rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	0-...!: (1 GPs behind) idle=63c4/1/0x4000000000000000 softirq=92753/92754 fqs=21
rcu: 	(detected by 1, t=10505 jiffies, g=88937, q=200 ncpus=2)
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 18307 Comm: syz.0.3454 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
RIP: 0010:check_preemption_disabled+0x1/0x120 lib/smp_processor_id.c:13
Code: 00 aa 03 8c 48 c7 c6 40 aa 03 8c eb 1c 66 66 66 2e 0f 1f 84 00 00 00 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 55 <41> 57 41 56 53 48 83 ec 10 65 48 8b 05 de 94 3e 07 48 89 44 24 08
RSP: 0018:ffffc90000007ce8 EFLAGS: 00000082
RAX: ffffffff81adfe57 RBX: 0000000000000001 RCX: 0000000000010000
RDX: ffff88807af3bc80 RSI: ffffffff8c03aa40 RDI: ffffffff8c03aa00
RBP: ffffc90000007e90 R08: ffffffff8fc39677 R09: 1ffffffff1f872ce
R10: dffffc0000000000 R11: fffffbfff1f872cf R12: ffff88807d27e340
R13: dffffc0000000000 R14: 0000000000000000 R15: ffff8880b8627bc0
FS:  00007f7bb09f66c0(0000) GS:ffff8881259e7000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f7bb09f5f98 CR3: 000000005e274000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000008
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
Call Trace:
 <IRQ>
 rcu_is_watching_curr_cpu include/linux/context_tracking.h:128 [inline]
 rcu_is_watching+0x15/0xb0 kernel/rcu/tree.c:751
 trace_hrtimer_cancel include/trace/events/timer.h:317 [inline]
 debug_deactivate+0x80/0x200 kernel/time/hrtimer.c:484
 __run_hrtimer kernel/time/hrtimer.c:1745 [inline]
 __hrtimer_run_queues+0x2b0/0xc60 kernel/time/hrtimer.c:1841
 hrtimer_interrupt+0x45b/0xaa0 kernel/time/hrtimer.c:1903
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1041 [inline]
 __sysvec_apic_timer_interrupt+0x10b/0x410 arch/x86/kernel/apic/apic.c:1058
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1052 [inline]
 sysvec_apic_timer_interrupt+0xa1/0xc0 arch/x86/kernel/apic/apic.c:1052
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
RIP: 0010:check_kcov_mode kernel/kcov.c:194 [inline]
RIP: 0010:__sanitizer_cov_trace_pc+0x37/0x70 kernel/kcov.c:217
Code: 08 90 c3 92 65 8b 15 f8 b6 03 11 81 e2 00 01 ff 00 74 11 81 fa 00 01 00 00 75 35 83 b9 7c 16 00 00 00 74 2c 8b 91 58 16 00 00 <83> fa 02 75 21 48 8b 91 60 16 00 00 48 8b 32 48 8d 7e 01 8b 89 5c
RSP: 0018:ffffc9000544f9e0 EFLAGS: 00000246
RAX: ffffffff820c15f2 RBX: ffff88807af3c218 RCX: ffff88807af3bc80
RDX: 0000000000000002 RSI: ffffffff8dd9240a RDI: ffffffff8c03aa60
RBP: 00000000000000a2 R08: ffffc9000544fad7 R09: 0000000000000000
R10: ffffc9000544faa0 R11: fffff52000a89f5b R12: dffffc0000000000
R13: 1ffff1100f5e7843 R14: ffffffff8c02fd60 R15: ffff88807d118ac0
 __might_fault+0xa2/0x130 mm/memory.c:7130
 _inline_copy_from_user include/linux/uaccess.h:162 [inline]
 _copy_from_user+0x28/0xb0 lib/usercopy.c:18
 copy_from_user include/linux/uaccess.h:212 [inline]
 copy_msghdr_from_user net/socket.c:2547 [inline]
 recvmsg_copy_msghdr net/socket.c:2803 [inline]
 ___sys_recvmsg+0x12e/0x510 net/socket.c:2875
 do_recvmmsg+0x307/0x770 net/socket.c:2974
 __sys_recvmmsg net/socket.c:3048 [inline]
 __do_sys_recvmmsg net/socket.c:3071 [inline]
 __se_sys_recvmmsg net/socket.c:3064 [inline]
 __x64_sys_recvmmsg+0x190/0x240 net/socket.c:3064
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f7bb278eec9
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 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 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f7bb09f6038 EFLAGS: 00000246 ORIG_RAX: 000000000000012b
RAX: ffffffffffffffda RBX: 00007f7bb29e6090 RCX: 00007f7bb278eec9
RDX: 0000000000010106 RSI: 00002000000000c0 RDI: 0000000000000005
RBP: 00007f7bb2811f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000002 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f7bb29e6128 R14: 00007f7bb29e6090 R15: 00007ffc28d11848
 </TASK>
rcu: rcu_preempt kthread starved for 10400 jiffies! g88937 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:26936 pid:16    tgid:16    ppid:2      task_flags:0x208040 flags:0x00080000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5360 [inline]
 __schedule+0x1798/0x4cc0 kernel/sched/core.c:6964
 __schedule_loop kernel/sched/core.c:7046 [inline]
 schedule+0x165/0x360 kernel/sched/core.c:7061
 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+0x4bc/0x870 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>
rcu: Stack dump where RCU GP kthread last ran:
CPU: 1 UID: 0 PID: 18127 Comm: udevd Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
RIP: 0010:csd_lock_wait kernel/smp.c:342 [inline]
RIP: 0010:smp_call_function_many_cond+0xd33/0x12d0 kernel/smp.c:877
Code: 45 8b 2c 24 44 89 ee 83 e6 01 31 ff e8 36 79 0b 00 41 83 e5 01 49 bd 00 00 00 00 00 fc ff df 75 07 e8 e1 74 0b 00 eb 38 f3 90 <42> 0f b6 04 2b 84 c0 75 11 41 f7 04 24 01 00 00 00 74 1e e8 c5 74
RSP: 0018:ffffc90003067540 EFLAGS: 00000293
RAX: ffffffff81b4645b RBX: 1ffff110170c8441 RCX: ffff88802c0a5ac0
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000
RBP: ffffc900030676c0 R08: ffffffff8fc39677 R09: 1ffffffff1f872ce
R10: dffffc0000000000 R11: fffffbfff1f872cf R12: ffff8880b8642208
R13: dffffc0000000000 R14: ffff8880b873b200 R15: 0000000000000000
FS:  00007f9250dd6880(0000) GS:ffff888125ae7000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000110c3967ff CR3: 000000007425a000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 000000000e000408
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 on_each_cpu_cond_mask+0x3f/0x80 kernel/smp.c:1043
 __flush_tlb_multi arch/x86/include/asm/paravirt.h:91 [inline]
 flush_tlb_multi arch/x86/mm/tlb.c:1361 [inline]
 flush_tlb_mm_range+0x6b1/0x12d0 arch/x86/mm/tlb.c:1451
 tlb_flush arch/x86/include/asm/tlb.h:23 [inline]
 tlb_flush_mmu_tlbonly include/asm-generic/tlb.h:490 [inline]
 tlb_flush_mmu+0x1a7/0x680 mm/mmu_gather.c:403
 tlb_finish_mmu+0xc3/0x1d0 mm/mmu_gather.c:497
 vms_clear_ptes+0x42c/0x540 mm/vma.c:1235
 vms_complete_munmap_vmas+0x206/0x8a0 mm/vma.c:1277
 do_vmi_align_munmap+0x364/0x440 mm/vma.c:1536
 do_vmi_munmap+0x253/0x2e0 mm/vma.c:1584
 __vm_munmap+0x207/0x380 mm/vma.c:3180
 __do_sys_munmap mm/mmap.c:1080 [inline]
 __se_sys_munmap mm/mmap.c:1077 [inline]
 __x64_sys_munmap+0x60/0x70 mm/mmap.c:1077
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f925071e097
Code: 73 01 c3 48 8b 0d 61 2d 0d 00 f7 d8 64 89 01 48 83 c8 ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 b8 0b 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d 31 2d 0d 00 f7 d8 64 89 01 48
RSP: 002b:00007fff0dee2938 EFLAGS: 00000206 ORIG_RAX: 000000000000000b
RAX: ffffffffffffffda RBX: 000055fc08d66bf0 RCX: 00007f925071e097
RDX: 0000000000000000 RSI: 00000000009480e8 RDI: 00007f924fc00000
RBP: 000055fc08d66910 R08: 000055fc08d79140 R09: 0000000000000006
R10: 0000000000000000 R11: 0000000000000206 R12: 000055fbfc17d588
R13: 00007fff0dee29c0 R14: 0000000000000000 R15: 0000000000000000
 </TASK>