general protection fault in ufs_sync_fs

Status: moderation: reported on 2026/08/09 00:09
Subsystems: fs
Labels: prio:high
[Documentation on labels]
Reported-by: syzbot+7e1eaaa4585fc7dacdd9@syzkaller.appspotmail.com
First crash: 6d01h, last: 5d09h
✨ AI Jobs (1)
ID Workflow Result Correct Bug Created Started Finished Revision
15306839 assessment-security DenialOfService: ✅ Exploitable: ❌ FilesystemTrigger: ✅ NetworkTrigger: ❌ PeripheralTrigger: ✅ RemoteTrigger: ❌ Unprivileged: ❌ UserNamespace: ❌ VMGuestTrigger: ❌ VMHostTrigger: ❌ general protection fault in ufs_sync_fs 2026/08/09 23:36 2026/08/09 23:36 2026/08/09 23:38 5d63f80b

Sample crash report:
Oops: general protection fault, probably for non-canonical address 0xdffffc000000003c: 0000 [#1] SMP KASAN NOPTI
KASAN: null-ptr-deref in range [0x00000000000001e0-0x00000000000001e7]
CPU: 0 UID: 0 PID: 12816 Comm: syz.0.2075 Tainted: G             L      syzkaller #0 PREEMPT(full) 
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/16/2026
RIP: 0010:__mutex_lock_common kernel/locking/mutex.c:625 [inline]
RIP: 0010:__mutex_lock+0x149/0x1550 kernel/locking/mutex.c:821
Code: c0 80 a5 78 9a 48 c1 e8 03 0f b6 04 18 84 c0 0f 85 35 12 00 00 83 3d 75 f5 a5 0e 00 75 22 49 8d 7c 24 58 48 89 f8 48 c1 e8 03 <80> 3c 18 00 74 05 e8 6c fb 61 f6 4d 39 64 24 58 0f 85 48 11 00 00
RSP: 0018:ffffc90005a37900 EFLAGS: 00010216
RAX: 000000000000003c RBX: dffffc0000000000 RCX: ffffffff9a78a503
RDX: 0000000000000000 RSI: ffffffff8e4b420d RDI: 00000000000001e0
RBP: ffffc90005a37a98 R08: ffffc90005a37a07 R09: ffffc90005a379e0
R10: dffffc0000000000 R11: fffff52000b46f41 R12: 0000000000000188
R13: 0000000000000000 R14: 1ffff92000b46f34 R15: 0000000000000000
FS:  00007f90f4be26c0(0000) GS:ffff888124f4b000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f5926c4e00d CR3: 000000002a90c000 CR4: 0000000000350ef0
Call Trace:
 <TASK>
 ufs_sync_fs+0x59/0x780 fs/ufs/super.c:631
 sync_filesystem+0xee/0x230 fs/sync.c:56
 generic_shutdown_super+0x77/0x2d0 fs/super.c:626
 kill_block_super+0x44/0x90 fs/super.c:1671
 deactivate_locked_super+0xbc/0x130 fs/super.c:477
 get_tree_bdev_flags+0x44e/0x4f0 fs/super.c:1642
 vfs_get_tree+0x92/0x2a0 fs/super.c:1700
 fc_mount fs/namespace.c:1198 [inline]
 do_new_mount_fc fs/namespace.c:3765 [inline]
 do_new_mount+0x319/0xdc0 fs/namespace.c:3841
 do_mount fs/namespace.c:4174 [inline]
 __do_sys_mount fs/namespace.c:4390 [inline]
 __se_sys_mount+0x31d/0x420 fs/namespace.c:4367
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f90f3d9e019
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:00007f90f4be2028 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007f90f4025fa0 RCX: 00007f90f3d9e019
RDX: 0000200000004000 RSI: 0000200000003000 RDI: 0000200000000040
RBP: 00007f90f3e3500c R08: 0000200000005000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f90f4026038 R14: 00007f90f4025fa0 R15: 00007ffca4f22028
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:__mutex_lock_common kernel/locking/mutex.c:625 [inline]
RIP: 0010:__mutex_lock+0x149/0x1550 kernel/locking/mutex.c:821
Code: c0 80 a5 78 9a 48 c1 e8 03 0f b6 04 18 84 c0 0f 85 35 12 00 00 83 3d 75 f5 a5 0e 00 75 22 49 8d 7c 24 58 48 89 f8 48 c1 e8 03 <80> 3c 18 00 74 05 e8 6c fb 61 f6 4d 39 64 24 58 0f 85 48 11 00 00
RSP: 0018:ffffc90005a37900 EFLAGS: 00010216
RAX: 000000000000003c RBX: dffffc0000000000 RCX: ffffffff9a78a503
RDX: 0000000000000000 RSI: ffffffff8e4b420d RDI: 00000000000001e0
RBP: ffffc90005a37a98 R08: ffffc90005a37a07 R09: ffffc90005a379e0
R10: dffffc0000000000 R11: fffff52000b46f41 R12: 0000000000000188
R13: 0000000000000000 R14: 1ffff92000b46f34 R15: 0000000000000000
FS:  00007f90f4be26c0(0000) GS:ffff88812504b000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b341f8ff8 CR3: 000000002a90c000 CR4: 0000000000350ef0
----------------
Code disassembly (best guess):
   0:	c0 80 a5 78 9a 48 c1 	rolb   $0xc1,0x489a78a5(%rax)
   7:	e8 03 0f b6 04       	call   0x4b60f0f
   c:	18 84 c0 0f 85 35 12 	sbb    %al,0x1235850f(%rax,%rax,8)
  13:	00 00                	add    %al,(%rax)
  15:	83 3d 75 f5 a5 0e 00 	cmpl   $0x0,0xea5f575(%rip)        # 0xea5f591
  1c:	75 22                	jne    0x40
  1e:	49 8d 7c 24 58       	lea    0x58(%r12),%rdi
  23:	48 89 f8             	mov    %rdi,%rax
  26:	48 c1 e8 03          	shr    $0x3,%rax
* 2a:	80 3c 18 00          	cmpb   $0x0,(%rax,%rbx,1) <-- trapping instruction
  2e:	74 05                	je     0x35
  30:	e8 6c fb 61 f6       	call   0xf661fba1
  35:	4d 39 64 24 58       	cmp    %r12,0x58(%r12)
  3a:	0f 85 48 11 00 00    	jne    0x1188

Crashes (9):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/08/04 18:51 upstream 848acc8ffe1b d4abbeac .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root general protection fault in ufs_sync_fs
2026/08/04 18:50 upstream 848acc8ffe1b d4abbeac .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root general protection fault in ufs_sync_fs
2026/08/04 18:36 upstream 848acc8ffe1b d4abbeac .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root general protection fault in ufs_sync_fs
2026/08/05 06:01 upstream 562bfb501c54 52aa2820 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root general protection fault in ufs_sync_fs
2026/08/05 06:01 upstream 562bfb501c54 52aa2820 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root general protection fault in ufs_sync_fs
2026/08/04 13:27 upstream 848acc8ffe1b 3c5eaa21 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root general protection fault in ufs_sync_fs
2026/08/04 13:27 upstream 848acc8ffe1b 3c5eaa21 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root general protection fault in ufs_sync_fs
2026/08/04 13:27 upstream 848acc8ffe1b 3c5eaa21 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root general protection fault in ufs_sync_fs
2026/08/04 13:27 upstream 848acc8ffe1b 3c5eaa21 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root general protection fault in ufs_sync_fs
* Struck through repros no longer work on HEAD.