Re: [syzbot] [mm?] general protection fault in sys_mremap

[Lorenzo Stoakes]

On Wed, Apr 02, 2025 at 05:51:02AM -0700, syzbot wrote:
> Hello,
>
> syzbot has tested the proposed patch but the reproducer is still triggering an issue:
> unregister_netdevice: waiting for DEV to become free
>
> unregister_netdevice: waiting for batadv0 to become free. Usage count = 3

OK so this looks like a broken test box.

For belts and suspenders purposes, I confirmed this repro, and the previously
reported one both work fine on mm-stable.

All is good, the issue is resolved :) just a matter of waiting for the merge to
mainline for this.

#syz fix: mm/mremap: do not set vrm->vma NULL immediately prior to checking it

>
>
> Tested on:
>
> commit:         e20706d5 mseal sysmap: add arch-support txt
> git tree:       https://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm.git/ mm-stable
> console output: https://syzkaller.appspot.com/x/log.txt?x=13bf9998580000
> kernel config:  https://syzkaller.appspot.com/x/.config?x=ccf540055069887f
> dashboard link: https://syzkaller.appspot.com/bug?extid=e3385f43b2897a19be24
> compiler:       Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
>
> Note: no patches were applied.