[v5.15] WARNING: refcount bug in blk_mq_put_rq_ref

[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=16871707980000
kernel config: https://syzkaller.appspot.com/x/.config?x=171882977b524c53
dashboard link: https://syzkaller.appspot.com/bug?extid=2c26b3bd318fbeb5bf0b
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
userspace arch: arm64

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

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/22ee27cb312d/disk-3a592870.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/90bf6a3e3d20/vmlinux-3a592870.xz
kernel image: https://storage.googleapis.com/syzbot-assets/096dd2c73ac3/Image-3a592870.gz.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+2c26b3...@syzkaller.appspotmail.com

WARNING: CPU: 0 PID: 5499 at lib/refcount.c:28 refcount_warn_saturate+0x1c8/0x20c lib/refcount.c:28
Modules linked in:
CPU: 0 PID: 5499 Comm: syz.2.291 Not tainted 5.15.167-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/06/2024
pstate: 60400005 (nZCv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--)
pc : refcount_warn_saturate+0x1c8/0x20c lib/refcount.c:28
lr : refcount_warn_saturate+0x1c8/0x20c lib/refcount.c:28
sp : ffff800020c47740
x29: ffff800020c47740 x28: ffff800020c479e0 x27: 0000000000000002
x26: 1ffff00004188f3f x25: dfff800000000000 x24: ffff0000cbe16800
x23: ffff0000cc268800 x22: ffff800020c479f0 x21: 0000000000000003
x20: ffff0000cc2688e8 x19: ffff800016f0c000 x18: 1fffe00036831b8e

x17: 1fffe00036831b8e x16: ffff800011ac23e0 x15: ffff800014b5ef40
x14: 1ffff0000295806a x13: dfff800000000000 x12: 0000000000040000
x11: 000000000003ffff x10: ffff800029003000
x9 : 3099da6abb3a5000
x8 : 3099da6abb3a5000 x7 : 0000000000000000 x6 : 0000000000000000
x5 : 0000000000000080 x4 : 0000000000000000 x3 : ffff80000a987d1c
x2 : ffff0001b418dd10 x1 : 0000000100000000 x0 : 0000000000000026
Call trace:
refcount_warn_saturate+0x1c8/0x20c lib/refcount.c:28
__refcount_sub_and_test include/linux/refcount.h:283 [inline]
__refcount_dec_and_test include/linux/refcount.h:315 [inline]
refcount_dec_and_test include/linux/refcount.h:333 [inline]
blk_mq_put_rq_ref+0xe8/0x11c block/blk-mq.c:925
bt_tags_iter+0x1b0/0x260 block/blk-mq-tag.c:307
__sbitmap_for_each_set include/linux/sbitmap.h:263 [inline]
sbitmap_for_each_set+0x28c/0x4a4 include/linux/sbitmap.h:284
bt_tags_for_each block/blk-mq-tag.c:334 [inline]
__blk_mq_all_tag_iter block/blk-mq-tag.c:345 [inline]
blk_mq_tagset_busy_iter+0x314/0x3f0 block/blk-mq-tag.c:386
nbd_clear_que drivers/block/nbd.c:849 [inline]
nbd_clear_sock drivers/block/nbd.c:1240 [inline]
nbd_clear_sock_ioctl drivers/block/nbd.c:1379 [inline]
__nbd_ioctl drivers/block/nbd.c:1407 [inline]
nbd_ioctl+0x280/0xc2c drivers/block/nbd.c:1467
blkdev_ioctl+0x3d8/0xbd0 block/ioctl.c:604
block_ioctl+0xa8/0x114 block/fops.c:493
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:874 [inline]
__se_sys_ioctl fs/ioctl.c:860 [inline]
__arm64_sys_ioctl+0x14c/0x1c8 fs/ioctl.c:860
__invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:52
el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:142
do_el0_svc+0x58/0x14c arch/arm64/kernel/syscall.c:181
el0_svc+0x7c/0x1f0 arch/arm64/kernel/entry-common.c:608
el0t_64_sync_handler+0x84/0xe4 arch/arm64/kernel/entry-common.c:626
el0t_64_sync+0x1a0/0x1a4 arch/arm64/kernel/entry.S:584
irq event stamp: 128
hardirqs last enabled at (127): [<ffff80000826ad58>] raw_spin_rq_unlock_irq kernel/sched/sched.h:1338 [inline]
hardirqs last enabled at (127): [<ffff80000826ad58>] finish_lock_switch+0xbc/0x1e8 kernel/sched/core.c:4781
hardirqs last disabled at (128): [<ffff800011abda6c>] el1_dbg+0x24/0x80 arch/arm64/kernel/entry-common.c:396
softirqs last enabled at (8): [<ffff8000080308b0>] local_bh_enable+0x10/0x34 include/linux/bottom_half.h:31
softirqs last disabled at (6): [<ffff80000803087c>] local_bh_disable+0x10/0x34 include/linux/bottom_half.h:18
---[ end trace 3601199a55b0affc ]---


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[syzbot]

Auto-closing this bug as obsolete.
Crashes did not happen for a while, no reproducer and no activity.