Re: [syzbot] KASAN: use-after-free Read in dbJoin

[syzbot]

syzbot has found a reproducer for the following issue on:

HEAD commit:    b208b9fbbcba Merge tag 'arm64-fixes' of git://git.kernel.o..
git tree:       upstream
console+strace: https://syzkaller.appspot.com/x/log.txt?x=162c2866880000
kernel config:  https://syzkaller.appspot.com/x/.config?x=f7e100ed8aaa828e
dashboard link: https://syzkaller.appspot.com/bug?extid=667a6d667592227b1452
compiler:       Debian clang version 13.0.1-++20220126092033+75e33f71c2da-1~exp1~20220126212112.63, GNU ld (GNU Binutils for Debian) 2.35.2
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=12f7ffb1880000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=17f9a066880000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/92fde6d92d82/disk-b208b9fb.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/ae3dbdb3faf8/vmlinux-b208b9fb.xz
kernel image: https://storage.googleapis.com/syzbot-assets/bbf4da09683c/bzImage-b208b9fb.xz
mounted in repro: https://storage.googleapis.com/syzbot-assets/69e8cbb81983/mount_0.gz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+667a6d667592227b1452@xxxxxxxxxxxxxxxxxxxxxxxxx

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UBSAN: array-index-out-of-bounds in fs/jfs/jfs_dmap.c:2745:24
index 1426063360 is out of range for type 's8 [1365]'
CPU: 0 PID: 122 Comm: jfsCommit Not tainted 6.1.0-rc3-syzkaller-00288-gb208b9fbbcba #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/26/2022
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x1b1/0x28e lib/dump_stack.c:106
 ubsan_epilogue lib/ubsan.c:151 [inline]
 __ubsan_handle_out_of_bounds+0xdb/0x130 lib/ubsan.c:283
 dbJoin+0x2c7/0x2f0 fs/jfs/jfs_dmap.c:2745
 dbFreeBits+0x50d/0xd40 fs/jfs/jfs_dmap.c:2305
 dbFreeDmap fs/jfs/jfs_dmap.c:2054 [inline]
 dbFree+0x35e/0x660 fs/jfs/jfs_dmap.c:379
 txFreeMap+0x97c/0xd70 fs/jfs/jfs_txnmgr.c:2510
 xtTruncate+0xe74/0x32d0 fs/jfs/jfs_xtree.c:2467
 jfs_free_zero_link+0x3f5/0x680 fs/jfs/namei.c:758
 jfs_evict_inode+0x35a/0x440 fs/jfs/inode.c:153
 evict+0x2a4/0x620 fs/inode.c:664
 txUpdateMap+0x8eb/0xaa0 fs/jfs/jfs_txnmgr.c:2362
 txLazyCommit fs/jfs/jfs_txnmgr.c:2659 [inline]
 jfs_lazycommit+0x488/0xb80 fs/jfs/jfs_txnmgr.c:2727
 kthread+0x266/0x300 kernel/kthread.c:376
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:306
 </TASK>
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