[syzbot] [block?] possible deadlock in bioset_exit
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syzbot
Apr 24, 2026, 10:12:45 PM (20 hours ago) Apr 24
to ax...@kernel.dk, linux...@vger.kernel.org, linux-...@vger.kernel.org, syzkall...@googlegroups.com
Hello,
syzbot found the following issue on:
HEAD commit: dd6c438c3e64 Merge tag 'vfs-7.1-rc1.fixes' of git://git.ke..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=14efc2ce580000
kernel config: https://syzkaller.appspot.com/x/.config?x=6d74203cd0463a9f
dashboard link: https://syzkaller.appspot.com/bug?extid=02b4e6eb8b1460d955a5
compiler: gcc (Debian 14.2.0-19) 14.2.0, GNU ld (GNU Binutils for Debian) 2.44
Unfortunately, I don't have any reproducer for this issue yet.
Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/8bebdd77187b/disk-dd6c438c.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/2527d5942bbb/vmlinux-dd6c438c.xz
kernel image: https://storage.googleapis.com/syzbot-assets/d446b541e2e0/bzImage-dd6c438c.xz
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+02b4e6...@syzkaller.appspotmail.com
ubi31: attaching mtd0
======================================================
WARNING: possible circular locking dependency detected
syzkaller #0 Tainted: G L
------------------------------------------------------
syz.7.5359/28440 is trying to acquire lock:
ffffffff8e9b1780 (fs_reclaim){+.+.}-{0:0}, at: might_alloc include/linux/sched/mm.h:317 [inline]
ffffffff8e9b1780 (fs_reclaim){+.+.}-{0:0}, at: slab_pre_alloc_hook mm/slub.c:4520 [inline]
ffffffff8e9b1780 (fs_reclaim){+.+.}-{0:0}, at: slab_alloc_node mm/slub.c:4875 [inline]
ffffffff8e9b1780 (fs_reclaim){+.+.}-{0:0}, at: kmem_cache_alloc_noprof+0x4c/0x6e0 mm/slub.c:4905
but task is already holding lock:
ffffffff8e97f100 (slab_mutex){+.+.}-{4:4}, at: __kmem_cache_create_args+0x44/0x420 mm/slab_common.c:350
which lock already depends on the new lock.
the existing dependency chain (in reverse order) is:
-> #7 (slab_mutex){+.+.}-{4:4}:
__mutex_lock_common kernel/locking/mutex.c:632 [inline]
__mutex_lock+0x1a4/0x1b10 kernel/locking/mutex.c:806
kmem_cache_destroy mm/slab_common.c:557 [inline]
kmem_cache_destroy+0x59/0x180 mm/slab_common.c:527
bio_put_slab block/bio.c:163 [inline]
bioset_exit+0x3b1/0x520 block/bio.c:1907
mddev_destroy drivers/md/md.c:819 [inline]
mddev_free drivers/md/md.c:911 [inline]
md_free_disk+0x18e/0x210 drivers/md/md.c:8578
disk_release+0x2b2/0x430 block/genhd.c:1311
device_release+0xd2/0x270 drivers/base/core.c:2566
kobject_cleanup lib/kobject.c:689 [inline]
kobject_release lib/kobject.c:720 [inline]
kref_put include/linux/kref.h:65 [inline]
kobject_put+0x1f7/0x640 lib/kobject.c:737
process_one_work+0xa0e/0x1980 kernel/workqueue.c:3302
process_scheduled_works kernel/workqueue.c:3385 [inline]
worker_thread+0x5ef/0xe50 kernel/workqueue.c:3466
kthread+0x370/0x450 kernel/kthread.c:436
ret_from_fork+0x72b/0xd50 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
-> #6 (cpu_hotplug_lock){++++}-{0:0}:
percpu_down_read_internal include/linux/percpu-rwsem.h:53 [inline]
percpu_down_read include/linux/percpu-rwsem.h:77 [inline]
cpus_read_lock+0x42/0x170 kernel/cpu.c:490
static_key_slow_inc+0x12/0x30 kernel/jump_label.c:190
nbd_reconnect_socket drivers/block/nbd.c:1342 [inline]
nbd_genl_reconfigure+0xd82/0x1a00 drivers/block/nbd.c:2431
genl_family_rcv_msg_doit+0x214/0x300 net/netlink/genetlink.c:1114
genl_family_rcv_msg net/netlink/genetlink.c:1194 [inline]
genl_rcv_msg+0x560/0x800 net/netlink/genetlink.c:1209
netlink_rcv_skb+0x159/0x420 net/netlink/af_netlink.c:2550
genl_rcv+0x28/0x40 net/netlink/genetlink.c:1218
netlink_unicast_kernel net/netlink/af_netlink.c:1318 [inline]
netlink_unicast+0x585/0x850 net/netlink/af_netlink.c:1344
netlink_sendmsg+0x8b0/0xda0 net/netlink/af_netlink.c:1894
sock_sendmsg_nosec net/socket.c:787 [inline]
__sock_sendmsg net/socket.c:802 [inline]
____sys_sendmsg+0x9e1/0xb70 net/socket.c:2698
___sys_sendmsg+0x190/0x1e0 net/socket.c:2752
__sys_sendmsg+0x170/0x220 net/socket.c:2784
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x10b/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
-> #5 (&nsock->tx_lock){+.+.}-{4:4}:
__mutex_lock_common kernel/locking/mutex.c:632 [inline]
__mutex_lock+0x1a4/0x1b10 kernel/locking/mutex.c:806
nbd_handle_cmd drivers/block/nbd.c:1143 [inline]
nbd_queue_rq+0x428/0x1080 drivers/block/nbd.c:1207
blk_mq_dispatch_rq_list+0x422/0x1e70 block/blk-mq.c:2148
__blk_mq_do_dispatch_sched block/blk-mq-sched.c:168 [inline]
blk_mq_do_dispatch_sched block/blk-mq-sched.c:182 [inline]
__blk_mq_sched_dispatch_requests+0xcea/0x1620 block/blk-mq-sched.c:307
blk_mq_sched_dispatch_requests+0xd7/0x1c0 block/blk-mq-sched.c:329
blk_mq_run_hw_queue+0x23c/0x670 block/blk-mq.c:2386
blk_mq_dispatch_list+0x51d/0x1360 block/blk-mq.c:2949
blk_mq_flush_plug_list block/blk-mq.c:2997 [inline]
blk_mq_flush_plug_list+0x130/0x600 block/blk-mq.c:2969
__blk_flush_plug+0x2c4/0x4b0 block/blk-core.c:1230
blk_finish_plug block/blk-core.c:1257 [inline]
__submit_bio+0x584/0x6c0 block/blk-core.c:649
__submit_bio_noacct_mq block/blk-core.c:722 [inline]
submit_bio_noacct_nocheck+0x543/0xbf0 block/blk-core.c:753
submit_bio_noacct+0xd18/0x2000 block/blk-core.c:884
blk_crypto_submit_bio include/linux/blk-crypto.h:203 [inline]
submit_bh_wbc+0x681/0x890 fs/buffer.c:2737
submit_bh fs/buffer.c:2742 [inline]
block_read_full_folio+0x4c8/0x8e0 fs/buffer.c:2358
filemap_read_folio+0xfc/0x3b0 mm/filemap.c:2502
do_read_cache_folio+0x2d7/0x6b0 mm/filemap.c:4107
read_mapping_folio include/linux/pagemap.h:1017 [inline]
read_part_sector+0xd1/0x370 block/partitions/core.c:724
adfspart_check_ICS+0x91/0x7d0 block/partitions/acorn.c:356
check_partition block/partitions/core.c:143 [inline]
blk_add_partitions block/partitions/core.c:591 [inline]
bdev_disk_changed+0x7a3/0x1250 block/partitions/core.c:695
blkdev_get_whole+0x187/0x290 block/bdev.c:756
bdev_open+0x2c7/0xe40 block/bdev.c:965
blkdev_open+0x34e/0x4f0 block/fops.c:697
do_dentry_open+0x6d8/0x1660 fs/open.c:947
vfs_open+0x82/0x3f0 fs/open.c:1079
do_open fs/namei.c:4699 [inline]
path_openat+0x208c/0x31a0 fs/namei.c:4858
do_file_open+0x20e/0x430 fs/namei.c:4887
do_sys_openat2+0x10d/0x1e0 fs/open.c:1364
do_sys_open fs/open.c:1370 [inline]
__do_sys_openat fs/open.c:1386 [inline]
__se_sys_openat fs/open.c:1381 [inline]
__x64_sys_openat+0x12d/0x210 fs/open.c:1381
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x10b/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
-> #4 (&cmd->lock){+.+.}-{4:4}:
__mutex_lock_common kernel/locking/mutex.c:632 [inline]
__mutex_lock+0x1a4/0x1b10 kernel/locking/mutex.c:806
nbd_queue_rq+0xba/0x1080 drivers/block/nbd.c:1199
blk_mq_dispatch_rq_list+0x422/0x1e70 block/blk-mq.c:2148
__blk_mq_do_dispatch_sched block/blk-mq-sched.c:168 [inline]
blk_mq_do_dispatch_sched block/blk-mq-sched.c:182 [inline]
__blk_mq_sched_dispatch_requests+0xcea/0x1620 block/blk-mq-sched.c:307
blk_mq_sched_dispatch_requests+0xd7/0x1c0 block/blk-mq-sched.c:329
blk_mq_run_hw_queue+0x23c/0x670 block/blk-mq.c:2386
blk_mq_dispatch_list+0x51d/0x1360 block/blk-mq.c:2949
blk_mq_flush_plug_list block/blk-mq.c:2997 [inline]
blk_mq_flush_plug_list+0x130/0x600 block/blk-mq.c:2969
__blk_flush_plug+0x2c4/0x4b0 block/blk-core.c:1230
blk_finish_plug block/blk-core.c:1257 [inline]
__submit_bio+0x584/0x6c0 block/blk-core.c:649
__submit_bio_noacct_mq block/blk-core.c:722 [inline]
submit_bio_noacct_nocheck+0x543/0xbf0 block/blk-core.c:753
submit_bio_noacct+0xd18/0x2000 block/blk-core.c:884
blk_crypto_submit_bio include/linux/blk-crypto.h:203 [inline]
submit_bh_wbc+0x681/0x890 fs/buffer.c:2737
submit_bh fs/buffer.c:2742 [inline]
block_read_full_folio+0x4c8/0x8e0 fs/buffer.c:2358
filemap_read_folio+0xfc/0x3b0 mm/filemap.c:2502
do_read_cache_folio+0x2d7/0x6b0 mm/filemap.c:4107
read_mapping_folio include/linux/pagemap.h:1017 [inline]
read_part_sector+0xd1/0x370 block/partitions/core.c:724
adfspart_check_ICS+0x91/0x7d0 block/partitions/acorn.c:356
check_partition block/partitions/core.c:143 [inline]
blk_add_partitions block/partitions/core.c:591 [inline]
bdev_disk_changed+0x7a3/0x1250 block/partitions/core.c:695
blkdev_get_whole+0x187/0x290 block/bdev.c:756
bdev_open+0x2c7/0xe40 block/bdev.c:965
blkdev_open+0x34e/0x4f0 block/fops.c:697
do_dentry_open+0x6d8/0x1660 fs/open.c:947
vfs_open+0x82/0x3f0 fs/open.c:1079
do_open fs/namei.c:4699 [inline]
path_openat+0x208c/0x31a0 fs/namei.c:4858
do_file_open+0x20e/0x430 fs/namei.c:4887
do_sys_openat2+0x10d/0x1e0 fs/open.c:1364
do_sys_open fs/open.c:1370 [inline]
__do_sys_openat fs/open.c:1386 [inline]
__se_sys_openat fs/open.c:1381 [inline]
__x64_sys_openat+0x12d/0x210 fs/open.c:1381
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x10b/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
-> #3 (set->srcu){.+.+}-{0:0}:
srcu_lock_sync include/linux/srcu.h:199 [inline]
__synchronize_srcu+0xa2/0x300 kernel/rcu/srcutree.c:1481
blk_mq_wait_quiesce_done block/blk-mq.c:284 [inline]
blk_mq_wait_quiesce_done block/blk-mq.c:281 [inline]
blk_mq_quiesce_queue block/blk-mq.c:304 [inline]
blk_mq_quiesce_queue+0x149/0x1c0 block/blk-mq.c:299
elevator_switch+0x17b/0x7e0 block/elevator.c:576
elevator_change+0x352/0x530 block/elevator.c:681
elevator_set_default+0x29e/0x360 block/elevator.c:754
blk_register_queue+0x48e/0x630 block/blk-sysfs.c:987
__add_disk+0x73f/0xe40 block/genhd.c:528
add_disk_fwnode+0x118/0x5c0 block/genhd.c:597
add_disk include/linux/blkdev.h:794 [inline]
nbd_dev_add+0x77a/0xb10 drivers/block/nbd.c:1984
nbd_init+0x291/0x2b0 drivers/block/nbd.c:2692
do_one_initcall+0x121/0x750 init/main.c:1392
do_initcall_level init/main.c:1454 [inline]
do_initcalls init/main.c:1470 [inline]
do_basic_setup init/main.c:1490 [inline]
kernel_init_freeable+0x6ea/0x7b0 init/main.c:1703
kernel_init+0x1f/0x1e0 init/main.c:1593
ret_from_fork+0x72b/0xd50 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
-> #2 (&q->elevator_lock){+.+.}-{4:4}:
__mutex_lock_common kernel/locking/mutex.c:632 [inline]
__mutex_lock+0x1a4/0x1b10 kernel/locking/mutex.c:806
elevator_change+0x1bc/0x530 block/elevator.c:679
elevator_set_none+0x92/0xf0 block/elevator.c:769
blk_mq_elv_switch_none block/blk-mq.c:5131 [inline]
__blk_mq_update_nr_hw_queues block/blk-mq.c:5176 [inline]
blk_mq_update_nr_hw_queues+0x4c1/0x15f0 block/blk-mq.c:5241
nbd_start_device+0x1a6/0xbd0 drivers/block/nbd.c:1489
nbd_genl_connect+0xff2/0x1a40 drivers/block/nbd.c:2239
genl_family_rcv_msg_doit+0x214/0x300 net/netlink/genetlink.c:1114
genl_family_rcv_msg net/netlink/genetlink.c:1194 [inline]
genl_rcv_msg+0x560/0x800 net/netlink/genetlink.c:1209
netlink_rcv_skb+0x159/0x420 net/netlink/af_netlink.c:2550
genl_rcv+0x28/0x40 net/netlink/genetlink.c:1218
netlink_unicast_kernel net/netlink/af_netlink.c:1318 [inline]
netlink_unicast+0x585/0x850 net/netlink/af_netlink.c:1344
netlink_sendmsg+0x8b0/0xda0 net/netlink/af_netlink.c:1894
sock_sendmsg_nosec net/socket.c:787 [inline]
__sock_sendmsg net/socket.c:802 [inline]
____sys_sendmsg+0x9e1/0xb70 net/socket.c:2698
___sys_sendmsg+0x190/0x1e0 net/socket.c:2752
__sys_sendmsg+0x170/0x220 net/socket.c:2784
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x10b/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
-> #1 (&q->q_usage_counter(io)#50){++++}-{0:0}:
blk_alloc_queue+0x610/0x790 block/blk-core.c:461
blk_mq_alloc_queue+0x174/0x290 block/blk-mq.c:4450
__blk_mq_alloc_disk+0x29/0x120 block/blk-mq.c:4497
nbd_dev_add+0x492/0xb10 drivers/block/nbd.c:1954
nbd_init+0x291/0x2b0 drivers/block/nbd.c:2692
do_one_initcall+0x121/0x750 init/main.c:1392
do_initcall_level init/main.c:1454 [inline]
do_initcalls init/main.c:1470 [inline]
do_basic_setup init/main.c:1490 [inline]
kernel_init_freeable+0x6ea/0x7b0 init/main.c:1703
kernel_init+0x1f/0x1e0 init/main.c:1593
ret_from_fork+0x72b/0xd50 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
-> #0 (fs_reclaim){+.+.}-{0:0}:
check_prev_add kernel/locking/lockdep.c:3165 [inline]
check_prevs_add kernel/locking/lockdep.c:3284 [inline]
validate_chain kernel/locking/lockdep.c:3908 [inline]
__lock_acquire+0x14b8/0x2630 kernel/locking/lockdep.c:5237
lock_acquire kernel/locking/lockdep.c:5868 [inline]
lock_acquire+0x1b1/0x370 kernel/locking/lockdep.c:5825
__fs_reclaim_acquire mm/page_alloc.c:4325 [inline]
fs_reclaim_acquire+0xc4/0x100 mm/page_alloc.c:4339
might_alloc include/linux/sched/mm.h:317 [inline]
slab_pre_alloc_hook mm/slub.c:4520 [inline]
slab_alloc_node mm/slub.c:4875 [inline]
kmem_cache_alloc_noprof+0x4c/0x6e0 mm/slub.c:4905
create_cache mm/slab_common.c:249 [inline]
__kmem_cache_create_args+0x366/0x420 mm/slab_common.c:380
__kmem_cache_create include/linux/slab.h:390 [inline]
alloc_ai drivers/mtd/ubi/attach.c:1464 [inline]
ubi_attach+0x32a/0x4d30 drivers/mtd/ubi/attach.c:1560
ubi_attach_mtd_dev+0x139f/0x32a0 drivers/mtd/ubi/build.c:1004
ctrl_cdev_ioctl+0x36a/0x400 drivers/mtd/ubi/cdev.c:1113
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:597 [inline]
__se_sys_ioctl fs/ioctl.c:583 [inline]
__x64_sys_ioctl+0x18e/0x210 fs/ioctl.c:583
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x10b/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
other info that might help us debug this:
Chain exists of:
fs_reclaim --> cpu_hotplug_lock --> slab_mutex
Possible unsafe locking scenario:
CPU0 CPU1
---- ----
lock(slab_mutex);
lock(cpu_hotplug_lock);
lock(slab_mutex);
lock(fs_reclaim);
*** DEADLOCK ***
2 locks held by syz.7.5359/28440:
#0: ffffffff8f930b20 (ubi_devices_mutex){+.+.}-{4:4}, at: ctrl_cdev_ioctl+0x323/0x400 drivers/mtd/ubi/cdev.c:1112
#1: ffffffff8e97f100 (slab_mutex){+.+.}-{4:4}, at: __kmem_cache_create_args+0x44/0x420 mm/slab_common.c:350
stack backtrace:
CPU: 1 UID: 0 PID: 28440 Comm: syz.7.5359 Tainted: G L syzkaller #0 PREEMPT(full)
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:94 [inline]
dump_stack_lvl+0x100/0x190 lib/dump_stack.c:120
print_circular_bug.cold+0x178/0x1c7 kernel/locking/lockdep.c:2043
check_noncircular+0x146/0x160 kernel/locking/lockdep.c:2175
check_prev_add kernel/locking/lockdep.c:3165 [inline]
check_prevs_add kernel/locking/lockdep.c:3284 [inline]
validate_chain kernel/locking/lockdep.c:3908 [inline]
__lock_acquire+0x14b8/0x2630 kernel/locking/lockdep.c:5237
lock_acquire kernel/locking/lockdep.c:5868 [inline]
lock_acquire+0x1b1/0x370 kernel/locking/lockdep.c:5825
__fs_reclaim_acquire mm/page_alloc.c:4325 [inline]
fs_reclaim_acquire+0xc4/0x100 mm/page_alloc.c:4339
might_alloc include/linux/sched/mm.h:317 [inline]
slab_pre_alloc_hook mm/slub.c:4520 [inline]
slab_alloc_node mm/slub.c:4875 [inline]
kmem_cache_alloc_noprof+0x4c/0x6e0 mm/slub.c:4905
create_cache mm/slab_common.c:249 [inline]
__kmem_cache_create_args+0x366/0x420 mm/slab_common.c:380
__kmem_cache_create include/linux/slab.h:390 [inline]
alloc_ai drivers/mtd/ubi/attach.c:1464 [inline]
ubi_attach+0x32a/0x4d30 drivers/mtd/ubi/attach.c:1560
ubi_attach_mtd_dev+0x139f/0x32a0 drivers/mtd/ubi/build.c:1004
ctrl_cdev_ioctl+0x36a/0x400 drivers/mtd/ubi/cdev.c:1113
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:597 [inline]
__se_sys_ioctl fs/ioctl.c:583 [inline]
__x64_sys_ioctl+0x18e/0x210 fs/ioctl.c:583
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x10b/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f5ceb79cdd9
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:00007f5cec650028 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f5ceba16270 RCX: 00007f5ceb79cdd9
RDX: 0000200000000440 RSI: 0000000040186f40 RDI: 0000000000000008
RBP: 00007f5ceb832d69 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f5ceba16308 R14: 00007f5ceba16270 R15: 00007ffca1349ce8
</TASK>
ubi31: scanning is finished
ubi31: empty MTD device detected
ubi31 error: ubi_attach_mtd_dev: cannot spawn "ubi_bgt31d", error -4
---
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If the report is a duplicate of another one, reply with:
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If you want to undo deduplication, reply with:
#syz undup
syzbot found the following issue on:
HEAD commit: dd6c438c3e64 Merge tag 'vfs-7.1-rc1.fixes' of git://git.ke..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=14efc2ce580000
kernel config: https://syzkaller.appspot.com/x/.config?x=6d74203cd0463a9f
dashboard link: https://syzkaller.appspot.com/bug?extid=02b4e6eb8b1460d955a5
compiler: gcc (Debian 14.2.0-19) 14.2.0, GNU ld (GNU Binutils for Debian) 2.44
Unfortunately, I don't have any reproducer for this issue yet.
Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/8bebdd77187b/disk-dd6c438c.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/2527d5942bbb/vmlinux-dd6c438c.xz
kernel image: https://storage.googleapis.com/syzbot-assets/d446b541e2e0/bzImage-dd6c438c.xz
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+02b4e6...@syzkaller.appspotmail.com
ubi31: attaching mtd0
======================================================
WARNING: possible circular locking dependency detected
syzkaller #0 Tainted: G L
------------------------------------------------------
syz.7.5359/28440 is trying to acquire lock:
ffffffff8e9b1780 (fs_reclaim){+.+.}-{0:0}, at: might_alloc include/linux/sched/mm.h:317 [inline]
ffffffff8e9b1780 (fs_reclaim){+.+.}-{0:0}, at: slab_pre_alloc_hook mm/slub.c:4520 [inline]
ffffffff8e9b1780 (fs_reclaim){+.+.}-{0:0}, at: slab_alloc_node mm/slub.c:4875 [inline]
ffffffff8e9b1780 (fs_reclaim){+.+.}-{0:0}, at: kmem_cache_alloc_noprof+0x4c/0x6e0 mm/slub.c:4905
but task is already holding lock:
ffffffff8e97f100 (slab_mutex){+.+.}-{4:4}, at: __kmem_cache_create_args+0x44/0x420 mm/slab_common.c:350
which lock already depends on the new lock.
the existing dependency chain (in reverse order) is:
-> #7 (slab_mutex){+.+.}-{4:4}:
__mutex_lock_common kernel/locking/mutex.c:632 [inline]
__mutex_lock+0x1a4/0x1b10 kernel/locking/mutex.c:806
kmem_cache_destroy mm/slab_common.c:557 [inline]
kmem_cache_destroy+0x59/0x180 mm/slab_common.c:527
bio_put_slab block/bio.c:163 [inline]
bioset_exit+0x3b1/0x520 block/bio.c:1907
mddev_destroy drivers/md/md.c:819 [inline]
mddev_free drivers/md/md.c:911 [inline]
md_free_disk+0x18e/0x210 drivers/md/md.c:8578
disk_release+0x2b2/0x430 block/genhd.c:1311
device_release+0xd2/0x270 drivers/base/core.c:2566
kobject_cleanup lib/kobject.c:689 [inline]
kobject_release lib/kobject.c:720 [inline]
kref_put include/linux/kref.h:65 [inline]
kobject_put+0x1f7/0x640 lib/kobject.c:737
process_one_work+0xa0e/0x1980 kernel/workqueue.c:3302
process_scheduled_works kernel/workqueue.c:3385 [inline]
worker_thread+0x5ef/0xe50 kernel/workqueue.c:3466
kthread+0x370/0x450 kernel/kthread.c:436
ret_from_fork+0x72b/0xd50 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
-> #6 (cpu_hotplug_lock){++++}-{0:0}:
percpu_down_read_internal include/linux/percpu-rwsem.h:53 [inline]
percpu_down_read include/linux/percpu-rwsem.h:77 [inline]
cpus_read_lock+0x42/0x170 kernel/cpu.c:490
static_key_slow_inc+0x12/0x30 kernel/jump_label.c:190
nbd_reconnect_socket drivers/block/nbd.c:1342 [inline]
nbd_genl_reconfigure+0xd82/0x1a00 drivers/block/nbd.c:2431
genl_family_rcv_msg_doit+0x214/0x300 net/netlink/genetlink.c:1114
genl_family_rcv_msg net/netlink/genetlink.c:1194 [inline]
genl_rcv_msg+0x560/0x800 net/netlink/genetlink.c:1209
netlink_rcv_skb+0x159/0x420 net/netlink/af_netlink.c:2550
genl_rcv+0x28/0x40 net/netlink/genetlink.c:1218
netlink_unicast_kernel net/netlink/af_netlink.c:1318 [inline]
netlink_unicast+0x585/0x850 net/netlink/af_netlink.c:1344
netlink_sendmsg+0x8b0/0xda0 net/netlink/af_netlink.c:1894
sock_sendmsg_nosec net/socket.c:787 [inline]
__sock_sendmsg net/socket.c:802 [inline]
____sys_sendmsg+0x9e1/0xb70 net/socket.c:2698
___sys_sendmsg+0x190/0x1e0 net/socket.c:2752
__sys_sendmsg+0x170/0x220 net/socket.c:2784
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x10b/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
-> #5 (&nsock->tx_lock){+.+.}-{4:4}:
__mutex_lock_common kernel/locking/mutex.c:632 [inline]
__mutex_lock+0x1a4/0x1b10 kernel/locking/mutex.c:806
nbd_handle_cmd drivers/block/nbd.c:1143 [inline]
nbd_queue_rq+0x428/0x1080 drivers/block/nbd.c:1207
blk_mq_dispatch_rq_list+0x422/0x1e70 block/blk-mq.c:2148
__blk_mq_do_dispatch_sched block/blk-mq-sched.c:168 [inline]
blk_mq_do_dispatch_sched block/blk-mq-sched.c:182 [inline]
__blk_mq_sched_dispatch_requests+0xcea/0x1620 block/blk-mq-sched.c:307
blk_mq_sched_dispatch_requests+0xd7/0x1c0 block/blk-mq-sched.c:329
blk_mq_run_hw_queue+0x23c/0x670 block/blk-mq.c:2386
blk_mq_dispatch_list+0x51d/0x1360 block/blk-mq.c:2949
blk_mq_flush_plug_list block/blk-mq.c:2997 [inline]
blk_mq_flush_plug_list+0x130/0x600 block/blk-mq.c:2969
__blk_flush_plug+0x2c4/0x4b0 block/blk-core.c:1230
blk_finish_plug block/blk-core.c:1257 [inline]
__submit_bio+0x584/0x6c0 block/blk-core.c:649
__submit_bio_noacct_mq block/blk-core.c:722 [inline]
submit_bio_noacct_nocheck+0x543/0xbf0 block/blk-core.c:753
submit_bio_noacct+0xd18/0x2000 block/blk-core.c:884
blk_crypto_submit_bio include/linux/blk-crypto.h:203 [inline]
submit_bh_wbc+0x681/0x890 fs/buffer.c:2737
submit_bh fs/buffer.c:2742 [inline]
block_read_full_folio+0x4c8/0x8e0 fs/buffer.c:2358
filemap_read_folio+0xfc/0x3b0 mm/filemap.c:2502
do_read_cache_folio+0x2d7/0x6b0 mm/filemap.c:4107
read_mapping_folio include/linux/pagemap.h:1017 [inline]
read_part_sector+0xd1/0x370 block/partitions/core.c:724
adfspart_check_ICS+0x91/0x7d0 block/partitions/acorn.c:356
check_partition block/partitions/core.c:143 [inline]
blk_add_partitions block/partitions/core.c:591 [inline]
bdev_disk_changed+0x7a3/0x1250 block/partitions/core.c:695
blkdev_get_whole+0x187/0x290 block/bdev.c:756
bdev_open+0x2c7/0xe40 block/bdev.c:965
blkdev_open+0x34e/0x4f0 block/fops.c:697
do_dentry_open+0x6d8/0x1660 fs/open.c:947
vfs_open+0x82/0x3f0 fs/open.c:1079
do_open fs/namei.c:4699 [inline]
path_openat+0x208c/0x31a0 fs/namei.c:4858
do_file_open+0x20e/0x430 fs/namei.c:4887
do_sys_openat2+0x10d/0x1e0 fs/open.c:1364
do_sys_open fs/open.c:1370 [inline]
__do_sys_openat fs/open.c:1386 [inline]
__se_sys_openat fs/open.c:1381 [inline]
__x64_sys_openat+0x12d/0x210 fs/open.c:1381
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x10b/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
-> #4 (&cmd->lock){+.+.}-{4:4}:
__mutex_lock_common kernel/locking/mutex.c:632 [inline]
__mutex_lock+0x1a4/0x1b10 kernel/locking/mutex.c:806
nbd_queue_rq+0xba/0x1080 drivers/block/nbd.c:1199
blk_mq_dispatch_rq_list+0x422/0x1e70 block/blk-mq.c:2148
__blk_mq_do_dispatch_sched block/blk-mq-sched.c:168 [inline]
blk_mq_do_dispatch_sched block/blk-mq-sched.c:182 [inline]
__blk_mq_sched_dispatch_requests+0xcea/0x1620 block/blk-mq-sched.c:307
blk_mq_sched_dispatch_requests+0xd7/0x1c0 block/blk-mq-sched.c:329
blk_mq_run_hw_queue+0x23c/0x670 block/blk-mq.c:2386
blk_mq_dispatch_list+0x51d/0x1360 block/blk-mq.c:2949
blk_mq_flush_plug_list block/blk-mq.c:2997 [inline]
blk_mq_flush_plug_list+0x130/0x600 block/blk-mq.c:2969
__blk_flush_plug+0x2c4/0x4b0 block/blk-core.c:1230
blk_finish_plug block/blk-core.c:1257 [inline]
__submit_bio+0x584/0x6c0 block/blk-core.c:649
__submit_bio_noacct_mq block/blk-core.c:722 [inline]
submit_bio_noacct_nocheck+0x543/0xbf0 block/blk-core.c:753
submit_bio_noacct+0xd18/0x2000 block/blk-core.c:884
blk_crypto_submit_bio include/linux/blk-crypto.h:203 [inline]
submit_bh_wbc+0x681/0x890 fs/buffer.c:2737
submit_bh fs/buffer.c:2742 [inline]
block_read_full_folio+0x4c8/0x8e0 fs/buffer.c:2358
filemap_read_folio+0xfc/0x3b0 mm/filemap.c:2502
do_read_cache_folio+0x2d7/0x6b0 mm/filemap.c:4107
read_mapping_folio include/linux/pagemap.h:1017 [inline]
read_part_sector+0xd1/0x370 block/partitions/core.c:724
adfspart_check_ICS+0x91/0x7d0 block/partitions/acorn.c:356
check_partition block/partitions/core.c:143 [inline]
blk_add_partitions block/partitions/core.c:591 [inline]
bdev_disk_changed+0x7a3/0x1250 block/partitions/core.c:695
blkdev_get_whole+0x187/0x290 block/bdev.c:756
bdev_open+0x2c7/0xe40 block/bdev.c:965
blkdev_open+0x34e/0x4f0 block/fops.c:697
do_dentry_open+0x6d8/0x1660 fs/open.c:947
vfs_open+0x82/0x3f0 fs/open.c:1079
do_open fs/namei.c:4699 [inline]
path_openat+0x208c/0x31a0 fs/namei.c:4858
do_file_open+0x20e/0x430 fs/namei.c:4887
do_sys_openat2+0x10d/0x1e0 fs/open.c:1364
do_sys_open fs/open.c:1370 [inline]
__do_sys_openat fs/open.c:1386 [inline]
__se_sys_openat fs/open.c:1381 [inline]
__x64_sys_openat+0x12d/0x210 fs/open.c:1381
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x10b/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
-> #3 (set->srcu){.+.+}-{0:0}:
srcu_lock_sync include/linux/srcu.h:199 [inline]
__synchronize_srcu+0xa2/0x300 kernel/rcu/srcutree.c:1481
blk_mq_wait_quiesce_done block/blk-mq.c:284 [inline]
blk_mq_wait_quiesce_done block/blk-mq.c:281 [inline]
blk_mq_quiesce_queue block/blk-mq.c:304 [inline]
blk_mq_quiesce_queue+0x149/0x1c0 block/blk-mq.c:299
elevator_switch+0x17b/0x7e0 block/elevator.c:576
elevator_change+0x352/0x530 block/elevator.c:681
elevator_set_default+0x29e/0x360 block/elevator.c:754
blk_register_queue+0x48e/0x630 block/blk-sysfs.c:987
__add_disk+0x73f/0xe40 block/genhd.c:528
add_disk_fwnode+0x118/0x5c0 block/genhd.c:597
add_disk include/linux/blkdev.h:794 [inline]
nbd_dev_add+0x77a/0xb10 drivers/block/nbd.c:1984
nbd_init+0x291/0x2b0 drivers/block/nbd.c:2692
do_one_initcall+0x121/0x750 init/main.c:1392
do_initcall_level init/main.c:1454 [inline]
do_initcalls init/main.c:1470 [inline]
do_basic_setup init/main.c:1490 [inline]
kernel_init_freeable+0x6ea/0x7b0 init/main.c:1703
kernel_init+0x1f/0x1e0 init/main.c:1593
ret_from_fork+0x72b/0xd50 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
-> #2 (&q->elevator_lock){+.+.}-{4:4}:
__mutex_lock_common kernel/locking/mutex.c:632 [inline]
__mutex_lock+0x1a4/0x1b10 kernel/locking/mutex.c:806
elevator_change+0x1bc/0x530 block/elevator.c:679
elevator_set_none+0x92/0xf0 block/elevator.c:769
blk_mq_elv_switch_none block/blk-mq.c:5131 [inline]
__blk_mq_update_nr_hw_queues block/blk-mq.c:5176 [inline]
blk_mq_update_nr_hw_queues+0x4c1/0x15f0 block/blk-mq.c:5241
nbd_start_device+0x1a6/0xbd0 drivers/block/nbd.c:1489
nbd_genl_connect+0xff2/0x1a40 drivers/block/nbd.c:2239
genl_family_rcv_msg_doit+0x214/0x300 net/netlink/genetlink.c:1114
genl_family_rcv_msg net/netlink/genetlink.c:1194 [inline]
genl_rcv_msg+0x560/0x800 net/netlink/genetlink.c:1209
netlink_rcv_skb+0x159/0x420 net/netlink/af_netlink.c:2550
genl_rcv+0x28/0x40 net/netlink/genetlink.c:1218
netlink_unicast_kernel net/netlink/af_netlink.c:1318 [inline]
netlink_unicast+0x585/0x850 net/netlink/af_netlink.c:1344
netlink_sendmsg+0x8b0/0xda0 net/netlink/af_netlink.c:1894
sock_sendmsg_nosec net/socket.c:787 [inline]
__sock_sendmsg net/socket.c:802 [inline]
____sys_sendmsg+0x9e1/0xb70 net/socket.c:2698
___sys_sendmsg+0x190/0x1e0 net/socket.c:2752
__sys_sendmsg+0x170/0x220 net/socket.c:2784
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x10b/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
-> #1 (&q->q_usage_counter(io)#50){++++}-{0:0}:
blk_alloc_queue+0x610/0x790 block/blk-core.c:461
blk_mq_alloc_queue+0x174/0x290 block/blk-mq.c:4450
__blk_mq_alloc_disk+0x29/0x120 block/blk-mq.c:4497
nbd_dev_add+0x492/0xb10 drivers/block/nbd.c:1954
nbd_init+0x291/0x2b0 drivers/block/nbd.c:2692
do_one_initcall+0x121/0x750 init/main.c:1392
do_initcall_level init/main.c:1454 [inline]
do_initcalls init/main.c:1470 [inline]
do_basic_setup init/main.c:1490 [inline]
kernel_init_freeable+0x6ea/0x7b0 init/main.c:1703
kernel_init+0x1f/0x1e0 init/main.c:1593
ret_from_fork+0x72b/0xd50 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
-> #0 (fs_reclaim){+.+.}-{0:0}:
check_prev_add kernel/locking/lockdep.c:3165 [inline]
check_prevs_add kernel/locking/lockdep.c:3284 [inline]
validate_chain kernel/locking/lockdep.c:3908 [inline]
__lock_acquire+0x14b8/0x2630 kernel/locking/lockdep.c:5237
lock_acquire kernel/locking/lockdep.c:5868 [inline]
lock_acquire+0x1b1/0x370 kernel/locking/lockdep.c:5825
__fs_reclaim_acquire mm/page_alloc.c:4325 [inline]
fs_reclaim_acquire+0xc4/0x100 mm/page_alloc.c:4339
might_alloc include/linux/sched/mm.h:317 [inline]
slab_pre_alloc_hook mm/slub.c:4520 [inline]
slab_alloc_node mm/slub.c:4875 [inline]
kmem_cache_alloc_noprof+0x4c/0x6e0 mm/slub.c:4905
create_cache mm/slab_common.c:249 [inline]
__kmem_cache_create_args+0x366/0x420 mm/slab_common.c:380
__kmem_cache_create include/linux/slab.h:390 [inline]
alloc_ai drivers/mtd/ubi/attach.c:1464 [inline]
ubi_attach+0x32a/0x4d30 drivers/mtd/ubi/attach.c:1560
ubi_attach_mtd_dev+0x139f/0x32a0 drivers/mtd/ubi/build.c:1004
ctrl_cdev_ioctl+0x36a/0x400 drivers/mtd/ubi/cdev.c:1113
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:597 [inline]
__se_sys_ioctl fs/ioctl.c:583 [inline]
__x64_sys_ioctl+0x18e/0x210 fs/ioctl.c:583
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x10b/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
other info that might help us debug this:
Chain exists of:
fs_reclaim --> cpu_hotplug_lock --> slab_mutex
Possible unsafe locking scenario:
CPU0 CPU1
---- ----
lock(slab_mutex);
lock(cpu_hotplug_lock);
lock(slab_mutex);
lock(fs_reclaim);
*** DEADLOCK ***
2 locks held by syz.7.5359/28440:
#0: ffffffff8f930b20 (ubi_devices_mutex){+.+.}-{4:4}, at: ctrl_cdev_ioctl+0x323/0x400 drivers/mtd/ubi/cdev.c:1112
#1: ffffffff8e97f100 (slab_mutex){+.+.}-{4:4}, at: __kmem_cache_create_args+0x44/0x420 mm/slab_common.c:350
stack backtrace:
CPU: 1 UID: 0 PID: 28440 Comm: syz.7.5359 Tainted: G L syzkaller #0 PREEMPT(full)
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:94 [inline]
dump_stack_lvl+0x100/0x190 lib/dump_stack.c:120
print_circular_bug.cold+0x178/0x1c7 kernel/locking/lockdep.c:2043
check_noncircular+0x146/0x160 kernel/locking/lockdep.c:2175
check_prev_add kernel/locking/lockdep.c:3165 [inline]
check_prevs_add kernel/locking/lockdep.c:3284 [inline]
validate_chain kernel/locking/lockdep.c:3908 [inline]
__lock_acquire+0x14b8/0x2630 kernel/locking/lockdep.c:5237
lock_acquire kernel/locking/lockdep.c:5868 [inline]
lock_acquire+0x1b1/0x370 kernel/locking/lockdep.c:5825
__fs_reclaim_acquire mm/page_alloc.c:4325 [inline]
fs_reclaim_acquire+0xc4/0x100 mm/page_alloc.c:4339
might_alloc include/linux/sched/mm.h:317 [inline]
slab_pre_alloc_hook mm/slub.c:4520 [inline]
slab_alloc_node mm/slub.c:4875 [inline]
kmem_cache_alloc_noprof+0x4c/0x6e0 mm/slub.c:4905
create_cache mm/slab_common.c:249 [inline]
__kmem_cache_create_args+0x366/0x420 mm/slab_common.c:380
__kmem_cache_create include/linux/slab.h:390 [inline]
alloc_ai drivers/mtd/ubi/attach.c:1464 [inline]
ubi_attach+0x32a/0x4d30 drivers/mtd/ubi/attach.c:1560
ubi_attach_mtd_dev+0x139f/0x32a0 drivers/mtd/ubi/build.c:1004
ctrl_cdev_ioctl+0x36a/0x400 drivers/mtd/ubi/cdev.c:1113
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:597 [inline]
__se_sys_ioctl fs/ioctl.c:583 [inline]
__x64_sys_ioctl+0x18e/0x210 fs/ioctl.c:583
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x10b/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f5ceb79cdd9
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:00007f5cec650028 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f5ceba16270 RCX: 00007f5ceb79cdd9
RDX: 0000200000000440 RSI: 0000000040186f40 RDI: 0000000000000008
RBP: 00007f5ceb832d69 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f5ceba16308 R14: 00007f5ceba16270 R15: 00007ffca1349ce8
</TASK>
ubi31: scanning is finished
ubi31: empty MTD device detected
ubi31 error: ubi_attach_mtd_dev: cannot spawn "ubi_bgt31d", error -4
---
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