From: Thomas Gleixner <tglx@linutronix.de>
To: Stephen Boyd <sboyd@kernel.org>,
Andrew Morton <akpm@linux-foundation.org>,
syzbot <syzbot+d6c75f383e01426a40b4@syzkaller.appspotmail.com>
Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org,
syzkaller-bugs@googlegroups.com, Waiman Long <llong@redhat.com>,
"Paul E. McKenney" <paulmck@kernel.org>,
Al Viro <viro@zeniv.linux.org.uk>, Jens Axboe <axboe@kernel.dk>,
linux-block@vger.kernel.org, linux-fsdevel@vger.kernel.org
Subject: Re: [syzbot] WARNING in __init_work
Date: Tue, 21 Sep 2021 22:19:46 +0200 [thread overview]
Message-ID: <87v92t65r1.ffs@tglx> (raw)
In-Reply-To: <163224949689.3714697.17466968510780664239@swboyd.mtv.corp.google.com>
Stephen,
On Tue, Sep 21 2021 at 11:38, Stephen Boyd wrote:
> Quoting Thomas Gleixner (2021-09-19 05:41:18)
>> Even if debug objects would support objects on irq stacks, the above is
>> still bogus. But it does not and will not because the operations here
>> have to be fully synchronous:
>>
>> init() -> queue() or arm() -> wait() -> destroy()
>>
>> because you obviously cannot queue work or arm a timer which are on stack
>> and then leave the function without waiting for the operation to complete.
>
> Is there some way to make it more obvious that initializing a timer or
> work on the stack in an irq context is a NONO because we can't wait for
> it? Maybe some sort of debugobjects call to might_sleep() when it's
> being told the object is on the stack, or throwing a might_sleep() into
> the initialization of any stack based timer or workqueue, or both?
Let me have a look.
prev parent reply other threads:[~2021-09-21 20:19 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-09-15 17:00 [syzbot] WARNING in __init_work syzbot
2021-09-15 23:14 ` Andrew Morton
2021-09-16 2:29 ` Stephen Boyd
2021-09-19 12:41 ` Thomas Gleixner
2021-09-20 4:03 ` Dave Chinner
2021-09-20 12:28 ` Christoph Hellwig
2021-09-20 12:38 ` Paul E. McKenney
2021-09-20 12:45 ` Christoph Hellwig
2021-09-20 12:54 ` Paul E. McKenney
2021-09-21 18:38 ` Stephen Boyd
2021-09-21 20:19 ` Thomas Gleixner [this message]
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