rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: 1-...!: (4 ticks this GP) idle=a27c/1/0x4000000000000000 softirq=29259/29266 fqs=4 rcu: (detected by 0, t=10502 jiffies, g=25477, q=175 ncpus=2) Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 8801 Comm: syz.2.757 Not tainted 6.14.0-next-20250402-syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025 RIP: 0010:timerqueue_del+0xb1/0x100 lib/timerqueue.c:58 Code: ff ff 41 80 3c 2f 00 74 0e 48 89 df 49 89 c7 e8 35 49 01 f6 4c 89 f8 48 89 03 4c 89 ef 4c 89 f6 e8 64 6e ff ff 41 80 3c 2c 00 <74> 08 4c 89 ef e8 15 49 01 f6 4d 89 6d 00 4c 89 f0 48 c1 e8 03 80 RSP: 0018:ffffc90000a08d08 EFLAGS: 00000046 RAX: 1ffff110170e4f02 RBX: ffff8880b8727818 RCX: dffffc0000000000 RDX: 0000000000010000 RSI: ffff8880b8727810 RDI: ffff888145785348 RBP: dffffc0000000000 R08: ffffffff8c2c2578 R09: 1ffffffff20bfe26 R10: dffffc0000000000 R11: fffffbfff20bfe27 R12: 1ffff11028af0a68 R13: ffff888145785340 R14: ffff8880b8727810 R15: 1ffff110170e4f03 FS: 00007f51631e26c0(0000) GS:ffff888125093000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f166499e772 CR3: 000000005d378000 CR4: 00000000003526f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: __remove_hrtimer kernel/time/hrtimer.c:1123 [inline] __run_hrtimer kernel/time/hrtimer.c:1771 [inline] __hrtimer_run_queues+0x3db/0xd40 kernel/time/hrtimer.c:1855 hrtimer_interrupt+0x403/0xa40 kernel/time/hrtimer.c:1917 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:rcu_preempt_read_enter kernel/rcu/tree_plugin.h:391 [inline] RIP: 0010:__rcu_read_lock+0x42/0xb0 kernel/rcu/tree_plugin.h:414 Code: 25 08 d0 68 93 49 81 c7 44 04 00 00 4c 89 fb 48 c1 eb 03 42 0f b6 04 33 84 c0 75 35 41 8b 2f ff c5 42 0f b6 04 33 84 c0 75 3e <41> 89 2f 42 0f b6 04 33 84 c0 75 49 41 8b 07 3d 00 00 00 40 7d 0b RSP: 0018:ffffc9000c9570d8 EFLAGS: 00000246 RAX: 0000000000000000 RBX: 1ffff1100b5f1808 RCX: 0000000000080000 RDX: ffffc9000bb02000 RSI: 000000000007ffff RDI: 0000000000080000 RBP: 0000000000000004 R08: ffffffff81fe80be R09: ffffffff81fe806e R10: 0000000000000002 R11: ffff88805af8bc00 R12: ffffc9000c957300 R13: dffffc0000000000 R14: dffffc0000000000 R15: ffff88805af8c044 rcu_read_lock include/linux/rcupdate.h:839 [inline] page_ref_add_unless include/linux/page_ref.h:235 [inline] folio_ref_add_unless include/linux/page_ref.h:248 [inline] folio_try_get+0x17/0x350 include/linux/page_ref.h:264 next_uptodate_folio+0xd3/0x5f0 mm/filemap.c:3562 filemap_map_pages+0x12d3/0x1900 mm/filemap.c:3745 do_fault_around mm/memory.c:5476 [inline] do_read_fault mm/memory.c:5509 [inline] do_fault mm/memory.c:5652 [inline] do_pte_missing mm/memory.c:4160 [inline] handle_pte_fault+0x3d6d/0x61c0 mm/memory.c:5997 __handle_mm_fault mm/memory.c:6140 [inline] handle_mm_fault+0x1129/0x1bf0 mm/memory.c:6309 faultin_page mm/gup.c:1188 [inline] __get_user_pages+0x1b4a/0x42f0 mm/gup.c:1491 populate_vma_page_range+0x266/0x340 mm/gup.c:1929 __mm_populate+0x27d/0x460 mm/gup.c:2032 mm_populate include/linux/mm.h:3470 [inline] vm_mmap_pgoff+0x390/0x530 mm/util.c:584 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xf3/0x230 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f516238d169 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:00007f51631e2038 EFLAGS: 00000246 ORIG_RAX: 0000000000000009 RAX: ffffffffffffffda RBX: 00007f51625a5fa0 RCX: 00007f516238d169 RDX: b635773f06ebbeef RSI: 0000000000b36000 RDI: 0000200000000000 RBP: 00007f516240e2a0 R08: ffffffffffffffff R09: 0000000000000000 R10: 0000000000008031 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 00007f51625a5fa0 R15: 00007ffff29a0188 rcu: rcu_preempt kthread starved for 10494 jiffies! g25477 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:26976 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5382 [inline] __schedule+0x1b88/0x5240 kernel/sched/core.c:6767 __schedule_loop kernel/sched/core.c:6845 [inline] schedule+0x163/0x360 kernel/sched/core.c:6860 schedule_timeout+0x15b/0x2b0 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x2e1/0x1340 kernel/rcu/tree.c:2046 rcu_gp_kthread+0xa7/0x3b0 kernel/rcu/tree.c:2248 kthread+0x7b7/0x940 kernel/kthread.c:464 ret_from_fork+0x4b/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: 0 UID: 0 PID: 7053 Comm: kworker/u8:15 Not tainted 6.14.0-next-20250402-syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025 Workqueue: events_unbound toggle_allocation_gate RIP: 0010:csd_lock_wait kernel/smp.c:340 [inline] RIP: 0010:smp_call_function_many_cond+0x1bac/0x2d40 kernel/smp.c:885 Code: 03 84 c0 75 7e 45 8b 65 00 44 89 e6 83 e6 01 31 ff e8 48 e8 0b 00 41 83 e4 01 4c 8b 64 24 68 75 07 e8 f8 e3 0b 00 eb 41 f3 90 <48> b8 00 00 00 00 00 fc ff df 0f b6 04 03 84 c0 75 11 41 f7 45 00 RSP: 0018:ffffc9000af4f640 EFLAGS: 00000293 RAX: ffffffff81b7732d RBX: 1ffff110170e7e91 RCX: ffff88802ca93c00 RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000 RBP: ffffc9000af4f840 R08: ffffffff81b772f8 R09: 1ffffffff20bfe26 R10: dffffc0000000000 R11: fffffbfff20bfe27 R12: ffff8880b863ad08 R13: ffff8880b873f488 R14: ffff8880b863ad00 R15: 0000000000000001 FS: 0000000000000000(0000) GS:ffff888124f93000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000001b31120000 CR3: 000000000eb38000 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:1052 on_each_cpu include/linux/smp.h:71 [inline] text_poke_sync arch/x86/kernel/alternative.c:2455 [inline] text_poke_bp_batch+0x44b/0xd40 arch/x86/kernel/alternative.c:2667 text_poke_flush arch/x86/kernel/alternative.c:2869 [inline] text_poke_finish+0x30/0x50 arch/x86/kernel/alternative.c:2876 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+0xc0/0x250 mm/kfence/core.c:850 process_one_work kernel/workqueue.c:3238 [inline] process_scheduled_works+0xac3/0x18e0 kernel/workqueue.c:3319 worker_thread+0x870/0xd50 kernel/workqueue.c:3400 kthread+0x7b7/0x940 kernel/kthread.c:464 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:153 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245