rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P21357/1:b..l rcu: (detected by 0, t=10505 jiffies, g=127073, q=488 ncpus=2) task:syz.7.3569 state:R running task stack:25592 pid:21357 tgid:21357 ppid:15835 task_flags:0x40004c flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5388 [inline] __schedule+0x1821/0x5740 kernel/sched/core.c:7189 preempt_schedule_common+0x82/0xd0 kernel/sched/core.c:7370 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+0x3f/0x50 kernel/locking/spinlock.c:190 spin_unlock include/linux/spinlock.h:390 [inline] zap_pte_range mm/memory.c:1964 [inline] zap_pmd_range mm/memory.c:2020 [inline] zap_pud_range mm/memory.c:2048 [inline] zap_p4d_range mm/memory.c:2069 [inline] __zap_vma_range+0x3d26/0x4b50 mm/memory.c:2109 unmap_vmas+0x379/0x530 mm/memory.c:2178 exit_mmap+0x280/0x9e0 mm/mmap.c:1300 __mmput+0x118/0x430 kernel/fork.c:1178 exit_mm+0x1f6/0x2d0 kernel/exit.c:582 do_exit+0x6a2/0x22c0 kernel/exit.c:964 do_group_exit+0x21b/0x2d0 kernel/exit.c:1119 __do_sys_exit_group kernel/exit.c:1130 [inline] __se_sys_exit_group kernel/exit.c:1128 [inline] __x64_sys_exit_group+0x3f/0x40 kernel/exit.c:1128 x64_sys_call+0x221a/0x2240 arch/x86/include/generated/asm/syscalls_64.h:232 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x15f/0x560 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7ff7cfd9ce59 RSP: 002b:00007ffcb9ef0878 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7 RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007ff7cfd9ce59 RDX: 0000000000000064 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 00007ffcb9ef08dc R08: 0000000000000000 R09: 00000000000927c0 R10: 0000000000000001 R11: 0000000000000246 R12: 00000000000000fc R13: 00000000000927c0 R14: 0000000000141f4f R15: 00007ffcb9ef0930 rcu: rcu_preempt kthread starved for 10505 jiffies! g127073 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:27736 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5388 [inline] __schedule+0x1821/0x5740 kernel/sched/core.c:7189 __schedule_loop kernel/sched/core.c:7268 [inline] schedule+0x164/0x360 kernel/sched/core.c:7283 schedule_timeout+0x158/0x2c0 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x312/0x11d0 kernel/rcu/tree.c:2095 rcu_gp_kthread+0x9e/0x2b0 kernel/rcu/tree.c:2297 kthread+0x389/0x470 kernel/kthread.c:436 ret_from_fork+0x514/0xb70 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: 21355 Comm: syz.8.3583 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:__lock_is_held kernel/locking/lockdep.c:5601 [inline] RIP: 0010:lock_is_held_type+0x8b/0x150 kernel/locking/lockdep.c:5940 Code: 41 83 bd 88 0b 00 00 00 7e 48 4c 89 eb 48 81 c3 90 0b 00 00 45 31 ff 49 83 ff 31 73 24 48 89 df 4c 89 f6 e8 f7 01 00 00 85 c0 <75> 2a 49 ff c7 49 63 85 88 0b 00 00 48 83 c3 28 49 39 c7 7c d8 eb RSP: 0018:ffffc90000a08da0 EFLAGS: 00000002 RAX: 0000000000000001 RBX: ffff888035198b90 RCX: 0000000000010002 RDX: ffff888035198000 RSI: ffff8880b8728298 RDI: ffff888035198b90 RBP: 00000000ffffffff R08: ffff888052343317 R09: ffff888052343308 R10: dffffc0000000000 R11: ffffed100a468663 R12: 0000000000000046 R13: ffff888035198000 R14: ffff8880b8728298 R15: 0000000000000000 FS: 00007fd6b7cc36c0(0000) GS:ffff888125387000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fd6b6dea540 CR3: 0000000036f50000 CR4: 0000000000350ef0 Call Trace: lock_is_held include/linux/lockdep.h:249 [inline] __run_hrtimer kernel/time/hrtimer.c:1896 [inline] __hrtimer_run_queues+0x20c/0xa20 kernel/time/hrtimer.c:1994 hrtimer_interrupt+0x44b/0x950 kernel/time/hrtimer.c:2113 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1050 [inline] __sysvec_apic_timer_interrupt+0x102/0x430 arch/x86/kernel/apic/apic.c:1067 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1061 [inline] sysvec_apic_timer_interrupt+0xa1/0xc0 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+0x427/0xbe0 kernel/sched/core.c:5245 Code: 41 c7 84 24 e0 0d 00 00 00 00 00 00 e9 27 06 00 00 49 83 c4 48 4c 89 e7 e8 56 28 17 0a e8 31 fc 38 00 fb 49 8d bd b0 16 00 00 <48> 89 f8 48 c1 e8 03 42 0f b6 04 38 84 c0 0f 85 7b 03 00 00 41 80 RSP: 0018:ffffc9000d38f210 EFLAGS: 00000202 RAX: 000000000000a6e9 RBX: 1ffff110170e7784 RCX: 0000000080000001 RDX: 0000000000000000 RSI: ffffffff8dfad31b RDI: ffff8880351996b0 RBP: ffffc9000d38f270 R08: ffffffff9030dbf7 R09: 1ffffffff2061b7e R10: dffffc0000000000 R11: fffffbfff2061b7f R12: ffff8880b863ae88 R13: ffff888035198000 R14: ffff88801dae8000 R15: dffffc0000000000 context_switch kernel/sched/core.c:5391 [inline] __schedule+0x1829/0x5740 kernel/sched/core.c:7189 __schedule_loop kernel/sched/core.c:7268 [inline] schedule+0x164/0x360 kernel/sched/core.c:7283 schedule_timeout+0xc3/0x2c0 kernel/time/sleep_timeout.c:75 unix_wait_for_peer+0x1f5/0x2f0 net/unix/af_unix.c:1622 unix_dgram_sendmsg+0xb73/0x18d0 net/unix/af_unix.c:2261 sock_sendmsg_nosec net/socket.c:787 [inline] __sock_sendmsg net/socket.c:802 [inline] ____sys_sendmsg+0x972/0x9f0 net/socket.c:2698 ___sys_sendmsg+0x2a5/0x360 net/socket.c:2752 __sys_sendmmsg+0x27c/0x4e0 net/socket.c:2841 __do_sys_sendmmsg net/socket.c:2868 [inline] __se_sys_sendmmsg net/socket.c:2865 [inline] __x64_sys_sendmmsg+0xa0/0xc0 net/socket.c:2865 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x15f/0x560 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fd6b6d9ce59 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:00007fd6b7cc3028 EFLAGS: 00000246 ORIG_RAX: 0000000000000133 RAX: ffffffffffffffda RBX: 00007fd6b7015fa0 RCX: 00007fd6b6d9ce59 RDX: 0000000000000651 RSI: 0000200000000000 RDI: 0000000000000005 RBP: 00007fd6b6e32d6f R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fd6b7016038 R14: 00007fd6b7015fa0 R15: 00007ffce0956938