rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P36/1:b..l rcu: (detected by 1, t=10502 jiffies, g=44341, q=1056 ncpus=2) task:kworker/u8:2 state:R running task stack:22936 pid:36 tgid:36 ppid:2 task_flags:0x4208160 flags:0x00004000 Workqueue: iou_exit io_ring_exit_work Call Trace: context_switch kernel/sched/core.c:5382 [inline] __schedule+0x116f/0x5de0 kernel/sched/core.c:6767 preempt_schedule_irq+0x51/0x90 kernel/sched/core.c:7090 irqentry_exit+0x36/0x90 kernel/entry/common.c:354 asm_sysvec_call_function_single+0x1a/0x20 arch/x86/include/asm/idtentry.h:709 RIP: 0010:unwind_next_frame+0x50c/0x20a0 arch/x86/kernel/unwind_orc.c:505 Code: e8 19 f1 ff ff 48 89 c1 48 85 c0 0f 84 05 fe ff ff 48 b8 00 00 00 00 00 fc ff df 4c 8d 79 05 4c 89 fa 48 c1 ea 03 0f b6 04 02 <4c> 89 fa 83 e2 07 38 d0 7f 08 84 c0 0f 85 32 14 00 00 0f b6 41 05 RSP: 0018:ffffc90000ad75f8 EFLAGS: 00000a03 RAX: 0000000000000000 RBX: 0000000000000001 RCX: ffffffff9114b8ca RDX: 1ffffffff2229719 RSI: 0000000000000000 RDI: ffffffff9093547c RBP: ffffc90000ad76b0 R08: ffffffff9114b8f4 R09: 0000000000000000 R10: 0000000000000003 R11: 0000000000002be0 R12: ffffc90000ad76b8 R13: ffffc90000ad7668 R14: ffffc90000ad769d R15: ffffffff9114b8cf arch_stack_walk+0x94/0x100 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0x8e/0xc0 kernel/stacktrace.c:122 kasan_save_stack+0x33/0x60 mm/kasan/common.c:47 kasan_save_track+0x14/0x30 mm/kasan/common.c:68 poison_kmalloc_redzone mm/kasan/common.c:377 [inline] __kasan_kmalloc+0xaa/0xb0 mm/kasan/common.c:394 kmalloc_noprof include/linux/slab.h:905 [inline] slab_free_hook mm/slub.c:2350 [inline] slab_free mm/slub.c:4656 [inline] kmem_cache_free+0x148/0x4d0 mm/slub.c:4758 io_req_caches_free+0xa0/0x3c0 io_uring/io_uring.c:2716 io_ring_exit_work+0x37a/0xf60 io_uring/io_uring.c:2916 process_one_work+0x9cc/0x1b70 kernel/workqueue.c:3238 process_scheduled_works kernel/workqueue.c:3319 [inline] worker_thread+0x6c8/0xf10 kernel/workqueue.c:3400 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: rcu_preempt kthread timer wakeup didn't happen for 10413 jiffies! g44341 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 rcu: Possible timer handling issue on cpu=0 timer-softirq=53334 rcu: rcu_preempt kthread starved for 10414 jiffies! g44341 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:28856 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: Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 12829 Comm: syz.1.1687 Not tainted 6.15.0-rc2-syzkaller-00400-g3088d26962e8 #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025 RIP: 0010:__sanitizer_cov_trace_pc+0x0/0x70 kernel/kcov.c:210 Code: b6 57 55 00 48 89 df 5b e9 dd b5 5a 00 be 03 00 00 00 5b e9 62 6b 14 03 66 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 0f 1e fa 48 8b 34 24 65 48 8b 15 78 90 eb 11 65 8b 05 89 90 eb RSP: 0018:ffffc90000007e38 EFLAGS: 00000097 RAX: 0000000000010002 RBX: ffff8880b8427940 RCX: ffffffff81a87a45 RDX: ffff88807c492440 RSI: 0000000000000007 RDI: 0000000000000005 RBP: 0000000000000001 R08: 0000000000000005 R09: 0000000000000007 R10: 0000000000000000 R11: 0000000000000000 R12: ffff8880b8427840 R13: 0000000000000000 R14: ffff88802836c340 R15: 0000000000000001 FS: 0000000000000000(0000) GS:ffff8881249b2000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000001b2ff1eff8 CR3: 000000000e180000 CR4: 00000000003526f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: cpumask_test_cpu include/linux/cpumask.h:587 [inline] cpu_online include/linux/cpumask.h:1143 [inline] trace_hrtimer_expire_exit include/trace/events/timer.h:306 [inline] __run_hrtimer kernel/time/hrtimer.c:1764 [inline] __hrtimer_run_queues+0x274/0xad0 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:preempt_count arch/x86/include/asm/preempt.h:27 [inline] RIP: 0010:check_kcov_mode kernel/kcov.c:183 [inline] RIP: 0010:write_comp_data+0x11/0x90 kernel/kcov.c:246 Code: cc cc 0f 1f 80 00 00 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 49 89 d2 49 89 f8 49 89 f1 65 48 8b 15 f7 96 eb 11 <65> 8b 05 08 97 eb 11 a9 00 01 ff 00 74 1d f6 c4 01 74 67 a9 00 00 RSP: 0018:ffffc9000c82f540 EFLAGS: 00000246 RAX: 0000000000000000 RBX: 000000000006ece4 RCX: ffffffff822c3aa5 RDX: ffff88807c492440 RSI: 0000000000000000 RDI: 0000000000000007 RBP: ffff88813fffa5a0 R08: 0000000000000007 R09: 0000000000000000 R10: 0000000000000008 R11: 0000000000000000 R12: 0000000000000008 R13: 0000000000000001 R14: 0000000000000001 R15: 0000000000000107 early_section include/linux/mmzone.h:1996 [inline] pfn_valid include/linux/mmzone.h:2125 [inline] page_table_check_clear+0x195/0xb30 mm/page_table_check.c:70 __page_table_check_pte_clear+0xf1/0x100 mm/page_table_check.c:154 page_table_check_pte_clear include/linux/page_table_check.h:49 [inline] ptep_get_and_clear_full arch/x86/include/asm/pgtable.h:1337 [inline] get_and_clear_full_ptes include/linux/pgtable.h:714 [inline] zap_present_folio_ptes mm/memory.c:1501 [inline] zap_present_ptes mm/memory.c:1586 [inline] do_zap_pte_range mm/memory.c:1687 [inline] zap_pte_range mm/memory.c:1731 [inline] zap_pmd_range mm/memory.c:1823 [inline] zap_pud_range mm/memory.c:1852 [inline] zap_p4d_range mm/memory.c:1873 [inline] unmap_page_range+0x2383/0x4320 mm/memory.c:1894 unmap_single_vma+0x194/0x2a0 mm/memory.c:1940 unmap_vmas+0x22c/0x490 mm/memory.c:1984 exit_mmap+0x1b9/0xb90 mm/mmap.c:1284 __mmput+0x12a/0x410 kernel/fork.c:1379 mmput+0x62/0x70 kernel/fork.c:1401 exit_mm kernel/exit.c:589 [inline] do_exit+0x9d1/0x2c30 kernel/exit.c:940 do_group_exit+0xd3/0x2a0 kernel/exit.c:1102 get_signal+0x2673/0x26d0 kernel/signal.c:3034 arch_do_signal_or_restart+0x8f/0x7d0 arch/x86/kernel/signal.c:337 exit_to_user_mode_loop kernel/entry/common.c:111 [inline] exit_to_user_mode_prepare include/linux/entry-common.h:329 [inline] __syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline] syscall_exit_to_user_mode+0x150/0x2a0 kernel/entry/common.c:218 do_syscall_64+0xda/0x260 arch/x86/entry/syscall_64.c:100 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f47e858e169 Code: Unable to access opcode bytes at 0x7f47e858e13f. RSP: 002b:00007f47e949e0e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca RAX: 0000000000000001 RBX: 00007f47e87b5fa8 RCX: 00007f47e858e169 RDX: 00000000000f4240 RSI: 0000000000000081 RDI: 00007f47e87b5fac RBP: 00007f47e87b5fa0 R08: 00007f47e949f000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007f47e87b5fac R13: 0000000000000000 R14: 00007fffc679d1e0 R15: 00007fffc679d2c8