syzbot


WARNING in folio_remove_rmap_ptes

Status: upstream: reported C repro on 2025/12/23 05:23
Subsystems: mm
[Documentation on labels]
Reported-by: syzbot+b165fc2e11771c66d8ba@syzkaller.appspotmail.com
Fix commit: mm/vma: fix anon_vma UAF on mremap() faulted, unfaulted merge
Patched on: [ci-upstream-linux-next-kasan-gce-root ci-upstream-rust-kasan-gce], missing on: [ci-qemu-gce-upstream-auto ci-qemu-native-arm64-kvm ci-qemu-upstream ci-qemu-upstream-386 ci-qemu2-arm32 ci-qemu2-arm64 ci-qemu2-arm64-compat ci-qemu2-arm64-mte ci-qemu2-riscv64 ci-snapshot-upstream-root ci-upstream-bpf-kasan-gce ci-upstream-bpf-next-kasan-gce ci-upstream-gce-arm64 ci-upstream-gce-leak ci-upstream-kasan-badwrites-root ci-upstream-kasan-gce ci-upstream-kasan-gce-386 ci-upstream-kasan-gce-root ci-upstream-kasan-gce-selinux-root ci-upstream-kasan-gce-smack-root ci-upstream-kmsan-gce-386-root ci-upstream-kmsan-gce-root ci-upstream-net-kasan-gce ci-upstream-net-this-kasan-gce ci2-upstream-fs ci2-upstream-kcsan-gce ci2-upstream-usb]
First crash: 17d, last: 3d11h
Discussions (3)
Title Replies (including bot) Last reply
[PATCH v2 1/4] mm/vma: fix anon_vma UAF on mremap() faulted, unfaulted merge 3 (3) 2026/01/06 15:01
[syzbot] [mm?] WARNING in folio_remove_rmap_ptes 22 (27) 2026/01/06 15:00
[PATCH] mm/vma: fix anon_vma UAF on mremap() faulted, unfaulted merge 7 (7) 2026/01/05 15:24
Last patch testing requests (5)
Created Duration User Patch Repo Result
2026/01/06 14:39 20m aha310510@gmail.com patch upstream OK log
2026/01/04 23:13 15m retest repro upstream report log
2026/01/03 03:13 20m aha310510@gmail.com patch upstream OK log
2026/01/01 08:33 19m aha310510@gmail.com patch upstream OK log
2025/12/23 09:42 12m hdanton@sina.com patch upstream report log

Sample crash report:
 handle_mm_fault+0x3fe/0xad0 mm/memory.c:6580
 do_user_addr_fault+0x60c/0x1370 arch/x86/mm/fault.c:1336
 handle_page_fault arch/x86/mm/fault.c:1476 [inline]
 exc_page_fault+0x64/0xc0 arch/x86/mm/fault.c:1532
 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:618
------------[ cut here ]------------
WARNING: ./include/linux/rmap.h:462 at __folio_rmap_sanity_checks include/linux/rmap.h:462 [inline], CPU#1: syz.0.18/6090
WARNING: ./include/linux/rmap.h:462 at __folio_remove_rmap mm/rmap.c:1663 [inline], CPU#1: syz.0.18/6090
WARNING: ./include/linux/rmap.h:462 at folio_remove_rmap_ptes+0xc27/0xfb0 mm/rmap.c:1779, CPU#1: syz.0.18/6090
Modules linked in:
CPU: 1 UID: 0 PID: 6090 Comm: syz.0.18 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014
RIP: 0010:__folio_rmap_sanity_checks include/linux/rmap.h:462 [inline]
RIP: 0010:__folio_remove_rmap mm/rmap.c:1663 [inline]
RIP: 0010:folio_remove_rmap_ptes+0xc27/0xfb0 mm/rmap.c:1779
Code: 00 e9 49 f4 ff ff e8 a8 35 aa ff e8 c3 55 17 ff e9 98 fc ff ff e8 99 35 aa ff 48 c7 c6 80 b7 9c 8b 4c 89 e7 e8 8a 12 f5 ff 90 <0f> 0b 90 e9 5a f6 ff ff e8 7c 35 aa ff 48 8b 54 24 10 48 b8 00 00
RSP: 0018:ffffc90003f5f260 EFLAGS: 00010293
RAX: 0000000000000000 RBX: ffffea0001417f80 RCX: ffffc90003f5f144
RDX: ffff88803368c980 RSI: ffffffff8214b106 RDI: ffff88803368ce04
RBP: 0000000000000001 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000001 R11: ffff88803368d4b0 R12: ffffea0001417f80
R13: ffff888030c90500 R14: 0000000000000000 R15: ffff888012660660
FS:  00007f98fd3fe6c0(0000) GS:ffff8880d69f5000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f98fd3ddd58 CR3: 000000003661c000 CR4: 0000000000352ef0
Call Trace:
 <TASK>
 zap_present_folio_ptes mm/memory.c:1650 [inline]
 zap_present_ptes mm/memory.c:1708 [inline]
 do_zap_pte_range mm/memory.c:1810 [inline]
 zap_pte_range mm/memory.c:1854 [inline]
 zap_pmd_range mm/memory.c:1946 [inline]
 zap_pud_range mm/memory.c:1975 [inline]
 zap_p4d_range mm/memory.c:1996 [inline]
 unmap_page_range+0x1b7d/0x43c0 mm/memory.c:2017
 unmap_single_vma+0x153/0x240 mm/memory.c:2059
 unmap_vmas+0x218/0x470 mm/memory.c:2101
 vms_clear_ptes+0x419/0x790 mm/vma.c:1231
 vms_complete_munmap_vmas+0x1ca/0x970 mm/vma.c:1280
 do_vmi_align_munmap+0x446/0x7e0 mm/vma.c:1539
 do_vmi_munmap+0x204/0x3e0 mm/vma.c:1587
 do_munmap+0xb6/0xf0 mm/mmap.c:1065
 mremap_to+0x236/0x450 mm/mremap.c:1378
 remap_move mm/mremap.c:1890 [inline]
 do_mremap+0x13a8/0x2020 mm/mremap.c:1933
 __do_sys_mremap+0x119/0x170 mm/mremap.c:1997
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xcd/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f98fdd8f7c9
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 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 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f98fd3fe038 EFLAGS: 00000246 ORIG_RAX: 0000000000000019
RAX: ffffffffffffffda RBX: 00007f98fdfe5fa0 RCX: 00007f98fdd8f7c9
RDX: 0000000000004000 RSI: 0000000000004000 RDI: 0000200000ffc000
RBP: 00007f98fde13f91 R08: 0000200000002000 R09: 0000000000000000
R10: 0000000000000007 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f98fdfe6038 R14: 00007f98fdfe5fa0 R15: 00007ffd69c60518
 </TASK>

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/12/21 23:09 upstream 9094662f6707 d1b870e1 .config console log report syz / log C [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream WARNING in folio_remove_rmap_ptes
* Struck through repros no longer work on HEAD.