rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: 1-...!: (1 ticks this GP) idle=5b44/1/0x4000000000000000 softirq=142912/142912 fqs=0 rcu: (detected by 0, t=10502 jiffies, g=153873, q=164 ncpus=2) Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 27175 Comm: syz.8.5620 Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/16/2026 RIP: 0010:write_comp_data+0x2b/0x90 kernel/kcov.c:272 Code: 8b 05 d9 ca 59 12 49 89 f8 49 89 f1 49 89 d2 65 48 8b 3d b0 ca 59 12 a9 00 01 ff 00 74 1b f6 c4 01 74 07 a9 00 00 ff 00 74 05 cc cc cc cc 8b 87 24 17 00 00 85 c0 74 f1 8b 87 f8 16 00 00 83 RSP: 0018:ffffc90000a08e48 EFLAGS: 00000046 RAX: 0000000080010002 RBX: ffff88807e1be300 RCX: ffffffff81f5f454 RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffff88807546ca80 RBP: ffff8880b8528640 R08: 0000000000000001 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000 R13: ffff8880b8528400 R14: 0000000000000000 R15: 0000000000000000 FS: 00007f68940096c0(0000) GS:ffff888123ede000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000001b3401aff8 CR3: 000000005164b000 CR4: 00000000003526f0 Call Trace: __remove_hrtimer+0x264/0x440 kernel/time/hrtimer.c:1173 __run_hrtimer kernel/time/hrtimer.c:2012 [inline] __hrtimer_run_queues+0x352/0x9c0 kernel/time/hrtimer.c:2096 hrtimer_interrupt+0x3e5/0x940 kernel/time/hrtimer.c:2215 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1051 [inline] __sysvec_apic_timer_interrupt+0x109/0x470 arch/x86/kernel/apic/apic.c:1068 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1062 [inline] sysvec_apic_timer_interrupt+0x9e/0xc0 arch/x86/kernel/apic/apic.c:1062 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:674 RIP: 0010:lock_acquire+0x5e/0x370 kernel/locking/lockdep.c:5872 Code: 05 fb 2d 7e 12 83 f8 07 0f 87 da 00 00 00 48 0f a3 05 86 7b 3c 0f 0f 82 ac 02 00 00 8b 35 4e af 3c 0f 85 f6 0f 85 c7 00 00 00 <48> 8b 44 24 30 65 48 2b 05 9d 2d 7e 12 0f 85 ec 02 00 00 48 83 c4 RSP: 0018:ffffc900057c7668 EFLAGS: 00000206 RAX: 0000000000000046 RBX: 0000000000000000 RCX: 8a3e25eea70996f7 RDX: 0000000000000000 RSI: ffffffff8e17f6ed RDI: ffffffff8c401580 RBP: ffff8880682a05f0 R08: 00000000ffffffff R09: 0000000000000645 R10: 0000000000000200 R11: 0000000000000000 R12: 0000000000000000 R13: 0000000000000001 R14: 0000000000000000 R15: 0000000000000000 __mutex_lock_common kernel/locking/mutex.c:646 [inline] __mutex_lock+0x1a4/0x1bd0 kernel/locking/mutex.c:821 __unix_dgram_recvmsg+0x255/0xc30 net/unix/af_unix.c:2579 unix_dgram_recvmsg+0xcd/0x100 net/unix/af_unix.c:2681 sock_recvmsg_nosec net/socket.c:1126 [inline] ____sys_recvmsg+0x5eb/0x670 net/socket.c:2902 ___sys_recvmsg+0x16a/0x1a0 net/socket.c:2946 do_recvmmsg+0x2f3/0x740 net/socket.c:3041 __sys_recvmmsg net/socket.c:3115 [inline] __do_sys_recvmmsg net/socket.c:3138 [inline] __se_sys_recvmmsg net/socket.c:3131 [inline] __x64_sys_recvmmsg+0x22a/0x280 net/socket.c:3131 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x115/0x870 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f689319de99 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:00007f6894009028 EFLAGS: 00000246 ORIG_RAX: 000000000000012b RAX: ffffffffffffffda RBX: 00007f6893426090 RCX: 00007f689319de99 RDX: 0000000000010106 RSI: 00002000000000c0 RDI: 0000000000000003 RBP: 00007f6893233eaf R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000002 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f6893426128 R14: 00007f6893426090 R15: 00007ffe35707d78 rcu: rcu_preempt kthread starved for 10502 jiffies! g153873 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:27672 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5510 [inline] __schedule+0x125c/0x6730 kernel/sched/core.c:7234 __schedule_loop kernel/sched/core.c:7311 [inline] schedule+0xdd/0x2c0 kernel/sched/core.c:7326 schedule_timeout+0x127/0x280 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x1a9/0x900 kernel/rcu/tree.c:2123 rcu_gp_kthread+0x179/0x230 kernel/rcu/tree.c:2325 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: CPU: 0 UID: 0 PID: 27178 Comm: syz.8.5620 Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/16/2026 RIP: 0010:__sanitizer_cov_trace_pc+0x3f/0x70 kernel/kcov.c:217 Code: 59 12 a9 00 01 ff 00 74 1b f6 c4 01 74 07 a9 00 00 ff 00 74 05 e9 91 c4 b3 09 8b 82 24 17 00 00 85 c0 74 f1 8b 82 f8 16 00 00 <83> f8 02 75 e6 48 8b 8a 00 17 00 00 8b 92 fc 16 00 00 48 8b 01 48 RSP: 0018:ffffc900056e7858 EFLAGS: 00000246 RAX: 0000000000000002 RBX: 0000000000000001 RCX: ffffffff81fdc6fd RDX: ffff888037a48000 RSI: ffffffff81fdc6d7 RDI: ffff888037a48000 RBP: ffff8880b8541240 R08: 0000000000000005 R09: 0000000000000000 R10: 0000000000000001 R11: 0000000000000000 R12: 0000000000000003 R13: ffffed10170a8249 R14: 0000000000000001 R15: ffff8880b843c880 FS: 00007f6893fc76c0(0000) GS:ffff888123dde000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000001b34010ff8 CR3: 000000005164b000 CR4: 00000000003526f0 DR0: ffffffffffffffff DR1: 00000000000001f8 DR2: 0000000000000002 DR3: ffffffffefffff15 DR6: 00000000ffff0ff0 DR7: 0000000000000400 Call Trace: native_pause arch/x86/include/asm/vdso/processor.h:13 [inline] cpu_relax arch/x86/include/asm/vdso/processor.h:18 [inline] csd_lock_wait kernel/smp.c:342 [inline] smp_call_function_many_cond+0x587/0x16c0 kernel/smp.c:892 on_each_cpu_cond_mask+0x40/0x90 kernel/smp.c:1057 bpf_prog_pack_alloc+0x2d9/0x8c0 kernel/bpf/core.c:1022 bpf_jit_binary_pack_alloc+0xab/0x2b0 kernel/bpf/core.c:1202 bpf_int_jit_compile+0x531/0x1790 arch/x86/net/bpf_jit_comp.c:3966 bpf_prog_jit_compile kernel/bpf/core.c:2627 [inline] __bpf_prog_select_runtime+0x8ac/0xc50 kernel/bpf/core.c:2696 bpf_migrate_filter net/core/filter.c:1318 [inline] bpf_prepare_filter+0xd3f/0x11e0 net/core/filter.c:1366 bpf_prog_create_from_user+0x1e8/0x2f0 net/core/filter.c:1460 seccomp_prepare_filter kernel/seccomp.c:701 [inline] seccomp_prepare_user_filter kernel/seccomp.c:738 [inline] seccomp_set_mode_filter kernel/seccomp.c:1990 [inline] do_seccomp+0x870/0x27d0 kernel/seccomp.c:2110 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x115/0x870 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f689319de99 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:00007f6893fc7028 EFLAGS: 00000246 ORIG_RAX: 000000000000013d RAX: ffffffffffffffda RBX: 00007f6893426270 RCX: 00007f689319de99 RDX: 0000200000000040 RSI: 000000000000001d RDI: 0000000000000001 RBP: 00007f6893233eaf R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f6893426308 R14: 00007f6893426270 R15: 00007ffe35707d78