rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: 0-...!: (1 GPs behind) idle=3cdc/1/0x4000000000000000 softirq=50160/50161 fqs=1 rcu: (detected by 1, t=10506 jiffies, g=42457, q=496 ncpus=2) Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 11979 Comm: syz.1.1187 Not tainted 6.12.0-rc6-next-20241108-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/30/2024 RIP: 0010:rcu_is_watching_curr_cpu include/linux/context_tracking.h:128 [inline] RIP: 0010:rcu_is_watching+0x17/0xb0 kernel/rcu/tree.c:737 Code: 1f 40 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 41 57 41 56 53 65 ff 05 18 d4 7e 7e e8 bb 3b 3f 0a 89 c3 <83> f8 08 73 7a 49 bf 00 00 00 00 00 fc ff df 4c 8d 34 dd 90 fa 30 RSP: 0018:ffffc90000007c50 EFLAGS: 00000086 RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffff88802f8fbc00 RDX: ffff88802f8fbc00 RSI: ffffffff8c605b40 RDI: ffffffff8c605b00 RBP: 0000000000000001 R08: ffffffff89c9e842 R09: 1ffffffff2857110 R10: dffffc0000000000 R11: fffffbfff2857111 R12: dffffc0000000000 R13: ffff88807c1b6808 R14: ffff88807c1b6800 R15: ffff88802717f360 FS: 00007f489d38b6c0(0000) GS:ffff8880b8600000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f489c5618a0 CR3: 000000007c734000 CR4: 00000000003526f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: rcu_read_lock include/linux/rcupdate.h:850 [inline] advance_sched+0xa3b/0xca0 net/sched/sch_taprio.c:985 __run_hrtimer kernel/time/hrtimer.c:1739 [inline] __hrtimer_run_queues+0x59b/0xd50 kernel/time/hrtimer.c:1803 hrtimer_interrupt+0x403/0xa40 kernel/time/hrtimer.c:1865 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1038 [inline] __sysvec_apic_timer_interrupt+0x110/0x420 arch/x86/kernel/apic/apic.c:1055 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1049 [inline] sysvec_apic_timer_interrupt+0xa1/0xc0 arch/x86/kernel/apic/apic.c:1049 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 RIP: 0010:lock_acquire+0x264/0x550 kernel/locking/lockdep.c:5853 Code: 2b 00 74 08 4c 89 f7 e8 7a 52 8f 00 f6 44 24 61 02 0f 85 85 01 00 00 41 f7 c7 00 02 00 00 74 01 fb 48 c7 44 24 40 0e 36 e0 45 <4b> c7 44 25 00 00 00 00 00 43 c7 44 25 09 00 00 00 00 43 c7 44 25 RSP: 0018:ffffc9000cbaf4e0 EFLAGS: 00000206 RAX: 0000000000000001 RBX: 1ffff92001975ea8 RCX: ffff88802f8fc6d8 RDX: dffffc0000000000 RSI: ffffffff8c0aea60 RDI: ffffffff8c605b60 RBP: ffffc9000cbaf628 R08: ffffffff942b8897 R09: 1ffffffff2857112 R10: dffffc0000000000 R11: fffffbfff2857113 R12: 1ffff92001975ea4 R13: dffffc0000000000 R14: ffffc9000cbaf540 R15: 0000000000000246 fs_reclaim_acquire+0xaf/0x130 mm/page_alloc.c:3904 might_alloc include/linux/sched/mm.h:318 [inline] slab_pre_alloc_hook mm/slub.c:4055 [inline] slab_alloc_node mm/slub.c:4133 [inline] __kmalloc_cache_noprof+0x41/0x390 mm/slub.c:4309 kmalloc_noprof include/linux/slab.h:901 [inline] kzalloc_noprof include/linux/slab.h:1037 [inline] mon_bin_open+0xe0/0x500 drivers/usb/mon/mon_bin.c:695 chrdev_open+0x521/0x600 fs/char_dev.c:414 do_dentry_open+0xbe1/0x1b70 fs/open.c:945 vfs_open+0x3e/0x330 fs/open.c:1075 do_open fs/namei.c:3828 [inline] path_openat+0x2c84/0x3590 fs/namei.c:3987 do_filp_open+0x27f/0x4e0 fs/namei.c:4014 do_sys_openat2+0x13e/0x1d0 fs/open.c:1402 do_sys_open fs/open.c:1417 [inline] __do_sys_openat fs/open.c:1433 [inline] __se_sys_openat fs/open.c:1428 [inline] __x64_sys_openat+0x247/0x2a0 fs/open.c:1428 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f489c57d0b0 Code: 48 89 44 24 20 75 93 44 89 54 24 0c e8 19 8f 02 00 44 8b 54 24 0c 89 da 48 89 ee 41 89 c0 bf 9c ff ff ff b8 01 01 00 00 0f 05 <48> 3d 00 f0 ff ff 77 38 44 89 c7 89 44 24 0c e8 6c 8f 02 00 8b 44 RSP: 002b:00007f489d38ab70 EFLAGS: 00000293 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 0000000000082002 RCX: 00007f489c57d0b0 RDX: 0000000000082002 RSI: 00007f489d38ac10 RDI: 00000000ffffff9c RBP: 00007f489d38ac10 R08: 0000000000000000 R09: 00236e6f6d627375 R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000000 R13: 0000000000000000 R14: 00007f489c735f80 R15: 00007ffc63883518 rcu: rcu_preempt kthread starved for 10500 jiffies! g42457 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:25392 pid:17 tgid:17 ppid:2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5369 [inline] __schedule+0x1850/0x4c30 kernel/sched/core.c:6753 __schedule_loop kernel/sched/core.c:6830 [inline] schedule+0x14b/0x320 kernel/sched/core.c:6845 schedule_timeout+0x15a/0x290 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x2df/0x1330 kernel/rcu/tree.c:2045 rcu_gp_kthread+0xa7/0x3b0 kernel/rcu/tree.c:2247 kthread+0x2f0/0x390 kernel/kthread.c:389 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244 rcu: Stack dump where RCU GP kthread last ran: CPU: 1 UID: 0 PID: 6963 Comm: kworker/u8:12 Not tainted 6.12.0-rc6-next-20241108-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/30/2024 Workqueue: events_unbound toggle_allocation_gate RIP: 0010:csd_lock_wait kernel/smp.c:340 [inline] RIP: 0010:smp_call_function_many_cond+0x19f3/0x2ca0 kernel/smp.c:884 Code: 45 8b 65 00 44 89 e6 83 e6 01 31 ff e8 86 f6 0b 00 41 83 e4 01 49 bc 00 00 00 00 00 fc ff df 75 07 e8 31 f2 0b 00 eb 38 f3 90 <42> 0f b6 04 23 84 c0 75 11 41 f7 45 00 01 00 00 00 74 1e e8 15 f2 RSP: 0018:ffffc90018fa76e0 EFLAGS: 00000293 RAX: ffffffff819389fb RBX: 1ffff110170c8c61 RCX: ffff88801db71e00 RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000 RBP: ffffc90018fa78e0 R08: ffffffff819389ca R09: 1ffffffff2857110 R10: dffffc0000000000 R11: fffffbfff2857111 R12: dffffc0000000000 R13: ffff8880b8646308 R14: ffff8880b873f980 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff8880b8700000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000000110c285fa4 CR3: 000000000e738000 CR4: 00000000003526f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: on_each_cpu_cond_mask+0x3f/0x80 kernel/smp.c:1051 on_each_cpu include/linux/smp.h:71 [inline] text_poke_sync arch/x86/kernel/alternative.c:2114 [inline] text_poke_bp_batch+0x352/0xb30 arch/x86/kernel/alternative.c:2324 text_poke_flush arch/x86/kernel/alternative.c:2515 [inline] text_poke_finish+0x30/0x50 arch/x86/kernel/alternative.c:2522 arch_jump_label_transform_apply+0x1c/0x30 arch/x86/kernel/jump_label.c:146 static_key_enable_cpuslocked+0x136/0x260 kernel/jump_label.c:210 static_key_enable+0x1a/0x20 kernel/jump_label.c:223 toggle_allocation_gate+0xbc/0x260 mm/kfence/core.c:849 process_one_work kernel/workqueue.c:3229 [inline] process_scheduled_works+0xa63/0x1850 kernel/workqueue.c:3310 worker_thread+0x870/0xd30 kernel/workqueue.c:3391 kthread+0x2f0/0x390 kernel/kthread.c:389 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244