rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P13056/1:b..l
	(detected by 1, t=10502 jiffies, g=50881, q=91)
task:syz.9.2125      state:R  running task     stack:25824 pid:13056 ppid:  8029 flags:0x00004004
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5049 [inline]
 __schedule+0x11bb/0x4390 kernel/sched/core.c:6395
 preempt_schedule_irq+0xb1/0x150 kernel/sched/core.c:6799
 irqentry_exit+0x63/0x70 kernel/entry/common.c:432
 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:676
RIP: 0010:__preempt_count_add kernel/rcu/tree.c:1119 [inline]
RIP: 0010:rcu_is_watching+0x2/0xa0 kernel/rcu/tree.c:1122
Code: 1b 48 8d 65 e8 5b 41 5e 41 5f 5d c3 e8 c7 bc 45 08 41 f7 c7 00 02 00 00 75 b8 eb b7 e8 a7 bc 45 08 0f 1f 80 00 00 00 00 41 57 <41> 56 53 65 ff 05 8c be 9e 7e e8 9f cc 45 08 89 c3 83 f8 08 73 5c
RSP: 0018:ffffc90003d8f640 EFLAGS: 00000246
RAX: 0000000000000001 RBX: 0000000000000000 RCX: ffff888063d9d940
RDX: 0000000000000002 RSI: 0000000000000001 RDI: 0000000000000000
RBP: ffffc90003d8f710 R08: dffffc0000000000 R09: fffffbfff1ff7c19
R10: fffffbfff1ff7c19 R11: 1ffffffff1ff7c18 R12: dffffc0000000000
R13: 1ffff920007b1ecc R14: ffff888063d9d940 R15: 0000000000000001
 rcu_read_lock_held_common kernel/rcu/update.c:108 [inline]
 rcu_read_lock_held+0x11/0x40 kernel/rcu/update.c:309
 count_memcg_event_mm+0x140/0x360 include/linux/memcontrol.h:1079
 handle_mm_fault+0x12d/0x43b0 mm/memory.c:4863
 do_user_addr_fault+0x489/0xc80 arch/x86/mm/fault.c:1357
 handle_page_fault arch/x86/mm/fault.c:1445 [inline]
 exc_page_fault+0x60/0x100 arch/x86/mm/fault.c:1501
 asm_exc_page_fault+0x22/0x30 arch/x86/include/asm/idtentry.h:606
RIP: 0010:copy_user_generic_unrolled+0x86/0xc0 arch/x86/lib/copy_user_64.S:91
Code: 4c 8b 5e 38 4c 89 47 20 4c 89 4f 28 4c 89 57 30 4c 89 5f 38 48 8d 76 40 48 8d 7f 40 ff c9 75 b6 89 d1 83 e2 07 c1 e9 03 74 12 <4c> 8b 06 4c 89 07 48 8d 76 08 48 8d 7f 08 ff c9 75 ee 21 d2 74 10
RSP: 0018:ffffc90003d8fa60 EFLAGS: 00050202
RAX: ffffffff83daed01 RBX: 0000000000000038 RCX: 0000000000000007
RDX: 0000000000000000 RSI: 00002000000cd000 RDI: ffffc90003d8fb00
RBP: 0000000000000000 R08: dffffc0000000000 R09: fffff520007b1f67
R10: fffff520007b1f67 R11: 1ffff920007b1f60 R12: 00007ffffffff000
R13: 00002000000cd038 R14: ffffc90003d8fb00 R15: 00002000000cd000
 copy_user_generic arch/x86/include/asm/uaccess_64.h:37 [inline]
 raw_copy_from_user arch/x86/include/asm/uaccess_64.h:52 [inline]
 _copy_from_user+0xfa/0x170 lib/usercopy.c:23
 copy_from_user include/linux/uaccess.h:192 [inline]
 __copy_msghdr_from_user net/socket.c:2328 [inline]
 copy_msghdr_from_user net/socket.c:2379 [inline]
 recvmsg_copy_msghdr net/socket.c:2631 [inline]
 ___sys_recvmsg+0x129/0x4f0 net/socket.c:2703
 do_recvmmsg+0x344/0x7a0 net/socket.c:2801
 __sys_recvmmsg net/socket.c:2880 [inline]
 __do_sys_recvmmsg net/socket.c:2903 [inline]
 __se_sys_recvmmsg net/socket.c:2896 [inline]
 __x64_sys_recvmmsg+0x18d/0x240 net/socket.c:2896
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7f714257e6c9
RSP: 002b:00007f71407c4038 EFLAGS: 00000246 ORIG_RAX: 000000000000012b
RAX: ffffffffffffffda RBX: 00007f71427d5090 RCX: 00007f714257e6c9
RDX: 0000000000010106 RSI: 00002000000000c0 RDI: 0000000000000005
RBP: 00007f7142600f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000002 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f71427d5128 R14: 00007f71427d5090 R15: 00007ffe94edb6f8
 </TASK>
rcu: rcu_preempt kthread starved for 10543 jiffies! g50881 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=1
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:27168 pid:   15 ppid:     2 flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5049 [inline]
 __schedule+0x11bb/0x4390 kernel/sched/core.c:6395
 schedule+0x11b/0x1e0 kernel/sched/core.c:6478
 schedule_timeout+0x15c/0x280 kernel/time/timer.c:1914
 rcu_gp_fqs_loop+0x29e/0x11b0 kernel/rcu/tree.c:1972
 rcu_gp_kthread+0x98/0x350 kernel/rcu/tree.c:2145
 kthread+0x436/0x520 kernel/kthread.c:334
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
 </TASK>
rcu: Stack dump where RCU GP kthread last ran:
NMI backtrace for cpu 1
CPU: 1 PID: 0 Comm: swapper/1 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025
Call Trace:
 <IRQ>
 dump_stack_lvl+0x168/0x230 lib/dump_stack.c:106
 nmi_cpu_backtrace+0x397/0x3d0 lib/nmi_backtrace.c:111
 nmi_trigger_cpumask_backtrace+0x163/0x280 lib/nmi_backtrace.c:62
 trigger_single_cpu_backtrace include/linux/nmi.h:166 [inline]
 rcu_check_gp_kthread_starvation+0x1cd/0x250 kernel/rcu/tree_stall.h:487
 print_other_cpu_stall+0x10c8/0x1220 kernel/rcu/tree_stall.h:592
 check_cpu_stall kernel/rcu/tree_stall.h:745 [inline]
 rcu_pending kernel/rcu/tree.c:3936 [inline]
 rcu_sched_clock_irq+0x831/0x1110 kernel/rcu/tree.c:2619
 update_process_times+0x193/0x200 kernel/time/timer.c:1818
 tick_sched_handle kernel/time/tick-sched.c:254 [inline]
 tick_sched_timer+0x37d/0x560 kernel/time/tick-sched.c:1473
 __run_hrtimer kernel/time/hrtimer.c:1685 [inline]
 __hrtimer_run_queues+0x4fe/0xc40 kernel/time/hrtimer.c:1749
 hrtimer_interrupt+0x3bb/0x8d0 kernel/time/hrtimer.c:1811
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1097 [inline]
 __sysvec_apic_timer_interrupt+0x137/0x4a0 arch/x86/kernel/apic/apic.c:1114
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1108 [inline]
 sysvec_apic_timer_interrupt+0x9b/0xc0 arch/x86/kernel/apic/apic.c:1108
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:676
RIP: 0010:default_idle+0xb/0x10 arch/x86/kernel/process.c:730
Code: bf 48 89 df e8 66 76 09 f8 eb b5 e8 9f af f6 ff 00 00 cc cc 00 00 cc cc 00 00 cc cc 00 00 cc 66 90 0f 00 2d 37 06 53 00 fb f4 <c3> 0f 1f 40 00 41 57 41 56 53 49 be 00 00 00 00 00 fc ff df 65 48
RSP: 0018:ffffc90000d67d48 EFLAGS: 000002c2
RAX: 45257b09a47ba700 RBX: ffff88813fe48000 RCX: 45257b09a47ba700
RDX: 0000000000000001 RSI: ffffffff8a0b1c60 RDI: ffffffff8a59e580
RBP: ffffc90000d67e80 R08: dffffc0000000000 R09: ffffed1017227662
R10: ffffed1017227662 R11: 1ffff11017227661 R12: ffffffff8d699d28
R13: 0000000000000001 R14: 0000000000000001 R15: 1ffff11027fc9000
 default_idle_call+0x81/0xc0 kernel/sched/idle.c:112
 cpuidle_idle_call kernel/sched/idle.c:194 [inline]
 do_idle+0x21b/0x5b0 kernel/sched/idle.c:306
 cpu_startup_entry+0x14/0x20 kernel/sched/idle.c:403
 start_secondary+0x31f/0x430 arch/x86/kernel/smpboot.c:281
 secondary_startup_64_no_verify+0xb1/0xbb
 </TASK>