rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P5602/1:b..l rcu: (detected by 0, t=10502 jiffies, g=41013, q=356 ncpus=2) task:syz-executor state:R running task stack:23320 pid:5602 tgid:5602 ppid:5599 task_flags:0x400140 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5387 [inline] __schedule+0x10e9/0x6820 kernel/sched/core.c:7188 preempt_schedule_common+0x42/0xc0 kernel/sched/core.c:7369 preempt_schedule_thunk+0x16/0x30 arch/x86/entry/thunk.S:12 __raw_spin_unlock include/linux/spinlock_api_smp.h:169 [inline] _raw_spin_unlock+0x3e/0x50 kernel/locking/spinlock.c:190 spin_unlock include/linux/spinlock.h:390 [inline] copy_pte_range mm/memory.c:1331 [inline] copy_pmd_range mm/memory.c:1392 [inline] copy_pud_range mm/memory.c:1429 [inline] copy_p4d_range mm/memory.c:1453 [inline] copy_page_range+0x1c02/0x5b00 mm/memory.c:1539 dup_mmap+0xd25/0x2180 mm/mmap.c:1840 dup_mm kernel/fork.c:1534 [inline] copy_mm kernel/fork.c:1586 [inline] copy_process+0x7b37/0x7fa0 kernel/fork.c:2262 kernel_clone+0x12e/0x9c0 kernel/fork.c:2723 __do_sys_clone+0xd9/0x120 kernel/fork.c:2864 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x10b/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f17fafc5852 RSP: 002b:00007fff410c32a0 EFLAGS: 00000246 ORIG_RAX: 0000000000000038 RAX: ffffffffffffffda RBX: 00007fff410c32a0 RCX: 00007f17fafc5852 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000001200011 RBP: 00007fff410c342c R08: 0000000000000000 R09: 0000000000000001 R10: 00005555875277d0 R11: 0000000000000246 R12: 0000000000000001 R13: 00000000000927c0 R14: 0000000000057b14 R15: 00007fff410c3480 rcu: rcu_preempt kthread starved for 10495 jiffies! g41013 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:27752 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5387 [inline] __schedule+0x10e9/0x6820 kernel/sched/core.c:7188 __schedule_loop kernel/sched/core.c:7267 [inline] schedule+0xdd/0x390 kernel/sched/core.c:7282 schedule_timeout+0x127/0x280 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x1a9/0x900 kernel/rcu/tree.c:2095 rcu_gp_kthread+0x179/0x230 kernel/rcu/tree.c:2297 kthread+0x370/0x450 kernel/kthread.c:436 ret_from_fork+0x72b/0xd50 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 rcu: Stack dump where RCU GP kthread last ran: Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 9545 Comm: syz.0.973 Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026 RIP: 0010:__raw_callee_save___pv_queued_spin_unlock+0x10/0x18 Code: 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 f3 0f 1e fa 52 b8 01 00 00 00 31 d2 f0 0f b0 17 <75> 06 5a c3 cc cc cc cc 56 0f b6 f0 e8 9f ff ff ff 5e 5a e9 d8 40 RSP: 0018:ffffc90000a08e40 EFLAGS: 00000046 RAX: 0000000000000001 RBX: ffff8880b85284c0 RCX: ffffffff81e4c7a3 RDX: 0000000000000000 RSI: 0000000000000004 RDI: ffff8880b85284c0 RBP: ffff8880b85284c8 R08: 0000000000000000 R09: ffffed10170a5098 R10: ffff8880b85284c3 R11: 0000000000000001 R12: ffff8880b85284d0 R13: 0000000000000001 R14: dffffc0000000000 R15: ffff8880b8528650 FS: 00007fe6532226c0(0000) GS:ffff888124479000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000000 CR3: 000000003411d000 CR4: 00000000003526f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600 Call Trace: pv_queued_spin_unlock arch/x86/include/asm/paravirt-spinlock.h:40 [inline] queued_spin_unlock arch/x86/include/asm/paravirt-spinlock.h:72 [inline] do_raw_spin_unlock+0x145/0x1e0 kernel/locking/spinlock_debug.c:142 __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:177 [inline] _raw_spin_unlock_irqrestore+0x22/0x80 kernel/locking/spinlock.c:198 __run_hrtimer kernel/time/hrtimer.c:1926 [inline] __hrtimer_run_queues+0x383/0xa00 kernel/time/hrtimer.c:1994 hrtimer_interrupt+0x3e5/0x940 kernel/time/hrtimer.c:2113 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1050 [inline] __sysvec_apic_timer_interrupt+0x10b/0x460 arch/x86/kernel/apic/apic.c:1067 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1061 [inline] sysvec_apic_timer_interrupt+0x9e/0xc0 arch/x86/kernel/apic/apic.c:1061 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697 RIP: 0010:finish_task_switch.isra.0+0x2d3/0x1010 kernel/sched/core.c:5244 Code: 2f 0a 00 00 41 c7 87 e0 0d 00 00 00 00 00 00 e9 0f 04 00 00 49 8d 7f 48 e8 fa 4b b7 09 e8 35 8d 3b 00 fb 48 8d bb a8 16 00 00 <48> b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 0f b6 04 02 84 RSP: 0018:ffffc9000848f4c8 EFLAGS: 00000202 RAX: 00000000000107b5 RBX: ffff8880294f8000 RCX: 0000000000000000 RDX: 0000000000000000 RSI: ffffffff8df1e366 RDI: ffff8880294f96a8 RBP: ffffc9000848f520 R08: 0000000000000001 R09: 0000000000000000 R10: 0000000000000001 R11: ffffffff81d54282 R12: ffff888054aeca00 R13: 0000000000000001 R14: ffffffff90d7b9e4 R15: ffff8880b853b240 context_switch kernel/sched/core.c:5390 [inline] __schedule+0x10f1/0x6820 kernel/sched/core.c:7188 __schedule_loop kernel/sched/core.c:7267 [inline] schedule+0xdd/0x390 kernel/sched/core.c:7282 schedule_timeout+0x1b2/0x280 kernel/time/sleep_timeout.c:75 unix_wait_for_peer+0x268/0x2a0 net/unix/af_unix.c:1622 unix_dgram_sendmsg+0x1696/0x1810 net/unix/af_unix.c:2261 sock_sendmsg_nosec net/socket.c:787 [inline] __sock_sendmsg net/socket.c:802 [inline] ____sys_sendmsg+0x9e1/0xb70 net/socket.c:2698 ___sys_sendmsg+0x190/0x1e0 net/socket.c:2752 __sys_sendmmsg+0x205/0x430 net/socket.c:2841 __do_sys_sendmmsg net/socket.c:2868 [inline] __se_sys_sendmmsg net/socket.c:2865 [inline] __x64_sys_sendmmsg+0x9c/0x100 net/socket.c:2865 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x10b/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fe65239cdd9 Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 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 e8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007fe653222028 EFLAGS: 00000246 ORIG_RAX: 0000000000000133 RAX: ffffffffffffffda RBX: 00007fe652615fa0 RCX: 00007fe65239cdd9 RDX: 0400000000000041 RSI: 0000200000000000 RDI: 0000000000000007 RBP: 00007fe652432d69 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fe652616038 R14: 00007fe652615fa0 R15: 00007ffdbd1dca28