rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: (detected by 1, t=10506 jiffies, g=164593, q=569 ncpus=2) rcu: All QSes seen, last rcu_preempt kthread activity 10506 (4295065581-4295055075), jiffies_till_next_fqs=1, root ->qsmask 0x0 rcu: rcu_preempt kthread starved for 10506 jiffies! g164593 f0x2 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:27656 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5388 [inline] __schedule+0x1295/0x67a0 kernel/sched/core.c:7189 __schedule_loop kernel/sched/core.c:7268 [inline] schedule+0xdd/0x390 kernel/sched/core.c:7283 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 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 22946 Comm: syz.2.5225 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026 RIP: 0010:taprio_set_budgets+0x251/0x310 net/sched/sch_taprio.c:680 Code: 30 01 00 00 4c 89 f6 e8 7d 19 6d f8 4d 39 f4 0f 85 ea fe ff ff 4c 63 64 24 08 41 be ff ff ff 7f e9 38 ff ff ff e8 3f 1f 6d f8 <48> 83 c4 38 5b 5d 41 5c 41 5d 41 5e 41 5f e9 4c ab f2 01 e8 c7 dc RSP: 0018:ffffc90000007d68 EFLAGS: 00000046 RAX: 0000000080010002 RBX: 0000000000000000 RCX: ffffffff899b8e3d RDX: ffff8880305f4a00 RSI: ffffffff899b8fc1 RDI: ffff8880305f4a00 RBP: ffff888053156000 R08: 0000000000000005 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000001 R12: 0000000000000000 R13: ffff888054f12400 R14: ffff888054f12400 R15: ffff888054f12400 FS: 00007f5f1190c6c0(0000) GS:ffff88812436d000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000001b31417ff8 CR3: 0000000074c0b000 CR4: 00000000003526f0 Call Trace: advance_sched+0x66e/0xd20 net/sched/sch_taprio.c:984 __run_hrtimer kernel/time/hrtimer.c:1930 [inline] __hrtimer_run_queues+0x470/0xa00 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:__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:179 [inline] RIP: 0010:_raw_spin_unlock_irqrestore+0x31/0x80 kernel/locking/spinlock.c:198 Code: f5 53 48 8b 74 24 10 48 89 fb 48 83 c7 18 e8 46 a2 56 f6 48 89 df e8 1e f2 56 f6 f7 c5 00 02 00 00 75 23 9c 58 f6 c4 02 75 37 01 00 00 00 e8 a5 bb 46 f6 65 8b 05 1e 3f 7d 08 85 c0 74 16 5b RSP: 0018:ffffc900042f7758 EFLAGS: 00000246 RAX: 0000000000000006 RBX: ffff88809819c500 RCX: 0000000000000040 RDX: 0000000000000000 RSI: ffffffff8df22fb5 RDI: ffffffff8c1c4180 RBP: 0000000000000246 R08: 0000000000000001 R09: 0000000000000000 R10: 0000000000000001 R11: 0000000000000000 R12: ffff888077f85500 R13: 0000000000000246 R14: ffff88809819c4e8 R15: ffffc900042f78d8 spin_unlock_irqrestore include/linux/spinlock.h:408 [inline] __skb_try_recv_datagram+0x16a/0x500 net/core/datagram.c:267 __unix_dgram_recvmsg+0x1bc/0xc30 net/unix/af_unix.c:2587 unix_dgram_recvmsg+0xcd/0x100 net/unix/af_unix.c:2686 sock_recvmsg_nosec net/socket.c:1137 [inline] ____sys_recvmsg+0x5b3/0x640 net/socket.c:2916 ___sys_recvmsg+0x16a/0x1a0 net/socket.c:2960 do_recvmmsg+0x301/0x760 net/socket.c:3055 __sys_recvmmsg net/socket.c:3129 [inline] __do_sys_recvmmsg net/socket.c:3152 [inline] __se_sys_recvmmsg net/socket.c:3145 [inline] __x64_sys_recvmmsg+0x22a/0x280 net/socket.c:3145 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: 0033:0x7f5f1099ce59 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:00007f5f1190c028 EFLAGS: 00000246 ORIG_RAX: 000000000000012b RAX: ffffffffffffffda RBX: 00007f5f10c16090 RCX: 00007f5f1099ce59 RDX: 00000000080002c1 RSI: 0000200000000040 RDI: 0000000000000004 RBP: 00007f5f10a32d6f R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000002 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f5f10c16128 R14: 00007f5f10c16090 R15: 00007fffb90f60d8