Messages in this thread | | | Date | Mon, 22 May 2023 15:22:45 +0200 | Subject | Re: [syzbot] [fs?] [usb?] INFO: rcu detected stall in vfs_readlink | From | Oliver Neukum <> |
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On 22.05.23 15:01, Christian Brauner wrote: > On Fri, May 19, 2023 at 08:18:45PM -0700, syzbot wrote: >> Hello, >> >> syzbot found the following issue on: >> >> HEAD commit: a4422ff22142 usb: typec: qcom: Add Qualcomm PMIC Type-C dr.. >> git tree: https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing >> console output: https://syzkaller.appspot.com/x/log.txt?x=10ce218e280000 >> kernel config: https://syzkaller.appspot.com/x/.config?x=2414a945e4542ec1 >> dashboard link: https://syzkaller.appspot.com/bug?extid=24d1639a31b024b125bd >> compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2 >> syz repro: https://syzkaller.appspot.com/x/repro.syz?x=137d4c06280000 >> C reproducer: https://syzkaller.appspot.com/x/repro.c?x=17b758a1280000 >> >> Downloadable assets: >> disk image: https://storage.googleapis.com/syzbot-assets/414817142fb7/disk-a4422ff2.raw.xz >> vmlinux: https://storage.googleapis.com/syzbot-assets/448dba0d344e/vmlinux-a4422ff2.xz >> kernel image: https://storage.googleapis.com/syzbot-assets/d0ad9fe848e2/bzImage-a4422ff2.xz >> >> IMPORTANT: if you fix the issue, please add the following tag to the commit: >> Reported-by: syzbot+24d1639a31b024b125bd@syzkaller.appspotmail.com >> >> imon 1-1:0.0: imon usb_rx_callback_intf0: status(-71): ignored >> imon 5-1:0.0: imon usb_rx_callback_intf0: status(-71): ignored > > I have the strong suspicion that the usb drive is removed or some such > nonsense. Doesn't seem an fs bug.
It hasn't been removed. On a real system it would likely be. The device keeps returning only -EPROTO. As we are dealing with virtual hardware that is fast enough to cause a livelock from the error handling retrying the IO without delay.
Handling this nicely would need a real error handler with a workqueue and some delays and evetually more drastic action like resetting the device.
Regards Oliver
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