syzbot

rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P6691/1:b..l
rcu: 	(detected by 0, t=10503 jiffies, g=10725, q=851 ncpus=2)
task:kworker/0:7     state:R  running task     stack:27992 pid:6691  tgid:6691  ppid:2      task_flags:0x4208060 flags:0x00004000
Workqueue: events send_dm_alert
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5396 [inline]
 __schedule+0x116a/0x5de0 kernel/sched/core.c:6785
 preempt_schedule_irq+0x51/0x90 kernel/sched/core.c:7108
 irqentry_exit+0x36/0x90 kernel/entry/common.c:307
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
RIP: 0010:lock_acquire+0x62/0x350 kernel/locking/lockdep.c:5875
Code: 42 34 12 83 f8 07 0f 87 bc 02 00 00 89 c0 48 0f a3 05 42 91 0f 0f 0f 82 74 02 00 00 8b 35 2a c3 0f 0f 85 f6 0f 85 8d 00 00 00 <48> 8b 44 24 30 65 48 2b 05 d9 41 34 12 0f 85 c7 02 00 00 48 83 c4
RSP: 0018:ffffc90003d8f820 EFLAGS: 00000206
RAX: 0000000000000046 RBX: ffffffff8e5c4840 RCX: 0000000074aa559f
RDX: 0000000000000000 RSI: ffffffff8ddf4151 RDI: ffffffff8c1570a0
RBP: 0000000000000002 R08: 4acf5f712843fc39 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000001 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
 rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
 rcu_read_lock include/linux/rcupdate.h:841 [inline]
 __page_table_check_zero+0x13d/0x5d0 mm/page_table_check.c:138
 page_table_check_free include/linux/page_table_check.h:43 [inline]
 free_pages_prepare mm/page_alloc.c:1249 [inline]
 __free_frozen_pages+0x7df/0x1180 mm/page_alloc.c:2706
 discard_slab mm/slub.c:2717 [inline]
 __put_partials+0x16d/0x1c0 mm/slub.c:3186
 qlink_free mm/kasan/quarantine.c:163 [inline]
 qlist_free_all+0x4d/0x120 mm/kasan/quarantine.c:179
 kasan_quarantine_reduce+0x195/0x1e0 mm/kasan/quarantine.c:286
 __kasan_kmalloc+0x8a/0xb0 mm/kasan/common.c:385
 kasan_kmalloc include/linux/kasan.h:260 [inline]
 __do_kmalloc_node mm/slub.c:4328 [inline]
 __kmalloc_node_track_caller_noprof+0x221/0x510 mm/slub.c:4347
 kmalloc_reserve+0xef/0x2c0 net/core/skbuff.c:601
 __alloc_skb+0x166/0x380 net/core/skbuff.c:670
 alloc_skb include/linux/skbuff.h:1336 [inline]
 nlmsg_new include/net/netlink.h:1041 [inline]
 genlmsg_new include/net/genetlink.h:611 [inline]
 reset_per_cpu_data+0x26/0x240 net/core/drop_monitor.c:146
 send_dm_alert+0x1e/0xf0 net/core/drop_monitor.c:197
 process_one_work+0x9cf/0x1b70 kernel/workqueue.c:3238
 process_scheduled_works kernel/workqueue.c:3321 [inline]
 worker_thread+0x6c8/0xf10 kernel/workqueue.c:3402
 kthread+0x3c5/0x780 kernel/kthread.c:464
 ret_from_fork+0x5d4/0x6f0 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>