rcu: INFO: rcu_preempt self-detected stall on CPU rcu: 1-...!: (10440 ticks this GP) idle=39a/1/0x4000000000000000 softirq=251997/252002 fqs=2 (t=10502 jiffies g=512653 q=654) rcu: rcu_preempt kthread timer wakeup didn't happen for 9644 jiffies! g512653 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 rcu: Possible timer handling issue on cpu=0 timer-softirq=255600 rcu: rcu_preempt kthread starved for 9647 jiffies! g512653 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:28880 pid: 14 ppid: 2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:4681 [inline] __schedule+0x93a/0x26f0 kernel/sched/core.c:5938 schedule+0xd3/0x270 kernel/sched/core.c:6017 schedule_timeout+0x14a/0x2a0 kernel/time/timer.c:1881 rcu_gp_fqs_loop kernel/rcu/tree.c:1996 [inline] rcu_gp_kthread+0xd34/0x1980 kernel/rcu/tree.c:2169 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: Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 PID: 10885 Comm: syz-executor.4 Not tainted 5.14.0-rc5-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:check_kcov_mode+0x26/0x40 kernel/kcov.c:165 Code: cc cc cc cc 65 8b 05 59 4e 8c 7e 89 c2 81 e2 00 01 00 00 a9 00 01 ff 00 74 10 31 c0 85 d2 74 15 8b 96 34 15 00 00 85 d2 74 0b <8b> 86 10 15 00 00 39 f8 0f 94 c0 c3 66 66 2e 0f 1f 84 00 00 00 00 RSP: 0018:ffffc9001a5c6ef0 EFLAGS: 00000046 RAX: 0000000000000001 RBX: 0000000000000000 RCX: 0000000000000000 RDX: 0000000000000000 RSI: ffff8880231e0000 RDI: 0000000000000003 RBP: ffffc9001a5c6f38 R08: 0000000000000000 R09: 0000000000000000 R10: ffffffff817bd3f7 R11: 0000000000000000 R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 FS: 00007f3456623700(0000) GS:ffff8880b9c00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000000c00a148cb0 CR3: 0000000059ef9000 CR4: 00000000001506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: write_comp_data kernel/kcov.c:218 [inline] __sanitizer_cov_trace_const_cmp4+0x1c/0x70 kernel/kcov.c:284 trace_hardirqs_off_finish+0x17/0x270 kernel/trace/trace_preemptirq.c:63 irqentry_enter+0x28/0x50 kernel/entry/common.c:379 sysvec_apic_timer_interrupt+0xb/0xc0 arch/x86/kernel/apic/apic.c:1100 asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:638 RIP: 0010:pv_wait_head_or_lock kernel/locking/qspinlock_paravirt.h:434 [inline] RIP: 0010:__pv_queued_spin_lock_slowpath+0x3ba/0xb40 kernel/locking/qspinlock.c:508 Code: eb c6 45 01 01 41 bc 00 80 00 00 48 c1 e9 03 83 e3 07 41 be 01 00 00 00 48 b8 00 00 00 00 00 fc ff df 4c 8d 2c 01 eb 0c f3 90 <41> 83 ec 01 0f 84 72 04 00 00 41 0f b6 45 00 38 d8 7f 08 84 c0 0f RSP: 0018:ffffc9001a5c6fe0 EFLAGS: 00000206 RAX: 0000000000000003 RBX: 0000000000000000 RCX: 1ffff11013f7b738 RDX: 0000000000000001 RSI: ffffffff817bd271 RDI: ffffffff81332591 RBP: ffff88809fbdb9c0 R08: 0000000000000001 R09: 0000000000000001 R10: ffffffff817bd239 R11: 0000000000000000 R12: 00000000000047a6 R13: ffffed1013f7b738 R14: 0000000000000001 R15: ffff8880b9c527c0 pv_queued_spin_lock_slowpath arch/x86/include/asm/paravirt.h:585 [inline] queued_spin_lock_slowpath arch/x86/include/asm/qspinlock.h:51 [inline] queued_spin_lock include/asm-generic/qspinlock.h:85 [inline] do_raw_spin_lock+0x200/0x2b0 kernel/locking/spinlock_debug.c:113 spin_lock include/linux/spinlock.h:354 [inline] wp_page_copy+0x63a/0x2450 mm/memory.c:3036 do_wp_page+0x2cb/0x1ad0 mm/memory.c:3313 handle_pte_fault mm/memory.c:4576 [inline] __handle_mm_fault+0x2ada/0x5320 mm/memory.c:4693 handle_mm_fault+0x1c8/0x790 mm/memory.c:4791 do_user_addr_fault+0x48b/0x11c0 arch/x86/mm/fault.c:1390 handle_page_fault arch/x86/mm/fault.c:1475 [inline] exc_page_fault+0x9e/0x180 arch/x86/mm/fault.c:1531 asm_exc_page_fault+0x1e/0x30 arch/x86/include/asm/idtentry.h:568 RIP: 0010:copy_user_enhanced_fast_string+0xe/0x40 arch/x86/lib/copy_user_64.S:206 Code: 89 d1 c1 e9 03 83 e2 07 f3 48 a5 89 d1 f3 a4 31 c0 0f 1f 00 c3 0f 1f 80 00 00 00 00 0f 1f 00 83 fa 40 0f 82 70 ff ff ff 89 d1 a4 31 c0 0f 1f 00 c3 66 2e 0f 1f 84 00 00 00 00 00 89 d1 83 f8 RSP: 0018:ffffc9001a5c75d8 EFLAGS: 00010206 RAX: 0000000000000001 RBX: 0000000000008000 RCX: 0000000000006a40 RDX: 0000000000008000 RSI: ffff8880a12d15c0 RDI: 0000000020261000 RBP: 000000002025fa40 R08: 0000000000000000 R09: ffff8880a12d7fff R10: ffffed101425afff R11: 0000000000000000 R12: ffff8880a12d0000 R13: 0000000020267a40 R14: 0000000000000000 R15: ffffc9001a5c7d38 copy_user_generic arch/x86/include/asm/uaccess_64.h:37 [inline] raw_copy_to_user arch/x86/include/asm/uaccess_64.h:58 [inline] copyout.part.0+0xe4/0x110 lib/iov_iter.c:157 copyout lib/iov_iter.c:620 [inline] _copy_to_iter+0x2b1/0x1600 lib/iov_iter.c:620 copy_to_iter include/linux/uio.h:139 [inline] simple_copy_to_iter+0x4c/0x70 net/core/datagram.c:519 __skb_datagram_iter+0x4a7/0x770 net/core/datagram.c:448 skb_copy_datagram_iter+0x40/0x50 net/core/datagram.c:533 skb_copy_datagram_msg include/linux/skbuff.h:3620 [inline] unix_stream_read_actor+0x78/0xc0 net/unix/af_unix.c:2750 unix_stream_read_generic+0x80e/0x2140 net/unix/af_unix.c:2669 unix_stream_recvmsg+0x191/0x1c0 net/unix/af_unix.c:2788 sock_recvmsg_nosec net/socket.c:944 [inline] sock_recvmsg net/socket.c:962 [inline] sock_recvmsg net/socket.c:958 [inline] ____sys_recvmsg+0x2c4/0x600 net/socket.c:2622 ___sys_recvmsg+0x127/0x200 net/socket.c:2664 __sys_recvmsg+0xe2/0x1a0 net/socket.c:2694 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0xae RIP: 0033:0x4665f9 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 bc ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f3456623188 EFLAGS: 00000246 ORIG_RAX: 000000000000002f RAX: ffffffffffffffda RBX: 000000000056bf80 RCX: 00000000004665f9 RDX: 0000000000003f9c RSI: 0000000020000200 RDI: 0000000000000004 RBP: 00000000004bfcc4 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000056bf80 R13: 00007ffd515777ef R14: 00007f3456623300 R15: 0000000000022000 NMI backtrace for cpu 1 CPU: 1 PID: 10886 Comm: syz-executor.4 Not tainted 5.14.0-rc5-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:105 nmi_cpu_backtrace.cold+0x44/0xd7 lib/nmi_backtrace.c:105 nmi_trigger_cpumask_backtrace+0x1b3/0x230 lib/nmi_backtrace.c:62 trigger_single_cpu_backtrace include/linux/nmi.h:164 [inline] rcu_dump_cpu_stacks+0x25e/0x3f0 kernel/rcu/tree_stall.h:342 print_cpu_stall kernel/rcu/tree_stall.h:625 [inline] check_cpu_stall kernel/rcu/tree_stall.h:700 [inline] rcu_pending kernel/rcu/tree.c:3922 [inline] rcu_sched_clock_irq.cold+0x9f/0x747 kernel/rcu/tree.c:2641 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:1537 [inline] __hrtimer_run_queues+0x1c0/0xe50 kernel/time/hrtimer.c:1601 hrtimer_interrupt+0x330/0xa00 kernel/time/hrtimer.c:1663 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1089 [inline] __sysvec_apic_timer_interrupt+0x146/0x530 arch/x86/kernel/apic/apic.c:1106 sysvec_apic_timer_interrupt+0x40/0xc0 arch/x86/kernel/apic/apic.c:1100 asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:638 RIP: 0010:mac80211_hwsim_tx_frame_no_nl.isra.0+0x77b/0x1330 drivers/net/wireless/mac80211_hwsim.c:1527 Code: 00 00 00 c6 84 24 98 00 00 00 00 74 bb e8 8d 6c 42 fc 48 8d bb ac 3c 00 00 48 89 f8 48 89 fa 48 c1 e8 03 83 e2 07 0f b6 04 28 <38> d0 7f 08 84 c0 0f 85 36 09 00 00 44 0f b6 bb ac 3c 00 00 31 ff RSP: 0018:ffffc90000dc0ba0 EFLAGS: 00000202 RAX: 0000000000000000 RBX: ffff88802d0cb260 RCX: 0000000000000100 RDX: 0000000000000004 RSI: ffffffff85333d23 RDI: ffff88802d0cef0c RBP: dffffc0000000000 R08: 0000000000000008 R09: 0000000000000000 R10: ffffffff85333d59 R11: 0000000000000000 R12: ffff8880b187a500 R13: ffff88802f3cb490 R14: ffff88802f3cb260 R15: 0000000000000000 mac80211_hwsim_tx_frame+0x1ee/0x2a0 drivers/net/wireless/mac80211_hwsim.c:1784 mac80211_hwsim_beacon_tx+0x49b/0x930 drivers/net/wireless/mac80211_hwsim.c:1838 __iterate_interfaces+0x1e5/0x520 net/mac80211/util.c:793 ieee80211_iterate_active_interfaces_atomic+0x70/0x180 net/mac80211/util.c:829 mac80211_hwsim_beacon+0xd5/0x1a0 drivers/net/wireless/mac80211_hwsim.c:1861 __run_hrtimer kernel/time/hrtimer.c:1537 [inline] __hrtimer_run_queues+0x609/0xe50 kernel/time/hrtimer.c:1601 hrtimer_run_softirq+0x17b/0x360 kernel/time/hrtimer.c:1618 __do_softirq+0x29b/0x9c2 kernel/softirq.c:558 invoke_softirq kernel/softirq.c:432 [inline] __irq_exit_rcu+0x16e/0x1c0 kernel/softirq.c:636 irq_exit_rcu+0x5/0x20 kernel/softirq.c:648 sysvec_apic_timer_interrupt+0x93/0xc0 arch/x86/kernel/apic/apic.c:1100 asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:638 RIP: 0010:__sanitizer_cov_trace_pc+0x59/0x60 kernel/kcov.c:205 Code: 74 2b 8b 82 10 15 00 00 83 f8 02 75 20 48 8b 8a 18 15 00 00 8b 92 14 15 00 00 48 8b 01 48 83 c0 01 48 39 c2 76 07 48 89 34 c1 <48> 89 01 c3 0f 1f 00 41 55 41 54 49 89 fc 55 48 bd eb 83 b5 80 46 RSP: 0018:ffffc9001a6072d0 EFLAGS: 00000202 RAX: 000000000002e320 RBX: 0000000000000000 RCX: ffffc90001e11000 RDX: 0000000000040000 RSI: ffffffff81afa9ee RDI: 0000000000000003 RBP: ffffea000295ef80 R08: 0000000000000000 R09: 0000000000000000 R10: ffffffff81afa9e1 R11: 0000000000000000 R12: ffff8880ad24b420 R13: 0000000020261000 R14: ffffea000295ef80 R15: 0000000000000001 PageTail include/linux/page-flags.h:196 [inline] PageCompound include/linux/page-flags.h:201 [inline] PageTransCompound include/linux/page-flags.h:632 [inline] page_add_new_anon_rmap+0x4ce/0x8f0 mm/rmap.c:1195 wp_page_copy+0x973/0x2450 mm/memory.c:3060 do_wp_page+0x2cb/0x1ad0 mm/memory.c:3313 handle_pte_fault mm/memory.c:4576 [inline] __handle_mm_fault+0x2ada/0x5320 mm/memory.c:4693 handle_mm_fault+0x1c8/0x790 mm/memory.c:4791 do_user_addr_fault+0x48b/0x11c0 arch/x86/mm/fault.c:1390 handle_page_fault arch/x86/mm/fault.c:1475 [inline] exc_page_fault+0x9e/0x180 arch/x86/mm/fault.c:1531 asm_exc_page_fault+0x1e/0x30 arch/x86/include/asm/idtentry.h:568 RIP: 0010:copy_user_enhanced_fast_string+0xe/0x40 arch/x86/lib/copy_user_64.S:206 Code: 89 d1 c1 e9 03 83 e2 07 f3 48 a5 89 d1 f3 a4 31 c0 0f 1f 00 c3 0f 1f 80 00 00 00 00 0f 1f 00 83 fa 40 0f 82 70 ff ff ff 89 d1 a4 31 c0 0f 1f 00 c3 66 2e 0f 1f 84 00 00 00 00 00 89 d1 83 f8 RSP: 0018:ffffc9001a6077a8 EFLAGS: 00010206 RAX: 0000000000000001 RBX: 00000000000101d0 RCX: 0000000000003560 RDX: 00000000000101d0 RSI: ffff8880b116cd58 RDI: 0000000020261000 RBP: 0000000020254390 R08: 0000000000000000 R09: ffff8880b11702b7 R10: ffffed101622e056 R11: 0000000000000000 R12: ffff8880b11600e8 R13: 0000000020264560 R14: 0000000000000000 R15: ffffc9001a607d38 copy_user_generic arch/x86/include/asm/uaccess_64.h:37 [inline] raw_copy_to_user arch/x86/include/asm/uaccess_64.h:58 [inline] copyout.part.0+0xe4/0x110 lib/iov_iter.c:157 copyout lib/iov_iter.c:620 [inline] _copy_to_iter+0x2b1/0x1600 lib/iov_iter.c:620 copy_to_iter include/linux/uio.h:139 [inline] simple_copy_to_iter+0x4c/0x70 net/core/datagram.c:519 __skb_datagram_iter+0x10f/0x770 net/core/datagram.c:425 skb_copy_datagram_iter+0x40/0x50 net/core/datagram.c:533 skb_copy_datagram_msg include/linux/skbuff.h:3620 [inline] tipc_recvstream+0x3e9/0x910 net/tipc/socket.c:2068 sock_recvmsg_nosec net/socket.c:944 [inline] sock_recvmsg net/socket.c:962 [inline] sock_recvmsg net/socket.c:958 [inline] ____sys_recvmsg+0x2c4/0x600 net/socket.c:2622 ___sys_recvmsg+0x127/0x200 net/socket.c:2664 __sys_recvmsg+0xe2/0x1a0 net/socket.c:2694 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0xae RIP: 0033:0x4665f9 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 bc ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f3456602188 EFLAGS: 00000246 ORIG_RAX: 000000000000002f RAX: ffffffffffffffda RBX: 000000000056c038 RCX: 00000000004665f9 RDX: 0000000000003f9c RSI: 0000000020000200 RDI: 0000000000000008 RBP: 00000000004bfcc4 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000056c038 R13: 00007ffd515777ef R14: 00007f3456602300 R15: 0000000000022000 ---------------- Code disassembly (best guess): 0: cc int3 1: cc int3 2: cc int3 3: cc int3 4: 65 8b 05 59 4e 8c 7e mov %gs:0x7e8c4e59(%rip),%eax # 0x7e8c4e64 b: 89 c2 mov %eax,%edx d: 81 e2 00 01 00 00 and $0x100,%edx 13: a9 00 01 ff 00 test $0xff0100,%eax 18: 74 10 je 0x2a 1a: 31 c0 xor %eax,%eax 1c: 85 d2 test %edx,%edx 1e: 74 15 je 0x35 20: 8b 96 34 15 00 00 mov 0x1534(%rsi),%edx 26: 85 d2 test %edx,%edx 28: 74 0b je 0x35 * 2a: 8b 86 10 15 00 00 mov 0x1510(%rsi),%eax <-- trapping instruction 30: 39 f8 cmp %edi,%eax 32: 0f 94 c0 sete %al 35: c3 retq 36: 66 data16 37: 66 data16 38: 2e cs 39: 0f .byte 0xf 3a: 1f (bad) 3b: 84 00 test %al,(%rax) 3d: 00 00 add %al,(%rax)