[v5.15] WARNING: refcount bug in blk_mq_dispatch_rq_list (2)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 3a5928702e71 Linux 5.15.167
git tree: linux-5.15.y
console output: https://syzkaller.appspot.com/x/log.txt?x=10664427980000
kernel config: https://syzkaller.appspot.com/x/.config?x=4d3fd5cca89ae935
dashboard link: https://syzkaller.appspot.com/bug?extid=4e6abb14fef0fca71895
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40

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

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/ef5025f3d708/disk-3a592870.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/776fbdad3aa8/vmlinux-3a592870.xz
kernel image: https://storage.googleapis.com/syzbot-assets/79541db5bd16/bzImage-3a592870.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+4e6abb...@syzkaller.appspotmail.com

blk_update_request: I/O error, dev nbd3, sector 0 op 0x0:(READ) flags 0x0 phys_seg 1 prio class 0
Buffer I/O error on dev nbd3, logical block 0, async page read
------------[ cut here ]------------
refcount_t: underflow; use-after-free.
WARNING: CPU: 1 PID: 150 at lib/refcount.c:28 refcount_warn_saturate+0x14e/0x1a0 lib/refcount.c:28
Modules linked in:
CPU: 1 PID: 150 Comm: kworker/1:1H Not tainted 5.15.167-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/06/2024
Workqueue: kblockd blk_mq_run_work_fn
RIP: 0010:refcount_warn_saturate+0x14e/0x1a0 lib/refcount.c:28
Code: 09 01 48 c7 c7 a0 c7 d8 8a e8 ee 9e 42 fd 0f 0b eb 8d e8 05 f5 76 fd c6 05 8e 63 cc 09 01 48 c7 c7 00 c8 d8 8a e8 d2 9e 42 fd <0f> 0b e9 6e ff ff ff e8 e6 f4 76 fd c6 05 70 63 cc 09 01 48 c7 c7
RSP: 0018:ffffc900018af7a8 EFLAGS: 00010246
RAX: 8d550dcc14d7a100 RBX: 0000000000000003 RCX: ffff88801d101dc0
RDX: 0000000000000000 RSI: 0000000080000000 RDI: 0000000000000000
RBP: 0000000000000003 R08: ffffffff81668a3c R09: fffff52000315e35
R10: 0000000000000000 R11: dffffc0000000001 R12: ffff888020a18000
R13: dffffc0000000000 R14: ffffc900018afa40 R15: ffff888020b00200
FS: 0000000000000000(0000) GS:ffff8880b9100000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000020404030 CR3: 000000002263b000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<TASK>
blk_mq_end_request block/blk-mq.c:577 [inline]
blk_mq_dispatch_rq_list+0xc47/0x1f30 block/blk-mq.c:1408
__blk_mq_do_dispatch_sched block/blk-mq-sched.c:200 [inline]
blk_mq_do_dispatch_sched+0x755/0xd50 block/blk-mq-sched.c:214
__blk_mq_sched_dispatch_requests+0x39b/0x490
blk_mq_sched_dispatch_requests+0xec/0x160 block/blk-mq-sched.c:366
__blk_mq_run_hw_queue+0x11a/0x1b0 block/blk-mq.c:1511
process_one_work+0x8a1/0x10c0 kernel/workqueue.c:2310
worker_thread+0xaca/0x1280 kernel/workqueue.c:2457
kthread+0x3f6/0x4f0 kernel/kthread.c:334
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
</TASK>


---
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[syzbot]

syzbot has found a reproducer for the following issue on:

HEAD commit: 3a5928702e71 Linux 5.15.167
git tree: linux-5.15.y

console output: https://syzkaller.appspot.com/x/log.txt?x=13643177980000

kernel config: https://syzkaller.appspot.com/x/.config?x=4d3fd5cca89ae935
dashboard link: https://syzkaller.appspot.com/bug?extid=4e6abb14fef0fca71895
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40

syz repro: https://syzkaller.appspot.com/x/repro.syz?x=13ce4427980000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=176da607980000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/ef5025f3d708/disk-3a592870.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/776fbdad3aa8/vmlinux-3a592870.xz
kernel image: https://storage.googleapis.com/syzbot-assets/79541db5bd16/bzImage-3a592870.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+4e6abb...@syzkaller.appspotmail.com

Buffer I/O error on dev nbd3, logical block 0, async page read
------------[ cut here ]------------
refcount_t: underflow; use-after-free.

WARNING: CPU: 0 PID: 1059 at lib/refcount.c:28 refcount_warn_saturate+0x14e/0x1a0 lib/refcount.c:28
Modules linked in:
CPU: 0 PID: 1059 Comm: kworker/0:1H Not tainted 5.15.167-syzkaller #0

Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/06/2024
Workqueue: kblockd blk_mq_run_work_fn
RIP: 0010:refcount_warn_saturate+0x14e/0x1a0 lib/refcount.c:28
Code: 09 01 48 c7 c7 a0 c7 d8 8a e8 ee 9e 42 fd 0f 0b eb 8d e8 05 f5 76 fd c6 05 8e 63 cc 09 01 48 c7 c7 00 c8 d8 8a e8 d2 9e 42 fd <0f> 0b e9 6e ff ff ff e8 e6 f4 76 fd c6 05 70 63 cc 09 01 48 c7 c7

RSP: 0018:ffffc900049877a8 EFLAGS: 00010246
RAX: e6214663b8d8f600 RBX: 0000000000000003 RCX: ffff8880216b8000

RDX: 0000000000000000 RSI: 0000000080000000 RDI: 0000000000000000

RBP: 0000000000000003 R08: ffffffff81668a3c R09: fffffbfff20e2424
R10: 0000000000000000 R11: dffffc0000000001 R12: ffff888020d29000
R13: dffffc0000000000 R14: ffffc90004987a40 R15: ffff888020e88200
FS: 0000000000000000(0000) GS:ffff8880b9000000(0000) knlGS:0000000000000000

CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033

CR2: 00007f14e4f72d58 CR3: 000000002174f000 CR4: 00000000003506f0

DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<TASK>
blk_mq_end_request block/blk-mq.c:577 [inline]
blk_mq_dispatch_rq_list+0xc47/0x1f30 block/blk-mq.c:1408
__blk_mq_do_dispatch_sched block/blk-mq-sched.c:200 [inline]
blk_mq_do_dispatch_sched+0x755/0xd50 block/blk-mq-sched.c:214
__blk_mq_sched_dispatch_requests+0x39b/0x490
blk_mq_sched_dispatch_requests+0xec/0x160 block/blk-mq-sched.c:366
__blk_mq_run_hw_queue+0x11a/0x1b0 block/blk-mq.c:1511
process_one_work+0x8a1/0x10c0 kernel/workqueue.c:2310
worker_thread+0xaca/0x1280 kernel/workqueue.c:2457
kthread+0x3f6/0x4f0 kernel/kthread.c:334
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
</TASK>


---

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