syzbot


kernel BUG in filemap_unaccount_folio

Status: upstream: reported on 2025/06/24 02:03
Reported-by: syzbot+344dc92e07dbfaf6fe78@syzkaller.appspotmail.com
First crash: 20d, last: 3d15h
Similar bugs (3)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream kernel BUG in filemap_unaccount_folio mm -1 C done error 398 19h48m 676d 0/29 upstream: reported C repro on 2023/09/06 18:51
linux-6.1 kernel BUG in filemap_unaccount_folio origin:upstream missing-backport -1 C done 980 17h19m 579d 0/3 upstream: reported C repro on 2023/12/13 08:56
upstream kernel BUG in __filemap_get_folio kernel -1 C done 814 1010d 1180d 22/29 fixed on 2023/02/24 13:50

Sample crash report:
 hugetlb_sysctl_handler_common mm/hugetlb.c:4612 [inline]
 hugetlb_sysctl_handler+0x1be/0x230 mm/hugetlb.c:4622
 proc_sys_call_handler+0x4d1/0x7d0 fs/proc/proc_sysctl.c:599
 __kernel_write_iter+0x274/0x670 fs/read_write.c:517
 __kernel_write fs/read_write.c:537 [inline]
 kernel_write+0x1a8/0x330 fs/read_write.c:558
 process_sysctl_arg+0x39d/0x5f0 fs/proc/proc_sysctl.c:1677
 parse_one kernel/params.c:154 [inline]
 parse_args+0x50d/0xb50 kernel/params.c:189
 do_sysctl_args+0xd1/0x150 fs/proc/proc_sysctl.c:1709
 kernel_init+0x75/0x1c0 init/main.c:1466
 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152
 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293
page_owner free stack trace missing
------------[ cut here ]------------
kernel BUG at mm/filemap.c:155!
invalid opcode: 0000 [#1] PREEMPT SMP KASAN
CPU: 1 PID: 6455 Comm: syz.1.142 Not tainted 6.6.97-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
RIP: 0010:filemap_unaccount_folio+0x704/0xc60 mm/filemap.c:155
Code: 48 25 ff 0f 00 00 0f 84 ec 00 00 00 e8 c5 4b d1 ff e9 74 f9 ff ff e8 bb 4b d1 ff 48 89 df 48 c7 c6 e0 34 b3 8a e8 ac 75 12 00 <0f> 0b e8 a5 4b d1 ff 48 89 df 48 c7 c6 60 3a b3 8a e8 96 75 12 00
RSP: 0000:ffffc900043773b8 EFLAGS: 00010046
RAX: 6a74fa00349ee500 RBX: ffffea00005d8000 RCX: 6a74fa00349ee500
RDX: 0000000000000005 RSI: ffffffff8aaacac0 RDI: ffffffff8afc7880
RBP: ffffc90004377518 R08: ffffffff8e4a92ef R09: 1ffffffff1c9525d
R10: dffffc0000000000 R11: fffffbfff1c9525e R12: 0000000000000040
R13: 1ffffd40000bb000 R14: 1ffffd40000bb001 R15: ffffea00005d8008
FS:  00007f2b597bf6c0(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f87cb5bf200 CR3: 000000005c271000 CR4: 00000000003526e0
Call Trace:
 <TASK>
 __filemap_remove_folio+0xc4/0x7f0 mm/filemap.c:224
 filemap_remove_folio+0xf1/0x2c0 mm/filemap.c:257
 hugetlb_delete_from_page_cache fs/hugetlbfs/inode.c:433 [inline]
 remove_inode_single_folio fs/hugetlbfs/inode.c:638 [inline]
 remove_inode_hugepages+0x5dc/0x1870 fs/hugetlbfs/inode.c:696
 hugetlbfs_punch_hole fs/hugetlbfs/inode.c:816 [inline]
 hugetlbfs_fallocate+0xd45/0x1090 fs/hugetlbfs/inode.c:842
 vfs_fallocate+0x58e/0x700 fs/open.c:324
 madvise_remove mm/madvise.c:1007 [inline]
 madvise_vma_behavior mm/madvise.c:1031 [inline]
 madvise_walk_vmas mm/madvise.c:1266 [inline]
 do_madvise+0x15fe/0x3710 mm/madvise.c:1446
 __do_sys_madvise mm/madvise.c:1459 [inline]
 __se_sys_madvise mm/madvise.c:1457 [inline]
 __x64_sys_madvise+0xa6/0xc0 mm/madvise.c:1457
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f2b5898e929
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:00007f2b597bf038 EFLAGS: 00000246 ORIG_RAX: 000000000000001c
RAX: ffffffffffffffda RBX: 00007f2b58bb6160 RCX: 00007f2b5898e929
RDX: 0000000000000009 RSI: 0000000000600002 RDI: 0000200000000000
RBP: 00007f2b58a10b39 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007f2b58bb6160 R15: 00007fff6dcead88
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:filemap_unaccount_folio+0x704/0xc60 mm/filemap.c:155
Code: 48 25 ff 0f 00 00 0f 84 ec 00 00 00 e8 c5 4b d1 ff e9 74 f9 ff ff e8 bb 4b d1 ff 48 89 df 48 c7 c6 e0 34 b3 8a e8 ac 75 12 00 <0f> 0b e8 a5 4b d1 ff 48 89 df 48 c7 c6 60 3a b3 8a e8 96 75 12 00
RSP: 0000:ffffc900043773b8 EFLAGS: 00010046
RAX: 6a74fa00349ee500 RBX: ffffea00005d8000 RCX: 6a74fa00349ee500
RDX: 0000000000000005 RSI: ffffffff8aaacac0 RDI: ffffffff8afc7880
RBP: ffffc90004377518 R08: ffffffff8e4a92ef R09: 1ffffffff1c9525d
R10: dffffc0000000000 R11: fffffbfff1c9525e R12: 0000000000000040
R13: 1ffffd40000bb000 R14: 1ffffd40000bb001 R15: ffffea00005d8008
FS:  00007f2b597bf6c0(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f87cb5bf200 CR3: 000000005c271000 CR4: 00000000003526e0

Crashes (3):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/07/11 00:00 linux-6.6.y 59a2de10b81a 3cda49cf .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan kernel BUG in filemap_unaccount_folio
2025/07/08 19:20 linux-6.6.y a5df3a702b2c 4d9fdfa4 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan kernel BUG in filemap_unaccount_folio
2025/06/24 02:02 linux-6.6.y 6282921b6825 e2f27c35 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan kernel BUG in filemap_unaccount_folio
* Struck through repros no longer work on HEAD.