WARNING in dbSplit

Status: upstream: reported C repro on 2026/08/11 10:17
Reported-by: syzbot+5b94d1864e08792c9126@syzkaller.appspotmail.com
First crash: 10d, last: 10d

Sample crash report:
loop0: detected capacity change from 0 to 32768
------------[ cut here ]------------
WARNING: CPU: 0 PID: 4441 at fs/jfs/jfs_dmap.c:2875 dbAdjTree fs/jfs/jfs_dmap.c:2875 [inline]
WARNING: CPU: 0 PID: 4441 at fs/jfs/jfs_dmap.c:2875 dbSplit+0x45c/0x86c fs/jfs/jfs_dmap.c:2648
Modules linked in:
CPU: 0 PID: 4441 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: ffff0000d211e018
x26: 0000000000000005 x25: dfff800000000000 x24: dfff800000000000
x23: ffff0000d211e010 x22: 000000000000000d x21: 0000000000000155
x20: ffff0000d211e021 x19: 0000000000002000 x18: 1fffe00033e7277e
x17: ffff80001537d000 x16: ffff8000082dbd3c x15: 0000000000000000
x14: 0000000000000001 x13: 1fffff80006908f0 x12: ffff0000d211e01c
x11: ff008000098c9b74 x10: 0000000000000000 x9 : ffff8000098c9b74
x8 : ffff0000d3999c00 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: 74074
hardirqs last  enabled at (74073): [<ffff8000089473ac>] mod_objcg_state+0x32c/0x4f0 mm/memcontrol.c:3217
hardirqs last disabled at (74074): [<ffff800011b8c2bc>] el1_dbg+0x24/0x80 arch/arm64/kernel/entry-common.c:405
softirqs last  enabled at (73456): [<ffff800008031254>] local_bh_enable+0x10/0x34 include/linux/bottom_half.h:32
softirqs last disabled at (73454): [<ffff800008031220>] local_bh_disable+0x10/0x34 include/linux/bottom_half.h:19
---[ end trace 0000000000000000 ]---

Crashes (4):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/08/11 12:22 linux-6.1.y e4f7d8be268e 508909ea .config console log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro (corrupt fs)] ci2-linux-6-1-kasan-arm64 WARNING in dbSplit
2026/08/11 11:42 linux-6.1.y e4f7d8be268e 508909ea .config console log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro (corrupt fs)] ci2-linux-6-1-kasan-arm64 WARNING in dbSplit
2026/08/11 10:59 linux-6.1.y e4f7d8be268e 508909ea .config console log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro (corrupt fs)] ci2-linux-6-1-kasan-arm64 WARNING in dbSplit
2026/08/11 10:17 linux-6.1.y e4f7d8be268e 508909ea .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 WARNING in dbSplit
* Struck through repros no longer work on HEAD.