linux-arm-kernel.lists.infradead.org archive mirror
 help / color / mirror / Atom feed
From: Russell King - ARM Linux admin <linux@armlinux.org.uk>
To: Dmitry Vyukov <dvyukov@google.com>
Cc: syzbot <syzbot+f09a12b2c77bfbbf51bd@syzkaller.appspotmail.com>,
	Mark Rutland <mark.rutland@arm.com>,
	Arnd Bergmann <arnd@arndb.de>,
	Linux ARM <linux-arm-kernel@lists.infradead.org>,
	Alexandre Chartre <alexandre.chartre@oracle.com>,
	LKML <linux-kernel@vger.kernel.org>,
	Masami Hiramatsu <mhiramat@kernel.org>,
	Peter Zijlstra <peterz@infradead.org>,
	syzkaller-bugs <syzkaller-bugs@googlegroups.com>,
	Thomas Gleixner <tglx@linutronix.de>
Subject: Re: [syzbot] upstream boot error: WARNING in __context_tracking_enter
Date: Fri, 19 Mar 2021 10:10:43 +0000	[thread overview]
Message-ID: <20210319101043.GU1463@shell.armlinux.org.uk> (raw)
In-Reply-To: <CACT4Y+bLkFSc8manYrCukj-_nzwVsV9y6xYWXmGyYFS-PoBRPQ@mail.gmail.com>

On Fri, Mar 19, 2021 at 10:54:48AM +0100, Dmitry Vyukov wrote:
> .On Fri, Mar 19, 2021 at 10:44 AM syzbot
> <syzbot+f09a12b2c77bfbbf51bd@syzkaller.appspotmail.com> wrote:
> > syzbot found the following issue on:
> >
> > HEAD commit:    8b12a62a Merge tag 'drm-fixes-2021-03-19' of git://anongit..
> > git tree:       upstream
> > console output: https://syzkaller.appspot.com/x/log.txt?x=17e815aed00000
> > kernel config:  https://syzkaller.appspot.com/x/.config?x=cfeed364fc353c32
> > dashboard link: https://syzkaller.appspot.com/bug?extid=f09a12b2c77bfbbf51bd
> > userspace arch: arm
> >
> > IMPORTANT: if you fix the issue, please add the following tag to the commit:
> > Reported-by: syzbot+f09a12b2c77bfbbf51bd@syzkaller.appspotmail.com
> 
> 
> +Mark, arm
> It did not get far with CONFIG_CONTEXT_TRACKING_FORCE (kernel doesn't boot).

It seems that the path:

context_tracking_user_enter()
user_enter()
context_tracking_enter()
__context_tracking_enter()
vtime_user_enter()

expects preemption to be disabled. It effectively is, because local
interrupts are disabled by context_tracking_enter().

However, the requirement for preemption to be disabled is not
documented... so shrug. Maybe someone can say what the real requirements
are here.

-- 
RMK's Patch system: https://www.armlinux.org.uk/developer/patches/
FTTP is here! 40Mbps down 10Mbps up. Decent connectivity at last!

_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

  reply	other threads:[~2021-03-19 10:28 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <0000000000004f14c105bde08f75@google.com>
2021-03-19  9:54 ` [syzbot] upstream boot error: WARNING in __context_tracking_enter Dmitry Vyukov
2021-03-19 10:10   ` Russell King - ARM Linux admin [this message]
2021-03-22 17:22     ` Mark Rutland
2021-04-13  5:14       ` Dmitry Vyukov
2021-11-10  9:08         ` Marco Elver

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=20210319101043.GU1463@shell.armlinux.org.uk \
    --to=linux@armlinux.org.uk \
    --cc=alexandre.chartre@oracle.com \
    --cc=arnd@arndb.de \
    --cc=dvyukov@google.com \
    --cc=linux-arm-kernel@lists.infradead.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=mark.rutland@arm.com \
    --cc=mhiramat@kernel.org \
    --cc=peterz@infradead.org \
    --cc=syzbot+f09a12b2c77bfbbf51bd@syzkaller.appspotmail.com \
    --cc=syzkaller-bugs@googlegroups.com \
    --cc=tglx@linutronix.de \
    /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).