From: "Paul E. McKenney" <paulmck@kernel.org>
To: Dmitry Vyukov <dvyukov@google.com>
Cc: syzbot <syzbot+792dec47d693ccdc05a0@syzkaller.appspotmail.com>,
Josh Triplett <josh@joshtriplett.org>,
Steven Rostedt <rostedt@goodmis.org>,
Mathieu Desnoyers <mathieu.desnoyers@efficios.com>,
Lai Jiangshan <jiangshanlai@gmail.com>,
Joel Fernandes <joel@joelfernandes.org>,
rcu@vger.kernel.org, LKML <linux-kernel@vger.kernel.org>,
syzkaller-bugs <syzkaller-bugs@googlegroups.com>
Subject: Re: linux-next build error (8)
Date: Fri, 20 Mar 2020 09:26:50 -0700 [thread overview]
Message-ID: <20200320162650.GP3199@paulmck-ThinkPad-P72> (raw)
In-Reply-To: <CACT4Y+YHQQWeeW44NYAxX+fFU6RyvFbbmcig1q8NSE7yV0zgjA@mail.gmail.com>
On Fri, Mar 20, 2020 at 04:38:54PM +0100, Dmitry Vyukov wrote:
> On Thu, Mar 19, 2020 at 4:04 PM Paul E. McKenney <paulmck@kernel.org> wrote:
> >
> > On Thu, Mar 19, 2020 at 08:13:35AM +0100, Dmitry Vyukov wrote:
> > > On Wed, Mar 18, 2020 at 10:41 PM Paul E. McKenney <paulmck@kernel.org> wrote:
> > > >
> > > > On Wed, Mar 18, 2020 at 09:54:07PM +0100, Dmitry Vyukov wrote:
> > > > > On Wed, Mar 18, 2020 at 5:57 PM syzbot
> > > > > <syzbot+792dec47d693ccdc05a0@syzkaller.appspotmail.com> wrote:
> > > > > >
> > > > > > Hello,
> > > > > >
> > > > > > syzbot found the following crash on:
> > > > > >
> > > > > > HEAD commit: 47780d78 Add linux-next specific files for 20200318
> > > > > > git tree: linux-next
> > > > > > console output: https://syzkaller.appspot.com/x/log.txt?x=14228745e00000
> > > > > > kernel config: https://syzkaller.appspot.com/x/.config?x=b68b7b89ad96c62a
> > > > > > dashboard link: https://syzkaller.appspot.com/bug?extid=792dec47d693ccdc05a0
> > > > > > compiler: gcc (GCC) 9.0.0 20181231 (experimental)
> > > > > >
> > > > > > Unfortunately, I don't have any reproducer for this crash yet.
> > > > > >
> > > > > > IMPORTANT: if you fix the bug, please add the following tag to the commit:
> > > > > > Reported-by: syzbot+792dec47d693ccdc05a0@syzkaller.appspotmail.com
> > > > > >
> > > > > > kernel/rcu/tasks.h:1070:37: error: 'rcu_tasks_rude' undeclared (first use in this function); did you mean 'rcu_tasks_qs'?
> > > > >
> > > > > +rcu maintainers
> > > >
> > > > The kbuild test robot beat you to it, and apologies for the hassle.
> > > > Fixed in -rcu on current "dev" branch.
> > >
> > > If the kernel dev process would only have a way to avoid dups from all
> > > test systems...
> >
> > I do significant testing before pushing to -next, but triggering this
> > one requires a combination of Kconfig options that are incompatible
> > with rcutorture. :-/
> >
> > I suppose one strategy would be to give kbuild test robot some time before
> > passing to -next, but they seem to sometimes get too far behind for me to
> > be willing to wait that long. So my current approach is to push my "dev"
> > branch, run moderate rcutorture testing (three hours per scenario other
> > than TREE10, which gets only one hour), and if that passes, push to -next.
> >
> > I suppose that I could push to -next only commits that are at least three
> > days old or some such. But I get in trouble pushing to -next too slowly
> > as often as I get in trouble pushing too quickly, so I suspect that my
> > current approach is in roughly the right place.
> >
> > > Now we need to spend time and deal with it. What has fixed it?
> >
> > It is fixed by commit c6ef38e4d595 ("rcu-tasks: Add RCU tasks to
> > rcutorture writer stall output") and some of its predecessors.
> >
> > Perhaps more useful to you, this commit is included in next-20200319
> > from the -next tree. ;-)
>
> Let's tell syzbot about the fix:
>
> #syz fix: rcu-tasks: Add RCU tasks to rcutorture writer stall output
>
> I think what you are doing is the best possible option in the current situation.
> I don't think requiring all human maintainers to do more manual
> repetitive work, which is not well defined and even without a way to
> really require something from them is scalable nor reliable nor the
> right approach.
Thank you, and I do greatly appreciate the automation!
> We would consume something like LKGR [1] if it existed for the kernel.
> But it would require tighter integration of testing systems with
> kernel dev processes, or of course throwing more manual labor at it to
> track all uncoordinated testing systems and publishing LKGR tags.
>
> [1] https://chromium.googlesource.com/chromiumos/docs/+/master/glossary.md
At my end, it is pretty quick and easy to detect duplicate notifications
of the same bug, so the current situation isn't causing me undue distress.
Thanx, Paul
next prev parent reply other threads:[~2020-03-20 16:26 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <000000000000ae2ab305a123f146@google.com>
2020-03-18 20:54 ` linux-next build error (8) Dmitry Vyukov
2020-03-18 21:41 ` Paul E. McKenney
2020-03-19 7:13 ` Dmitry Vyukov
2020-03-19 15:04 ` Paul E. McKenney
2020-03-20 15:38 ` Dmitry Vyukov
2020-03-20 16:26 ` Paul E. McKenney [this message]
2020-03-20 16:34 ` Randy Dunlap
2020-03-20 17:04 ` Paul E. McKenney
2020-03-20 13:08 ` Dan Carpenter
2020-03-20 15:42 ` Dmitry Vyukov
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