rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P11955/1:b..l P6573/1:b..l (detected by 0, t=10502 jiffies, g=187725, q=8220) task:syz-executor.0 state:R running task stack:22984 pid: 6573 ppid: 1 flags:0x00004006 Call Trace: context_switch kernel/sched/core.c:4756 [inline] __schedule+0x943/0x2700 kernel/sched/core.c:6029 preempt_schedule_common+0x49/0xd0 kernel/sched/core.c:6201 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+0x279/0x670 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+0x129/0x310 kernel/exit.c:922 get_signal+0x482/0x2170 kernel/signal.c:2846 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+0x46/0xb0 arch/x86/entry/common.c:86 entry_SYSCALL_64_after_hwframe+0x44/0xae RIP: 0033:0x464bdb RSP: 002b:00007ffd536124a0 EFLAGS: 00000246 ORIG_RAX: 0000000000000038 RAX: fffffffffffffff4 RBX: 0000000000000000 RCX: 0000000000464bdb RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000001200011 RBP: 0000000000000001 R08: 0000000000000000 R09: 00000000031d2400 R10: 00000000031d26d0 R11: 0000000000000246 R12: 0000000000000001 R13: 0000000000000000 R14: 0000000000000001 R15: 00007ffd53612590 task:kworker/u4:12 state:R running task stack:25008 pid:11955 ppid: 2 flags:0x00004000 Workqueue: phy26 ieee80211_iface_work Call Trace: context_switch kernel/sched/core.c:4756 [inline] __schedule+0x943/0x2700 kernel/sched/core.c:6029 preempt_schedule_irq+0x52/0xa0 kernel/sched/core.c:6429 irqentry_exit+0x35/0x90 kernel/entry/common.c:427 asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:638 RIP: 0010:__sanitizer_cov_trace_cmp8+0x69/0x70 kernel/kcov.c:265 Code: 3c cd 28 00 00 00 48 39 fe 72 1f 48 83 c2 01 4c 89 44 38 e8 48 c7 44 38 e0 06 00 00 00 48 89 4c 38 f0 4e 89 54 c8 20 48 89 10 66 0f 1f 44 00 00 53 41 89 fb 41 89 f1 bf 03 00 00 00 65 48 8b RSP: 0018:ffffc9000216f540 EFLAGS: 00000246 RAX: 0000000000000000 RBX: 000000000000005a RCX: 000000000000000c RDX: 0000000000000000 RSI: ffff88818bad5580 RDI: 0000000000000003 RBP: 000000000000000c R08: 000000000000000a R09: 0000000000000012 R10: ffffffff8893b3f9 R11: 0000000000000000 R12: 000000000000000a R13: 000000000000000a R14: 0000000000000168 R15: 0000000000000000 ieee80211_sta_get_rates+0x479/0x960 net/mac80211/util.c:2108 ieee80211_update_sta_info net/mac80211/ibss.c:1003 [inline] ieee80211_rx_bss_info net/mac80211/ibss.c:1117 [inline] ieee80211_rx_mgmt_probe_beacon+0x4f5/0x1660 net/mac80211/ibss.c:1608 ieee80211_ibss_rx_queued_mgmt+0xd45/0x1620 net/mac80211/ibss.c:1635 ieee80211_iface_process_skb net/mac80211/iface.c:1427 [inline] ieee80211_iface_work+0x7f7/0xa40 net/mac80211/iface.c:1463 process_one_work+0x9c9/0x16b0 kernel/workqueue.c:2297 worker_thread+0x65b/0x1200 kernel/workqueue.c:2444 kthread+0x3e5/0x4d0 kernel/kthread.c:319 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295 rcu: rcu_preempt kthread timer wakeup didn't happen for 2300 jiffies! g187725 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 rcu: Possible timer handling issue on cpu=0 timer-softirq=95894 rcu: rcu_preempt kthread starved for 2301 jiffies! g187725 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:28944 pid: 14 ppid: 2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:4756 [inline] __schedule+0x943/0x2700 kernel/sched/core.c:6029 schedule+0xd7/0x280 kernel/sched/core.c:6108 schedule_timeout+0x14e/0x2a0 kernel/time/timer.c:1881 rcu_gp_fqs_loop+0x186/0x810 kernel/rcu/tree.c:1955 rcu_gp_kthread+0x1e1/0x320 kernel/rcu/tree.c:2128 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: 12613 Comm: syz-executor.0 Not tainted 5.14.0-rc6-next-20210820-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+0x200/0x205 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:3878 [inline] rcu_sched_clock_irq+0x2138/0x2220 kernel/rcu/tree.c:2597 update_process_times+0x171/0x200 kernel/time/timer.c:1785 tick_sched_handle+0x9b/0x180 kernel/time/tick-sched.c:226 tick_sched_timer+0x1b8/0x2d0 kernel/time/tick-sched.c:1421 __run_hrtimer kernel/time/hrtimer.c:1685 [inline] __hrtimer_run_queues+0x1c3/0xe60 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+0x96/0xc0 arch/x86/kernel/apic/apic.c:1097 asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:638 RIP: 0010:folio_test_anon include/linux/page-flags.h:572 [inline] RIP: 0010:PageAnon include/linux/page-flags.h:577 [inline] RIP: 0010:mm_counter include/linux/mm.h:2054 [inline] RIP: 0010:zap_pte_range mm/memory.c:1361 [inline] RIP: 0010:zap_pmd_range mm/memory.c:1481 [inline] RIP: 0010:zap_pud_range mm/memory.c:1510 [inline] RIP: 0010:zap_p4d_range mm/memory.c:1531 [inline] RIP: 0010:unmap_page_range+0xdae/0x2a60 mm/memory.c:1552 Code: ed 0f 85 20 12 00 00 e8 b0 ff cb ff 48 89 eb e8 a8 ff cb ff 48 8d 7b 18 48 89 f8 48 c1 e8 03 42 80 3c 30 00 0f 85 0f 18 00 00 <48> 8b 43 18 31 ff bb 01 00 00 00 41 89 c5 41 83 e5 01 44 89 ee e8 RSP: 0018:ffffc900058df748 EFLAGS: 00000246 RAX: 1ffffd4000388ae3 RBX: ffffea0001c45700 RCX: 0000000000000000 RDX: ffff888025abd580 RSI: ffffffff81aa78e8 RDI: ffffea0001c45718 RBP: ffffea0001c45700 R08: 0000000000000000 R09: 0000000000000000 R10: ffffffff81aa78d2 R11: 0000000000000000 R12: ffffea0001c45708 R13: 0000000000000000 R14: dffffc0000000000 R15: 00007f940df00000 unmap_single_vma+0x19a/0x310 mm/memory.c:1597 unmap_vmas+0x173/0x2f0 mm/memory.c:1629 exit_mmap+0x1d0/0x620 mm/mmap.c:3200 __mmput+0x122/0x470 kernel/fork.c:1152 mmput+0x60/0x70 kernel/fork.c:1173 exit_mm kernel/exit.c:501 [inline] do_exit+0xabc/0x2a30 kernel/exit.c:812 do_group_exit+0x129/0x310 kernel/exit.c:922 get_signal+0x482/0x2170 kernel/signal.c:2846 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+0x46/0xb0 arch/x86/entry/common.c:86 entry_SYSCALL_64_after_hwframe+0x44/0xae RIP: 0033:0x4665e9 Code: Unable to access opcode bytes at RIP 0x4665bf. RSP: 002b:00007f940ce4a218 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca RAX: fffffffffffffe00 RBX: 000000000056bf88 RCX: 00000000004665e9 RDX: 0000000000000000 RSI: 0000000000000080 RDI: 000000000056bf88 RBP: 000000000056bf80 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000056bf8c R13: 00007ffd5361226f R14: 00007f940ce4a300 R15: 0000000000022000 ---------------- Code disassembly (best guess): 0: 3c cd cmp $0xcd,%al 2: 28 00 sub %al,(%rax) 4: 00 00 add %al,(%rax) 6: 48 39 fe cmp %rdi,%rsi 9: 72 1f jb 0x2a b: 48 83 c2 01 add $0x1,%rdx f: 4c 89 44 38 e8 mov %r8,-0x18(%rax,%rdi,1) 14: 48 c7 44 38 e0 06 00 movq $0x6,-0x20(%rax,%rdi,1) 1b: 00 00 1d: 48 89 4c 38 f0 mov %rcx,-0x10(%rax,%rdi,1) 22: 4e 89 54 c8 20 mov %r10,0x20(%rax,%r9,8) 27: 48 89 10 mov %rdx,(%rax) * 2a: c3 retq <-- trapping instruction 2b: 66 0f 1f 44 00 00 nopw 0x0(%rax,%rax,1) 31: 53 push %rbx 32: 41 89 fb mov %edi,%r11d 35: 41 89 f1 mov %esi,%r9d 38: bf 03 00 00 00 mov $0x3,%edi 3d: 65 gs 3e: 48 rex.W 3f: 8b .byte 0x8b