syzbot

rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1):
 P24279/1:b..l
rcu: 	(detected by 0, t=10502 jiffies, g=108217, q=868 ncpus=2)
task:syz.9.7415      state:R
  running task     stack:24344 pid:24279 tgid:24277 ppid:18574  task_flags:0x400040 flags:0x00004006
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5357 [inline]
 __schedule+0x1798/0x4cc0 kernel/sched/core.c:6961
 preempt_schedule_irq+0xb5/0x150 kernel/sched/core.c:7288
 irqentry_exit+0x6f/0x90 kernel/entry/common.c:197
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
RIP: 0010:lock_release+0x2b5/0x3e0 kernel/locking/lockdep.c:5893
Code: 51 48 c7 44 24 20 00 00 00 00 9c 8f 44 24 20 f7 44 24 20 00 02 00 00 75 56 f7 c3 00 02 00 00 74 01 fb 65 48 8b 05 1b 0f 03 11 <48> 3b 44 24 28 0f 85 8b 00 00 00 48 83 c4 30 5b 41 5c 41 5d 41 5e
RSP: 0018:ffffc90011fd6770 EFLAGS: 00000206

RAX: 48cb2b61cfc7c100 RBX: 0000000000000202 RCX: 48cb2b61cfc7c100
RDX: 0000000000000003 RSI: ffffffff8dba7f2b RDI: ffffffff8be33880
RBP: ffff88802e6dc768 R08: ffffc90011fd6907 R09: ffffc90011fd68f8
R10: dffffc0000000000 R11: fffff520023fad21 R12: 0000000000000003
R13: 0000000000000003 R14: ffffffff8e139f20 R15: ffff88802e6dbc00
 rcu_lock_release include/linux/rcupdate.h:341 [inline]
 rcu_read_unlock include/linux/rcupdate.h:871 [inline]
 class_rcu_destructor include/linux/rcupdate.h:1155 [inline]
 unwind_next_frame+0x19a9/0x2390 arch/x86/kernel/unwind_orc.c:680
 arch_stack_walk+0x11c/0x150 arch/x86/kernel/stacktrace.c:25
 stack_trace_save+0x9c/0xe0 kernel/stacktrace.c:122
 save_stack+0xf5/0x1f0 mm/page_owner.c:156
 __reset_page_owner+0x71/0x1f0 mm/page_owner.c:308
 reset_page_owner include/linux/page_owner.h:25 [inline]
 free_pages_prepare mm/page_alloc.c:1395 [inline]
 __free_frozen_pages+0xbc4/0xd30 mm/page_alloc.c:2895
 discard_slab mm/slub.c:2753 [inline]
 __put_partials+0x156/0x1a0 mm/slub.c:3218
 put_cpu_partial+0x17c/0x250 mm/slub.c:3293
 __slab_free+0x2d5/0x3c0 mm/slub.c:4550
 qlink_free mm/kasan/quarantine.c:163 [inline]
 qlist_free_all+0x97/0x140 mm/kasan/quarantine.c:179
 kasan_quarantine_reduce+0x148/0x160 mm/kasan/quarantine.c:286
 __kasan_slab_alloc+0x22/0x80 mm/kasan/common.c:340
 kasan_slab_alloc include/linux/kasan.h:250 [inline]
 slab_post_alloc_hook mm/slub.c:4180 [inline]
 slab_alloc_node mm/slub.c:4229 [inline]
 kmem_cache_alloc_noprof+0x1c1/0x3c0 mm/slub.c:4236
 skb_clone+0x212/0x3a0 net/core/skbuff.c:2049
 do_one_broadcast net/netlink/af_netlink.c:1457 [inline]
 netlink_broadcast_filtered+0x749/0x12c0 net/netlink/af_netlink.c:1535
 netlink_broadcast+0x37/0x50 net/netlink/af_netlink.c:1559
 uevent_net_broadcast_untagged lib/kobject_uevent.c:331 [inline]
 kobject_uevent_net_broadcast+0x378/0x560 lib/kobject_uevent.c:410
 kobject_uevent_env+0x55b/0x8c0 lib/kobject_uevent.c:608
 loop_configure+0xb84/0xe50 drivers/block/loop.c:1090
 lo_ioctl+0x810/0x1c10 drivers/block/loop.c:-1
 blkdev_ioctl+0x5a8/0x6d0 block/ioctl.c:705
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:598 [inline]
 __se_sys_ioctl+0xfc/0x170 fs/ioctl.c:584
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f3fc8b8e7eb
RSP: 002b:00007f3fc99e7dc0 EFLAGS: 00000246
 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 0000000000000004 RCX: 00007f3fc8b8e7eb
RDX: 0000000000000003 RSI: 0000000000004c00 RDI: 0000000000000004
RBP: 0000000000000000 R08: 0000000000000000 R09: 000000000001f21d
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000003
R13: 00007f3fc99e7ef0 R14: 00007f3fc99e7eb0 R15: 00007f3fbe800000
 </TASK>
rcu: rcu_preempt kthread starved for 7621 jiffies! g108217 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=0
rcu: 	Unless rcu_preempt kthread gets sufficient CPU time, OOM is now expected behavior.
rcu: RCU grace-period kthread stack dump:
task:rcu_preempt     state:R
  running task     stack:27160 pid:16    tgid:16    ppid:2      task_flags:0x208040 flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5357 [inline]
 __schedule+0x1798/0x4cc0 kernel/sched/core.c:6961
 __schedule_loop kernel/sched/core.c:7043 [inline]
 schedule+0x165/0x360 kernel/sched/core.c:7058
 schedule_timeout+0x12b/0x270 kernel/time/sleep_timeout.c:99
 rcu_gp_fqs_loop+0x301/0x1540 kernel/rcu/tree.c:2083
 rcu_gp_kthread+0x99/0x390 kernel/rcu/tree.c:2285
 kthread+0x711/0x8a0 kernel/kthread.c:463
 ret_from_fork+0x3fc/0x770 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>
rcu: Stack dump where RCU GP kthread last ran:
CPU: 0 UID: 0 PID: 14 Comm: kworker/R-mm_pe Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
Workqueue:  0x0
 (mm_percpu_wq)

RIP: 0010:__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:152 [inline]
RIP: 0010:_raw_spin_unlock_irqrestore+0xa8/0x110 kernel/locking/spinlock.c:194
Code: 74 05 e8 7b e9 4a f6 48 c7 44 24 20 00 00 00 00 9c 8f 44 24 20 f6 44 24 21 02 75 4f f7 c3 00 02 00 00 74 01 fb bf 01 00 00 00 <e8> e3 8e 13 f6 65 8b 05 6c 11 24 07 85 c0 74 40 48 c7 04 24 0e 36
RSP: 0018:ffffc90000007900 EFLAGS: 00000206

RAX: 1f7a357c5ccacc00 RBX: 0000000000000212 RCX: 1f7a357c5ccacc00
RDX: 0000000000000000 RSI: ffffffff8d9b8acb RDI: 0000000000000001
RBP: ffffc90000007990 R08: ffffffff8fa39637 R09: 1ffffffff1f472c6
R10: dffffc0000000000 R11: fffffbfff1f472c7 R12: dffffc0000000000
R13: 000000000000d000 R14: ffff888145320000 R15: 1ffff92000000f20
FS:  0000000000000000(0000) GS:ffff888125c18000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f27ace4f5c6 CR3: 0000000078215000 CR4: 0000000000350ef0
Call Trace:
 <IRQ>
 spin_unlock_irqrestore include/linux/spinlock.h:406 [inline]
 dummy_timer+0x441f/0x4550 drivers/usb/gadget/udc/dummy_hcd.c:-1
 __run_hrtimer kernel/time/hrtimer.c:1761 [inline]
 __hrtimer_run_queues+0x52c/0xc60 kernel/time/hrtimer.c:1825
 hrtimer_run_softirq+0x187/0x2b0 kernel/time/hrtimer.c:1842
 handle_softirqs+0x286/0x870 kernel/softirq.c:579
 __do_softirq kernel/softirq.c:613 [inline]
 invoke_softirq kernel/softirq.c:453 [inline]
 __irq_exit_rcu+0xca/0x1f0 kernel/softirq.c:680
 irq_exit_rcu+0x9/0x30 kernel/softirq.c:696
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1050 [inline]
 sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1050
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
RIP: 0010:__raw_spin_unlock_irq include/linux/spinlock_api_smp.h:160 [inline]
RIP: 0010:_raw_spin_unlock_irq+0x29/0x50 kernel/locking/spinlock.c:202
Code: 90 f3 0f 1e fa 53 48 89 fb 48 83 c7 18 48 8b 74 24 08 e8 0a ff 20 f6 48 89 df e8 62 96 21 f6 e8 bd e8 4a f6 fb bf 01 00 00 00 <e8> 42 8e 13 f6 65 8b 05 cb 10 24 07 85 c0 74 07 5b e9 9c d1 93 f5
RSP: 0018:ffffc90000137c60 EFLAGS: 00000286

RAX: 1f7a357c5ccacc00 RBX: ffffffff8dfe1700 RCX: 1f7a357c5ccacc00
RDX: 0000000000000000 RSI: ffffffff8d9b8acb RDI: 0000000000000001
RBP: ffff88801ceb9e18 R08: ffffffff8fa39637 R09: 1ffffffff1f472c6
R10: dffffc0000000000 R11: fffffbfff1f472c7 R12: dffffc0000000000
R13: ffff88801b6888a0 R14: ffff88801b688898 R15: ffff8880b8639700
 rescuer_thread+0x36a/0xdd0 kernel/workqueue.c:3478
 kthread+0x711/0x8a0 kernel/kthread.c:463
 ret_from_fork+0x3fc/0x770 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>