syzbot


stack segment fault in gfs2_glock_dq

Status: upstream: reported C repro on 2025/05/01 19:08
Subsystems: gfs2
[Documentation on labels]
Reported-by: syzbot+e0dbe53de58ffe4a5f31@syzkaller.appspotmail.com
First crash: 6d15h, last: 5h35m
Discussions (1)
Title Replies (including bot) Last reply
[syzbot] [gfs2?] stack segment fault in gfs2_glock_dq 0 (1) 2025/05/01 19:08

Sample crash report:
gfs2: fsid=syz:syz.0: first mount done, others may mount
gfs2: fsid=syz:syz.0: Error 10 writing to journal, jid=0
Oops: stack segment: 0000 [#1] SMP KASAN NOPTI
CPU: 0 UID: 0 PID: 5304 Comm: syz-executor172 Not tainted 6.15.0-rc3-syzkaller-00342-g5bc1018675ec #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:gfs2_glock_dq+0x60/0xb20 fs/gfs2/glock.c:1657
Code: 4c 89 ff e8 12 2c 37 fe 4c 89 64 24 28 4c 89 7c 24 30 4d 8b 2f 4d 8d 7d 10 4c 89 fd 48 c1 ed 03 48 b8 00 00 00 00 00 fc ff df <80> 7c 05 00 00 74 08 4c 89 ff e8 e1 2b 37 fe 49 8b 45 10 48 89 44
RSP: 0018:ffffc9000d357c20 EFLAGS: 00010202
RAX: dffffc0000000000 RBX: dffffc0000000000 RCX: ffff88801e8a8000
RDX: 0000000000000000 RSI: 0000000000000004 RDI: ffffc9000d357d00
RBP: 0000000000000002 R08: ffff888042107a3b R09: 1ffff11008420f47
R10: dffffc0000000000 R11: ffffed1008420f48 R12: 1ffff92001a6afa2
R13: 0000000000000000 R14: ffffc9000d357d00 R15: 0000000000000010
FS:  00007feba52726c0(0000) GS:ffff88808d6cc000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000000 CR3: 000000003fd8e000 CR4: 0000000000352ef0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 gfs2_glock_dq_uninit+0x25/0xb0 fs/gfs2/glock.c:1723
 gfs2_seek_data+0x16c/0x240 fs/gfs2/inode.c:2133
 gfs2_llseek+0x1a4/0x240 fs/gfs2/file.c:75
 vfs_llseek fs/read_write.c:387 [inline]
 ksys_lseek fs/read_write.c:400 [inline]
 __do_sys_lseek fs/read_write.c:410 [inline]
 __se_sys_lseek fs/read_write.c:408 [inline]
 __x64_sys_lseek+0x14c/0x1e0 fs/read_write.c:408
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xf6/0x210 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7feba52bd689
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 81 18 00 00 90 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 b0 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007feba5272218 EFLAGS: 00000246 ORIG_RAX: 0000000000000008
RAX: ffffffffffffffda RBX: 00007feba537c648 RCX: 00007feba52bd689
RDX: 0000000000000003 RSI: 0000000002000005 RDI: 0000000000000008
RBP: 00007feba537c640 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007feba5349028
R13: 0031656c69662f2e R14: 0000200000000240 R15: 0000200000000140
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:gfs2_glock_dq+0x60/0xb20 fs/gfs2/glock.c:1657
Code: 4c 89 ff e8 12 2c 37 fe 4c 89 64 24 28 4c 89 7c 24 30 4d 8b 2f 4d 8d 7d 10 4c 89 fd 48 c1 ed 03 48 b8 00 00 00 00 00 fc ff df <80> 7c 05 00 00 74 08 4c 89 ff e8 e1 2b 37 fe 49 8b 45 10 48 89 44
RSP: 0018:ffffc9000d357c20 EFLAGS: 00010202
RAX: dffffc0000000000 RBX: dffffc0000000000 RCX: ffff88801e8a8000
RDX: 0000000000000000 RSI: 0000000000000004 RDI: ffffc9000d357d00
RBP: 0000000000000002 R08: ffff888042107a3b R09: 1ffff11008420f47
R10: dffffc0000000000 R11: ffffed1008420f48 R12: 1ffff92001a6afa2
R13: 0000000000000000 R14: ffffc9000d357d00 R15: 0000000000000010
FS:  00007feba52726c0(0000) GS:ffff88808d6cc000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007feba52f9090 CR3: 000000003fd8e000 CR4: 0000000000352ef0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
----------------
Code disassembly (best guess):
   0:	4c 89 ff             	mov    %r15,%rdi
   3:	e8 12 2c 37 fe       	call   0xfe372c1a
   8:	4c 89 64 24 28       	mov    %r12,0x28(%rsp)
   d:	4c 89 7c 24 30       	mov    %r15,0x30(%rsp)
  12:	4d 8b 2f             	mov    (%r15),%r13
  15:	4d 8d 7d 10          	lea    0x10(%r13),%r15
  19:	4c 89 fd             	mov    %r15,%rbp
  1c:	48 c1 ed 03          	shr    $0x3,%rbp
  20:	48 b8 00 00 00 00 00 	movabs $0xdffffc0000000000,%rax
  27:	fc ff df
* 2a:	80 7c 05 00 00       	cmpb   $0x0,0x0(%rbp,%rax,1) <-- trapping instruction
  2f:	74 08                	je     0x39
  31:	4c 89 ff             	mov    %r15,%rdi
  34:	e8 e1 2b 37 fe       	call   0xfe372c1a
  39:	49 8b 45 10          	mov    0x10(%r13),%rax
  3d:	48                   	rex.W
  3e:	89                   	.byte 0x89
  3f:	44                   	rex.R

Crashes (3):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/04/27 22:10 upstream 5bc1018675ec c6b4fb39 .config console log report syz / log C [disk image (non-bootable)] [vmlinux] [kernel image] [mounted in repro (clean fs)] ci-snapshot-upstream-root stack segment fault in gfs2_glock_dq
2025/05/04 05:28 upstream 2a239ffbebb5 b0714e37 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root stack segment fault in gfs2_glock_dq
2025/04/27 19:05 upstream 5bc1018675ec c6b4fb39 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root stack segment fault in gfs2_glock_dq
* Struck through repros no longer work on HEAD.