rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: 1-...!: (1 GPs behind) idle=e3ac/1/0x4000000000000000 softirq=53737/53738 fqs=0 rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P14155/1:b..l P14168/1:b..l rcu: (detected by 0, t=10502 jiffies, g=62917, q=223 ncpus=2) Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 14169 Comm: syz.0.2264 Not tainted 6.14.0-syzkaller-10514-g7f2ff7b62617 #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025 RIP: 0010:enqueue_hrtimer+0x7/0x3c0 kernel/time/hrtimer.c:1089 Code: 00 e9 3d 90 ff ff 66 66 66 66 2e 0f 1f 84 00 00 00 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 55 41 57 41 56 41 55 <41> 54 53 89 d5 49 89 f5 49 89 fe 49 bc 00 00 00 00 00 fc ff df e8 RSP: 0018:ffffc90000a08d18 EFLAGS: 00000046 RAX: ffffffff81b080d7 RBX: 0000000000000000 RCX: ffff8880226f5a00 RDX: 0000000000000000 RSI: ffff8880b87277c0 RDI: ffff88805abb8340 RBP: ffffc90000a08ea0 R08: ffffffff81b080cd R09: fffff52000141184 R10: dffffc0000000000 R11: fffff52000141184 R12: 1ffff110170e4f03 R13: dffffc0000000000 R14: ffff88805abb8340 R15: ffff8880b87276c0 FS: 00007f385c96f6c0(0000) GS:ffff8881250ed000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000020000001d000 CR3: 000000007d4a4000 CR4: 00000000003526f0 DR0: 0000000000000000 DR1: 0000000000000097 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: __run_hrtimer kernel/time/hrtimer.c:1808 [inline] __hrtimer_run_queues+0x6d6/0xd40 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:finish_task_switch+0x1ea/0x870 kernel/sched/core.c:5250 Code: c9 50 e8 59 2d 0d 00 48 83 c4 08 4c 89 f7 e8 ad 41 00 00 e9 de 04 00 00 4c 89 f7 e8 00 e1 95 0a e8 1b 8c 39 00 fb 48 8b 5d c0 <48> 8d bb 18 16 00 00 48 89 f8 48 c1 e8 03 49 be 00 00 00 00 00 fc RSP: 0018:ffffc90005b7f548 EFLAGS: 00000286 RAX: 37078fed4aa8a300 RBX: ffff8880226f5a00 RCX: ffffffff81cb327c RDX: 0000000000000000 RSI: ffffffff8e6795bc RDI: ffffffff8ca08700 RBP: ffffc90005b7f590 R08: ffffffff905dfe77 R09: 1ffffffff20bbfce R10: dffffc0000000000 R11: fffffbfff20bbfcf R12: 1ffff110170e74f6 R13: dffffc0000000000 R14: ffff8880b8639980 R15: ffff8880b873a7b0 context_switch kernel/sched/core.c:5385 [inline] __schedule+0x1b3b/0x51f0 kernel/sched/core.c:6767 __schedule_loop kernel/sched/core.c:6845 [inline] schedule+0x163/0x360 kernel/sched/core.c:6860 schedule_timeout+0xb1/0x2b0 kernel/time/sleep_timeout.c:75 do_wait_for_common kernel/sched/completion.c:95 [inline] __wait_for_common kernel/sched/completion.c:116 [inline] wait_for_common kernel/sched/completion.c:127 [inline] wait_for_completion+0x32f/0x600 kernel/sched/completion.c:148 rdmsr_safe_on_cpu+0x199/0x360 arch/x86/lib/msr-smp.c:181 msr_read+0x1a7/0x270 arch/x86/kernel/msr.c:66 vfs_read+0x21f/0xb90 fs/read_write.c:568 ksys_read+0x19d/0x2d0 fs/read_write.c:713 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: 0033:0x7f385bb8d169 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:00007f385c96f038 EFLAGS: 00000246 ORIG_RAX: 0000000000000000 RAX: ffffffffffffffda RBX: 00007f385bda6160 RCX: 00007f385bb8d169 RDX: 0000000000018ff8 RSI: 0000200000019680 RDI: 0000000000000005 RBP: 00007f385bc0e2a0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 00007f385bda6160 R15: 00007ffeb1eb2d28 task:sed state:R running task stack:23720 pid:14168 tgid:14168 ppid:14166 task_flags:0x40000c flags:0x00004002 Call Trace: context_switch kernel/sched/core.c:5382 [inline] __schedule+0x1b33/0x51f0 kernel/sched/core.c:6767 preempt_schedule_common+0x84/0xd0 kernel/sched/core.c:6947 preempt_schedule+0xe4/0xf0 kernel/sched/core.c:6971 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] zap_pte_range mm/memory.c:1771 [inline] zap_pmd_range mm/memory.c:1833 [inline] zap_pud_range mm/memory.c:1862 [inline] zap_p4d_range mm/memory.c:1883 [inline] unmap_page_range+0x3a12/0x4520 mm/memory.c:1904 unmap_vmas+0x3ce/0x5f0 mm/memory.c:1994 exit_mmap+0x2bc/0xdd0 mm/mmap.c:1284 __mmput+0x115/0x410 kernel/fork.c:1356 exit_mm+0x221/0x310 kernel/exit.c:586 do_exit+0x994/0x2950 kernel/exit.c:941 do_group_exit+0x207/0x2c0 kernel/exit.c:1103 __do_sys_exit_group kernel/exit.c:1114 [inline] __se_sys_exit_group kernel/exit.c:1112 [inline] __x64_sys_exit_group+0x3f/0x40 kernel/exit.c:1112 x64_sys_call+0x26c3/0x26d0 arch/x86/include/generated/asm/syscalls_64.h:232 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: 0033:0x7feee62a9a90 RSP: 002b:00007ffd036f3d08 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7 RAX: ffffffffffffffda RBX: 00007feee639a860 RCX: 00007feee62a9a90 RDX: 00000000000000e7 RSI: 000000000000003c RDI: 0000000000000000 RBP: 00007feee639a860 R08: 00007ffd036f3b80 R09: 00007ffd036f3c60 R10: 00007ffd036f3bc0 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 00007feee639e658 R15: 0000000000000001 task:syz.6.2261 state:R running task stack:26640 pid:14155 tgid:14151 ppid:12578 task_flags:0x40044c flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5382 [inline] __schedule+0x1b33/0x51f0 kernel/sched/core.c:6767 preempt_schedule_common+0x84/0xd0 kernel/sched/core.c:6947 preempt_schedule+0xe4/0xf0 kernel/sched/core.c:6971 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] zap_pte_range mm/memory.c:1771 [inline] zap_pmd_range mm/memory.c:1833 [inline] zap_pud_range mm/memory.c:1862 [inline] zap_p4d_range mm/memory.c:1883 [inline] unmap_page_range+0x3a12/0x4520 mm/memory.c:1904 unmap_vmas+0x3ce/0x5f0 mm/memory.c:1994 exit_mmap+0x2bc/0xdd0 mm/mmap.c:1284 __mmput+0x115/0x410 kernel/fork.c:1356 exit_mm+0x221/0x310 kernel/exit.c:586 do_exit+0x994/0x2950 kernel/exit.c:941 do_group_exit+0x207/0x2c0 kernel/exit.c:1103 get_signal+0x1696/0x1730 kernel/signal.c:3035 arch_do_signal_or_restart+0x98/0x840 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+0xce/0x340 kernel/entry/common.c:218 do_syscall_64+0x100/0x230 arch/x86/entry/syscall_64.c:100 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f54dc98d169 RSP: 002b:00007f54dd84c0e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca RAX: fffffffffffffe00 RBX: 00007f54dcba6088 RCX: 00007f54dc98d169 RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007f54dcba6088 RBP: 00007f54dcba6080 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007f54dcba608c R13: 0000000000000000 R14: 00007ffc7f8ece80 R15: 00007ffc7f8ecf68 rcu: rcu_preempt kthread starved for 10502 jiffies! g62917 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:26720 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5382 [inline] __schedule+0x1b33/0x51f0 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: 14159 Comm: syz.0.2264 Not tainted 6.14.0-syzkaller-10514-g7f2ff7b62617 #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025 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 02 0c 00 41 83 e4 01 4c 8b 64 24 68 75 07 e8 f8 fd 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: 0000:ffffc9000421f440 EFLAGS: 00000293 RAX: ffffffff81b75c7d RBX: 1ffff110170e7e31 RCX: ffff88805875bc00 RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000 RBP: ffffc9000421f640 R08: ffffffff81b75c48 R09: 1ffffffff20bbfce R10: dffffc0000000000 R11: fffffbfff20bbfcf R12: ffff8880b863ab88 R13: ffff8880b873f188 R14: ffff8880b863ab80 R15: 0000000000000001 FS: 0000555594a94500(0000) GS:ffff888124fed000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007ffeb1eb0c00 CR3: 000000007d4a4000 CR4: 00000000003526f0 DR0: 0000000000000000 DR1: 0000000000000097 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400 Call Trace: on_each_cpu_cond_mask+0x3f/0x80 kernel/smp.c:1052 __flush_tlb_multi arch/x86/include/asm/paravirt.h:91 [inline] flush_tlb_multi arch/x86/mm/tlb.c:1275 [inline] flush_tlb_mm_range+0xb8d/0x13f0 arch/x86/mm/tlb.c:1365 flush_tlb_page arch/x86/include/asm/tlbflush.h:324 [inline] ptep_clear_flush+0x11a/0x170 mm/pgtable-generic.c:101 wp_page_copy mm/memory.c:3513 [inline] do_wp_page+0x1c69/0x49b0 mm/memory.c:3839 handle_pte_fault mm/memory.c:5909 [inline] __handle_mm_fault+0x2305/0x6ef0 mm/memory.c:6036 handle_mm_fault+0x2dd/0x800 mm/memory.c:6205 do_user_addr_fault arch/x86/mm/fault.c:1337 [inline] handle_page_fault arch/x86/mm/fault.c:1480 [inline] exc_page_fault+0x45b/0x8b0 arch/x86/mm/fault.c:1538 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:623 RIP: 0033:0x7f385bb3a78b Code: c0 8b 87 c0 00 00 00 66 0f 6c c0 85 c0 0f 85 44 01 00 00 c7 87 c0 00 00 00 ff ff ff ff 48 8d 84 24 20 21 00 00 48 8d 7c 24 20 <0f> 29 44 24 40 49 89 e4 48 89 44 24 50 8b 43 74 48 89 9c 24 00 01 RSP: 002b:00007ffeb1eb0bc0 EFLAGS: 00010246 RAX: 00007ffeb1eb2ce0 RBX: 00007f385bd7c620 RCX: 0000000000000000 RDX: 00007ffeb1eb2d28 RSI: 00007f385bc0efbf RDI: 00007ffeb1eb0be0 RBP: 000000000000006e R08: 00007f385bda5fa0 R09: 0000000000000001 R10: 0000000000000000 R11: 0000000000000001 R12: 00007f385bda5fa0 R13: 00007f385bda66a0 R14: 00000000000000e3 R15: 0000000000000003