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From: Peter Zijlstra <peterz@infradead.org>
To: "Paul E. McKenney" <paulmck@linux.ibm.com>
Cc: Dmitry Vyukov <dvyukov@google.com>, Theodore Ts'o <tytso@mit.edu>,
	syzbot <syzbot+4bfbbf28a2e50ab07368@syzkaller.appspotmail.com>,
	Andreas Dilger <adilger.kernel@dilger.ca>,
	David Miller <davem@davemloft.net>,
	eladr@mellanox.com, Ido Schimmel <idosch@mellanox.com>,
	Jiri Pirko <jiri@mellanox.com>,
	John Stultz <john.stultz@linaro.org>,
	linux-ext4@vger.kernel.org, LKML <linux-kernel@vger.kernel.org>,
	netdev <netdev@vger.kernel.org>,
	syzkaller-bugs <syzkaller-bugs@googlegroups.com>,
	Thomas Gleixner <tglx@linutronix.de>,
	Ingo Molnar <mingo@kernel.org>
Subject: Re: INFO: rcu detected stall in ext4_write_checks
Date: Mon, 15 Jul 2019 15:29:11 +0200	[thread overview]
Message-ID: <20190715132911.GG3419@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <20190714184915.GK26519@linux.ibm.com>

On Sun, Jul 14, 2019 at 11:49:15AM -0700, Paul E. McKenney wrote:
> On Sun, Jul 14, 2019 at 05:48:00PM +0300, Dmitry Vyukov wrote:
> > But short term I don't see any other solution than stop testing
> > sched_setattr because it does not check arguments enough to prevent
> > system misbehavior. Which is a pity because syzkaller has found some
> > bad misconfigurations that were oversight on checking side.
> > Any other suggestions?
> 
> Keep the times down to a few seconds?  Of course, that might also
> fail to find interesting bugs.

Right, if syzcaller can put a limit on the period/deadline parameters
(and make sure to not write "-1" to
/proc/sys/kernel/sched_rt_runtime_us) then per the in-kernel
access-control should not allow these things to happen.

  reply	other threads:[~2019-07-15 13:29 UTC|newest]

Thread overview: 31+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-06-26 17:27 INFO: rcu detected stall in ext4_write_checks syzbot
2019-06-26 18:42 ` Theodore Ts'o
2019-06-26 21:03   ` Theodore Ts'o
2019-06-26 22:47     ` Theodore Ts'o
2019-07-05 13:24       ` Dmitry Vyukov
2019-07-05 15:16         ` Paul E. McKenney
2019-07-05 15:47           ` Amir Goldstein
2019-07-05 15:48           ` Dmitry Vyukov
2019-07-05 19:10             ` Paul E. McKenney
2019-07-06  4:28               ` Theodore Ts'o
2019-07-06  6:16                 ` Paul E. McKenney
2019-07-06 15:02                   ` Theodore Ts'o
2019-07-06 18:03                     ` Paul E. McKenney
2019-07-07  1:16                       ` Paul E. McKenney
2019-07-14 14:48                         ` Dmitry Vyukov
2019-07-14 18:49                           ` Paul E. McKenney
2019-07-15 13:29                             ` Peter Zijlstra [this message]
2019-07-15 13:33                               ` Dmitry Vyukov
2019-07-15 13:46                                 ` Peter Zijlstra
2019-07-15 14:02                                   ` Paul E. McKenney
2019-07-22 10:03                                   ` Dmitry Vyukov
2019-07-23  8:51                                     ` Dmitry Vyukov
2019-07-14 19:05                           ` Theodore Ts'o
2019-07-14 19:29                             ` Paul E. McKenney
2019-07-15  3:10                               ` Paul E. McKenney
2019-07-15 13:01                                 ` Paul E. McKenney
2019-07-15 13:29                                   ` Dmitry Vyukov
2019-07-15 13:39                                   ` Peter Zijlstra
2019-07-15 14:03                                     ` Paul E. McKenney
2019-07-15 13:22                         ` Peter Zijlstra
2019-07-05 13:18   ` Dmitry Vyukov

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