rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P21942 (detected by 1, t=10502 jiffies, g=89165, q=1129) task:syz.0.6551 state:R running task stack:22992 pid:21942 ppid: 20633 flags:0x0000400c Call Trace: rcu: rcu_preempt kthread timer wakeup didn't happen for 10501 jiffies! g89165 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 rcu: Possible timer handling issue on cpu=0 timer-softirq=43644 rcu: rcu_preempt kthread starved for 10502 jiffies! g89165 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 ->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:I stack:27152 pid: 15 ppid: 2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5049 [inline] __schedule+0x11ef/0x43c0 kernel/sched/core.c:6395 schedule+0x11b/0x1e0 kernel/sched/core.c:6478 schedule_timeout+0x184/0x2d0 kernel/time/timer.c:2117 rcu_gp_fqs_loop+0x2be/0x11d0 kernel/rcu/tree.c:1972 rcu_gp_kthread+0x9b/0x370 kernel/rcu/tree.c:2145 kthread+0x436/0x520 kernel/kthread.c:334 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287 rcu: Stack dump where RCU GP kthread last ran: Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 PID: 21942 Comm: syz.0.6551 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026 RIP: 0010:tracing_gen_ctx_irq_test+0xdb/0x130 kernel/trace/trace.c:2634 Code: fc ff 41 0f b6 c4 83 f8 0f 41 bc 0f 00 00 00 41 0f 43 c4 48 81 c3 38 04 00 00 48 89 d9 48 c1 e9 03 42 0f b6 0c 39 84 c9 75 34 <8b> 0b 66 83 f9 0f 44 0f 42 e1 41 c1 e4 04 41 c1 e6 10 44 89 f1 81 RSP: 0018:ffffc9000307e748 EFLAGS: 00000046 RAX: 0000000000000002 RBX: ffff888022e73fb8 RCX: 0000000000000000 RDX: 0000000000000002 RSI: 0000000000000002 RDI: 0000000000000000 RBP: 0000000000000002 R08: ffff888022e73b87 R09: 1ffff110045ce770 R10: dffffc0000000000 R11: ffffed10045ce771 R12: 000000000000000f R13: 0000000000000000 R14: 0000000000000005 R15: dffffc0000000000 FS: 00007f215f4836c0(0000) GS:ffff8880b9000000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000001b30323ffc CR3: 000000004bd89000 CR4: 00000000003506f0 DR0: 0000200000000300 DR1: 0000200000000300 DR2: 0000200000000300 DR3: 0000200000000300 DR6: 00000000ffff0ff0 DR7: 0000000000000600 Call Trace: tracing_gen_ctx_flags include/linux/trace_events.h:183 [inline] tracing_gen_ctx include/linux/trace_events.h:190 [inline] perf_trace_buf_update+0xa8/0x230 kernel/trace/trace_event_perf.c:433 perf_tp_event+0x1a2/0xbf0 kernel/events/core.c:10043 perf_trace_run_bpf_submit+0xf3/0x1c0 kernel/events/core.c:10021 perf_trace_preemptirq_template+0x2aa/0x360 include/trace/events/preemptirq.h:14 trace_irq_enable_rcuidle+0x108/0x180 include/trace/events/preemptirq.h:40 trace_hardirqs_on+0x57/0x80 kernel/trace/trace_preemptirq.c:44 asm_sysvec_irq_work+0x16/0x20 arch/x86/include/asm/idtentry.h:713 RIP: 0010:rcu_read_unlock_special+0x7f/0x4a0 kernel/rcu/tree_plugin.h:674 Code: eb 03 48 b8 f1 f1 f1 f1 f8 f2 f2 f2 4a 89 04 2b 42 c7 44 2b 08 f8 f3 f3 f3 65 44 8b 35 f2 cc 9c 7e 41 f7 c6 00 00 f0 00 74 40 <48> c7 44 24 20 0e 36 e0 45 4a c7 04 2b 00 00 00 00 42 c7 44 2b 08 RSP: 0018:ffffc9000307ece0 EFLAGS: 00000206 RAX: e91472b23f738a00 RBX: 1ffff9200060fda0 RCX: e91472b23f738a00 RDX: dffffc0000000000 RSI: ffffffff8a2b3180 RDI: ffffffff8a7a09c0 RBP: ffffc9000307edb8 R08: ffffffff901d80e7 R09: 1ffffffff203b01c R10: dffffc0000000000 R11: fffffbfff203b01d R12: 0000000000000000 R13: dffffc0000000000 R14: 0000000000000246 R15: ffffffff8c3238a0 __rcu_read_unlock+0x78/0xd0 kernel/rcu/tree_plugin.h:422 rcu_read_unlock include/linux/rcupdate.h:772 [inline] d_alloc_parallel+0x107b/0x1330 fs/dcache.c:2673 __lookup_slow+0x134/0x410 fs/namei.c:1656 lookup_one_len+0x19d/0x2d0 fs/namei.c:2726 start_creating+0x184/0x310 fs/debugfs/inode.c:354 __debugfs_create_file+0x6f/0x510 fs/debugfs/inode.c:399 debugfs_hw_add+0x3c6/0x420 net/mac80211/debugfs.c:714 ieee80211_register_hw+0x2ac6/0x3af0 net/mac80211/main.c:1312 mac80211_hwsim_new_radio+0x20d3/0x4080 drivers/net/wireless/mac80211_hwsim.c:3373 hwsim_new_radio_nl+0xa6f/0xc40 drivers/net/wireless/mac80211_hwsim.c:3949 genl_family_rcv_msg_doit net/netlink/genetlink.c:731 [inline] genl_family_rcv_msg net/netlink/genetlink.c:775 [inline] genl_rcv_msg+0xcea/0xf90 net/netlink/genetlink.c:792 netlink_rcv_skb+0x1f5/0x440 net/netlink/af_netlink.c:2507 genl_rcv+0x24/0x40 net/netlink/genetlink.c:803 netlink_unicast_kernel net/netlink/af_netlink.c:1318 [inline] netlink_unicast+0x774/0x920 net/netlink/af_netlink.c:1344 netlink_sendmsg+0x8ba/0xbe0 net/netlink/af_netlink.c:1918 sock_sendmsg_nosec net/socket.c:706 [inline] __sock_sendmsg net/socket.c:718 [inline] ____sys_sendmsg+0x5b7/0x8f0 net/socket.c:2445 ___sys_sendmsg+0x236/0x2e0 net/socket.c:2499 __sys_sendmsg net/socket.c:2528 [inline] __do_sys_sendmsg net/socket.c:2537 [inline] __se_sys_sendmsg+0x1af/0x290 net/socket.c:2535 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: 0033:0x7f2161229e59 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:00007f215f483028 EFLAGS: 00000246 ORIG_RAX: 000000000000002e RAX: ffffffffffffffda RBX: 00007f21614a2fa0 RCX: 00007f2161229e59 RDX: 0000000000000000 RSI: 0000200000000000 RDI: 000000000000000b RBP: 00007f21612bfd6f R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f21614a3038 R14: 00007f21614a2fa0 R15: 00007ffc8294c2b8