[syzbot] [kernel?] possible deadlock in device_create (3)
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syzbot
8:02 AM (8 hours ago) 8:02 AM
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Hello,
syzbot found the following issue on:
HEAD commit: 0257f64bdac7 Merge tag 'pm-7.0-rc4' of git://git.kernel.or..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=17f444d6580000
kernel config: https://syzkaller.appspot.com/x/.config?x=2b9fbb898accd2e4
dashboard link: https://syzkaller.appspot.com/bug?extid=4ba8a624812f10a13c48
compiler: Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8
Unfortunately, I don't have any reproducer for this issue yet.
Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/fe2c2d3a356f/disk-0257f64b.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/814567bbd30d/vmlinux-0257f64b.xz
kernel image: https://storage.googleapis.com/syzbot-assets/5cecf46c0268/bzImage-0257f64b.xz
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+4ba8a6...@syzkaller.appspotmail.com
Dev nbd6: unable to read RDB block 0
nbd6: unable to read partition table
ldm_validate_partition_table(): Disk read failed.
Dev nbd6: unable to read RDB block 0
nbd6: unable to read partition table
======================================================
WARNING: possible circular locking dependency detected
syzkaller #0 Tainted: G L
------------------------------------------------------
udevd/17714 is trying to acquire lock:
ffffffff8deedda0 (fs_reclaim){+.+.}-{0:0}, at: might_alloc include/linux/sched/mm.h:317 [inline]
ffffffff8deedda0 (fs_reclaim){+.+.}-{0:0}, at: slab_pre_alloc_hook mm/slub.c:4493 [inline]
ffffffff8deedda0 (fs_reclaim){+.+.}-{0:0}, at: slab_alloc_node mm/slub.c:4846 [inline]
ffffffff8deedda0 (fs_reclaim){+.+.}-{0:0}, at: kmem_cache_alloc_node_noprof+0x4b/0x6e0 mm/slub.c:4921
but task is already holding lock:
ffffffff8f50f6f8 (uevent_sock_mutex){+.+.}-{4:4}, at: uevent_net_broadcast_untagged lib/kobject_uevent.c:317 [inline]
ffffffff8f50f6f8 (uevent_sock_mutex){+.+.}-{4:4}, at: kobject_uevent_net_broadcast+0x281/0x560 lib/kobject_uevent.c:410
which lock already depends on the new lock.
the existing dependency chain (in reverse order) is:
-> #9 (uevent_sock_mutex){+.+.}-{4:4}:
__mutex_lock_common kernel/locking/rtmutex_api.c:533 [inline]
mutex_lock_nested+0x5a/0x1d0 kernel/locking/rtmutex_api.c:552
uevent_net_broadcast_untagged lib/kobject_uevent.c:317 [inline]
kobject_uevent_net_broadcast+0x281/0x560 lib/kobject_uevent.c:410
kobject_uevent_env+0x55f/0x9e0 lib/kobject_uevent.c:608
device_add+0x557/0xb80 drivers/base/core.c:3670
device_create_groups_vargs drivers/base/core.c:4371 [inline]
device_create+0x269/0x300 drivers/base/core.c:4410
msr_device_create+0x33/0x50 arch/x86/kernel/msr.c:251
cpuhp_invoke_callback+0x445/0x860 kernel/cpu.c:194
cpuhp_thread_fun+0x36b/0x780 kernel/cpu.c:1109
smpboot_thread_fn+0x541/0xa50 kernel/smpboot.c:160
kthread+0x388/0x470 kernel/kthread.c:436
ret_from_fork+0x51e/0xb90 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
-> #8 (cpuhp_state-up){+.+.}-{0:0}:
cpuhp_lock_acquire kernel/cpu.c:103 [inline]
cpuhp_thread_fun+0x127/0x780 kernel/cpu.c:1086
smpboot_thread_fn+0x541/0xa50 kernel/smpboot.c:160
kthread+0x388/0x470 kernel/kthread.c:436
ret_from_fork+0x51e/0xb90 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
-> #7 (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+0x42/0x160 kernel/cpu.c:490
static_key_slow_inc+0x12/0x30 kernel/jump_label.c:190
fl_create net/ipv6/ip6_flowlabel.c:457 [inline]
ipv6_flowlabel_get net/ipv6/ip6_flowlabel.c:637 [inline]
ipv6_flowlabel_opt+0x160a/0x2340 net/ipv6/ip6_flowlabel.c:740
do_ipv6_setsockopt+0xda7/0x31c0 net/ipv6/ipv6_sockglue.c:936
ipv6_setsockopt+0x59/0x170 net/ipv6/ipv6_sockglue.c:973
do_sock_setsockopt+0x17c/0x1b0 net/socket.c:2322
__sys_setsockopt net/socket.c:2347 [inline]
__do_sys_setsockopt net/socket.c:2353 [inline]
__se_sys_setsockopt net/socket.c:2350 [inline]
__x64_sys_setsockopt+0x143/0x1b0 net/socket.c:2350
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
-> #6 (sk_lock-AF_INET6){+.+.}-{0:0}:
lock_sock_nested+0x3e/0x130 net/core/sock.c:3780
lock_sock include/net/sock.h:1709 [inline]
inet_shutdown+0x6a/0x390 net/ipv4/af_inet.c:919
nbd_mark_nsock_dead+0x2e9/0x560 drivers/block/nbd.c:318
recv_work+0x1c9d/0x1dc0 drivers/block/nbd.c:1021
process_one_work kernel/workqueue.c:3275 [inline]
process_scheduled_works+0xb02/0x1830 kernel/workqueue.c:3358
worker_thread+0xa50/0xfc0 kernel/workqueue.c:3439
kthread+0x388/0x470 kernel/kthread.c:436
ret_from_fork+0x51e/0xb90 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
-> #5 (&nsock->tx_lock){+.+.}-{4:4}:
__mutex_lock_common kernel/locking/rtmutex_api.c:533 [inline]
mutex_lock_nested+0x5a/0x1d0 kernel/locking/rtmutex_api.c:552
nbd_handle_cmd drivers/block/nbd.c:1143 [inline]
nbd_queue_rq+0x37b/0x1100 drivers/block/nbd.c:1207
blk_mq_dispatch_rq_list+0xa77/0x1910 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+0xddb/0x1610 block/blk-mq-sched.c:307
blk_mq_sched_dispatch_requests+0xda/0x1a0 block/blk-mq-sched.c:329
blk_mq_run_hw_queue+0x368/0x520 block/blk-mq.c:2386
blk_mq_dispatch_list+0xd1f/0xe20 include/linux/spinlock_rt.h:-1
blk_mq_flush_plug_list+0x48d/0x570 block/blk-mq.c:2997
__blk_flush_plug+0x3ed/0x4d0 block/blk-core.c:1230
blk_finish_plug block/blk-core.c:1257 [inline]
__submit_bio+0x28d/0x580 block/blk-core.c:649
__submit_bio_noacct_mq block/blk-core.c:722 [inline]
submit_bio_noacct_nocheck+0x2f4/0xa70 block/blk-core.c:753
submit_bh fs/buffer.c:2826 [inline]
block_read_full_folio+0x599/0x830 fs/buffer.c:2444
filemap_read_folio+0x137/0x3b0 mm/filemap.c:2501
do_read_cache_folio+0x2bf/0x560 mm/filemap.c:4101
read_mapping_folio include/linux/pagemap.h:1028 [inline]
read_part_sector+0xb8/0x2b0 block/partitions/core.c:723
adfspart_check_ICS+0xa5/0xa40 block/partitions/acorn.c:360
check_partition block/partitions/core.c:142 [inline]
blk_add_partitions block/partitions/core.c:590 [inline]
bdev_disk_changed+0x7ba/0x1550 block/partitions/core.c:694
blkdev_get_whole+0x2e5/0x480 block/bdev.c:764
bdev_open+0x31e/0xcc0 block/bdev.c:973
blkdev_open+0x485/0x620 block/fops.c:697
do_dentry_open+0x83d/0x13e0 fs/open.c:949
vfs_open+0x3b/0x350 fs/open.c:1081
do_open fs/namei.c:4671 [inline]
path_openat+0x2e43/0x38a0 fs/namei.c:4830
do_file_open+0x23e/0x4a0 fs/namei.c:4859
do_sys_openat2+0x113/0x200 fs/open.c:1366
do_sys_open fs/open.c:1372 [inline]
__do_sys_openat fs/open.c:1388 [inline]
__se_sys_openat fs/open.c:1383 [inline]
__x64_sys_openat+0x138/0x170 fs/open.c:1383
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x14d/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/rtmutex_api.c:533 [inline]
mutex_lock_nested+0x5a/0x1d0 kernel/locking/rtmutex_api.c:552
nbd_queue_rq+0xc6/0x1100 drivers/block/nbd.c:1199
blk_mq_dispatch_rq_list+0xa77/0x1910 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+0xddb/0x1610 block/blk-mq-sched.c:307
blk_mq_sched_dispatch_requests+0xda/0x1a0 block/blk-mq-sched.c:329
blk_mq_run_hw_queue+0x368/0x520 block/blk-mq.c:2386
blk_mq_dispatch_list+0xd1f/0xe20 include/linux/spinlock_rt.h:-1
blk_mq_flush_plug_list+0x48d/0x570 block/blk-mq.c:2997
__blk_flush_plug+0x3ed/0x4d0 block/blk-core.c:1230
blk_finish_plug block/blk-core.c:1257 [inline]
__submit_bio+0x28d/0x580 block/blk-core.c:649
__submit_bio_noacct_mq block/blk-core.c:722 [inline]
submit_bio_noacct_nocheck+0x2f4/0xa70 block/blk-core.c:753
submit_bh fs/buffer.c:2826 [inline]
block_read_full_folio+0x599/0x830 fs/buffer.c:2444
filemap_read_folio+0x137/0x3b0 mm/filemap.c:2501
do_read_cache_folio+0x2bf/0x560 mm/filemap.c:4101
read_mapping_folio include/linux/pagemap.h:1028 [inline]
read_part_sector+0xb8/0x2b0 block/partitions/core.c:723
adfspart_check_ICS+0xa5/0xa40 block/partitions/acorn.c:360
check_partition block/partitions/core.c:142 [inline]
blk_add_partitions block/partitions/core.c:590 [inline]
bdev_disk_changed+0x7ba/0x1550 block/partitions/core.c:694
blkdev_get_whole+0x2e5/0x480 block/bdev.c:764
bdev_open+0x31e/0xcc0 block/bdev.c:973
blkdev_open+0x485/0x620 block/fops.c:697
do_dentry_open+0x83d/0x13e0 fs/open.c:949
vfs_open+0x3b/0x350 fs/open.c:1081
do_open fs/namei.c:4671 [inline]
path_openat+0x2e43/0x38a0 fs/namei.c:4830
do_file_open+0x23e/0x4a0 fs/namei.c:4859
do_sys_openat2+0x113/0x200 fs/open.c:1366
do_sys_open fs/open.c:1372 [inline]
__do_sys_openat fs/open.c:1388 [inline]
__se_sys_openat fs/open.c:1383 [inline]
__x64_sys_openat+0x138/0x170 fs/open.c:1383
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x14d/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+0xca/0x3e0 kernel/rcu/srcutree.c:1505
elevator_switch+0x1e8/0x7a0 block/elevator.c:576
elevator_change+0x2cc/0x450 block/elevator.c:681
elevator_set_default+0x36c/0x430 block/elevator.c:754
blk_register_queue+0x366/0x430 block/blk-sysfs.c:946
__add_disk+0x677/0xd50 block/genhd.c:528
add_disk_fwnode+0xfb/0x480 block/genhd.c:597
add_disk include/linux/blkdev.h:785 [inline]
nbd_dev_add+0x72c/0xb50 drivers/block/nbd.c:1984
nbd_init+0x168/0x1f0 drivers/block/nbd.c:2692
do_one_initcall+0x250/0x8d0 init/main.c:1382
do_initcall_level+0x104/0x190 init/main.c:1444
do_initcalls+0x59/0xa0 init/main.c:1460
kernel_init_freeable+0x2a6/0x3e0 init/main.c:1692
kernel_init+0x1d/0x1d0 init/main.c:1582
ret_from_fork+0x51e/0xb90 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/rtmutex_api.c:533 [inline]
mutex_lock_nested+0x5a/0x1d0 kernel/locking/rtmutex_api.c:552
elevator_change+0x1b3/0x450 block/elevator.c:679
elevator_set_none+0xb5/0x140 block/elevator.c:769
blk_mq_elv_switch_none block/blk-mq.c:5110 [inline]
__blk_mq_update_nr_hw_queues block/blk-mq.c:5155 [inline]
blk_mq_update_nr_hw_queues+0x607/0x1a80 block/blk-mq.c:5220
nbd_start_device+0x17f/0xb20 drivers/block/nbd.c:1489
nbd_start_device_ioctl drivers/block/nbd.c:1548 [inline]
__nbd_ioctl drivers/block/nbd.c:1623 [inline]
nbd_ioctl+0x57b/0xe40 drivers/block/nbd.c:1663
blkdev_ioctl+0x5e6/0x750 block/ioctl.c:804
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:597 [inline]
__se_sys_ioctl+0xff/0x170 fs/ioctl.c:583
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
-> #1 (&q->q_usage_counter(io)#53){++++}-{0:0}:
blk_alloc_queue+0x54e/0x690 block/blk-core.c:461
blk_mq_alloc_queue block/blk-mq.c:4429 [inline]
__blk_mq_alloc_disk+0x197/0x390 block/blk-mq.c:4476
nbd_dev_add+0x499/0xb50 drivers/block/nbd.c:1954
nbd_init+0x168/0x1f0 drivers/block/nbd.c:2692
do_one_initcall+0x250/0x8d0 init/main.c:1382
do_initcall_level+0x104/0x190 init/main.c:1444
do_initcalls+0x59/0xa0 init/main.c:1460
kernel_init_freeable+0x2a6/0x3e0 init/main.c:1692
kernel_init+0x1d/0x1d0 init/main.c:1582
ret_from_fork+0x51e/0xb90 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+0x15a5/0x2cf0 kernel/locking/lockdep.c:5237
lock_acquire+0xf0/0x2e0 kernel/locking/lockdep.c:5868
__fs_reclaim_acquire mm/page_alloc.c:4348 [inline]
fs_reclaim_acquire+0x71/0x100 mm/page_alloc.c:4362
might_alloc include/linux/sched/mm.h:317 [inline]
slab_pre_alloc_hook mm/slub.c:4493 [inline]
slab_alloc_node mm/slub.c:4846 [inline]
kmem_cache_alloc_node_noprof+0x4b/0x6e0 mm/slub.c:4921
__alloc_skb+0x1d0/0x7d0 net/core/skbuff.c:702
alloc_skb include/linux/skbuff.h:1383 [inline]
alloc_uevent_skb+0x7d/0x230 lib/kobject_uevent.c:289
uevent_net_broadcast_untagged lib/kobject_uevent.c:326 [inline]
kobject_uevent_net_broadcast+0x2fd/0x560 lib/kobject_uevent.c:410
kobject_uevent_env+0x55f/0x9e0 lib/kobject_uevent.c:608
nbd_config_put+0x14e/0x580 drivers/block/nbd.c:1440
nbd_release+0x101/0x140 drivers/block/nbd.c:1756
bdev_release+0x541/0x660 block/bdev.c:-1
blkdev_release+0x15/0x20 block/fops.c:705
__fput+0x461/0xa90 fs/file_table.c:469
fput_close_sync+0x11f/0x240 fs/file_table.c:574
__do_sys_close fs/open.c:1509 [inline]
__se_sys_close fs/open.c:1494 [inline]
__x64_sys_close+0x7e/0x110 fs/open.c:1494
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x14d/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 --> cpuhp_state-up --> uevent_sock_mutex
Possible unsafe locking scenario:
CPU0 CPU1
---- ----
lock(uevent_sock_mutex);
lock(cpuhp_state-up);
lock(uevent_sock_mutex);
lock(fs_reclaim);
*** DEADLOCK ***
3 locks held by udevd/17714:
#0: ffff8880265394c8 (&disk->open_mutex){+.+.}-{4:4}, at: bdev_release+0x1af/0x660 block/bdev.c:1144
#1: ffff888026357a48 (&nbd->config_lock){+.+.}-{4:4}, at: refcount_dec_and_mutex_lock+0x30/0xa0 lib/refcount.c:118
#2: ffffffff8f50f6f8 (uevent_sock_mutex){+.+.}-{4:4}, at: uevent_net_broadcast_untagged lib/kobject_uevent.c:317 [inline]
#2: ffffffff8f50f6f8 (uevent_sock_mutex){+.+.}-{4:4}, at: kobject_uevent_net_broadcast+0x281/0x560 lib/kobject_uevent.c:410
stack backtrace:
CPU: 1 UID: 0 PID: 17714 Comm: udevd Tainted: G L syzkaller #0 PREEMPT_{RT,(full)}
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/27/2026
Call Trace:
<TASK>
dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
print_circular_bug+0x2e1/0x300 kernel/locking/lockdep.c:2043
check_noncircular+0x12e/0x150 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+0x15a5/0x2cf0 kernel/locking/lockdep.c:5237
lock_acquire+0xf0/0x2e0 kernel/locking/lockdep.c:5868
__fs_reclaim_acquire mm/page_alloc.c:4348 [inline]
fs_reclaim_acquire+0x71/0x100 mm/page_alloc.c:4362
might_alloc include/linux/sched/mm.h:317 [inline]
slab_pre_alloc_hook mm/slub.c:4493 [inline]
slab_alloc_node mm/slub.c:4846 [inline]
kmem_cache_alloc_node_noprof+0x4b/0x6e0 mm/slub.c:4921
__alloc_skb+0x1d0/0x7d0 net/core/skbuff.c:702
alloc_skb include/linux/skbuff.h:1383 [inline]
alloc_uevent_skb+0x7d/0x230 lib/kobject_uevent.c:289
uevent_net_broadcast_untagged lib/kobject_uevent.c:326 [inline]
kobject_uevent_net_broadcast+0x2fd/0x560 lib/kobject_uevent.c:410
kobject_uevent_env+0x55f/0x9e0 lib/kobject_uevent.c:608
nbd_config_put+0x14e/0x580 drivers/block/nbd.c:1440
nbd_release+0x101/0x140 drivers/block/nbd.c:1756
bdev_release+0x541/0x660 block/bdev.c:-1
blkdev_release+0x15/0x20 block/fops.c:705
__fput+0x461/0xa90 fs/file_table.c:469
fput_close_sync+0x11f/0x240 fs/file_table.c:574
__do_sys_close fs/open.c:1509 [inline]
__se_sys_close fs/open.c:1494 [inline]
__x64_sys_close+0x7e/0x110 fs/open.c:1494
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f8673677407
Code: 48 89 fa 4c 89 df e8 38 aa 00 00 8b 93 08 03 00 00 59 5e 48 83 f8 fc 74 1a 5b c3 0f 1f 84 00 00 00 00 00 48 8b 44 24 10 0f 05 <5b> c3 0f 1f 80 00 00 00 00 83 e2 39 83 fa 08 75 de e8 23 ff ff ff
RSP: 002b:00007ffde0577e70 EFLAGS: 00000202 ORIG_RAX: 0000000000000003
RAX: ffffffffffffffda RBX: 00007f8673589880 RCX: 00007f8673677407
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000008
RBP: 00007f86735896e8 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000000002
R13: 0000560ef6049190 R14: 0000000000000008 R15: 0000560ef607f370
</TASK>
---
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#syz set subsystems: new-subsystem
(See the list of subsystem names on the web dashboard)
If the report is a duplicate of another one, reply with:
#syz dup: exact-subject-of-another-report
If you want to undo deduplication, reply with:
#syz undup
syzbot found the following issue on:
HEAD commit: 0257f64bdac7 Merge tag 'pm-7.0-rc4' of git://git.kernel.or..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=17f444d6580000
kernel config: https://syzkaller.appspot.com/x/.config?x=2b9fbb898accd2e4
dashboard link: https://syzkaller.appspot.com/bug?extid=4ba8a624812f10a13c48
compiler: Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8
Unfortunately, I don't have any reproducer for this issue yet.
Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/fe2c2d3a356f/disk-0257f64b.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/814567bbd30d/vmlinux-0257f64b.xz
kernel image: https://storage.googleapis.com/syzbot-assets/5cecf46c0268/bzImage-0257f64b.xz
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+4ba8a6...@syzkaller.appspotmail.com
Dev nbd6: unable to read RDB block 0
nbd6: unable to read partition table
ldm_validate_partition_table(): Disk read failed.
Dev nbd6: unable to read RDB block 0
nbd6: unable to read partition table
======================================================
WARNING: possible circular locking dependency detected
syzkaller #0 Tainted: G L
------------------------------------------------------
udevd/17714 is trying to acquire lock:
ffffffff8deedda0 (fs_reclaim){+.+.}-{0:0}, at: might_alloc include/linux/sched/mm.h:317 [inline]
ffffffff8deedda0 (fs_reclaim){+.+.}-{0:0}, at: slab_pre_alloc_hook mm/slub.c:4493 [inline]
ffffffff8deedda0 (fs_reclaim){+.+.}-{0:0}, at: slab_alloc_node mm/slub.c:4846 [inline]
ffffffff8deedda0 (fs_reclaim){+.+.}-{0:0}, at: kmem_cache_alloc_node_noprof+0x4b/0x6e0 mm/slub.c:4921
but task is already holding lock:
ffffffff8f50f6f8 (uevent_sock_mutex){+.+.}-{4:4}, at: uevent_net_broadcast_untagged lib/kobject_uevent.c:317 [inline]
ffffffff8f50f6f8 (uevent_sock_mutex){+.+.}-{4:4}, at: kobject_uevent_net_broadcast+0x281/0x560 lib/kobject_uevent.c:410
which lock already depends on the new lock.
the existing dependency chain (in reverse order) is:
-> #9 (uevent_sock_mutex){+.+.}-{4:4}:
__mutex_lock_common kernel/locking/rtmutex_api.c:533 [inline]
mutex_lock_nested+0x5a/0x1d0 kernel/locking/rtmutex_api.c:552
uevent_net_broadcast_untagged lib/kobject_uevent.c:317 [inline]
kobject_uevent_net_broadcast+0x281/0x560 lib/kobject_uevent.c:410
kobject_uevent_env+0x55f/0x9e0 lib/kobject_uevent.c:608
device_add+0x557/0xb80 drivers/base/core.c:3670
device_create_groups_vargs drivers/base/core.c:4371 [inline]
device_create+0x269/0x300 drivers/base/core.c:4410
msr_device_create+0x33/0x50 arch/x86/kernel/msr.c:251
cpuhp_invoke_callback+0x445/0x860 kernel/cpu.c:194
cpuhp_thread_fun+0x36b/0x780 kernel/cpu.c:1109
smpboot_thread_fn+0x541/0xa50 kernel/smpboot.c:160
kthread+0x388/0x470 kernel/kthread.c:436
ret_from_fork+0x51e/0xb90 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
-> #8 (cpuhp_state-up){+.+.}-{0:0}:
cpuhp_lock_acquire kernel/cpu.c:103 [inline]
cpuhp_thread_fun+0x127/0x780 kernel/cpu.c:1086
smpboot_thread_fn+0x541/0xa50 kernel/smpboot.c:160
kthread+0x388/0x470 kernel/kthread.c:436
ret_from_fork+0x51e/0xb90 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
-> #7 (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+0x42/0x160 kernel/cpu.c:490
static_key_slow_inc+0x12/0x30 kernel/jump_label.c:190
fl_create net/ipv6/ip6_flowlabel.c:457 [inline]
ipv6_flowlabel_get net/ipv6/ip6_flowlabel.c:637 [inline]
ipv6_flowlabel_opt+0x160a/0x2340 net/ipv6/ip6_flowlabel.c:740
do_ipv6_setsockopt+0xda7/0x31c0 net/ipv6/ipv6_sockglue.c:936
ipv6_setsockopt+0x59/0x170 net/ipv6/ipv6_sockglue.c:973
do_sock_setsockopt+0x17c/0x1b0 net/socket.c:2322
__sys_setsockopt net/socket.c:2347 [inline]
__do_sys_setsockopt net/socket.c:2353 [inline]
__se_sys_setsockopt net/socket.c:2350 [inline]
__x64_sys_setsockopt+0x143/0x1b0 net/socket.c:2350
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
-> #6 (sk_lock-AF_INET6){+.+.}-{0:0}:
lock_sock_nested+0x3e/0x130 net/core/sock.c:3780
lock_sock include/net/sock.h:1709 [inline]
inet_shutdown+0x6a/0x390 net/ipv4/af_inet.c:919
nbd_mark_nsock_dead+0x2e9/0x560 drivers/block/nbd.c:318
recv_work+0x1c9d/0x1dc0 drivers/block/nbd.c:1021
process_one_work kernel/workqueue.c:3275 [inline]
process_scheduled_works+0xb02/0x1830 kernel/workqueue.c:3358
worker_thread+0xa50/0xfc0 kernel/workqueue.c:3439
kthread+0x388/0x470 kernel/kthread.c:436
ret_from_fork+0x51e/0xb90 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
-> #5 (&nsock->tx_lock){+.+.}-{4:4}:
__mutex_lock_common kernel/locking/rtmutex_api.c:533 [inline]
mutex_lock_nested+0x5a/0x1d0 kernel/locking/rtmutex_api.c:552
nbd_handle_cmd drivers/block/nbd.c:1143 [inline]
nbd_queue_rq+0x37b/0x1100 drivers/block/nbd.c:1207
blk_mq_dispatch_rq_list+0xa77/0x1910 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+0xddb/0x1610 block/blk-mq-sched.c:307
blk_mq_sched_dispatch_requests+0xda/0x1a0 block/blk-mq-sched.c:329
blk_mq_run_hw_queue+0x368/0x520 block/blk-mq.c:2386
blk_mq_dispatch_list+0xd1f/0xe20 include/linux/spinlock_rt.h:-1
blk_mq_flush_plug_list+0x48d/0x570 block/blk-mq.c:2997
__blk_flush_plug+0x3ed/0x4d0 block/blk-core.c:1230
blk_finish_plug block/blk-core.c:1257 [inline]
__submit_bio+0x28d/0x580 block/blk-core.c:649
__submit_bio_noacct_mq block/blk-core.c:722 [inline]
submit_bio_noacct_nocheck+0x2f4/0xa70 block/blk-core.c:753
submit_bh fs/buffer.c:2826 [inline]
block_read_full_folio+0x599/0x830 fs/buffer.c:2444
filemap_read_folio+0x137/0x3b0 mm/filemap.c:2501
do_read_cache_folio+0x2bf/0x560 mm/filemap.c:4101
read_mapping_folio include/linux/pagemap.h:1028 [inline]
read_part_sector+0xb8/0x2b0 block/partitions/core.c:723
adfspart_check_ICS+0xa5/0xa40 block/partitions/acorn.c:360
check_partition block/partitions/core.c:142 [inline]
blk_add_partitions block/partitions/core.c:590 [inline]
bdev_disk_changed+0x7ba/0x1550 block/partitions/core.c:694
blkdev_get_whole+0x2e5/0x480 block/bdev.c:764
bdev_open+0x31e/0xcc0 block/bdev.c:973
blkdev_open+0x485/0x620 block/fops.c:697
do_dentry_open+0x83d/0x13e0 fs/open.c:949
vfs_open+0x3b/0x350 fs/open.c:1081
do_open fs/namei.c:4671 [inline]
path_openat+0x2e43/0x38a0 fs/namei.c:4830
do_file_open+0x23e/0x4a0 fs/namei.c:4859
do_sys_openat2+0x113/0x200 fs/open.c:1366
do_sys_open fs/open.c:1372 [inline]
__do_sys_openat fs/open.c:1388 [inline]
__se_sys_openat fs/open.c:1383 [inline]
__x64_sys_openat+0x138/0x170 fs/open.c:1383
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x14d/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/rtmutex_api.c:533 [inline]
mutex_lock_nested+0x5a/0x1d0 kernel/locking/rtmutex_api.c:552
nbd_queue_rq+0xc6/0x1100 drivers/block/nbd.c:1199
blk_mq_dispatch_rq_list+0xa77/0x1910 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+0xddb/0x1610 block/blk-mq-sched.c:307
blk_mq_sched_dispatch_requests+0xda/0x1a0 block/blk-mq-sched.c:329
blk_mq_run_hw_queue+0x368/0x520 block/blk-mq.c:2386
blk_mq_dispatch_list+0xd1f/0xe20 include/linux/spinlock_rt.h:-1
blk_mq_flush_plug_list+0x48d/0x570 block/blk-mq.c:2997
__blk_flush_plug+0x3ed/0x4d0 block/blk-core.c:1230
blk_finish_plug block/blk-core.c:1257 [inline]
__submit_bio+0x28d/0x580 block/blk-core.c:649
__submit_bio_noacct_mq block/blk-core.c:722 [inline]
submit_bio_noacct_nocheck+0x2f4/0xa70 block/blk-core.c:753
submit_bh fs/buffer.c:2826 [inline]
block_read_full_folio+0x599/0x830 fs/buffer.c:2444
filemap_read_folio+0x137/0x3b0 mm/filemap.c:2501
do_read_cache_folio+0x2bf/0x560 mm/filemap.c:4101
read_mapping_folio include/linux/pagemap.h:1028 [inline]
read_part_sector+0xb8/0x2b0 block/partitions/core.c:723
adfspart_check_ICS+0xa5/0xa40 block/partitions/acorn.c:360
check_partition block/partitions/core.c:142 [inline]
blk_add_partitions block/partitions/core.c:590 [inline]
bdev_disk_changed+0x7ba/0x1550 block/partitions/core.c:694
blkdev_get_whole+0x2e5/0x480 block/bdev.c:764
bdev_open+0x31e/0xcc0 block/bdev.c:973
blkdev_open+0x485/0x620 block/fops.c:697
do_dentry_open+0x83d/0x13e0 fs/open.c:949
vfs_open+0x3b/0x350 fs/open.c:1081
do_open fs/namei.c:4671 [inline]
path_openat+0x2e43/0x38a0 fs/namei.c:4830
do_file_open+0x23e/0x4a0 fs/namei.c:4859
do_sys_openat2+0x113/0x200 fs/open.c:1366
do_sys_open fs/open.c:1372 [inline]
__do_sys_openat fs/open.c:1388 [inline]
__se_sys_openat fs/open.c:1383 [inline]
__x64_sys_openat+0x138/0x170 fs/open.c:1383
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x14d/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+0xca/0x3e0 kernel/rcu/srcutree.c:1505
elevator_switch+0x1e8/0x7a0 block/elevator.c:576
elevator_change+0x2cc/0x450 block/elevator.c:681
elevator_set_default+0x36c/0x430 block/elevator.c:754
blk_register_queue+0x366/0x430 block/blk-sysfs.c:946
__add_disk+0x677/0xd50 block/genhd.c:528
add_disk_fwnode+0xfb/0x480 block/genhd.c:597
add_disk include/linux/blkdev.h:785 [inline]
nbd_dev_add+0x72c/0xb50 drivers/block/nbd.c:1984
nbd_init+0x168/0x1f0 drivers/block/nbd.c:2692
do_one_initcall+0x250/0x8d0 init/main.c:1382
do_initcall_level+0x104/0x190 init/main.c:1444
do_initcalls+0x59/0xa0 init/main.c:1460
kernel_init_freeable+0x2a6/0x3e0 init/main.c:1692
kernel_init+0x1d/0x1d0 init/main.c:1582
ret_from_fork+0x51e/0xb90 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/rtmutex_api.c:533 [inline]
mutex_lock_nested+0x5a/0x1d0 kernel/locking/rtmutex_api.c:552
elevator_change+0x1b3/0x450 block/elevator.c:679
elevator_set_none+0xb5/0x140 block/elevator.c:769
blk_mq_elv_switch_none block/blk-mq.c:5110 [inline]
__blk_mq_update_nr_hw_queues block/blk-mq.c:5155 [inline]
blk_mq_update_nr_hw_queues+0x607/0x1a80 block/blk-mq.c:5220
nbd_start_device+0x17f/0xb20 drivers/block/nbd.c:1489
nbd_start_device_ioctl drivers/block/nbd.c:1548 [inline]
__nbd_ioctl drivers/block/nbd.c:1623 [inline]
nbd_ioctl+0x57b/0xe40 drivers/block/nbd.c:1663
blkdev_ioctl+0x5e6/0x750 block/ioctl.c:804
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:597 [inline]
__se_sys_ioctl+0xff/0x170 fs/ioctl.c:583
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
-> #1 (&q->q_usage_counter(io)#53){++++}-{0:0}:
blk_alloc_queue+0x54e/0x690 block/blk-core.c:461
blk_mq_alloc_queue block/blk-mq.c:4429 [inline]
__blk_mq_alloc_disk+0x197/0x390 block/blk-mq.c:4476
nbd_dev_add+0x499/0xb50 drivers/block/nbd.c:1954
nbd_init+0x168/0x1f0 drivers/block/nbd.c:2692
do_one_initcall+0x250/0x8d0 init/main.c:1382
do_initcall_level+0x104/0x190 init/main.c:1444
do_initcalls+0x59/0xa0 init/main.c:1460
kernel_init_freeable+0x2a6/0x3e0 init/main.c:1692
kernel_init+0x1d/0x1d0 init/main.c:1582
ret_from_fork+0x51e/0xb90 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+0x15a5/0x2cf0 kernel/locking/lockdep.c:5237
lock_acquire+0xf0/0x2e0 kernel/locking/lockdep.c:5868
__fs_reclaim_acquire mm/page_alloc.c:4348 [inline]
fs_reclaim_acquire+0x71/0x100 mm/page_alloc.c:4362
might_alloc include/linux/sched/mm.h:317 [inline]
slab_pre_alloc_hook mm/slub.c:4493 [inline]
slab_alloc_node mm/slub.c:4846 [inline]
kmem_cache_alloc_node_noprof+0x4b/0x6e0 mm/slub.c:4921
__alloc_skb+0x1d0/0x7d0 net/core/skbuff.c:702
alloc_skb include/linux/skbuff.h:1383 [inline]
alloc_uevent_skb+0x7d/0x230 lib/kobject_uevent.c:289
uevent_net_broadcast_untagged lib/kobject_uevent.c:326 [inline]
kobject_uevent_net_broadcast+0x2fd/0x560 lib/kobject_uevent.c:410
kobject_uevent_env+0x55f/0x9e0 lib/kobject_uevent.c:608
nbd_config_put+0x14e/0x580 drivers/block/nbd.c:1440
nbd_release+0x101/0x140 drivers/block/nbd.c:1756
bdev_release+0x541/0x660 block/bdev.c:-1
blkdev_release+0x15/0x20 block/fops.c:705
__fput+0x461/0xa90 fs/file_table.c:469
fput_close_sync+0x11f/0x240 fs/file_table.c:574
__do_sys_close fs/open.c:1509 [inline]
__se_sys_close fs/open.c:1494 [inline]
__x64_sys_close+0x7e/0x110 fs/open.c:1494
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x14d/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 --> cpuhp_state-up --> uevent_sock_mutex
Possible unsafe locking scenario:
CPU0 CPU1
---- ----
lock(uevent_sock_mutex);
lock(cpuhp_state-up);
lock(uevent_sock_mutex);
lock(fs_reclaim);
*** DEADLOCK ***
3 locks held by udevd/17714:
#0: ffff8880265394c8 (&disk->open_mutex){+.+.}-{4:4}, at: bdev_release+0x1af/0x660 block/bdev.c:1144
#1: ffff888026357a48 (&nbd->config_lock){+.+.}-{4:4}, at: refcount_dec_and_mutex_lock+0x30/0xa0 lib/refcount.c:118
#2: ffffffff8f50f6f8 (uevent_sock_mutex){+.+.}-{4:4}, at: uevent_net_broadcast_untagged lib/kobject_uevent.c:317 [inline]
#2: ffffffff8f50f6f8 (uevent_sock_mutex){+.+.}-{4:4}, at: kobject_uevent_net_broadcast+0x281/0x560 lib/kobject_uevent.c:410
stack backtrace:
CPU: 1 UID: 0 PID: 17714 Comm: udevd Tainted: G L syzkaller #0 PREEMPT_{RT,(full)}
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/27/2026
Call Trace:
<TASK>
dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
print_circular_bug+0x2e1/0x300 kernel/locking/lockdep.c:2043
check_noncircular+0x12e/0x150 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+0x15a5/0x2cf0 kernel/locking/lockdep.c:5237
lock_acquire+0xf0/0x2e0 kernel/locking/lockdep.c:5868
__fs_reclaim_acquire mm/page_alloc.c:4348 [inline]
fs_reclaim_acquire+0x71/0x100 mm/page_alloc.c:4362
might_alloc include/linux/sched/mm.h:317 [inline]
slab_pre_alloc_hook mm/slub.c:4493 [inline]
slab_alloc_node mm/slub.c:4846 [inline]
kmem_cache_alloc_node_noprof+0x4b/0x6e0 mm/slub.c:4921
__alloc_skb+0x1d0/0x7d0 net/core/skbuff.c:702
alloc_skb include/linux/skbuff.h:1383 [inline]
alloc_uevent_skb+0x7d/0x230 lib/kobject_uevent.c:289
uevent_net_broadcast_untagged lib/kobject_uevent.c:326 [inline]
kobject_uevent_net_broadcast+0x2fd/0x560 lib/kobject_uevent.c:410
kobject_uevent_env+0x55f/0x9e0 lib/kobject_uevent.c:608
nbd_config_put+0x14e/0x580 drivers/block/nbd.c:1440
nbd_release+0x101/0x140 drivers/block/nbd.c:1756
bdev_release+0x541/0x660 block/bdev.c:-1
blkdev_release+0x15/0x20 block/fops.c:705
__fput+0x461/0xa90 fs/file_table.c:469
fput_close_sync+0x11f/0x240 fs/file_table.c:574
__do_sys_close fs/open.c:1509 [inline]
__se_sys_close fs/open.c:1494 [inline]
__x64_sys_close+0x7e/0x110 fs/open.c:1494
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f8673677407
Code: 48 89 fa 4c 89 df e8 38 aa 00 00 8b 93 08 03 00 00 59 5e 48 83 f8 fc 74 1a 5b c3 0f 1f 84 00 00 00 00 00 48 8b 44 24 10 0f 05 <5b> c3 0f 1f 80 00 00 00 00 83 e2 39 83 fa 08 75 de e8 23 ff ff ff
RSP: 002b:00007ffde0577e70 EFLAGS: 00000202 ORIG_RAX: 0000000000000003
RAX: ffffffffffffffda RBX: 00007f8673589880 RCX: 00007f8673677407
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000008
RBP: 00007f86735896e8 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000000002
R13: 0000560ef6049190 R14: 0000000000000008 R15: 0000560ef607f370
</TASK>
---
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#syz fix: exact-commit-title
If you want to overwrite report's subsystems, reply with:
#syz set subsystems: new-subsystem
(See the list of subsystem names on the web dashboard)
If the report is a duplicate of another one, reply with:
#syz dup: exact-subject-of-another-report
If you want to undo deduplication, reply with:
#syz undup
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