Re: [syzbot] [gfs2?] general protection fault in gfs2_print_dbg (3)

[syzbot <syzbot+fa7122891ab9e0bbc6a7@syzkaller.appspotmail.com>]

Hello,

syzbot has tested the proposed patch but the reproducer is still triggering an issue:
general protection fault in gfs2_print_dbg

Oops: general protection fault, probably for non-canonical address 0xe7697c1115925d6c: 0000 [#1] SMP KASAN PTI
KASAN: maybe wild-memory-access in range [0x3b4c0088ac92eb60-0x3b4c0088ac92eb67]
CPU: 1 UID: 0 PID: 6617 Comm: syz.0.23 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
RIP: 0010:string_nocheck lib/vsprintf.c:653 [inline]
RIP: 0010:string+0x1bb/0x2b0 lib/vsprintf.c:735
Code: 15 a5 f6 eb b3 41 c1 fd 10 4c 89 6c 24 10 49 8d 5d ff 45 31 ed 4b 8d 3c 2c 48 89 f8 48 c1 e8 03 48 b9 00 00 00 00 00 fc ff df <0f> b6 04 08 84 c0 75 60 4b 8d 2c 2e 47 0f b6 3c 2c 31 ff 44 89 fe
RSP: 0018:ffffc900034b6f00 EFLAGS: 00010007
RAX: 0769801115925d6c RBX: 00000000fffffffe RCX: dffffc0000000000
RDX: ffff88802f929e40 RSI: 00000000ffff0a00 RDI: 3b4c0088ac92eb67
RBP: ffffffff8bf0acfe R08: ffff88802f929e40 R09: 0000000000000008
R10: 0000000000000007 R11: 0000000000000000 R12: 3b4c0088ac92eb67
R13: 0000000000000000 R14: ffffc900034b7319 R15: 0000000000000030
FS:  00007fb88c0ac6c0(0000) GS:ffff888125ae8000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fa707863000 CR3: 000000005caf0000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 vsnprintf+0x739/0xf00 lib/vsprintf.c:2926
 va_format lib/vsprintf.c:1728 [inline]
 pointer+0x940/0x1190 lib/vsprintf.c:2548
 vsnprintf+0x60f/0xf00 lib/vsprintf.c:2930
 vprintk_store+0x3c7/0xd00 kernel/printk/printk.c:2252
 vprintk_emit+0x15f/0x590 kernel/printk/printk.c:2399
 _printk+0xcf/0x120 kernel/printk/printk.c:2448
 gfs2_print_dbg+0x19a/0x1b0 fs/gfs2/glock.c:1444
 dump_holder fs/gfs2/glock.c:2287 [inline]
 gfs2_dump_glock+0x152d/0x1bc0 fs/gfs2/glock.c:2398
 gfs2_consist_inode_i+0xf5/0x110 fs/gfs2/util.c:446
 gfs2_dirent_scan+0x545/0x690 fs/gfs2/dir.c:-1
 gfs2_dir_read+0x804/0x16f0 fs/gfs2/dir.c:1600
 gfs2_readdir+0x14c/0x1b0 fs/gfs2/file.c:116
 iterate_dir+0x399/0x570 fs/readdir.c:108
 __do_sys_getdents64 fs/readdir.c:410 [inline]
 __se_sys_getdents64+0xe4/0x260 fs/readdir.c:396
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fb88b18eba9
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:00007fb88c0ac038 EFLAGS: 00000246 ORIG_RAX: 00000000000000d9
RAX: ffffffffffffffda RBX: 00007fb88b3d6090 RCX: 00007fb88b18eba9
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000005
RBP: 00007fb88b211e19 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fb88b3d6128 R14: 00007fb88b3d6090 R15: 00007ffde70dec98
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:string_nocheck lib/vsprintf.c:653 [inline]
RIP: 0010:string+0x1bb/0x2b0 lib/vsprintf.c:735
Code: 15 a5 f6 eb b3 41 c1 fd 10 4c 89 6c 24 10 49 8d 5d ff 45 31 ed 4b 8d 3c 2c 48 89 f8 48 c1 e8 03 48 b9 00 00 00 00 00 fc ff df <0f> b6 04 08 84 c0 75 60 4b 8d 2c 2e 47 0f b6 3c 2c 31 ff 44 89 fe
RSP: 0018:ffffc900034b6f00 EFLAGS: 00010007
RAX: 0769801115925d6c RBX: 00000000fffffffe RCX: dffffc0000000000
RDX: ffff88802f929e40 RSI: 00000000ffff0a00 RDI: 3b4c0088ac92eb67
RBP: ffffffff8bf0acfe R08: ffff88802f929e40 R09: 0000000000000008
R10: 0000000000000007 R11: 0000000000000000 R12: 3b4c0088ac92eb67
R13: 0000000000000000 R14: ffffc900034b7319 R15: 0000000000000030
FS:  00007fb88c0ac6c0(0000) GS:ffff888125ae8000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fa707863000 CR3: 000000005caf0000 CR4: 00000000003526f0
----------------
Code disassembly (best guess):
   0:	15 a5 f6 eb b3       	adc    $0xb3ebf6a5,%eax
   5:	41 c1 fd 10          	sar    $0x10,%r13d
   9:	4c 89 6c 24 10       	mov    %r13,0x10(%rsp)
   e:	49 8d 5d ff          	lea    -0x1(%r13),%rbx
  12:	45 31 ed             	xor    %r13d,%r13d
  15:	4b 8d 3c 2c          	lea    (%r12,%r13,1),%rdi
  19:	48 89 f8             	mov    %rdi,%rax
  1c:	48 c1 e8 03          	shr    $0x3,%rax
  20:	48 b9 00 00 00 00 00 	movabs $0xdffffc0000000000,%rcx
  27:	fc ff df
* 2a:	0f b6 04 08          	movzbl (%rax,%rcx,1),%eax <-- trapping instruction
  2e:	84 c0                	test   %al,%al
  30:	75 60                	jne    0x92
  32:	4b 8d 2c 2e          	lea    (%r14,%r13,1),%rbp
  36:	47 0f b6 3c 2c       	movzbl (%r12,%r13,1),%r15d
  3b:	31 ff                	xor    %edi,%edi
  3d:	44 89 fe             	mov    %r15d,%esi


Tested on:

commit:         590b221e Add linux-next specific files for 20250912
git tree:       https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/
console output: https://syzkaller.appspot.com/x/log.txt?x=1205f762580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=12a1d1f3a8199632
dashboard link: https://syzkaller.appspot.com/bug?extid=fa7122891ab9e0bbc6a7
compiler:       Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8

Note: no patches were applied.