rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: 1-...!: (0 ticks this GP) idle=b9c4/1/0x4000000000000000 softirq=55464/55464 fqs=5 rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P12836/1:b..l (detected by 0, t=10502 jiffies, g=76857, q=32 ncpus=2) Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 PID: 12853 Comm: syz.5.2907 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025 RIP: 0010:hrtimer_set_expires include/linux/hrtimer.h:245 [inline] RIP: 0010:advance_sched+0x692/0x970 net/sched/sch_taprio.c:751 Code: 3c 28 00 48 8b 1c 24 74 0a 48 8b 7c 24 60 e8 65 f8 7c f9 48 89 5d e8 4c 89 e7 e8 39 cf cd 01 48 8d 7d 18 48 89 f8 48 c1 e8 03 <42> 80 3c 28 00 74 05 e8 42 f8 7c f9 4c 89 7d 18 48 83 c5 20 48 89 RSP: 0018:ffffc900001e0c80 EFLAGS: 00000802 RAX: 1ffff11005d7d66b RBX: ffff88805807b300 RCX: 0000000000010000 RDX: 0000000000000000 RSI: 0000000000000004 RDI: ffff88802ebeb358 RBP: ffff88802ebeb340 R08: dffffc0000000000 R09: ffffed1005d7d65e R10: ffffed1005d7d65e R11: 1ffff11005d7d65d R12: ffff88802ebeb2e8 R13: dffffc0000000000 R14: ffff88802ebeb000 R15: 18788c9624000000 FS: 0000000000000000(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000001b34222ff8 CR3: 000000000c88e000 CR4: 00000000003506e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: __run_hrtimer kernel/time/hrtimer.c:1747 [inline] __hrtimer_run_queues+0x554/0xd60 kernel/time/hrtimer.c:1811 hrtimer_interrupt+0x3c5/0x9c0 kernel/time/hrtimer.c:1873 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1107 [inline] __sysvec_apic_timer_interrupt+0x153/0x5a0 arch/x86/kernel/apic/apic.c:1124 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1118 [inline] sysvec_apic_timer_interrupt+0x9b/0xc0 arch/x86/kernel/apic/apic.c:1118 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:691 RIP: 0010:lock_acquire+0x20f/0x490 kernel/locking/lockdep.c:5666 Code: 00 9c 8f 84 24 80 00 00 00 f6 84 24 81 00 00 00 02 0f 85 f5 00 00 00 41 f7 c6 00 02 00 00 74 01 fb 48 c7 44 24 60 0e 36 e0 45 <4b> c7 44 3d 00 00 00 00 00 66 43 c7 44 3d 09 00 00 43 c6 44 3d 0b RSP: 0018:ffffc9000677f220 EFLAGS: 00000206 RAX: 0000000000000001 RBX: 0000000000000000 RCX: d0f90152feaded00 RDX: 0000000000000000 RSI: ffffffff8a8c1700 RDI: ffffffff8adef3a0 RBP: ffffc9000677f328 R08: dffffc0000000000 R09: fffffbfff215c449 R10: fffffbfff215c449 R11: 1ffffffff215c448 R12: 0000000000000001 R13: 1ffff92000cefe50 R14: 0000000000000246 R15: dffffc0000000000 rcu_lock_acquire include/linux/rcupdate.h:350 [inline] rcu_read_lock include/linux/rcupdate.h:791 [inline] folio_memcg_lock+0xa2/0x2e0 mm/memcontrol.c:2101 page_remove_rmap+0x2e/0xea0 mm/rmap.c:1426 zap_pte_range mm/memory.c:1453 [inline] zap_pmd_range mm/memory.c:1574 [inline] zap_pud_range mm/memory.c:1603 [inline] zap_p4d_range mm/memory.c:1624 [inline] unmap_page_range+0x1149/0x2500 mm/memory.c:1645 unmap_vmas+0x22c/0x330 mm/memory.c:1730 exit_mmap+0x1cc/0x8e0 mm/mmap.c:3250 __mmput+0x118/0x3c0 kernel/fork.c:1200 exit_mm+0x1e6/0x2c0 kernel/exit.c:565 do_exit+0x8c1/0x2400 kernel/exit.c:867 do_group_exit+0x217/0x2d0 kernel/exit.c:1022 get_signal+0x1272/0x1350 kernel/signal.c:2871 arch_do_signal_or_restart+0xb7/0x1240 arch/x86/kernel/signal.c:871 exit_to_user_mode_loop+0x70/0x110 kernel/entry/common.c:174 exit_to_user_mode_prepare+0xee/0x180 kernel/entry/common.c:210 __syscall_exit_to_user_mode_work kernel/entry/common.c:292 [inline] syscall_exit_to_user_mode+0x16/0x40 kernel/entry/common.c:303 do_syscall_64+0x58/0xa0 arch/x86/entry/common.c:87 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7fbf6c58efc9 Code: Unable to access opcode bytes at 0x7fbf6c58ef9f. RSP: 002b:00007fbf6d50a0e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca RAX: fffffffffffffe00 RBX: 00007fbf6c7e5fa8 RCX: 00007fbf6c58efc9 RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007fbf6c7e5fa8 RBP: 00007fbf6c7e5fa0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fbf6c7e6038 R14: 00007ffea9efa720 R15: 00007ffea9efa808 task:syz.7.2899 state:R running task stack:23584 pid:12836 ppid:9091 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5244 [inline] __schedule+0x10ec/0x40b0 kernel/sched/core.c:6561 preempt_schedule_common+0x82/0xd0 kernel/sched/core.c:6730 preempt_schedule+0xa7/0xb0 kernel/sched/core.c:6754 preempt_schedule_thunk+0x16/0x18 arch/x86/entry/thunk_64.S:34 unwind_next_frame+0x1892/0x20b0 arch/x86/kernel/unwind_orc.c:629 arch_stack_walk+0x10c/0x140 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0x98/0xe0 kernel/stacktrace.c:122 save_stack+0xf3/0x1e0 mm/page_owner.c:127 __reset_page_owner+0x51/0x1a0 mm/page_owner.c:148 reset_page_owner include/linux/page_owner.h:24 [inline] free_pages_prepare mm/page_alloc.c:1459 [inline] free_pcp_prepare mm/page_alloc.c:1509 [inline] free_unref_page_prepare+0x8b4/0x9a0 mm/page_alloc.c:3384 free_unref_page+0x2e/0x3f0 mm/page_alloc.c:3479 __vunmap+0x856/0xa00 mm/vmalloc.c:2726 vb2_vmalloc_put+0x64/0xa0 drivers/media/common/videobuf2/videobuf2-vmalloc.c:68 __vb2_buf_mem_free+0x113/0x2c0 drivers/media/common/videobuf2/videobuf2-core.c:266 __vb2_free_mem drivers/media/common/videobuf2/videobuf2-core.c:496 [inline] __vb2_queue_free+0x447/0xd80 drivers/media/common/videobuf2/videobuf2-core.c:541 vb2_core_queue_release+0x5b/0x80 drivers/media/common/videobuf2/videobuf2-core.c:2477 vb2_queue_release drivers/media/common/videobuf2/videobuf2-v4l2.c:934 [inline] _vb2_fop_release drivers/media/common/videobuf2/videobuf2-v4l2.c:1119 [inline] vb2_fop_release+0x160/0x1e0 drivers/media/common/videobuf2/videobuf2-v4l2.c:1133 v4l2_release+0x1f9/0x390 drivers/media/v4l2-core/v4l2-dev.c:456 __fput+0x22c/0x920 fs/file_table.c:320 task_work_run+0x1ca/0x250 kernel/task_work.c:203 resume_user_mode_work include/linux/resume_user_mode.h:49 [inline] exit_to_user_mode_loop+0xe6/0x110 kernel/entry/common.c:177 exit_to_user_mode_prepare+0xee/0x180 kernel/entry/common.c:210 __syscall_exit_to_user_mode_work kernel/entry/common.c:292 [inline] syscall_exit_to_user_mode+0x16/0x40 kernel/entry/common.c:303 do_syscall_64+0x58/0xa0 arch/x86/entry/common.c:87 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7fba0598efc9 RSP: 002b:00007ffcb2f00238 EFLAGS: 00000246 ORIG_RAX: 00000000000001b4 RAX: 0000000000000000 RBX: 00007fba05be7da0 RCX: 00007fba0598efc9 RDX: 0000000000000000 RSI: 000000000000001e RDI: 0000000000000003 RBP: 00007fba05be7da0 R08: 000000000000269c R09: 00000004b2f0052f R10: 00000000005fce84 R11: 0000000000000246 R12: 000000000006e594 R13: 00007ffcb2f00330 R14: ffffffffffffffff R15: 00007ffcb2f00350 rcu: rcu_preempt kthread starved for 10492 jiffies! g76857 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:27840 pid:16 ppid:2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5244 [inline] __schedule+0x10ec/0x40b0 kernel/sched/core.c:6561 schedule+0xb9/0x180 kernel/sched/core.c:6637 schedule_timeout+0x15c/0x280 kernel/time/timer.c:1965 rcu_gp_fqs_loop+0x2f2/0x1310 kernel/rcu/tree.c:1706 rcu_gp_kthread+0x95/0x380 kernel/rcu/tree.c:1905 kthread+0x29d/0x330 kernel/kthread.c:376 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295 rcu: Stack dump where RCU GP kthread last ran: CPU: 0 PID: 4372 Comm: kworker/u4:7 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025 Workqueue: events_unbound toggle_allocation_gate RIP: 0010:csd_lock_wait kernel/smp.c:424 [inline] RIP: 0010:smp_call_function_many_cond+0xe7b/0x1270 kernel/smp.c:998 Code: 00 00 00 41 8b 1f 89 de 83 e6 01 31 ff e8 5d d9 0a 00 83 e3 01 48 bb 00 00 00 00 00 fc ff df 75 07 e8 e9 d5 0a 00 eb 37 f3 90 <41> 0f b6 04 1c 84 c0 75 10 41 f7 07 01 00 00 00 74 1e e8 ce d5 0a RSP: 0018:ffffc90004a6f800 EFLAGS: 00000293 RAX: ffffffff8175fd42 RBX: dffffc0000000000 RCX: ffff8880271b3b80 RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000 RBP: ffffc90004a6f960 R08: dffffc0000000000 R09: fffffbfff215c449 R10: fffffbfff215c449 R11: 1ffffffff215c448 R12: 1ffff110171e81c9 R13: ffff8880b8e3bb80 R14: 0000000000000001 R15: ffff8880b8f40e48 FS: 0000000000000000(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000001b2f522ff8 CR3: 000000000c88e000 CR4: 00000000003506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: on_each_cpu_cond_mask+0x3b/0x80 kernel/smp.c:1165 on_each_cpu include/linux/smp.h:71 [inline] text_poke_sync arch/x86/kernel/alternative.c:1574 [inline] text_poke_bp_batch+0x2b0/0x7d0 arch/x86/kernel/alternative.c:1774 text_poke_flush arch/x86/kernel/alternative.c:1965 [inline] text_poke_finish+0x16/0x30 arch/x86/kernel/alternative.c:1972 arch_jump_label_transform_apply+0x13/0x20 arch/x86/kernel/jump_label.c:146 static_key_enable_cpuslocked+0x11f/0x240 kernel/jump_label.c:207 static_key_enable+0x16/0x20 kernel/jump_label.c:220 toggle_allocation_gate+0xb4/0x430 mm/kfence/core.c:805 process_one_work+0x898/0x1160 kernel/workqueue.c:2292 worker_thread+0xaa2/0x1250 kernel/workqueue.c:2439 kthread+0x29d/0x330 kernel/kthread.c:376 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295