==================================================================
BUG: KASAN: use-after-free in dbJoin+0x295/0x2b0 fs/jfs/jfs_dmap.c:2894
Read of size 1 at addr ffff8881547f8a6c by task jfsCommit/116

CPU: 1 UID: 0 PID: 116 Comm: jfsCommit Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x100/0x190 lib/dump_stack.c:120
 print_address_description mm/kasan/report.c:378 [inline]
 print_report+0x13d/0x4b0 mm/kasan/report.c:482
 kasan_report+0xdf/0x1c0 mm/kasan/report.c:595
 dbJoin+0x295/0x2b0 fs/jfs/jfs_dmap.c:2894
 dbFreeBits+0x170/0x8d0 fs/jfs/jfs_dmap.c:2427
 dbFreeDmap+0x62/0x1c0 fs/jfs/jfs_dmap.c:2176
 dbFree+0x266/0x550 fs/jfs/jfs_dmap.c:485
 txFreeMap+0x2d3/0xe10 fs/jfs/jfs_txnmgr.c:2517
 xtTruncate+0x24fe/0x2e20 fs/jfs/jfs_xtree.c:2481
 jfs_free_zero_link+0x262/0x4c0 fs/jfs/namei.c:760
 jfs_evict_inode+0x40a/0x4a0 fs/jfs/inode.c:159
 evict+0x3c2/0xad0 fs/inode.c:825
 iput_final fs/inode.c:2019 [inline]
 iput.part.0+0x989/0x1050 fs/inode.c:2068
 iput+0x35/0x40 fs/inode.c:2034
 txUpdateMap+0x8bc/0xb00 fs/jfs/jfs_txnmgr.c:2369
 txLazyCommit fs/jfs/jfs_txnmgr.c:2666 [inline]
 jfs_lazycommit+0x5be/0xab0 fs/jfs/jfs_txnmgr.c:2735
 kthread+0x370/0x450 kernel/kthread.c:436
 ret_from_fork+0x72b/0xd50 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x1547f8
flags: 0x57ff00000000000(node=1|zone=2|lastcpupid=0x7ff)
raw: 057ff00000000000 ffffea000551fe08 ffffea000551fe08 0000000000000000
raw: 0000000000000000 0000000000000000 00000000ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner info is not present (never set?)

Memory state around the buggy address:
 ffff8881547f8900: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff8881547f8980: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
>ffff8881547f8a00: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                                                          ^
 ffff8881547f8a80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff8881547f8b00: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
==================================================================
------------[ cut here ]------------
lp >= size || lp < 0
WARNING: fs/jfs/jfs_dmap.c:2962 at dbAdjTree+0x2fa/0x3f0 fs/jfs/jfs_dmap.c:2962, CPU#1: jfsCommit/116
Modules linked in:
CPU: 1 UID: 0 PID: 116 Comm: jfsCommit Tainted: G    B               syzkaller #0 PREEMPT(full) 
Tainted: [B]=BAD_PAGE
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026
RIP: 0010:dbAdjTree+0x2fa/0x3f0 fs/jfs/jfs_dmap.c:2962
Code: 00 00 0f 82 8c fe ff ff 48 89 d6 48 c7 c7 00 86 05 8f 48 89 14 24 e8 e5 48 8c fd 48 8b 14 24 e9 70 fe ff ff e8 b7 69 5e fe 90 <0f> 0b 90 e8 ae 69 5e fe 48 83 c4 18 5b 5d 41 5c 41 5d 41 5e 41 5f
RSP: 0018:ffffc90002e07568 EFLAGS: 00010293
RAX: 0000000000000000 RBX: 0000000000000155 RCX: ffffffff83aaf2e1
RDX: ffff88801f3d5d00 RSI: ffffffff83aaf549 RDI: ffff88801f3d5d00
RBP: ffff888055758010 R08: 0000000000000005 R09: 0000000000000000
R10: 00000000ff0a0a0b R11: 6e696c6261736944 R12: 00000000ff0a0a0b
R13: 0000000000000005 R14: ffff888055758010 R15: 0000000000000001
FS:  0000000000000000(0000) GS:ffff8881241e1000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f2058637000 CR3: 000000005aa92000 CR4: 0000000000350ef0
Call Trace:
 <TASK>
 dbJoin+0x24b/0x2b0 fs/jfs/jfs_dmap.c:2930
 dbFreeBits+0x170/0x8d0 fs/jfs/jfs_dmap.c:2427
 dbFreeDmap+0x62/0x1c0 fs/jfs/jfs_dmap.c:2176
 dbFree+0x266/0x550 fs/jfs/jfs_dmap.c:485
 txFreeMap+0x2d3/0xe10 fs/jfs/jfs_txnmgr.c:2517
 xtTruncate+0x24fe/0x2e20 fs/jfs/jfs_xtree.c:2481
 jfs_free_zero_link+0x262/0x4c0 fs/jfs/namei.c:760
 jfs_evict_inode+0x40a/0x4a0 fs/jfs/inode.c:159
 evict+0x3c2/0xad0 fs/inode.c:825
 iput_final fs/inode.c:2019 [inline]
 iput.part.0+0x989/0x1050 fs/inode.c:2068
 iput+0x35/0x40 fs/inode.c:2034
 txUpdateMap+0x8bc/0xb00 fs/jfs/jfs_txnmgr.c:2369
 txLazyCommit fs/jfs/jfs_txnmgr.c:2666 [inline]
 jfs_lazycommit+0x5be/0xab0 fs/jfs/jfs_txnmgr.c:2735
 kthread+0x370/0x450 kernel/kthread.c:436
 ret_from_fork+0x72b/0xd50 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>