Re: Reminder: 3 open syzbot bugs in vhost subsystem

Jason Wang
2019-07-24T03:05:23Z

On 2019/7/24 上午10:38, Eric Biggers wrote:
> [This email was generated by a script. Let me know if you have any suggestions
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>
> Of the currently open syzbot reports against the upstream kernel, I've manually
> marked 3 of them as possibly being bugs in the vhost subsystem. I've listed
> these reports below, sorted by an algorithm that tries to list first the reports
> most likely to be still valid, important, and actionable.
>
> Of these 3 bugs, 2 were seen in mainline in the last week.
>
> Of these 3 bugs, 2 were bisected to commits from the following person:
>
> Jason Wang <jasowang@redhat.com>
>
> If you believe a bug is no longer valid, please close the syzbot report by
> sending a '#syz fix', '#syz dup', or '#syz invalid' command in reply to the
> original thread, as explained at https://goo.gl/tpsmEJ#status
>
> If you believe I misattributed a bug to the vhost subsystem, please let me know,
> and if possible forward the report to the correct people or mailing list.
>
> Here are the bugs:
>
> --------------------------------------------------------------------------------
> Title: KASAN: use-after-free Write in tlb_finish_mmu
> Last occurred: 5 days ago
> Reported: 4 days ago
> Branches: Mainline
> Dashboard link: https://syzkaller.appspot.com/bug?id=d57b94f89e48c85ef7d95acc208209ea4bdc10de
> Original thread: https://lkml.kernel.org/lkml/00000000000045e7a1058e02458a@google.com/T/#u
>
> This bug has a syzkaller reproducer only.
>
> This bug was bisected to:
>
> commit 7f466032dc9e5a61217f22ea34b2df932786bbfc
> Author: Jason Wang <jasowang@redhat.com>
> Date: Fri May 24 08:12:18 2019 +0000
>
>   vhost: access vq metadata through kernel virtual address
>
> No one has replied to the original thread for this bug yet.
>
> If you fix this bug, please add the following tag to the commit:
> Reported-by: syzbot+8267e9af795434ffadad@syzkaller.appspotmail.com
>
> If you send any email or patch for this bug, please reply to the original
> thread. For the git send-email command to use, or tips on how to reply if the
> thread isn't in your mailbox, see the "Reply instructions" at
> https://lkml.kernel.org/r/00000000000045e7a1058e02458a@google.com
>
> --------------------------------------------------------------------------------
> Title: KASAN: use-after-free Read in finish_task_switch (2)
> Last occurred: 5 days ago
> Reported: 4 days ago
> Branches: Mainline
> Dashboard link: https://syzkaller.appspot.com/bug?id=9a98fcad6c8bd31f5c3afbdc6c75de9f082c0ffa
> Original thread: https://lkml.kernel.org/lkml/000000000000490679058e0245ee@google.com/T/#u
>
> This bug has a syzkaller reproducer only.
>
> This bug was bisected to:
>
> commit 7f466032dc9e5a61217f22ea34b2df932786bbfc
> Author: Jason Wang <jasowang@redhat.com>
> Date: Fri May 24 08:12:18 2019 +0000
>
>   vhost: access vq metadata through kernel virtual address
>
> No one has replied to the original thread for this bug yet.

Hi:

We believe above two bugs are duplicated with the report "WARNING in
__mmdrop". Can I just dup them with

#syz dup "WARNING in __mmdrop"

(If yes, just wonder how syzbot differ bugs, technically, several
different bug can hit the same warning).

>
> If you fix this bug, please add the following tag to the commit:
> Reported-by: syzbot+7f067c796eee2acbc57a@syzkaller.appspotmail.com
>
> If you send any email or patch for this bug, please reply to the original
> thread. For the git send-email command to use, or tips on how to reply if the
> thread isn't in your mailbox, see the "Reply instructions" at
> https://lkml.kernel.org/r/000000000000490679058e0245ee@google.com
>
> --------------------------------------------------------------------------------
> Title: memory leak in vhost_net_ioctl
> Last occurred: 22 days ago
> Reported: 48 days ago
> Branches: Mainline
> Dashboard link: https://syzkaller.appspot.com/bug?id=12ba349d7e26ccfe95317bc376e812ebbae2ee0f
> Original thread: https://lkml.kernel.org/lkml/000000000000188da1058a9c25e3@google.com/T/#u
>
> This bug has a C reproducer.
>
> The original thread for this bug has received 4 replies; the last was 39 days
> ago.
>
> If you fix this bug, please add the following tag to the commit:
> Reported-by: syzbot+0789f0c7e45efd7bb643@syzkaller.appspotmail.com

I do remember it can not be reproduced upstream, let me double check and
close this one.

Thanks

>
> If you send any email or patch for this bug, please consider replying to the
> original thread. For the git send-email command to use, or tips on how to reply
> if the thread isn't in your mailbox, see the "Reply instructions" at
> https://lkml.kernel.org/r/000000000000188da1058a9c25e3@google.com
>