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From:   Andrey Konovalov <andreyknvl@google.com>
Date:   Fri, 13 Dec 2019 13:19:16 +0100
Message-ID: <CAAeHK+xSWEFUA7DQyhm90uiwggx60gYa8q7QqzOWp7DX_xWSWg@mail.gmail.com>
Subject: Re: Re: general protection fault in usb_set_interface
To:     syzbot <syzbot+7fa38a608b1075dfd634@syzkaller.appspotmail.com>
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Kai Heng Feng <kai.heng.feng@canonical.com>,
        LKML <linux-kernel@vger.kernel.org>,
        USB list <linux-usb@vger.kernel.org>, mans@mansr.com,
        Oliver Neukum <oneukum@suse.com>,
        Alan Stern <stern@rowland.harvard.edu>,
        syzkaller-bugs <syzkaller-bugs@googlegroups.com>
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Sender: linux-kernel-owner@vger.kernel.org
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On Fri, Dec 13, 2019 at 1:16 PM syzbot
<syzbot+7fa38a608b1075dfd634@syzkaller.appspotmail.com> wrote:
>
> > On Mon, Sep 16, 2019 at 3:29 PM syzbot
> > <syzbot+7fa38a608b1075dfd634@syzkaller.appspotmail.com> wrote:
>
> >> Hello,
>
> >> syzbot found the following crash on:
>
> >> HEAD commit:    f0df5c1b usb-fuzzer: main usb gadget fuzzer driver
> >> git tree:       https://github.com/google/kasan.git usb-fuzzer
> >> console output: https://syzkaller.appspot.com/x/log.txt?x=158b66f1600000
> >> kernel config:
> >> https://syzkaller.appspot.com/x/.config?x=5c6633fa4ed00be5
> >> dashboard link:
> >> https://syzkaller.appspot.com/bug?extid=7fa38a608b1075dfd634
> >> compiler:       gcc (GCC) 9.0.0 20181231 (experimental)
> >> syz repro:
> >> https://syzkaller.appspot.com/x/repro.syz?x=14f57db9600000
> >> C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=127b61a5600000
>
> >> IMPORTANT: if you fix the bug, please add the following tag to the
> >> commit:
> >> Reported-by: syzbot+7fa38a608b1075dfd634@syzkaller.appspotmail.com
>
> >> usb 3-1: usbvision_write_reg: failed: error -2
> >> usbvision_set_audio: can't write iopin register for audio switching
> >> kasan: CONFIG_KASAN_INLINE enabled
> >> kasan: GPF could be caused by NULL-ptr deref or user memory access
> >> general protection fault: 0000 [#1] SMP KASAN
> >> CPU: 1 PID: 1955 Comm: v4l_id Not tainted 5.3.0-rc7+ #0
> >> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
> >> Google 01/01/2011
> >> RIP: 0010:usb_set_interface+0x34/0xa50 drivers/usb/core/message.c:1362
> >> Code: fc 55 53 48 83 ec 40 89 54 24 18 89 74 24 10 e8 22 1c ef fd 49 8d
> >> 7c
> >> 24 48 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 <80> 3c 02 00 0f
> >> 85 fb 08 00 00 49 8b 44 24 48 49 8d 7c 24 18 48 89
> >> RSP: 0018:ffff8881cb19fd50 EFLAGS: 00010206
> >> RAX: dffffc0000000000 RBX: 0000000000000000 RCX: 0000000000000000
> >> RDX: 0000000000000009 RSI: ffffffff834ebe7e RDI: 0000000000000048
> >> RBP: ffff8881cb8e4200 R08: ffffffff88d21878 R09: ffffed103971cb43
> >> R10: ffff8881cb19fdc8 R11: ffff8881cb8e5a17 R12: 0000000000000000
> >> R13: ffff8881cb8e5a10 R14: ffff8881cb8e4cc8 R15: ffff8881cb8e5178
> >> FS:  00007f4f60b6d700(0000) GS:ffff8881db300000(0000)
> >> knlGS:0000000000000000
> >> CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> >> CR2: 00007f4f6060c330 CR3: 00000001cc3a8000 CR4: 00000000001406e0
> >> DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
> >> DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
> >> Call Trace:
> >>    usbvision_radio_close+0x105/0x250
> >> drivers/media/usb/usbvision/usbvision-video.c:1114
> >>    v4l2_release+0x2e7/0x390 drivers/media/v4l2-core/v4l2-dev.c:455
> >>    __fput+0x2d7/0x840 fs/file_table.c:280
> >>    task_work_run+0x13f/0x1c0 kernel/task_work.c:113
> >>    tracehook_notify_resume include/linux/tracehook.h:188 [inline]
> >>    exit_to_usermode_loop+0x1d2/0x200 arch/x86/entry/common.c:163
> >>    prepare_exit_to_usermode arch/x86/entry/common.c:194 [inline]
> >>    syscall_return_slowpath arch/x86/entry/common.c:274 [inline]
> >>    do_syscall_64+0x45f/0x580 arch/x86/entry/common.c:299
> >>    entry_SYSCALL_64_after_hwframe+0x49/0xbe
> >> RIP: 0033:0x7f4f6069b2b0
> >> Code: 40 75 0b 31 c0 48 83 c4 08 e9 0c ff ff ff 48 8d 3d c5 32 08 00 e8
> >> c0
> >> 07 02 00 83 3d 45 a3 2b 00 00 75 10 b8 03 00 00 00 0f 05 <48> 3d 01 f0 ff
> >> ff 73 31 c3 48 83 ec 08 e8 ce 8a 01 00 48 89 04 24
> >> RSP: 002b:00007ffde2d50ee8 EFLAGS: 00000246 ORIG_RAX: 0000000000000003
> >> RAX: 0000000000000000 RBX: 0000000000000003 RCX: 00007f4f6069b2b0
> >> RDX: 00007f4f60951df0 RSI: 0000000000000001 RDI: 0000000000000003
> >> RBP: 0000000000000000 R08: 00007f4f60951df0 R09: 000000000000000a
> >> R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000400884
> >> R13: 00007ffde2d51040 R14: 0000000000000000 R15: 0000000000000000
> >> Modules linked in:
> >> ---[ end trace 62bd2b7512ab49ee ]---
> >> RIP: 0010:usb_set_interface+0x34/0xa50 drivers/usb/core/message.c:1362
> >> Code: fc 55 53 48 83 ec 40 89 54 24 18 89 74 24 10 e8 22 1c ef fd 49 8d
> >> 7c
> >> 24 48 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 <80> 3c 02 00 0f
> >> 85 fb 08 00 00 49 8b 44 24 48 49 8d 7c 24 18 48 89
> >> RSP: 0018:ffff8881cb19fd50 EFLAGS: 00010206
> >> RAX: dffffc0000000000 RBX: 0000000000000000 RCX: 0000000000000000
> >> RDX: 0000000000000009 RSI: ffffffff834ebe7e RDI: 0000000000000048
> >> RBP: ffff8881cb8e4200 R08: ffffffff88d21878 R09: ffffed103971cb43
> >> R10: ffff8881cb19fdc8 R11: ffff8881cb8e5a17 R12: 0000000000000000
> >> R13: ffff8881cb8e5a10 R14: ffff8881cb8e4cc8 R15: ffff8881cb8e5178
> >> FS:  00007f4f60b6d700(0000) GS:ffff8881db300000(0000)
> >> knlGS:0000000000000000
> >> CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> >> CR2: 00007f4f6060c330 CR3: 00000001cc3a8000 CR4: 00000000001406e0
> >> DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
> >> DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
>
>
> >> ---
> >> This bug is generated by a bot. It may contain errors.
> >> See https://goo.gl/tpsmEJ for more information about syzbot.
> >> syzbot engineers can be reached at syzkaller@googlegroups.com.
>
> >> syzbot will keep track of this bug report. See:
> >> https://goo.gl/tpsmEJ#status for how to communicate with syzbot.
> >> syzbot can test patches for this bug, for details see:
> >> https://goo.gl/tpsmEJ#testing-patches
>
> > Let's retry here:
>
> > #syz test: https://github.com/google/kasan.git f0df5c1b
>
> This bug is already marked as fixed. No point in testing.
>

Hm, that explains some of the weirdness. It doesn't explain though
neither why the patch was actually tested when Alan requested it nor
why syzbot sent no reply.