syzbot


general protection fault in metapage_writepage (3)

Status: upstream: reported on 2026/06/18 09:35
Reported-by: syzbot+a24e49b323214d9c1010@syzkaller.appspotmail.com
First crash: 1d07h, last: 1d07h
Similar bugs (2)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-6.6 general protection fault in metapage_writepage 2 1 357d 357d 0/2 auto-obsoleted due to no activity on 2025/10/05 11:17
linux-6.6 general protection fault in metapage_writepage (2) 2 1 145d 145d 0/2 auto-obsoleted due to no activity on 2026/05/05 04:55

Sample crash report:
bn = 72c, index = 96
bn = 0, index = 0
bn = 72c, index = 96
bn = 0, index = 0
bn = 72c, index = 96
bn = 0, index = 0
bn = 0, index = 0
general protection fault, probably for non-canonical address 0xdffffc0000000000: 0000 [#1] PREEMPT SMP KASAN
KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007]
CPU: 0 PID: 5869 Comm: syz.3.9 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026
RIP: 0010:metapage_writepage+0xa3/0x11f0 fs/jfs/jfs_metapage.c:340
Code: f3 e8 01 4e 81 fe 4c 8d 73 18 4c 89 f0 48 c1 e8 03 42 80 3c 38 00 74 08 4c 89 f7 e8 07 8e d9 fe 4d 8b 36 4c 89 f0 48 c1 e8 03 <42> 80 3c 38 00 74 08 4c 89 f7 e8 ee 8d d9 fe 4d 8b 2e 43 c6 44 3c
RSP: 0018:ffffc900048ef700 EFLAGS: 00010246
RAX: 0000000000000000 RBX: ffffea000097cc80 RCX: 0000000000080000
RDX: ffffc9000d11c000 RSI: 0000000000037b32 RDI: 0000000000037b33
RBP: ffffc900048ef7f0 R08: ffffea000097ccb7 R09: 1ffffd400012f996
R10: dffffc0000000000 R11: fffff9400012f997 R12: 1ffff9200091dee8
R13: ffffea000097ccb4 R14: 0000000000000000 R15: dffffc0000000000
FS:  00007f005f65f6c0(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f801f182000 CR3: 000000002e93b000 CR4: 00000000003506f0
Call Trace:
 <TASK>
 metapage_write_one+0x2d3/0x790 fs/jfs/jfs_metapage.c:710
 release_metapage+0x48a/0x870 fs/jfs/jfs_metapage.c:778
 dtSearch+0x1c45/0x21b0 fs/jfs/jfs_dtree.c:793
 jfs_symlink+0x854/0xfa0 fs/jfs/namei.c:1016
 vfs_symlink+0x138/0x2b0 fs/namei.c:4481
 do_symlinkat+0x1ba/0x400 fs/namei.c:4507
 __do_sys_symlinkat fs/namei.c:4523 [inline]
 __se_sys_symlinkat fs/namei.c:4520 [inline]
 __x64_sys_symlinkat+0x99/0xb0 fs/namei.c:4520
 do_syscall_x64 arch/x86/entry/common.c:46 [inline]
 do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:76
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f005e79ce59
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:00007f005f65f028 EFLAGS: 00000246 ORIG_RAX: 000000000000010a
RAX: ffffffffffffffda RBX: 00007f005ea15fa0 RCX: 00007f005e79ce59
RDX: 00002000000005c0 RSI: ffffffffffffff9c RDI: 0000200000000700
RBP: 00007f005e832d6f R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f005ea16038 R14: 00007f005ea15fa0 R15: 00007ffd244846a8
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:metapage_writepage+0xa3/0x11f0 fs/jfs/jfs_metapage.c:340
Code: f3 e8 01 4e 81 fe 4c 8d 73 18 4c 89 f0 48 c1 e8 03 42 80 3c 38 00 74 08 4c 89 f7 e8 07 8e d9 fe 4d 8b 36 4c 89 f0 48 c1 e8 03 <42> 80 3c 38 00 74 08 4c 89 f7 e8 ee 8d d9 fe 4d 8b 2e 43 c6 44 3c
RSP: 0018:ffffc900048ef700 EFLAGS: 00010246
RAX: 0000000000000000 RBX: ffffea000097cc80 RCX: 0000000000080000
RDX: ffffc9000d11c000 RSI: 0000000000037b32 RDI: 0000000000037b33
RBP: ffffc900048ef7f0 R08: ffffea000097ccb7 R09: 1ffffd400012f996
R10: dffffc0000000000 R11: fffff9400012f997 R12: 1ffff9200091dee8
R13: ffffea000097ccb4 R14: 0000000000000000 R15: dffffc0000000000
FS:  00007f005f65f6c0(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f801f1a6000 CR3: 000000002e93b000 CR4: 00000000003506e0
----------------
Code disassembly (best guess):
   0:	f3 e8 01 4e 81 fe    	repz call 0xfe814e07
   6:	4c 8d 73 18          	lea    0x18(%rbx),%r14
   a:	4c 89 f0             	mov    %r14,%rax
   d:	48 c1 e8 03          	shr    $0x3,%rax
  11:	42 80 3c 38 00       	cmpb   $0x0,(%rax,%r15,1)
  16:	74 08                	je     0x20
  18:	4c 89 f7             	mov    %r14,%rdi
  1b:	e8 07 8e d9 fe       	call   0xfed98e27
  20:	4d 8b 36             	mov    (%r14),%r14
  23:	4c 89 f0             	mov    %r14,%rax
  26:	48 c1 e8 03          	shr    $0x3,%rax
* 2a:	42 80 3c 38 00       	cmpb   $0x0,(%rax,%r15,1) <-- trapping instruction
  2f:	74 08                	je     0x39
  31:	4c 89 f7             	mov    %r14,%rdi
  34:	e8 ee 8d d9 fe       	call   0xfed98e27
  39:	4d 8b 2e             	mov    (%r14),%r13
  3c:	43                   	rex.XB
  3d:	c6                   	.byte 0xc6
  3e:	44                   	rex.R
  3f:	3c                   	.byte 0x3c

Crashes (4):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/06/18 09:40 linux-6.6.y 924b4a879cbb b62b3ded .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan general protection fault in metapage_writepage
2026/06/18 09:39 linux-6.6.y 924b4a879cbb b62b3ded .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan general protection fault in metapage_writepage
2026/06/18 09:36 linux-6.6.y 924b4a879cbb b62b3ded .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan general protection fault in metapage_writepage
2026/06/18 09:35 linux-6.6.y 924b4a879cbb b62b3ded .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan general protection fault in metapage_writepage
* Struck through repros no longer work on HEAD.