[v6.1] WARNING in dbSplit

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: e4f7d8be268e Linux 6.1.182
git tree: linux-6.1.y
console output: https://syzkaller.appspot.com/x/log.txt?x=116a1079580000
kernel config: https://syzkaller.appspot.com/x/.config?x=872c04466179833f
dashboard link: https://syzkaller.appspot.com/bug?extid=5b94d1864e08792c9126
compiler: Debian clang version 22.1.8 (++20260613092233+e80beda6e255-1~exp1~20260613092250.77), Debian LLD 22.1.8
userspace arch: arm64

Unfortunately, I don't have any reproducer for this issue yet.

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/7cd9b1875376/disk-e4f7d8be.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/4b5d35d18c31/vmlinux-e4f7d8be.xz
kernel image: https://storage.googleapis.com/syzbot-assets/d5ee64c2af77/Image-e4f7d8be.gz.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+5b94d1...@syzkaller.appspotmail.com

------------[ cut here ]------------
WARNING: CPU: 0 PID: 11252 at fs/jfs/jfs_dmap.c:2875 dbAdjTree fs/jfs/jfs_dmap.c:2875 [inline]
WARNING: CPU: 0 PID: 11252 at fs/jfs/jfs_dmap.c:2875 dbSplit+0x45c/0x86c fs/jfs/jfs_dmap.c:2648
Modules linked in:
CPU: 0 PID: 11252 Comm: syz.4.2035 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/02/2026
pstate: 82400005 (Nzcv daif +PAN -UAO +TCO -DIT -SSBS BTYPE=--)
pc : dbAdjTree fs/jfs/jfs_dmap.c:2875 [inline]
pc : dbSplit+0x45c/0x86c fs/jfs/jfs_dmap.c:2648
lr : dbAdjTree fs/jfs/jfs_dmap.c:2875 [inline]
lr : dbSplit+0x45c/0x86c fs/jfs/jfs_dmap.c:2648
sp : ffff8000211371d0
x29: ffff800021137220 x28: 0000000000002057 x27: ffff0000ced1b018
x26: 0000000000000005 x25: dfff800000000000 x24: dfff800000000000
x23: ffff0000ced1b010 x22: 000000000000000d x21: 0000000000000155
x20: ffff0000ced1b021 x19: 0000000000002000 x18: 1fffe00033e7277e
x17: ffff80001537d000 x16: ffff8000082dbd3c x15: 0000000000000002
x14: 0000000000000001 x13: 1fffff80006768d8 x12: 0000000000080000
x11: 000000000002167d x10: ffff80002c959000 x9 : ffff8000098c9b74
x8 : 000000000002167e x7 : ffff8000086fdd10 x6 : 0000000000000000
x5 : 0000000000000000 x4 : 0000000000000000 x3 : 0000000000000004
x2 : 0000000000000005 x1 : 0000000000000155 x0 : 0000000000002057

Call trace:
dbAdjTree fs/jfs/jfs_dmap.c:2875 [inline]
dbSplit+0x45c/0x86c fs/jfs/jfs_dmap.c:2648
dbAllocBits+0x410/0x888 fs/jfs/jfs_dmap.c:2193
dbAllocDmap+0x6c/0x128 fs/jfs/jfs_dmap.c:2034
dbAllocNext+0x37c/0x3bc fs/jfs/jfs_dmap.c:1171
dbAlloc+0x320/0x9dc fs/jfs/jfs_dmap.c:805
extBalloc fs/jfs/jfs_extent.c:326 [inline]
extAlloc+0x400/0xda0 fs/jfs/jfs_extent.c:122
jfs_get_block+0x2cc/0x8cc fs/jfs/inode.c:254
__block_write_begin_int+0x3d8/0x13c0 fs/buffer.c:1991
__block_write_begin fs/buffer.c:2041 [inline]
block_write_begin+0x98/0x11c fs/buffer.c:2102
jfs_write_begin+0x44/0x88 fs/jfs/inode.c:310
generic_perform_write+0x240/0x508 mm/filemap.c:3862
__generic_file_write_iter+0x130/0x250 mm/filemap.c:3960
generic_file_write_iter+0xb4/0x2b0 mm/filemap.c:3989
call_write_iter include/linux/fs.h:2265 [inline]
new_sync_write fs/read_write.c:491 [inline]
vfs_write+0x3c8/0x7c8 fs/read_write.c:584
ksys_write+0x12c/0x228 fs/read_write.c:637
__do_sys_write fs/read_write.c:649 [inline]
__se_sys_write fs/read_write.c:646 [inline]
__arm64_sys_write+0x7c/0x90 fs/read_write.c:646
__invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
invoke_syscall+0x98/0x290 arch/arm64/kernel/syscall.c:52
el0_svc_common+0x13c/0x258 arch/arm64/kernel/syscall.c:140
do_el0_svc+0x5c/0x134 arch/arm64/kernel/syscall.c:204
el0_svc+0x58/0x128 arch/arm64/kernel/entry-common.c:637
el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655
el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:585
irq event stamp: 74436
hardirqs last enabled at (74435): [<ffff8000089473ac>] mod_objcg_state+0x32c/0x4f0 mm/memcontrol.c:3217
hardirqs last disabled at (74436): [<ffff800011b8c2bc>] el1_dbg+0x24/0x80 arch/arm64/kernel/entry-common.c:405
softirqs last enabled at (74012): [<ffff800008031254>] local_bh_enable+0x10/0x34 include/linux/bottom_half.h:32
softirqs last disabled at (74010): [<ffff800008031220>] local_bh_disable+0x10/0x34 include/linux/bottom_half.h:19
---[ end trace 0000000000000000 ]---


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[syzbot]

syzbot has found a reproducer for the following issue on:

HEAD commit: e4f7d8be268e Linux 6.1.182
git tree: linux-6.1.y

console output: https://syzkaller.appspot.com/x/log.txt?x=154712c6580000

kernel config: https://syzkaller.appspot.com/x/.config?x=872c04466179833f
dashboard link: https://syzkaller.appspot.com/bug?extid=5b94d1864e08792c9126
compiler: Debian clang version 22.1.8 (++20260613092233+e80beda6e255-1~exp1~20260613092250.77), Debian LLD 22.1.8
userspace arch: arm64

syz repro: https://syzkaller.appspot.com/x/repro.syz?x=10382a9e580000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=155e6149580000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/7cd9b1875376/disk-e4f7d8be.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/4b5d35d18c31/vmlinux-e4f7d8be.xz
kernel image: https://storage.googleapis.com/syzbot-assets/d5ee64c2af77/Image-e4f7d8be.gz.xz

mounted in repro: https://storage.googleapis.com/syzbot-assets/7b017c7d8424/mount_0.gz
fsck result: failed (log: https://syzkaller.appspot.com/x/fsck.log?x=141e3132580000)

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+5b94d1...@syzkaller.appspotmail.com

loop0: detected capacity change from 0 to 32768
------------[ cut here ]------------
WARNING: CPU: 1 PID: 4519 at fs/jfs/jfs_dmap.c:2875 dbAdjTree fs/jfs/jfs_dmap.c:2875 [inline]
WARNING: CPU: 1 PID: 4519 at fs/jfs/jfs_dmap.c:2875 dbSplit+0x45c/0x86c fs/jfs/jfs_dmap.c:2648
Modules linked in:
CPU: 1 PID: 4519 Comm: syz.0.17 Not tainted syzkaller #0

Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/02/2026
pstate: 82400005 (Nzcv daif +PAN -UAO +TCO -DIT -SSBS BTYPE=--)
pc : dbAdjTree fs/jfs/jfs_dmap.c:2875 [inline]
pc : dbSplit+0x45c/0x86c fs/jfs/jfs_dmap.c:2648
lr : dbAdjTree fs/jfs/jfs_dmap.c:2875 [inline]
lr : dbSplit+0x45c/0x86c fs/jfs/jfs_dmap.c:2648

sp : ffff8000214a71d0
x29: ffff8000214a7220 x28: 0000000000002057 x27: ffff0000d4bd0018

x26: 0000000000000005 x25: dfff800000000000 x24: dfff800000000000

x23: ffff0000d4bd0010 x22: 000000000000000d x21: 0000000000000155
x20: ffff0000d4bd0021 x19: 0000000000002000 x18: 1fffe00033e7697e
x17: ffff80001537d000 x16: ffff8000082dbd3c x15: 0000000000000000
x14: 0000000000000001 x13: 1fffff80006a5e80 x12: ffff0000d4bd001c
x11: ff008000098c9b74 x10: 0000000000000000 x9 : ffff8000098c9b74
x8 : ffff0000d39f5400 x7 : ffff8000086fdd10 x6 : 0000000000000000

irq event stamp: 74608
hardirqs last enabled at (74607): [<ffff8000089473ac>] mod_objcg_state+0x32c/0x4f0 mm/memcontrol.c:3217
hardirqs last disabled at (74608): [<ffff800011b8c2bc>] el1_dbg+0x24/0x80 arch/arm64/kernel/entry-common.c:405
softirqs last enabled at (74080): [<ffff8000081ae3bc>] softirq_handle_end kernel/softirq.c:439 [inline]
softirqs last enabled at (74080): [<ffff8000081ae3bc>] handle_softirqs+0xb1c/0xc90 kernel/softirq.c:624
softirqs last disabled at (74071): [<ffff800008020e6c>] __do_softirq+0x14/0x20 kernel/softirq.c:630

---[ end trace 0000000000000000 ]---


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