Re: INFO: task hung in wdm_flush

[Tetsuo Handa]

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@xxxxxxxxxxxxxxxxxxxxxxxxx
> 
> 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@xxxxxxxxxxxxxxxxxxxxxxxxx
> 
> 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@xxxxxxxxxxxxxxxxxxxxxxxxx
> 
> 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@xxxxxxxxxxxxxxxxxxxxxxxxx
> 
> 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@xxxxxxxxxxxxxxxxxxxxxxxxx
> 
> 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@xxxxxxxxxxxxxxxxxxxxxxxxx
> 
> 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.
>