From: syzbot ci <syzbot+ci8c594ed0fdfcc0e4@syzkaller.appspotmail.com>
To: aarcange@redhat.com, akpm@linux-foundation.org,
apopple@nvidia.com, axelrasmussen@google.com, baohua@kernel.org,
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yuanchu@google.com, ziy@nvidia.com
Cc: syzbot@lists.linux.dev, syzkaller-bugs@googlegroups.com
Subject: [syzbot ci] Re: mm/virtio: skip redundant zeroing of host-zeroed reported pages
Date: Mon, 20 Apr 2026 11:09:37 -0700 [thread overview]
Message-ID: <69e66be1.a00a0220.9259.0007.GAE@google.com> (raw)
In-Reply-To: <cover.1776689093.git.mst@redhat.com>
syzbot ci has tested the following series
[v2] mm/virtio: skip redundant zeroing of host-zeroed reported pages
https://lore.kernel.org/all/cover.1776689093.git.mst@redhat.com
* [PATCH RFC v2 01/18] mm: page_alloc: propagate PageReported flag across buddy splits
* [PATCH RFC v2 02/18] mm: add pghint_t type and vma_alloc_folio_hints API
* [PATCH RFC v2 03/18] mm: add PG_zeroed page flag for known-zero pages
* [PATCH RFC v2 04/18] mm: page_alloc: track PG_zeroed across buddy merges
* [PATCH RFC v2 05/18] mm: page_alloc: preserve PG_zeroed in try_to_claim_block
* [PATCH RFC v2 06/18] mm: page_alloc: thread pghint_t through get_page_from_freelist
* [PATCH RFC v2 07/18] mm: post_alloc_hook: use PG_zeroed to skip zeroing, return pghint_t
* [PATCH RFC v2 08/18] mm: hugetlb: thread pghint_t through buddy allocation chain
* [PATCH RFC v2 09/18] mm: hugetlb: use PG_zeroed for pool pages, skip redundant zeroing
* [PATCH RFC v2 10/18] mm: page_reporting: support host-zeroed reported pages
* [PATCH RFC v2 11/18] mm: skip zeroing in vma_alloc_zeroed_movable_folio for pre-zeroed pages
* [PATCH RFC v2 12/18] mm: skip zeroing in alloc_anon_folio for pre-zeroed pages
* [PATCH RFC v2 13/18] mm: skip zeroing in vma_alloc_anon_folio_pmd for pre-zeroed pages
* [PATCH RFC v2 14/18] mm: memfd: skip zeroing for pre-zeroed hugetlb pages
* [PATCH RFC v2 15/18] virtio_balloon: add host_zeroes_pages module parameter
* [PATCH RFC v2 16/18] mm: page_reporting: add flush parameter with page budget
* [PATCH RFC v2 17/18] mm: add free_frozen_pages_hint and put_page_hint APIs
* [PATCH RFC v2 18/18] virtio_balloon: mark deflated pages as pre-zeroed
and found the following issue:
kernel BUG in free_huge_folio
Full report is available here:
https://ci.syzbot.org/series/329d9cff-a0ad-46d2-8ff4-d9f4341a611f
***
kernel BUG in free_huge_folio
tree: mm-new
URL: https://kernel.googlesource.com/pub/scm/linux/kernel/git/akpm/mm.git
base: b8a5774cd49996e8ef83b1637a9b547158f18de9
arch: amd64
compiler: Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8
config: https://ci.syzbot.org/builds/60e99a0e-08bf-474f-b034-a8bfd2eb90b0/config
syz repro: https://ci.syzbot.org/findings/2868ce13-1752-4f9f-9aa9-c5ce89f01fc7/syz_repro
ret_from_fork+0x51e/0xb90 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
page_owner free stack trace missing
------------[ cut here ]------------
kernel BUG at ./include/linux/page-flags.h:698!
Oops: invalid opcode: 0000 [#1] SMP KASAN PTI
CPU: 1 UID: 0 PID: 6015 Comm: syz.2.19 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014
RIP: 0010:__ClearPageZeroed include/linux/page-flags.h:698 [inline]
RIP: 0010:free_huge_folio+0xf93/0x12e0 mm/hugetlb.c:1749
Code: c7 c6 a0 64 db 8b e8 5c 9b fe fe 90 0f 0b e8 74 40 9c ff eb 05 e8 6d 40 9c ff 48 89 df 48 c7 c6 e0 63 db 8b e8 3e 9b fe fe 90 <0f> 0b e8 56 40 9c ff 48 89 df 48 c7 c6 40 64 db 8b e8 27 9b fe fe
RSP: 0018:ffffc90003a675b8 EFLAGS: 00010246
RAX: c71fb9abd148e700 RBX: ffffea0005808000 RCX: 0000000000000000
RDX: 0000000000000007 RSI: ffffffff8defcd3f RDI: 00000000ffffffff
RBP: 1ffffd4000b0101a R08: ffffffff9011ddb7 R09: 1ffffffff2023bb6
R10: dffffc0000000000 R11: fffffbfff2023bb7 R12: ffffea0005808008
R13: ffffea00058080d0 R14: ffffffff9a2e27c0 R15: 0000000000000040
FS: 00007fe11abed6c0(0000) GS:ffff8882a9453000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fe119de9f00 CR3: 00000001ba914000 CR4: 00000000000006f0
Call Trace:
<TASK>
__folio_put+0xfc/0x4f0 mm/swap.c:105
hugetlb_mfill_atomic_pte+0x130a/0x1730 mm/hugetlb.c:6294
mfill_atomic_hugetlb mm/userfaultfd.c:601 [inline]
mfill_atomic mm/userfaultfd.c:773 [inline]
mfill_atomic_copy+0xe28/0x1420 mm/userfaultfd.c:872
userfaultfd_copy fs/userfaultfd.c:1642 [inline]
userfaultfd_ioctl+0x2c17/0x5130 fs/userfaultfd.c:2059
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:597 [inline]
__se_sys_ioctl+0xfc/0x170 fs/ioctl.c:583
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fe119d9c819
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fe11abed028 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007fe11a015fa0 RCX: 00007fe119d9c819
RDX: 00002000000000c0 RSI: 00000000c028aa03 RDI: 0000000000000003
RBP: 00007fe119e32c91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fe11a016038 R14: 00007fe11a015fa0 R15: 00007ffe7cd6ce28
</TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:__ClearPageZeroed include/linux/page-flags.h:698 [inline]
RIP: 0010:free_huge_folio+0xf93/0x12e0 mm/hugetlb.c:1749
Code: c7 c6 a0 64 db 8b e8 5c 9b fe fe 90 0f 0b e8 74 40 9c ff eb 05 e8 6d 40 9c ff 48 89 df 48 c7 c6 e0 63 db 8b e8 3e 9b fe fe 90 <0f> 0b e8 56 40 9c ff 48 89 df 48 c7 c6 40 64 db 8b e8 27 9b fe fe
RSP: 0018:ffffc90003a675b8 EFLAGS: 00010246
RAX: c71fb9abd148e700 RBX: ffffea0005808000 RCX: 0000000000000000
RDX: 0000000000000007 RSI: ffffffff8defcd3f RDI: 00000000ffffffff
RBP: 1ffffd4000b0101a R08: ffffffff9011ddb7 R09: 1ffffffff2023bb6
R10: dffffc0000000000 R11: fffffbfff2023bb7 R12: ffffea0005808008
R13: ffffea00058080d0 R14: ffffffff9a2e27c0 R15: 0000000000000040
FS: 00007fe11abed6c0(0000) GS:ffff8882a9453000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fe119de9f00 CR3: 00000001ba914000 CR4: 00000000000006f0
***
If these findings have caused you to resend the series or submit a
separate fix, please add the following tag to your commit message:
Tested-by: syzbot@syzkaller.appspotmail.com
---
This report is generated by a bot. It may contain errors.
syzbot ci engineers can be reached at syzkaller@googlegroups.com.
To test a patch for this bug, please reply with `#syz test`
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next prev parent reply other threads:[~2026-04-20 18:09 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-04-20 12:51 [PATCH RFC v2 00/18] mm/virtio: skip redundant zeroing of host-zeroed reported pages Michael S. Tsirkin
2026-04-20 12:50 ` [PATCH RFC v2 01/18] mm: page_alloc: propagate PageReported flag across buddy splits Michael S. Tsirkin
2026-04-20 12:50 ` [PATCH RFC v2 02/18] mm: add pghint_t type and vma_alloc_folio_hints API Michael S. Tsirkin
2026-04-21 0:58 ` Huang, Ying
2026-04-20 12:50 ` [PATCH RFC v2 03/18] mm: add PG_zeroed page flag for known-zero pages Michael S. Tsirkin
2026-04-20 12:50 ` [PATCH RFC v2 04/18] mm: page_alloc: track PG_zeroed across buddy merges Michael S. Tsirkin
2026-04-20 12:50 ` [PATCH RFC v2 05/18] mm: page_alloc: preserve PG_zeroed in try_to_claim_block Michael S. Tsirkin
2026-04-20 12:50 ` [PATCH RFC v2 06/18] mm: page_alloc: thread pghint_t through get_page_from_freelist Michael S. Tsirkin
2026-04-20 12:50 ` [PATCH RFC v2 07/18] mm: post_alloc_hook: use PG_zeroed to skip zeroing, return pghint_t Michael S. Tsirkin
2026-04-20 12:50 ` [PATCH RFC v2 08/18] mm: hugetlb: thread pghint_t through buddy allocation chain Michael S. Tsirkin
2026-04-20 12:50 ` [PATCH RFC v2 09/18] mm: hugetlb: use PG_zeroed for pool pages, skip redundant zeroing Michael S. Tsirkin
2026-04-20 12:50 ` [PATCH RFC v2 10/18] mm: page_reporting: support host-zeroed reported pages Michael S. Tsirkin
2026-04-20 12:50 ` [PATCH RFC v2 11/18] mm: skip zeroing in vma_alloc_zeroed_movable_folio for pre-zeroed pages Michael S. Tsirkin
2026-04-20 12:50 ` [PATCH RFC v2 12/18] mm: skip zeroing in alloc_anon_folio " Michael S. Tsirkin
2026-04-20 12:50 ` [PATCH RFC v2 13/18] mm: skip zeroing in vma_alloc_anon_folio_pmd " Michael S. Tsirkin
2026-04-20 12:50 ` [PATCH RFC v2 14/18] mm: memfd: skip zeroing for pre-zeroed hugetlb pages Michael S. Tsirkin
2026-04-20 12:51 ` [PATCH RFC v2 15/18] virtio_balloon: add host_zeroes_pages module parameter Michael S. Tsirkin
2026-04-20 12:51 ` [PATCH RFC v2 16/18] mm: page_reporting: add flush parameter with page budget Michael S. Tsirkin
2026-04-20 12:51 ` [PATCH RFC v2 17/18] mm: add free_frozen_pages_hint and put_page_hint APIs Michael S. Tsirkin
2026-04-20 12:51 ` [PATCH RFC v2 18/18] virtio_balloon: mark deflated pages as pre-zeroed Michael S. Tsirkin
2026-04-20 18:09 ` syzbot ci [this message]
2026-04-20 18:20 ` [PATCH RFC v2 00/18] mm/virtio: skip redundant zeroing of host-zeroed reported pages David Hildenbrand (Arm)
2026-04-20 23:33 ` Michael S. Tsirkin
2026-04-21 2:38 ` Gregory Price
2026-04-21 2:21 ` Gregory Price
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