Tetsuo Handa wrote on Wed, Mar 30, 2022 at 07:35:47AM +0900:
> This seems to be an example of
> https://lkml.kernel.org/r/[email protected]
> introduced by "ext4: truncate during setxattr leads to kernel panic".
Thanks for the pointer
> Please don't use schedule_work() if you need to use flush_scheduled_work().
In this case we don't call flush_scheduled_work -- ext4 does.
The problem is mixing in the two subsystems when someone (e.g. syzbot)
opens an ext4 file and passes that fd to 9p when mounting with e.g.
mount -t 9p -o rfdno=<no>,wfdno=<no>
Frankly that's just not something I consider useful, interacting through
9p to a local file doesn't make sense except for testing.
If that is a real problem, the simplest way out would be to just forbid
non-socket FDs if it's something we can check.
--
Dominique