Re: [syzbot] [mm?] kernel BUG in page_table_check_set

[Andrew Morton <akpm@linux-foundation.org>]

On Sat, 23 Aug 2025 08:53:28 +0530 Ritesh Harjani (IBM) <ritesh.list@gmail.com> wrote:

> Andrew Morton <akpm@linux-foundation.org> writes:
> 
> > On Thu, 21 Aug 2025 21:16:32 -0700 syzbot <syzbot+49a796ed2c9709652f1e@syzkaller.appspotmail.com> wrote:
> >
> >> Hello,
> >> 
> >> syzbot found the following issue on:
> >> 
> >> HEAD commit:    8f5ae30d69d7 Linux 6.17-rc1
> >> git tree:       git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci
> >> console output: https://syzkaller.appspot.com/x/log.txt?x=15f926f0580000
> >> kernel config:  https://syzkaller.appspot.com/x/.config?x=8c5ac3d8b8abfcb
> >> dashboard link: https://syzkaller.appspot.com/bug?extid=49a796ed2c9709652f1e
> >> compiler:       Debian clang version 20.1.7 (++20250616065708+6146a88f6049-1~exp1~20250616065826.132), Debian LLD 20.1.7
> >> userspace arch: arm64
> >> syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=15faa7a2580000
> >> C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=144143bc580000
> >> 
> >> Downloadable assets:
> >> disk image: https://storage.googleapis.com/syzbot-assets/18a2e4bd0c4a/disk-8f5ae30d.raw.xz
> >> vmlinux: https://storage.googleapis.com/syzbot-assets/3b5395881b25/vmlinux-8f5ae30d.xz
> >> kernel image: https://storage.googleapis.com/syzbot-assets/e875f4e3b7ff/Image-8f5ae30d.gz.xz
> >> 
> >> IMPORTANT: if you fix the issue, please add the following tag to the commit:
> >> Reported-by: syzbot+49a796ed2c9709652f1e@syzkaller.appspotmail.com
> >> 
> >> ------------[ cut here ]------------
> >> kernel BUG at mm/page_table_check.c:118!
> >
> > Thanks.
> >
> > Presumably due to the series "Support page table check on PowerPC". 
> 
> The syzbot triggered this on:
>  HEAD commit:    8f5ae30d69d7 Linux 6.17-rc1
>  git tree:       git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci
> 
> This tree does not have "Support page table check on PowerPC", correct?

Yep, sorry.

> Also, I guess Dev's change fixes this reported problem which could happen in
> this path: commit_anon_folio_batch() -> change_pte_range() ... 
> 
> [1]: https://lore.kernel.org/all/20250812060124.C9344C4CEF0@smtp.kernel.org/
> [2]: https://lore.kernel.org/all/68a80cc6.050a0220.3809a8.0002.GAE@google.com/

Cool.  Dev's fix is in 6.17-rc2 as cf1b80dc31a1.

#syz test git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git c17b750b3ad9