syzbot


kernel BUG in shmem_undo_range

Status: upstream: reported syz repro on 2025/02/17 07:54
Subsystems: mm bcachefs
[Documentation on labels]
Reported-by: syzbot+0f74a9bc5e47528935fe@syzkaller.appspotmail.com
First crash: 4d20h, last: 4d20h
Discussions (1)
Title Replies (including bot) Last reply
[syzbot] [mm?] [bcachefs?] kernel BUG in shmem_undo_range 0 (1) 2025/02/17 07:54

Sample crash report:
 __vm_munmap+0x372/0x510 mm/vma.c:2951
 __do_sys_munmap mm/mmap.c:1084 [inline]
 __se_sys_munmap mm/mmap.c:1081 [inline]
 __x64_sys_munmap+0x60/0x70 mm/mmap.c:1081
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
------------[ cut here ]------------
kernel BUG at mm/filemap.c:2138!
Oops: invalid opcode: 0000 [#1] PREEMPT SMP KASAN NOPTI
CPU: 0 UID: 0 PID: 5647 Comm: syz.3.19 Not tainted 6.14.0-rc2-syzkaller-00303-gad1b832bf1cf #0
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014
RIP: 0010:find_lock_entries+0xb8a/0xbb0 mm/filemap.c:2137
Code: f4 c6 ff 4c 89 ff 48 c7 c6 40 d7 33 8c e8 9e 91 11 00 90 0f 0b e8 16 f4 c6 ff 4c 89 ff 48 c7 c6 20 d1 33 8c e8 87 91 11 00 90 <0f> 0b e8 ff f3 c6 ff 4c 89 ff 48 c7 c6 00 da 33 8c e8 70 91 11 00
RSP: 0018:ffffc90002d2f100 EFLAGS: 00010246
RAX: 9a94e420221a6800 RBX: ffffc90002d2f5c0 RCX: ffffc90002d2ed03
RDX: 0000000000000001 RSI: ffffffff8c2ab6a0 RDI: ffffffff8c80ed00
RBP: ffffc90002d2f250 R08: ffffffff903cdd77 R09: 1ffffffff2079bae
R10: dffffc0000000000 R11: fffffbfff2079baf R12: 000000000000030e
R13: 0000000000000001 R14: ffffea000135cec0 R15: ffffea000135cec0
FS:  0000000000000000(0000) GS:ffff88801fc00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00005604856a8600 CR3: 00000000534c6000 CR4: 0000000000352ef0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 shmem_undo_range+0x2d4/0x1820 mm/shmem.c:1094
 shmem_truncate_range mm/shmem.c:1224 [inline]
 shmem_evict_inode+0x29b/0xa80 mm/shmem.c:1352
 evict+0x4e8/0x9a0 fs/inode.c:796
 __dentry_kill+0x20d/0x630 fs/dcache.c:643
 dput+0x19f/0x2b0 fs/dcache.c:885
 __fput+0x60b/0x9f0 fs/file_table.c:472
 task_work_run+0x24f/0x310 kernel/task_work.c:227
 exit_task_work include/linux/task_work.h:40 [inline]
 do_exit+0xa2a/0x28e0 kernel/exit.c:938
 do_group_exit+0x207/0x2c0 kernel/exit.c:1087
 get_signal+0x168c/0x1720 kernel/signal.c:3036
 arch_do_signal_or_restart+0x96/0x860 arch/x86/kernel/signal.c:337
 exit_to_user_mode_loop kernel/entry/common.c:111 [inline]
 exit_to_user_mode_prepare include/linux/entry-common.h:329 [inline]
 __syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline]
 syscall_exit_to_user_mode+0xce/0x340 kernel/entry/common.c:218
 do_syscall_64+0x100/0x230 arch/x86/entry/common.c:89
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f6d6738b89f
Code: Unable to access opcode bytes at 0x7f6d6738b875.
RSP: 002b:00007f6d68182df0 EFLAGS: 00000293 ORIG_RAX: 0000000000000001
RAX: 0000000000772000 RBX: 0000000001000000 RCX: 00007f6d6738b89f
RDX: 0000000001000000 RSI: 00007f6d5e000000 RDI: 0000000000000003
RBP: 0000000000000000 R08: 0000000000000000 R09: 000000000000590c
R10: 0000000000000002 R11: 0000000000000293 R12: 0000000000000003
R13: 00007f6d68182ef0 R14: 00007f6d68182eb0 R15: 00007f6d5e000000
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:find_lock_entries+0xb8a/0xbb0 mm/filemap.c:2137
Code: f4 c6 ff 4c 89 ff 48 c7 c6 40 d7 33 8c e8 9e 91 11 00 90 0f 0b e8 16 f4 c6 ff 4c 89 ff 48 c7 c6 20 d1 33 8c e8 87 91 11 00 90 <0f> 0b e8 ff f3 c6 ff 4c 89 ff 48 c7 c6 00 da 33 8c e8 70 91 11 00
RSP: 0018:ffffc90002d2f100 EFLAGS: 00010246
RAX: 9a94e420221a6800 RBX: ffffc90002d2f5c0 RCX: ffffc90002d2ed03
RDX: 0000000000000001 RSI: ffffffff8c2ab6a0 RDI: ffffffff8c80ed00
RBP: ffffc90002d2f250 R08: ffffffff903cdd77 R09: 1ffffffff2079bae
R10: dffffc0000000000 R11: fffffbfff2079baf R12: 000000000000030e
R13: 0000000000000001 R14: ffffea000135cec0 R15: ffffea000135cec0
FS:  0000000000000000(0000) GS:ffff88801fc00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00005604856a8600 CR3: 00000000534c6000 CR4: 0000000000352ef0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/02/16 08:31 upstream ad1b832bf1cf 40a34ec9 .config console log report syz / log [disk image (non-bootable)] [vmlinux] [kernel image] [mounted in repro] ci-snapshot-upstream-root kernel BUG in shmem_undo_range
* Struck through repros no longer work on HEAD.