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Subject: Re: INFO: task hung in wdm_flush
To:     Dmitry Vyukov <dvyukov@google.com>
Cc:     Oliver Neukum <oneukum@suse.de>,
        syzbot <syzbot+854768b99f19e89d7f81@syzkaller.appspotmail.com>,
        Andrey Konovalov <andreyknvl@google.com>,
        Jia-Ju Bai <baijiaju1990@gmail.com>,
        Sebastian Andrzej Siewior <bigeasy@linutronix.de>,
        Colin King <colin.king@canonical.com>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        LKML <linux-kernel@vger.kernel.org>,
        USB list <linux-usb@vger.kernel.org>,
        syzkaller-bugs <syzkaller-bugs@googlegroups.com>,
        yuehaibing@huawei.com, =?UTF-8?Q?Bj=c3=b8rn_Mork?= <bjorn@mork.no>
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From:   Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>
Message-ID: <ebc7b5e0-e968-0bdb-d75d-346e0b763d14@i-love.sakura.ne.jp>
Date:   Mon, 10 Feb 2020 21:46:11 +0900
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On 2020/02/10 19:09, Dmitry Vyukov wrote:
> You may also try on the exact commit the bug was reported, because
> usb-fuzzer is tracking branch, things may change there.

OK. I explicitly tried

  #syz test: https://github.com/google/kasan.git e5cd56e94edde38ca4dafae5a450c5a16b8a5f23

but syzbot still cannot reproduce this bug using the reproducer...

On 2020/02/10 21:02, syzbot wrote:
> Hello,
> 
> syzbot has tested the proposed patch and the reproducer did not trigger crash:
> 
> Reported-and-tested-by: syzbot+854768b99f19e89d7f81@syzkaller.appspotmail.com
> 
> Tested on:
> 
> commit:         e5cd56e9 usb: gadget: add raw-gadget interface
> git tree:       https://github.com/google/kasan.git
> kernel config:  https://syzkaller.appspot.com/x/.config?x=c372cdb7140fc162
> dashboard link: https://syzkaller.appspot.com/bug?extid=854768b99f19e89d7f81
> compiler:       gcc (GCC) 9.0.0 20181231 (experimental)
> 
> Note: testing is done by a robot and is best-effort only.
> 

Anyway, I'm just suspecting that we are forgetting to wake up all waiters
after clearing WDM_IN_USE bit because sometimes multiple threads are reported
as hung.

On 2020/02/10 15:27, syzbot wrote:
> Hello,
> 
> syzbot has tested the proposed patch and the reproducer did not trigger crash:
> 
> Reported-and-tested-by: syzbot+854768b99f19e89d7f81@syzkaller.appspotmail.com
> 
> Tested on:
> 
> commit:         e5cd56e9 usb: gadget: add raw-gadget interface
> git tree:       https://github.com/google/kasan.git usb-fuzzer
> kernel config:  https://syzkaller.appspot.com/x/.config?x=c372cdb7140fc162
> dashboard link: https://syzkaller.appspot.com/bug?extid=854768b99f19e89d7f81
> compiler:       gcc (GCC) 9.0.0 20181231 (experimental)
> patch:          https://syzkaller.appspot.com/x/patch.diff?x=117c3ae9e00000
> 
> Note: testing is done by a robot and is best-effort only.
> 

On 2020/02/10 15:55, syzbot wrote:
> Hello,
> 
> syzbot has tested the proposed patch and the reproducer did not trigger crash:
> 
> Reported-and-tested-by: syzbot+854768b99f19e89d7f81@syzkaller.appspotmail.com
> 
> Tested on:
> 
> commit:         e5cd56e9 usb: gadget: add raw-gadget interface
> git tree:       https://github.com/google/kasan.git usb-fuzzer
> kernel config:  https://syzkaller.appspot.com/x/.config?x=c372cdb7140fc162
> dashboard link: https://syzkaller.appspot.com/bug?extid=854768b99f19e89d7f81
> compiler:       gcc (GCC) 9.0.0 20181231 (experimental)
> patch:          https://syzkaller.appspot.com/x/patch.diff?x=13b3f6e9e00000
> 
> Note: testing is done by a robot and is best-effort only.
> 

On 2020/02/10 16:21, syzbot wrote:
> Hello,
> 
> syzbot has tested the proposed patch and the reproducer did not trigger crash:
> 
> Reported-and-tested-by: syzbot+854768b99f19e89d7f81@syzkaller.appspotmail.com
> 
> Tested on:
> 
> commit:         e5cd56e9 usb: gadget: add raw-gadget interface
> git tree:       https://github.com/google/kasan.git usb-fuzzer
> kernel config:  https://syzkaller.appspot.com/x/.config?x=c372cdb7140fc162
> dashboard link: https://syzkaller.appspot.com/bug?extid=854768b99f19e89d7f81
> compiler:       gcc (GCC) 9.0.0 20181231 (experimental)
> patch:          https://syzkaller.appspot.com/x/patch.diff?x=115026b5e00000
> 
> Note: testing is done by a robot and is best-effort only.
> 

On 2020/02/10 16:44, syzbot wrote:
> Hello,
> 
> syzbot has tested the proposed patch and the reproducer did not trigger crash:
> 
> Reported-and-tested-by: syzbot+854768b99f19e89d7f81@syzkaller.appspotmail.com
> 
> Tested on:
> 
> commit:         e5cd56e9 usb: gadget: add raw-gadget interface
> git tree:       https://github.com/google/kasan.git usb-fuzzer
> kernel config:  https://syzkaller.appspot.com/x/.config?x=c372cdb7140fc162
> dashboard link: https://syzkaller.appspot.com/bug?extid=854768b99f19e89d7f81
> compiler:       gcc (GCC) 9.0.0 20181231 (experimental)
> patch:          https://syzkaller.appspot.com/x/patch.diff?x=17285431e00000
> 
> Note: testing is done by a robot and is best-effort only.
> 

On 2020/02/10 17:05, syzbot wrote:
> Hello,
> 
> syzbot has tested the proposed patch and the reproducer did not trigger crash:
> 
> Reported-and-tested-by: syzbot+854768b99f19e89d7f81@syzkaller.appspotmail.com
> 
> Tested on:
> 
> commit:         e5cd56e9 usb: gadget: add raw-gadget interface
> git tree:       https://github.com/google/kasan.git usb-fuzzer
> kernel config:  https://syzkaller.appspot.com/x/.config?x=c372cdb7140fc162
> dashboard link: https://syzkaller.appspot.com/bug?extid=854768b99f19e89d7f81
> compiler:       gcc (GCC) 9.0.0 20181231 (experimental)
> 
> Note: testing is done by a robot and is best-effort only.
>