On 23.09.24 14:18, syzbot wrote:
Hello,
syzbot found the following issue on:
HEAD commit: 88264981f208 Merge tag 'sched_ext-for-6.12' of git://git.k..
git tree: upstream
console+strace: https://syzkaller.appspot.com/x/log.txt?x=16c36c27980000
kernel config: https://syzkaller.appspot.com/x/.config?x=e851828834875d6f
dashboard link: https://syzkaller.appspot.com/bug?extid=bf2c35fa302ebe3c7471
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=12773080580000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=16ed5e9f980000
Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/0e011ac37c93/disk-88264981.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/f5c65577e19e/vmlinux-88264981.xz
kernel image: https://storage.googleapis.com/syzbot-assets/984d963c8ea1/bzImage-88264981.xz
The issue was bisected to:
commit 75182022a0439788415b2dd1db3086e07aa506f7
Author: Peter Xu <peterx@xxxxxxxxxx>
Date: Mon Aug 26 20:43:51 2024 +0000
mm/x86: support large pfn mappings
bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=17df9c27980000
final oops: https://syzkaller.appspot.com/x/report.txt?x=143f9c27980000
console output: https://syzkaller.appspot.com/x/log.txt?x=103f9c27980000
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+bf2c35fa302ebe3c7471@xxxxxxxxxxxxxxxxxxxxxxxxx
Fixes: 75182022a043 ("mm/x86: support large pfn mappings")
------------[ cut here ]------------
WARNING: CPU: 1 PID: 5508 at mm/huge_memory.c:1602 copy_huge_pmd+0x102c/0x1c60 mm/huge_memory.c:1602
This is the
VM_WARN_ON_ONCE(is_cow_mapping(src_vma->vm_flags) && pmd_write(pmd))
So we have a special-marked PMD in a COW mapping.
The reproducer seems to involve fuse, but not sure if that makes a
difference here.
--
Cheers,
David / dhildenb
