@elte.hu \
--to=mingo@elte.hu \
--cc=balbir@linux.vnet.ibm.com \
--cc=dhaval@linux.vnet.ibm.com \
--cc=jens.axboe@oracle.com \
--cc=kamalesh@linux.vnet.ibm.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linuxppc-dev@ozlabs.org \
--cc=vatsa@linux.vnet.ibm.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).