Re: KASAN: use-after-free Read in f_hidg_poll

[Greg KH]

On Sun, May 17, 2020 at 01:02:40AM +0000, Kyungtae Kim wrote:
> We report a bug (in linux-5.6.11) found by FuzzUSB (a modified version
> of syzkaller)
> 
> kernel config: https://kt0755.github.io/etc/config_v5.6.11
> 
> This bug happened when accessing a f_hidg instance deallocated.
> Specifically, f_hidg_poll() tries to access hidg (at line 424), 
> but memory error occurs because hidg has been freed 
> by configfs_unlink() in another thread (PID: 3190).
> 
> To fix, we check if either hidg is still in use when deallocating
> or it is still vaild after poll_wait()  in f_hidg_poll().

Great, can you send a patch for this to resolve the issue?

thanks,

gre gk-h