linux-kernel - Re: [syzbot] [jfs?] UBSAN: array-index-out-of-bounds in dtDelete

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Message-ID: <6801cc9f.050a0220.243d89.0017.GAE@google.com>
Date: Thu, 17 Apr 2025 20:53:03 -0700
From: syzbot <syzbot+4f9c823a6f63d87491ba@...kaller.appspotmail.com>
To: linux-kernel@...r.kernel.org, richard120310@...il.com, 
	syzkaller-bugs@...glegroups.com
Subject: Re: [syzbot] [jfs?] UBSAN: array-index-out-of-bounds in dtDelete

Hello,

syzbot has tested the proposed patch but the reproducer is still triggering an issue:
divide error in dtDelete

Oops: divide error: 0000 [#1] PREEMPT SMP KASAN NOPTI
CPU: 0 UID: 0 PID: 6398 Comm: syz.0.176 Not tainted 6.14.0-rc6-syzkaller-00115-ge3a854b577cb-dirty #0
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014
RIP: 0010:dtDelete+0x1d29/0x2de0 fs/jfs/jfs_dtree.c:2133
Code: 04 28 84 c0 0f 85 ef 0c 00 00 44 0f b6 3b 49 8d 5e 14 48 89 d8 48 c1 e8 03 42 0f b6 04 28 84 c0 0f 85 ed 0c 00 00 41 0f b6 c7 <f6> 33 0f b6 dc bf 81 00 00 00 89 de e8 86 ec 68 fe 80 fb 80 0f 87
RSP: 0018:ffffc9000d54f4e0 EFLAGS: 00010246
RAX: 0000000000000000 RBX: ffff888012dc3014 RCX: ffff88801d184880
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000081
RBP: ffffc9000d54f7d0 R08: ffffffff83586b02 R09: 1ffffd4000096e18
R10: dffffc0000000000 R11: fffff94000096e19 R12: ffff8880598a81f0
R13: dffffc0000000000 R14: ffff888012dc3000 R15: 0000000000000000
FS:  00007fc17c5f26c0(0000) GS:ffff88801fc00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fc17c5f1fe0 CR3: 0000000012d60000 CR4: 0000000000352ef0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 jfs_rename+0xf91/0x1bf0 fs/jfs/namei.c:1239
 vfs_rename+0xbdb/0xf00 fs/namei.c:5069
 do_renameat2+0xd94/0x13f0 fs/namei.c:5226
 __do_sys_rename fs/namei.c:5273 [inline]
 __se_sys_rename fs/namei.c:5271 [inline]
 __x64_sys_rename+0x82/0x90 fs/namei.c:5271
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xf3/0x210 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fc17b78d169
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:00007fc17c5f2038 EFLAGS: 00000246 ORIG_RAX: 0000000000000052
RAX: ffffffffffffffda RBX: 00007fc17b9a6080 RCX: 00007fc17b78d169
RDX: 0000000000000000 RSI: 0000400000000f40 RDI: 0000400000000300
RBP: 00007fc17b80e2a0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000001 R14: 00007fc17b9a6080 R15: 00007ffcc2700f98
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:dtDelete+0x1d29/0x2de0 fs/jfs/jfs_dtree.c:2133
Code: 04 28 84 c0 0f 85 ef 0c 00 00 44 0f b6 3b 49 8d 5e 14 48 89 d8 48 c1 e8 03 42 0f b6 04 28 84 c0 0f 85 ed 0c 00 00 41 0f b6 c7 <f6> 33 0f b6 dc bf 81 00 00 00 89 de e8 86 ec 68 fe 80 fb 80 0f 87
RSP: 0018:ffffc9000d54f4e0 EFLAGS: 00010246
RAX: 0000000000000000 RBX: ffff888012dc3014 RCX: ffff88801d184880
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000081
RBP: ffffc9000d54f7d0 R08: ffffffff83586b02 R09: 1ffffd4000096e18
R10: dffffc0000000000 R11: fffff94000096e19 R12: ffff8880598a81f0
R13: dffffc0000000000 R14: ffff888012dc3000 R15: 0000000000000000
FS:  00007fc17c5f26c0(0000) GS:ffff88801fc00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fc17c5f1fe0 CR3: 0000000012d60000 CR4: 0000000000352ef0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
----------------
Code disassembly (best guess):
   0:	04 28                	add    $0x28,%al
   2:	84 c0                	test   %al,%al
   4:	0f 85 ef 0c 00 00    	jne    0xcf9
   a:	44 0f b6 3b          	movzbl (%rbx),%r15d
   e:	49 8d 5e 14          	lea    0x14(%r14),%rbx
  12:	48 89 d8             	mov    %rbx,%rax
  15:	48 c1 e8 03          	shr    $0x3,%rax
  19:	42 0f b6 04 28       	movzbl (%rax,%r13,1),%eax
  1e:	84 c0                	test   %al,%al
  20:	0f 85 ed 0c 00 00    	jne    0xd13
  26:	41 0f b6 c7          	movzbl %r15b,%eax
* 2a:	f6 33                	divb   (%rbx) <-- trapping instruction
  2c:	0f b6 dc             	movzbl %ah,%ebx
  2f:	bf 81 00 00 00       	mov    $0x81,%edi
  34:	89 de                	mov    %ebx,%esi
  36:	e8 86 ec 68 fe       	call   0xfe68ecc1
  3b:	80 fb 80             	cmp    $0x80,%bl
  3e:	0f                   	.byte 0xf
  3f:	87                   	.byte 0x87


Tested on:

commit:         e3a854b5 Merge tag 'clk-fixes-for-linus' of git://git...
git tree:       git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
console output: https://syzkaller.appspot.com/x/log.txt?x=14ad9470580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=522f1f3e5f61442b
dashboard link: https://syzkaller.appspot.com/bug?extid=4f9c823a6f63d87491ba
compiler:       Debian clang version 15.0.6, Debian LLD 15.0.6
patch:          https://syzkaller.appspot.com/x/patch.diff?x=1167ba3f980000