FS#71823 - [linux] general protection fault in cifs

Attached to Project: Arch Linux
Opened by Arne Hoch (derhoch) - Friday, 13 August 2021, 07:58 GMT
Last edited by Toolybird (Toolybird) - Tuesday, 06 June 2023, 03:38 GMT
Task Type Bug Report
Category Kernel
Status Closed
Assigned To Jan Alexander Steffens (heftig)
Architecture x86_64
Severity High
Priority Normal
Reported Version
Due in Version Undecided
Due Date Undecided
Percent Complete 100%
Votes 0
Private No

Details

Description:
I have a cifs mount via OpenVPN, that is sometimes a bit unstable. After upgrading from linux-5.12.14 to linux-5.13.9, I regularly get general protection faults that leave an unresponsive system. Even magic sysrq isn't able to reboot.

A downgrade to linux-5.12.14 solves the issue.

Additional info:
I've attached the kernel log until the system dies. The ip address of the network share is replaced with '****'
   backtrace.txt (187.7 KiB)
This task depends upon

Closed by  Toolybird (Toolybird)
Tuesday, 06 June 2023, 03:38 GMT
Reason for closing:  Not a bug
Additional comments about closing:  At least not an Arch packaging bug. See comments. If still an issue, please report upstream to the kernel folks.
Comment by Arne Hoch (derhoch) - Monday, 16 August 2021, 09:13 GMT
The problem persists with linux-5.13.10. I have an OpenVPN link open and as soon as I mount the share via tun0 device, I get a load of backtraces and the system halts. But if I add "vers=1.0" to the mount options, the system is stable, so far.
Mounting local network shares is no problem. So it seems to be a combination of vpn and cifs.
Comment by Arne Hoch (derhoch) - Wednesday, 18 August 2021, 15:08 GMT
I think I got to the bottom of this issue. I use a systemd.mount and systemd.automount unit to mount the network share. In the .mount unit I had TimeoutSec=500ms. Due to the latency of the vpn tunnel, the timeout was too short to complete the mount. It seems that linux-5.13 needs more time than linux-5.12 to complete the mount and when the mount command is killed at exactly the right time, I get a nice kernel panic.

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