rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P7479/1:b..l P7592/1:b..l (detected by 0, t=10502 jiffies, g=233065, q=21813) task:syz-executor.0 state:R running task stack:23000 pid: 7592 ppid: 1 flags:0x00004006 Call Trace: context_switch kernel/sched/core.c:4940 [inline] __schedule+0x940/0x26f0 kernel/sched/core.c:6287 preempt_schedule_common+0x45/0xc0 kernel/sched/core.c:6459 preempt_schedule_thunk+0x16/0x18 arch/x86/entry/thunk_64.S:35 __raw_read_unlock include/linux/rwlock_api_smp.h:227 [inline] _raw_read_unlock+0x36/0x40 kernel/locking/spinlock.c:260 zap_pid_ns_processes+0x271/0x660 kernel/pid_namespace.c:207 find_child_reaper kernel/exit.c:542 [inline] forget_original_parent kernel/exit.c:631 [inline] exit_notify kernel/exit.c:668 [inline] do_exit+0x234c/0x2a30 kernel/exit.c:845 do_group_exit+0x125/0x310 kernel/exit.c:922 get_signal+0x47f/0x2160 kernel/signal.c:2868 arch_do_signal_or_restart+0x2a9/0x1c40 arch/x86/kernel/signal.c:865 handle_signal_work kernel/entry/common.c:148 [inline] exit_to_user_mode_loop kernel/entry/common.c:172 [inline] exit_to_user_mode_prepare+0x17d/0x290 kernel/entry/common.c:209 __syscall_exit_to_user_mode_work kernel/entry/common.c:291 [inline] syscall_exit_to_user_mode+0x19/0x60 kernel/entry/common.c:302 do_syscall_64+0x42/0xb0 arch/x86/entry/common.c:86 entry_SYSCALL_64_after_hwframe+0x44/0xae RIP: 0033:0x7f38bc18c621 RSP: 002b:00007f38bc79fd00 EFLAGS: 00000293 ORIG_RAX: 00000000000000e6 RAX: 0000000000000000 RBX: 0000000000001c16 RCX: 00007f38bc18c621 RDX: 00007f38bc79fd40 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 00007f38bc79fddc R08: 0000000000000000 R09: 00007fffe1071080 R10: 0000000000000000 R11: 0000000000000293 R12: 000000000000003f R13: 000000000016bf3e R14: 0000000000000001 R15: 00007f38bc79fe40 task:syz-executor.5 state:R running task stack:23936 pid: 7479 ppid: 1 flags:0x00004006 Call Trace: context_switch kernel/sched/core.c:4940 [inline] __schedule+0x940/0x26f0 kernel/sched/core.c:6287 preempt_schedule_common+0x45/0xc0 kernel/sched/core.c:6459 preempt_schedule_thunk+0x16/0x18 arch/x86/entry/thunk_64.S:35 __raw_read_unlock include/linux/rwlock_api_smp.h:227 [inline] _raw_read_unlock+0x36/0x40 kernel/locking/spinlock.c:260 zap_pid_ns_processes+0x271/0x660 kernel/pid_namespace.c:207 find_child_reaper kernel/exit.c:542 [inline] forget_original_parent kernel/exit.c:631 [inline] exit_notify kernel/exit.c:668 [inline] do_exit+0x234c/0x2a30 kernel/exit.c:845 do_group_exit+0x125/0x310 kernel/exit.c:922 get_signal+0x47f/0x2160 kernel/signal.c:2868 arch_do_signal_or_restart+0x2a9/0x1c40 arch/x86/kernel/signal.c:865 handle_signal_work kernel/entry/common.c:148 [inline] exit_to_user_mode_loop kernel/entry/common.c:172 [inline] exit_to_user_mode_prepare+0x17d/0x290 kernel/entry/common.c:209 __syscall_exit_to_user_mode_work kernel/entry/common.c:291 [inline] syscall_exit_to_user_mode+0x19/0x60 kernel/entry/common.c:302 do_syscall_64+0x42/0xb0 arch/x86/entry/common.c:86 entry_SYSCALL_64_after_hwframe+0x44/0xae RIP: 0033:0x7f574f9b6621 RSP: 002b:00007f574ffc9d00 EFLAGS: 00000293 ORIG_RAX: 00000000000000e6 RAX: 0000000000000000 RBX: 000000000000292f RCX: 00007f574f9b6621 RDX: 00007f574ffc9d40 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 00007f574ffc9ddc R08: 0000000000000000 R09: 00007ffce0d71080 R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000053 R13: 000000000016c848 R14: 0000000000000000 R15: 00007f574ffc9e40 rcu: rcu_preempt kthread timer wakeup didn't happen for 2844 jiffies! g233065 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 rcu: Possible timer handling issue on cpu=0 timer-softirq=118761 rcu: rcu_preempt kthread starved for 2845 jiffies! g233065 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:28088 pid: 14 ppid: 2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:4940 [inline] __schedule+0x940/0x26f0 kernel/sched/core.c:6287 schedule+0xd3/0x270 kernel/sched/core.c:6366 schedule_timeout+0x14a/0x2a0 kernel/time/timer.c:1881 rcu_gp_fqs_loop+0x186/0x800 kernel/rcu/tree.c:1957 rcu_gp_kthread+0x1de/0x320 kernel/rcu/tree.c:2130 kthread+0x3e5/0x4d0 kernel/kthread.c:319 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295 rcu: Stack dump where RCU GP kthread last ran: NMI backtrace for cpu 0 CPU: 0 PID: 31365 Comm: syz-executor.4 Not tainted 5.15.0-rc1-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106 nmi_cpu_backtrace.cold+0x47/0x144 lib/nmi_backtrace.c:105 nmi_trigger_cpumask_backtrace+0x1ae/0x220 lib/nmi_backtrace.c:62 trigger_single_cpu_backtrace include/linux/nmi.h:164 [inline] rcu_check_gp_kthread_starvation.cold+0x1fb/0x200 kernel/rcu/tree_stall.h:481 print_other_cpu_stall kernel/rcu/tree_stall.h:586 [inline] check_cpu_stall kernel/rcu/tree_stall.h:729 [inline] rcu_pending kernel/rcu/tree.c:3880 [inline] rcu_sched_clock_irq+0x2125/0x2200 kernel/rcu/tree.c:2599 update_process_times+0x16d/0x200 kernel/time/timer.c:1785 tick_sched_handle+0x9b/0x180 kernel/time/tick-sched.c:226 tick_sched_timer+0x1b0/0x2d0 kernel/time/tick-sched.c:1421 __run_hrtimer kernel/time/hrtimer.c:1685 [inline] __hrtimer_run_queues+0x1c0/0xe50 kernel/time/hrtimer.c:1749 hrtimer_interrupt+0x31c/0x790 kernel/time/hrtimer.c:1811 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1086 [inline] __sysvec_apic_timer_interrupt+0x146/0x530 arch/x86/kernel/apic/apic.c:1103 sysvec_apic_timer_interrupt+0x8e/0xc0 arch/x86/kernel/apic/apic.c:1097 asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:638 RIP: 0010:_compound_head include/linux/page-flags.h:189 [inline] RIP: 0010:release_pages+0x11a/0x20b0 mm/swap.c:894 Code: 49 8d 7f 08 48 89 f8 48 c1 e8 03 42 80 3c 30 00 0f 85 a9 19 00 00 4d 8b 67 08 31 ff 4c 89 e5 83 e5 01 48 89 ee e8 96 e9 d6 ff <48> 85 ed 0f 85 7a 07 00 00 e8 28 e4 d6 ff e8 23 e4 d6 ff 48 8b 44 RSP: 0000:ffffc9001a98f658 EFLAGS: 00000246 RAX: 0000000000000000 RBX: ffff88808e067e88 RCX: 0000000000000000 RDX: 0000000000000000 RSI: ffff888075475580 RDI: 0000000000000003 RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000c10e00 R10: ffffffff819f27aa R11: 0000000000000000 R12: 0000000000000000 R13: 00000000000001ce R14: dffffc0000000000 R15: ffffea0000c10e80 tlb_batch_pages_flush mm/mmu_gather.c:49 [inline] tlb_flush_mmu_free mm/mmu_gather.c:242 [inline] tlb_flush_mmu+0xe9/0x6b0 mm/mmu_gather.c:249 zap_pte_range mm/memory.c:1432 [inline] zap_pmd_range mm/memory.c:1481 [inline] zap_pud_range mm/memory.c:1510 [inline] zap_p4d_range mm/memory.c:1531 [inline] unmap_page_range+0x1c58/0x2a10 mm/memory.c:1552 unmap_single_vma+0x198/0x310 mm/memory.c:1597 unmap_vmas+0x16d/0x2f0 mm/memory.c:1629 exit_mmap+0x1d0/0x630 mm/mmap.c:3171 __mmput+0x122/0x4b0 kernel/fork.c:1115 mmput+0x58/0x60 kernel/fork.c:1136 exit_mm kernel/exit.c:501 [inline] do_exit+0xabc/0x2a30 kernel/exit.c:812 do_group_exit+0x125/0x310 kernel/exit.c:922 get_signal+0x47f/0x2160 kernel/signal.c:2868 arch_do_signal_or_restart+0x2a9/0x1c40 arch/x86/kernel/signal.c:865 handle_signal_work kernel/entry/common.c:148 [inline] exit_to_user_mode_loop kernel/entry/common.c:172 [inline] exit_to_user_mode_prepare+0x17d/0x290 kernel/entry/common.c:209 __syscall_exit_to_user_mode_work kernel/entry/common.c:291 [inline] syscall_exit_to_user_mode+0x19/0x60 kernel/entry/common.c:302 do_syscall_64+0x42/0xb0 arch/x86/entry/common.c:86 entry_SYSCALL_64_after_hwframe+0x44/0xae RIP: 0033:0x7fa818862739 Code: Unable to access opcode bytes at RIP 0x7fa81886270f. RSP: 002b:00007fa815dd9218 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca RAX: fffffffffffffe00 RBX: 00007fa818966f88 RCX: 00007fa818862739 RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007fa818966f88 RBP: 00007fa818966f80 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007fa818966f8c R13: 00007fa818e9ab1f R14: 00007fa815dd9300 R15: 0000000000022000 ---------------- Code disassembly (best guess): 0: 49 8d 7f 08 lea 0x8(%r15),%rdi 4: 48 89 f8 mov %rdi,%rax 7: 48 c1 e8 03 shr $0x3,%rax b: 42 80 3c 30 00 cmpb $0x0,(%rax,%r14,1) 10: 0f 85 a9 19 00 00 jne 0x19bf 16: 4d 8b 67 08 mov 0x8(%r15),%r12 1a: 31 ff xor %edi,%edi 1c: 4c 89 e5 mov %r12,%rbp 1f: 83 e5 01 and $0x1,%ebp 22: 48 89 ee mov %rbp,%rsi 25: e8 96 e9 d6 ff callq 0xffd6e9c0 * 2a: 48 85 ed test %rbp,%rbp <-- trapping instruction 2d: 0f 85 7a 07 00 00 jne 0x7ad 33: e8 28 e4 d6 ff callq 0xffd6e460 38: e8 23 e4 d6 ff callq 0xffd6e460 3d: 48 rex.W 3e: 8b .byte 0x8b 3f: 44 rex.R