From: Paul Mackerras <paulus@samba.org>
To: Peter Zijlstra <a.p.zijlstra@chello.nl>, Ingo Molnar <mingo@elte.hu>
Cc: linux-kernel@vger.kernel.org
Subject: NMI between switch_mm and switch_to
Date: Tue, 28 Jul 2009 14:49:59 +1000 [thread overview]
Message-ID: <19054.33655.297932.261580@cargo.ozlabs.ibm.com> (raw)
Ben H. suggested there might be a problem if we get a PMU interrupt
and try to do a stack trace of userspace in the interval between when
we call switch_mm() from sched.c:context_switch() and when we call
switch_to(). If we get an NMI in that interval and do a stack trace
of userspace, we'll see the registers of the old task but when we peek
at user addresses we'll see the memory image for the new task, so the
stack trace we get will be completely bogus.
Is this in fact also a problem on x86, or is there some subtle reason
why it can't happen there?
Paul.
next reply other threads:[~2009-07-28 6:35 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-07-28 4:49 Paul Mackerras [this message]
2009-07-28 7:51 ` Peter Zijlstra
2009-07-28 9:23 ` Andi Kleen
2009-08-03 8:29 ` Ingo Molnar
2009-08-03 10:32 ` Paul Mackerras
2009-08-03 10:43 ` Ingo Molnar
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=19054.33655.297932.261580@cargo.ozlabs.ibm.com \
--to=paulus@samba.org \
--cc=a.p.zijlstra@chello.nl \
--cc=linux-kernel@vger.kernel.org \
--cc=mingo@elte.hu \
/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®