Re: [syzbot] [jfs?] INFO: task hung in txBegin

[syzbot <syzbot+eda89a33c5856f66f823@syzkaller.appspotmail.com>]

Hello,

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

Oops: general protection fault, probably for non-canonical address 0xdffffc0000000006: 0000 [#1] PREEMPT SMP KASAN PTI
KASAN: null-ptr-deref in range [0x0000000000000030-0x0000000000000037]
CPU: 1 PID: 114 Comm: jfsCommit Not tainted 6.10.0-rc4-syzkaller-00148-g50736169ecc8-dirty #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/27/2024
RIP: 0010:write_special_inodes fs/jfs/jfs_logmgr.c:208 [inline]
RIP: 0010:lmLogSync+0x130/0xae0 fs/jfs/jfs_logmgr.c:935
Code: a6 fe 49 8d 5f f0 48 89 d8 48 c1 e8 03 42 80 3c 28 00 74 08 48 89 df e8 1e 97 d3 fe 48 8b 1b 48 83 c3 30 48 89 d8 48 c1 e8 03 <42> 80 3c 28 00 74 08 48 89 df e8 01 97 d3 fe 48 8b 3b e8 b9 c5 a6
RSP: 0018:ffffc90002cefc00 EFLAGS: 00010206
RAX: 0000000000000006 RBX: 0000000000000030 RCX: 328fe0b8e03e5b00
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffffc90002cefd18 R08: ffffffff81cbb49a R09: 0000000000000000
R10: ffffc90002cef9e8 R11: fffff5200059df6b R12: ffff88806a112800
R13: dffffc0000000000 R14: 0000000000000001 R15: ffff88807cb0ba38
FS:  0000000000000000(0000) GS:ffff8880b9500000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055559488b938 CR3: 000000000e132000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 jfs_syncpt+0x7d/0xa0 fs/jfs/jfs_logmgr.c:1041
 txEnd+0x30f/0x560 fs/jfs/jfs_txnmgr.c:549
 txLazyCommit fs/jfs/jfs_txnmgr.c:2684 [inline]
 jfs_lazycommit+0x634/0xb80 fs/jfs/jfs_txnmgr.c:2733
 kthread+0x2f0/0x390 kernel/kthread.c:389
 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:write_special_inodes fs/jfs/jfs_logmgr.c:208 [inline]
RIP: 0010:lmLogSync+0x130/0xae0 fs/jfs/jfs_logmgr.c:935
Code: a6 fe 49 8d 5f f0 48 89 d8 48 c1 e8 03 42 80 3c 28 00 74 08 48 89 df e8 1e 97 d3 fe 48 8b 1b 48 83 c3 30 48 89 d8 48 c1 e8 03 <42> 80 3c 28 00 74 08 48 89 df e8 01 97 d3 fe 48 8b 3b e8 b9 c5 a6
RSP: 0018:ffffc90002cefc00 EFLAGS: 00010206
RAX: 0000000000000006 RBX: 0000000000000030 RCX: 328fe0b8e03e5b00
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffffc90002cefd18 R08: ffffffff81cbb49a R09: 0000000000000000
R10: ffffc90002cef9e8 R11: fffff5200059df6b R12: ffff88806a112800
R13: dffffc0000000000 R14: 0000000000000001 R15: ffff88807cb0ba38
FS:  0000000000000000(0000) GS:ffff8880b9500000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055559488b938 CR3: 000000002bf6a000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
----------------
Code disassembly (best guess):
   0:	a6                   	cmpsb  %es:(%rdi),%ds:(%rsi)
   1:	fe 49 8d             	decb   -0x73(%rcx)
   4:	5f                   	pop    %rdi
   5:	f0 48 89 d8          	lock mov %rbx,%rax
   9:	48 c1 e8 03          	shr    $0x3,%rax
   d:	42 80 3c 28 00       	cmpb   $0x0,(%rax,%r13,1)
  12:	74 08                	je     0x1c
  14:	48 89 df             	mov    %rbx,%rdi
  17:	e8 1e 97 d3 fe       	call   0xfed3973a
  1c:	48 8b 1b             	mov    (%rbx),%rbx
  1f:	48 83 c3 30          	add    $0x30,%rbx
  23:	48 89 d8             	mov    %rbx,%rax
  26:	48 c1 e8 03          	shr    $0x3,%rax
* 2a:	42 80 3c 28 00       	cmpb   $0x0,(%rax,%r13,1) <-- trapping instruction
  2f:	74 08                	je     0x39
  31:	48 89 df             	mov    %rbx,%rdi
  34:	e8 01 97 d3 fe       	call   0xfed3973a
  39:	48 8b 3b             	mov    (%rbx),%rdi
  3c:	e8                   	.byte 0xe8
  3d:	b9                   	.byte 0xb9
  3e:	c5                   	.byte 0xc5
  3f:	a6                   	cmpsb  %es:(%rdi),%ds:(%rsi)


Tested on:

commit:         50736169 Merge tag 'for-6.10-rc4-tag' of git://git.ker..
git tree:       git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
console output: https://syzkaller.appspot.com/x/log.txt?x=16ca70f3980000
kernel config:  https://syzkaller.appspot.com/x/.config?x=12f98862a3c0c799
dashboard link: https://syzkaller.appspot.com/bug?extid=eda89a33c5856f66f823
compiler:       Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
patch:          https://syzkaller.appspot.com/x/patch.diff?x=1688319d980000