Re: [syzbot] [jfs?] UBSAN: array-index-out-of-bounds in add_missing_indices

[syzbot <syzbot+b974bd41515f770c608b@syzkaller.appspotmail.com>]

Hello,

syzbot has tested the proposed patch but the reproducer is still triggering an issue:
BUG: unable to handle kernel paging request in lmLogSync

Unable to handle kernel paging request at virtual address dfff800000000006
KASAN: null-ptr-deref in range [0x0000000000000030-0x0000000000000037]
Mem abort info:
  ESR = 0x0000000096000005
  EC = 0x25: DABT (current EL), IL = 32 bits
  SET = 0, FnV = 0
  EA = 0, S1PTW = 0
  FSC = 0x05: level 1 translation fault
Data abort info:
  ISV = 0, ISS = 0x00000005, ISS2 = 0x00000000
  CM = 0, WnR = 0, TnD = 0, TagAccess = 0
  GCS = 0, Overlay = 0, DirtyBit = 0, Xs = 0
[dfff800000000006] address between user and kernel address ranges
Internal error: Oops: 0000000096000005 [#1] PREEMPT SMP
Modules linked in:
CPU: 0 UID: 0 PID: 102 Comm: jfsCommit Not tainted 6.14.0-rc7-syzkaller-ga2392f333575-dirty #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
pstate: 20400005 (nzCv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--)
pc : write_special_inodes fs/jfs/jfs_logmgr.c:207 [inline]
pc : lmLogSync+0xec/0x978 fs/jfs/jfs_logmgr.c:935
lr : lmLogSync+0xa4/0x978 fs/jfs/jfs_logmgr.c:934
sp : ffff80009ba17aa0
x29: ffff80009ba17b70 x28: ffff80009b359000 x27: dfff800000000000
x26: dfff800000000000 x25: ffff80009ba17ac0 x24: 1ffff0001202ba48
x23: 0000000000000002 x22: 0000000000000006 x21: 0000000000000030
x20: ffff0000edad3838 x19: ffff0000e80de000 x18: 1fffe000366f8886
x17: ffff80008fb6d000 x16: ffff80008b74b408 x15: ffff700013742f60
x14: 1ffff00013742f5d x13: 0000000000000004 x12: ffffffffffffffff
x11: ffff700013742f60 x10: 0000000000ff0100 x9 : 0000000000000000
x8 : 0000000000000006 x7 : 0000000000000000 x6 : 0000000000000000
x5 : 0000000000000001 x4 : 0000000000000004 x3 : 0000000000000010
x2 : 0000000000000004 x1 : 0000000000000001 x0 : 0000000000000000
Call trace:
 write_special_inodes fs/jfs/jfs_logmgr.c:207 [inline] (P)
 lmLogSync+0xec/0x978 fs/jfs/jfs_logmgr.c:935 (P)
 jfs_syncpt+0x74/0x98 fs/jfs/jfs_logmgr.c:1041
 txEnd+0x2ec/0x558 fs/jfs/jfs_txnmgr.c:549
 txLazyCommit fs/jfs/jfs_txnmgr.c:2684 [inline]
 jfs_lazycommit+0x4e0/0x9a8 fs/jfs/jfs_txnmgr.c:2733
 kthread+0x65c/0x7b0 kernel/kthread.c:464
 ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:862
Code: 97bd83a8 f94002a8 9100c115 d343fea8 (387b6908) 
---[ end trace 0000000000000000 ]---
----------------
Code disassembly (best guess):
   0:	97bd83a8 	bl	0xfffffffffef60ea0
   4:	f94002a8 	ldr	x8, [x21]
   8:	9100c115 	add	x21, x8, #0x30
   c:	d343fea8 	lsr	x8, x21, #3
* 10:	387b6908 	ldrb	w8, [x8, x27] <-- trapping instruction


Tested on:

commit:         a2392f33 drm/panthor: Clean up FW version information ..
git tree:       git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci
console output: https://syzkaller.appspot.com/x/log.txt?x=12ae95e4580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=5f4c5deae8cc60fe
dashboard link: https://syzkaller.appspot.com/bug?extid=b974bd41515f770c608b
compiler:       Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
userspace arch: arm64
patch:          https://syzkaller.appspot.com/x/patch.diff?x=11c7043f980000