From: syzbot <syzbot+abd6a8dca0f2b7726060@syzkaller.appspotmail.com>
To: axboe@kernel.dk, linux-block@vger.kernel.org,
linux-kernel@vger.kernel.org, syzkaller-bugs@googlegroups.com
Subject: Re: [syzbot] [block?] UBSAN: shift-out-of-bounds in null_process_zoned_cmd
Date: Thu, 13 Aug 2026 05:10:31 -0700 [thread overview]
Message-ID: <6a7db437.bc649fcc.f9e73.014c.GAE@google.com> (raw)
In-Reply-To: <6a74aa44.01d0871a.3a0d52.0028.GAE@google.com>
syzbot has found a reproducer for the following issue on:
HEAD commit: 3d6d817622b0 Merge tag 'scsi-fixes' of git://git.kernel.or..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=1767f479580000
kernel config: https://syzkaller.appspot.com/x/.config?x=c44651ea7dd2f307
dashboard link: https://syzkaller.appspot.com/bug?extid=abd6a8dca0f2b7726060
compiler: gcc (Debian 14.2.0-19) 14.2.0, GNU ld (GNU Binutils for Debian) 2.44
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=16038ac6580000
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+abd6a8dca0f2b7726060@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: 6032 Comm: syz-executor192 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:94 [inline]
dump_stack_lvl+0x100/0x190 lib/dump_stack.c:120
ubsan_epilogue+0xa/0x30 lib/ubsan.c:233
__ubsan_handle_shift_out_of_bounds+0x279/0x2a0 lib/ubsan.c:494
null_zone_no drivers/block/null_blk/zoned.c:21 [inline]
null_process_zoned_cmd.cold+0x17/0x38 drivers/block/null_blk/zoned.c:728
null_handle_cmd drivers/block/null_blk/main.c:1455 [inline]
null_queue_rq+0x664/0xfb0 drivers/block/null_blk/main.c:1703
__blk_mq_issue_directly+0xe2/0x200 block/blk-mq.c:2694
blk_mq_try_issue_directly+0x21b/0x420 block/blk-mq.c:2754
blk_mq_submit_bio+0x21ec/0x3000 block/blk-mq.c:3208
__submit_bio+0x90/0x3d0 block/blk-core.c:673
__submit_bio_noacct_mq block/blk-core.c:756 [inline]
submit_bio_noacct_nocheck+0x549/0xc00 block/blk-core.c:790
submit_bio_noacct+0xd18/0x1ff0 block/blk-core.c:921
blk_crypto_submit_bio include/linux/blk-crypto.h:203 [inline]
__bh_submit+0x721/0x950 fs/buffer.c:1225
bh_submit fs/buffer.c:1239 [inline]
block_read_full_folio+0x496/0x8c0 fs/buffer.c:2463
filemap_read_folio+0xfc/0x3b0 mm/filemap.c:2516
do_read_cache_folio+0x2d7/0x6b0 mm/filemap.c:4146
read_mapping_folio include/linux/pagemap.h:1015 [inline]
read_part_sector+0xd1/0x370 block/partitions/core.c:724
adfspart_check_ICS+0x91/0x7d0 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+0x7b1/0x1260 block/partitions/core.c:695
blkdev_get_whole+0x187/0x290 block/bdev.c:751
bdev_open+0x2c7/0xe40 block/bdev.c:960
bdev_file_open_by_dev block/bdev.c:1062 [inline]
bdev_file_open_by_dev+0x179/0x210 block/bdev.c:1037
disk_scan_partitions+0x1ef/0x320 block/genhd.c:387
add_disk_final block/genhd.c:412 [inline]
add_disk_fwnode+0x3f4/0x480 block/genhd.c:606
add_disk include/linux/blkdev.h:800 [inline]
null_add_dev+0x129d/0x1df0 drivers/block/null_blk/main.c:2052
nullb_device_power_store+0x29d/0x350 drivers/block/null_blk/main.c:501
flush_write_buffer fs/configfs/file.c:207 [inline]
configfs_write_iter+0x302/0x4e0 fs/configfs/file.c:229
new_sync_write fs/read_write.c:595 [inline]
vfs_write+0x6ac/0x1050 fs/read_write.c:687
ksys_write+0x12a/0x250 fs/read_write.c:739
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x115/0x870 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fc39344769e
Code: 08 0f 85 f5 e2 ff ff 49 89 fb 48 89 f0 48 89 d7 48 89 ce 4c 89 c2 4d 89 ca 4c 8b 44 24 08 4c 8b 4c 24 10 4c 89 5c 24 08 0f 05 <c3> 90 41 57 41 56 4d 89 c6 41 55 4d 89 cd 41 54 55 53 48 83 ec 08
RSP: 002b:00007fc3933ea128 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007fc3933ea6c0 RCX: 00007fc39344769e
RDX: 0000000000000002 RSI: 00007fc39348c03a RDI: 0000000000000003
RBP: 0000000000000021 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: ffffffffffffffd0
R13: 0000000000000011 R14: 00007ffcdf31cc10 R15: 00007ffcdf31ccf8
</TASK>
---[ end trace ]---
---
If you want syzbot to run the reproducer, reply with:
#syz test: git://repo/address.git branch-or-commit-hash
If you attach or paste a git patch, syzbot will apply it before testing.
prev parent reply other threads:[~2026-08-13 12:10 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-08-06 15:37 [syzbot] [block?] UBSAN: shift-out-of-bounds in null_process_zoned_cmd syzbot
2026-08-13 12:10 ` syzbot [this message]
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