linux-kernel - Re: [syzbot] [io-uring?] INFO: task hung in io_wq_put_and

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Message-ID: <b51adba8-7722-4f74-a865-47bf1638820f@kernel.dk>
Date: Sat, 26 Oct 2024 18:07:10 -0600
From: Jens Axboe <axboe@...nel.dk>
To: syzbot <syzbot+58928048fd1416f1457c@...kaller.appspotmail.com>,
 asml.silence@...il.com, io-uring@...r.kernel.org,
 linux-kernel@...r.kernel.org, syzkaller-bugs@...glegroups.com
Subject: Re: [syzbot] [io-uring?] INFO: task hung in io_wq_put_and_exit (4)

On 10/26/24 7:44 AM, Jens Axboe wrote:
> On 10/25/24 11:43 PM, syzbot wrote:
>> syzbot has found a reproducer for the following issue on:
>>
>> HEAD commit:    b423f5a9a61f Merge tag 'acpi-6.12-rc5' of git://git.kernel..
>> git tree:       upstream
>> console+strace: https://syzkaller.appspot.com/x/log.txt?x=1393565f980000
>> kernel config:  https://syzkaller.appspot.com/x/.config?x=fd919c0fc1af4272
>> dashboard link: https://syzkaller.appspot.com/bug?extid=58928048fd1416f1457c
>> compiler:       Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
>> syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=122f04a7980000
>> C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=132cbe40580000
> 
> Perfect thanks, we'll take a look.

Took a look, and it's one of the usual stupid cases of "let's just flood
it with things and exit will take a while". In this case it's adding a ton
of classic provided buffers, and then exit takes a while to prune them.
Not convinced there's a real bug here, outside of the config have lots
of debug options that slows everything down. It'll finish eventually,
it'll just take a while with how it's being used.

-- 
Jens Axboe