Re: [BUG] KASAN: slab-use-after-free Read in slip_receive_buf

[Eric Dumazet]

On Tue, Aug 25, 2026 at 5:07 PM Jaeyoung Chung <jjy600901@xxxxxxxxx> wrote:
>
> Hello,
>
> We found a "KASAN: slab-use-after-free Read in slip_receive_buf" on Linux v7.2.
> The issue was found by our own race fuzzer. We have not analyzed the root cause,
> so we do not have a proposed fix to offer.
>
> To reproduce the race reliably, we applied the delay patch below to the
> kernel and ran the C reproducer as root inside an x86_64 QEMU guest. The
> crash log we observed, the delay patch and the reproducer are all included
> below.
>
> The following kernel config options are required to reproduce the issue:
>     CONFIG_SLIP=y
>     CONFIG_LEGACY_TIOCSTI=y
>     CONFIG_UNIX98_PTYS=y
>     CONFIG_TTY=y
>     CONFIG_KASAN=y
>
> We hope this report is useful. Please let us know if any further
> information would help.
>
> Reported-by: Eulgyu Kim <eulgyukim@xxxxxxxxx>
> Reported-by: Jaeyoung Chung <jjy600901@xxxxxxxxx>

This rings a bell; I had a local syzbot report for this issue a while back.

I think we should remove slip_hangup().