[syzbot] [block?] UBSAN: shift-out-of-bounds in null_process_zoned_cmd

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: c21bb4193868 Merge tag 'for_linus' of git://git.kernel.org..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=1218ecc6580000
kernel config: https://syzkaller.appspot.com/x/.config?x=4e38b15c29e6a1d9
dashboard link: https://syzkaller.appspot.com/bug?extid=abd6a8dca0f2b7726060
compiler: Debian clang version 22.1.8 (++20260613092233+e80beda6e255-1~exp1~20260613092250.77), Debian LLD 22.1.8

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

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/cf4c0f46390e/disk-c21bb419.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/21802e5d4446/vmlinux-c21bb419.xz
kernel image: https://storage.googleapis.com/syzbot-assets/6c46db810c9d/bzImage-c21bb419.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+abd6a8...@syzkaller.appspotmail.com

------------[ cut here ]------------
UBSAN: shift-out-of-bounds in drivers/block/null_blk/zoned.c:21:14
shift exponent -1 is negative
CPU: 0 UID: 0 PID: 5906 Comm: syz.0.14 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/16/2026
Call Trace:
<TASK>
dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
ubsan_epilogue+0xa/0x30 lib/ubsan.c:233
__ubsan_handle_shift_out_of_bounds+0x36d/0x400 lib/ubsan.c:494
null_zone_no drivers/block/null_blk/zoned.c:21 [inline]
null_process_zoned_cmd+0xf76/0xf80 drivers/block/null_blk/zoned.c:728
null_handle_cmd drivers/block/null_blk/main.c:1455 [inline]
null_queue_rq+0x8bc/0xe70 drivers/block/null_blk/main.c:1703
__blk_mq_issue_directly block/blk-mq.c:2694 [inline]
blk_mq_try_issue_directly+0x3f4/0x880 block/blk-mq.c:2754
blk_mq_submit_bio+0x20c0/0x2a40 block/blk-mq.c:3208
__submit_bio_noacct_mq block/blk-core.c:756 [inline]
submit_bio_noacct_nocheck+0x2f4/0xa40 block/blk-core.c:790
bh_submit fs/buffer.c:1239 [inline]
block_read_full_folio+0x7a6/0x810 fs/buffer.c:2463
filemap_read_folio+0x12c/0x3a0 mm/filemap.c:2510
do_read_cache_folio+0x354/0x590 mm/filemap.c:4140
read_mapping_folio include/linux/pagemap.h:1015 [inline]
read_part_sector+0xb6/0x2b0 block/partitions/core.c:724
adfspart_check_ICS+0xb1/0x960 block/partitions/acorn.c:357
check_partition block/partitions/core.c:143 [inline]
blk_add_partitions block/partitions/core.c:591 [inline]
bdev_disk_changed+0x851/0x17a0 block/partitions/core.c:695
blkdev_get_whole+0x372/0x510 block/bdev.c:751
bdev_open+0x324/0xd70 block/bdev.c:960
bdev_file_open_by_dev+0x1be/0x240 block/bdev.c:1062
disk_scan_partitions+0x1bb/0x2c0 block/genhd.c:387
add_disk_final block/genhd.c:412 [inline]
add_disk_fwnode+0x24b/0x3a0 block/genhd.c:606
add_disk include/linux/blkdev.h:800 [inline]
null_add_dev+0x130b/0x1d70 drivers/block/null_blk/main.c:2052
nullb_device_power_store+0x240/0x380 drivers/block/null_blk/main.c:501
flush_write_buffer fs/configfs/file.c:207 [inline]
configfs_write_iter+0x337/0x430 fs/configfs/file.c:229
new_sync_write fs/read_write.c:595 [inline]
vfs_write+0x612/0xba0 fs/read_write.c:687
ksys_write+0x150/0x270 fs/read_write.c:739
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f444919e0d9
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f444a0ae028 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007f4449425fa0 RCX: 00007f444919e0d9
RDX: 0000000000000002 RSI: 0000200000000700 RDI: 0000000000000004
RBP: 00007f4449235024 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f4449426038 R14: 00007f4449425fa0 R15: 00007ffc895cc1c8
</TASK>
---[ end trace ]---


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