From: Michael Holzheu <holzheu@linux.vnet.ibm.com>
To: Vivek Goyal <vgoyal@redhat.com>
Cc: ebiederm@xmission.com, akpm@linux-foundation.org,
schwidefsky@de.ibm.com, heiko.carstens@de.ibm.com,
kexec@lists.infradead.org, linux-kernel@vger.kernel.org
Subject: kdump: crash_kexec()-smp_send_stop() race in panic
Date: Mon, 24 Oct 2011 16:55:37 +0200 [thread overview]
Message-ID: <1319468137.3615.16.camel@br98xy6r> (raw)
Hello Vivek,
In our tests we ran into the following scenario:
Two CPUs have called panic at the same time. The first CPU called
crash_kexec() and the second CPU called smp_send_stop() in panic()
before crash_kexec() finished on the first CPU. So the second CPU
stopped the first CPU and therefore kdump failed.
1st CPU:
panic()->crash_kexec()->mutex_trylock(&kexec_mutex)-> do kdump
2nd CPU:
panic()->crash_kexec()->kexec_mutex already held by 1st CPU
->smp_send_stop()-> stop CPU 1 (stop kdump)
How should we fix this problem? One possibility could be to do
smp_send_stop() before we call crash_kexec().
What do you think?
Michael
next reply other threads:[~2011-10-24 14:55 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-10-24 14:55 Michael Holzheu [this message]
2011-10-24 15:14 ` Eric W. Biederman
2011-10-24 15:23 ` Américo Wang
2011-10-24 17:07 ` Eric W. Biederman
2011-10-24 17:33 ` Vivek Goyal
2011-10-24 22:24 ` Seiji Aguchi
2011-10-25 8:33 ` Michael Holzheu
2011-10-25 8:44 ` Michael Holzheu
2011-10-25 12:04 ` Eric W. Biederman
2011-10-25 14:54 ` Vivek Goyal
2011-10-25 14:58 ` Michael Holzheu
2011-10-25 15:08 ` Vivek Goyal
2011-10-25 15:28 ` Michael Holzheu
2011-10-25 15:28 ` Don Zickus
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=1319468137.3615.16.camel@br98xy6r \
--to=holzheu@linux.vnet.ibm.com \
--cc=akpm@linux-foundation.org \
--cc=ebiederm@xmission.com \
--cc=heiko.carstens@de.ibm.com \
--cc=kexec@lists.infradead.org \
--cc=linux-kernel@vger.kernel.org \
--cc=schwidefsky@de.ibm.com \
--cc=vgoyal@redhat.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
all inboxes | Powered by JetHome®