rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: 0-...!: (1 GPs behind) idle=244c/1/0x4000000000000000 softirq=72631/72632 fqs=1 rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P13380/1:b..l rcu: (detected by 1, t=10505 jiffies, g=63093, q=660 ncpus=2) Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 15278 Comm: syz.2.2338 Not tainted 6.15.0-rc6-syzkaller-00346-g5723cc3450bc #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025 RIP: 0010:list_is_last include/linux/list.h:354 [inline] RIP: 0010:should_restart_cycle net/sched/sch_taprio.c:869 [inline] RIP: 0010:advance_sched+0x269/0xc80 net/sched/sch_taprio.c:948 Code: 61 39 f8 48 8b 04 24 4c 8d b5 10 01 00 00 48 8d b8 40 01 00 00 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 80 3c 02 00 <0f> 85 2f 09 00 00 48 8b 04 24 48 8d bd 28 01 00 00 48 89 fa 4c 8b RSP: 0018:ffffc90000007d90 EFLAGS: 00000046 RAX: dffffc0000000000 RBX: ffff888079e4f340 RCX: ffffffff8981e424 RDX: 1ffff1100752c728 RSI: ffffffff8981e432 RDI: ffff88803a963940 RBP: ffff88803a962800 R08: 0000000000000006 R09: 184b96f3eee5bb77 R10: 0000000000000000 R11: 0000000000000000 R12: 184b96f3eee5bb77 R13: 0000000000000000 R14: ffff88803a962910 R15: ffffffff8981e1f0 FS: 00007f73b89fd6c0(0000) GS:ffff8881249da000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007ff8bdee56c0 CR3: 000000008fa04000 CR4: 00000000003526f0 Call Trace: __run_hrtimer kernel/time/hrtimer.c:1761 [inline] __hrtimer_run_queues+0x202/0xad0 kernel/time/hrtimer.c:1825 hrtimer_interrupt+0x397/0x8e0 kernel/time/hrtimer.c:1887 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1038 [inline] __sysvec_apic_timer_interrupt+0x108/0x3f0 arch/x86/kernel/apic/apic.c:1055 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1049 [inline] sysvec_apic_timer_interrupt+0x9f/0xc0 arch/x86/kernel/apic/apic.c:1049 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 RIP: 0010:finish_task_switch.isra.0+0x22a/0xc10 kernel/sched/core.c:5250 Code: fb 09 00 00 44 8b 05 49 cb fb 0e 45 85 c0 0f 85 be 01 00 00 4c 89 e7 e8 a4 f6 ff ff e8 ff 77 39 00 fb 65 48 8b 1d 8e cd 1a 12 <48> 8d bb 18 16 00 00 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 RSP: 0018:ffffc9000e237580 EFLAGS: 00000206 RAX: 0000000000008435 RBX: ffff8880454aa440 RCX: 0000000000000006 RDX: 0000000000000000 RSI: ffffffff8dbe4615 RDI: ffffffff8bf4a2a0 RBP: ffffc9000e2375c8 R08: 0000000000000001 R09: 0000000000000001 R10: ffffffff90852e17 R11: 0000000000000000 R12: ffff8880b8439dc0 R13: ffff88807732a440 R14: 0000000000000001 R15: ffff8880b843abf0 context_switch kernel/sched/core.c:5385 [inline] __schedule+0x1177/0x5de0 kernel/sched/core.c:6767 preempt_schedule_common+0x44/0xc0 kernel/sched/core.c:6947 preempt_schedule_thunk+0x16/0x30 arch/x86/entry/thunk.S:12 __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:152 [inline] _raw_spin_unlock_irqrestore+0x61/0x80 kernel/locking/spinlock.c:194 __unix_dgram_recvmsg+0x326/0xee0 net/unix/af_unix.c:2447 unix_dgram_recvmsg+0xd0/0x110 net/unix/af_unix.c:2522 sock_recvmsg_nosec net/socket.c:1017 [inline] ____sys_recvmsg+0x5f6/0x6b0 net/socket.c:2784 ___sys_recvmsg+0x114/0x1a0 net/socket.c:2828 do_recvmmsg+0x2fe/0x740 net/socket.c:2923 __sys_recvmmsg net/socket.c:2997 [inline] __do_sys_recvmmsg net/socket.c:3020 [inline] __se_sys_recvmmsg net/socket.c:3013 [inline] __x64_sys_recvmmsg+0x22a/0x280 net/socket.c:3013 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xcd/0x260 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f73b7b8e969 Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 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 a8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f73b89fd038 EFLAGS: 00000246 ORIG_RAX: 000000000000012b RAX: ffffffffffffffda RBX: 00007f73b7db6080 RCX: 00007f73b7b8e969 RDX: 0000000000010106 RSI: 00002000000000c0 RDI: 0000000000000004 RBP: 00007f73b7c10ab1 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000002 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000001 R14: 00007f73b7db6080 R15: 00007ffe0318b348 task:syz-executor state:R running task stack:23560 pid:13380 tgid:13380 ppid:13358 task_flags:0x400140 flags:0x00000000 Call Trace: context_switch kernel/sched/core.c:5382 [inline] __schedule+0x116f/0x5de0 kernel/sched/core.c:6767 preempt_schedule_common+0x44/0xc0 kernel/sched/core.c:6947 preempt_schedule_thunk+0x16/0x30 arch/x86/entry/thunk.S:12 __raw_spin_unlock include/linux/spinlock_api_smp.h:143 [inline] _raw_spin_unlock+0x3e/0x50 kernel/locking/spinlock.c:186 spin_unlock include/linux/spinlock.h:391 [inline] copy_pte_range mm/memory.c:1194 [inline] copy_pmd_range mm/memory.c:1255 [inline] copy_pud_range mm/memory.c:1292 [inline] copy_p4d_range mm/memory.c:1316 [inline] copy_page_range+0x1952/0x5fe0 mm/memory.c:1410 dup_mmap kernel/fork.c:727 [inline] dup_mm kernel/fork.c:1735 [inline] copy_mm kernel/fork.c:1787 [inline] copy_process+0x8644/0x91b0 kernel/fork.c:2430 kernel_clone+0xfc/0x960 kernel/fork.c:2845 __do_sys_clone+0xce/0x120 kernel/fork.c:2988 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xcd/0x260 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7ff8bd1851d3 RSP: 002b:00007fff2bb7d208 EFLAGS: 00000246 ORIG_RAX: 0000000000000038 RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007ff8bd1851d3 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000001200011 RBP: 0000000000000001 R08: 0000000000000000 R09: 0000000000000001 R10: 00005555569717d0 R11: 0000000000000246 R12: 0000000000000000 R13: 00000000000927c0 R14: 00000000000e2675 R15: 00007fff2bb7d3a0 rcu: rcu_preempt kthread starved for 10500 jiffies! g63093 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:28200 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5382 [inline] __schedule+0x116f/0x5de0 kernel/sched/core.c:6767 __schedule_loop kernel/sched/core.c:6845 [inline] schedule+0xe7/0x3a0 kernel/sched/core.c:6860 schedule_timeout+0x123/0x290 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x1ea/0xb00 kernel/rcu/tree.c:2046 rcu_gp_kthread+0x270/0x380 kernel/rcu/tree.c:2248 kthread+0x3c2/0x780 kernel/kthread.c:464 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:153 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 rcu: Stack dump where RCU GP kthread last ran: CPU: 1 UID: 0 PID: 5809 Comm: syz-executor Not tainted 6.15.0-rc6-syzkaller-00346-g5723cc3450bc #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025 RIP: 0010:csd_lock_wait kernel/smp.c:340 [inline] RIP: 0010:smp_call_function_many_cond+0x4aa/0x1290 kernel/smp.c:885 Code: 0c 00 85 ed 74 48 48 8b 44 24 20 49 89 c4 83 e0 07 49 c1 ec 03 48 89 c5 4d 01 f4 83 c5 03 e8 7d 17 0c 00 f3 90 41 0f b6 04 24 <40> 38 c5 7c 08 84 c0 0f 85 de 0b 00 00 8b 43 08 31 ff 83 e0 01 41 RSP: 0018:ffffc9000437f8b8 EFLAGS: 00000293 RAX: 0000000000000000 RBX: ffff8880b8441720 RCX: ffffffff81af2e99 RDX: ffff88803228a440 RSI: ffffffff81af2e73 RDI: 0000000000000005 RBP: 0000000000000003 R08: 0000000000000005 R09: 0000000000000000 R10: 0000000000000001 R11: 0000000000000000 R12: ffffed10170882e5 R13: 0000000000000001 R14: dffffc0000000000 R15: ffff8880b853b040 FS: 00005555607b1500(0000) GS:ffff888124ada000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007eff566e56c0 CR3: 000000005e795000 CR4: 00000000003526f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: on_each_cpu_cond_mask+0x40/0x90 kernel/smp.c:1052 __flush_tlb_multi arch/x86/include/asm/paravirt.h:91 [inline] flush_tlb_multi arch/x86/mm/tlb.c:1291 [inline] flush_tlb_mm_range+0x322/0x1780 arch/x86/mm/tlb.c:1381 dup_mmap kernel/fork.c:766 [inline] dup_mm kernel/fork.c:1735 [inline] copy_mm kernel/fork.c:1787 [inline] copy_process+0x7957/0x91b0 kernel/fork.c:2430 kernel_clone+0xfc/0x960 kernel/fork.c:2845 __do_sys_clone+0xce/0x120 kernel/fork.c:2988 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xcd/0x260 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7eff559851d3 Code: 1f 84 00 00 00 00 00 64 48 8b 04 25 10 00 00 00 45 31 c0 31 d2 31 f6 bf 11 00 20 01 4c 8d 90 d0 02 00 00 b8 38 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 35 89 c2 85 c0 75 2c 64 48 8b 04 25 10 00 00 RSP: 002b:00007ffdbdaadbe8 EFLAGS: 00000246 ORIG_RAX: 0000000000000038 RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007eff559851d3 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000001200011 RBP: 0000000000000001 R08: 0000000000000000 R09: 0000000000000001 R10: 00005555607b17d0 R11: 0000000000000246 R12: 0000000000000000 R13: 00000000000927c0 R14: 00000000000e225e R15: 00007ffdbdaadd80