rcu: INFO: rcu_preempt self-detected stall on CPU rcu: 1-....: (10500 ticks this GP) idle=fdd/1/0x4000000000000000 softirq=35851/35851 fqs=5234 (t=10502 jiffies g=59973 q=3287) NMI backtrace for cpu 1 CPU: 1 PID: 19144 Comm: syz-executor.4 Not tainted 5.14.0-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+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_dump_cpu_stacks+0x25e/0x3f0 kernel/rcu/tree_stall.h:343 print_cpu_stall kernel/rcu/tree_stall.h:627 [inline] check_cpu_stall kernel/rcu/tree_stall.h:711 [inline] rcu_pending kernel/rcu/tree.c:3880 [inline] rcu_sched_clock_irq.cold+0x9d/0x746 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:perf_output_read_group kernel/events/core.c:6894 [inline] RIP: 0010:perf_output_read+0xbfa/0x1310 kernel/events/core.c:6935 Code: 00 00 48 89 f8 48 c1 e8 03 42 0f b6 04 28 84 c0 74 08 3c 03 0f 8e b3 05 00 00 48 8b 44 24 10 bf 01 00 00 00 8b a8 a8 00 00 00 <89> ee e8 9f 5e e2 ff 83 fd 01 0f 84 a5 02 00 00 e8 e1 55 e2 ff 48 RSP: 0018:ffffc90002047098 EFLAGS: 00000246 RAX: ffff88802d468040 RBX: ffffc900020473e0 RCX: ffffc900123d0000 RDX: 0000000000040000 RSI: ffffffff8192f42b RDI: 0000000000000001 RBP: 0000000000000001 R08: 0000000000000000 R09: ffff888017e16a97 R10: ffffffff8192f6c4 R11: 0000000000000001 R12: ffffc900020471e0 R13: dffffc0000000000 R14: ffff88802d468040 R15: 0000000000000010 perf_output_sample+0xd12/0x1d80 kernel/events/core.c:6982 __perf_event_output kernel/events/core.c:7467 [inline] perf_event_output_forward+0x119/0x280 kernel/events/core.c:7481 __perf_event_overflow+0x13c/0x3d0 kernel/events/core.c:9153 perf_swevent_overflow kernel/events/core.c:9229 [inline] perf_swevent_event+0x347/0x550 kernel/events/core.c:9257 do_perf_sw_event kernel/events/core.c:9370 [inline] ___perf_sw_event+0x31a/0x570 kernel/events/core.c:9401 __perf_sw_event+0x54/0x130 kernel/events/core.c:9413 perf_sw_event include/linux/perf_event.h:1171 [inline] mm_account_fault mm/memory.c:4754 [inline] handle_mm_fault+0x5ef/0x790 mm/memory.c:4805 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:ffffc90002047910 EFLAGS: 00010206 RAX: 0000000000000001 RBX: 0000000000008000 RCX: 0000000000004fcb RDX: 0000000000008000 RSI: 0000000020fd0000 RDI: ffff888030663035 RBP: ffff888030660000 R08: 0000000000000001 R09: ffff888030667fff R10: ffffed10060ccfff R11: 0000000000000000 R12: 0000000020fccfcb R13: 0000000020fd4fcb R14: 0000000000000000 R15: ffffc90002047d70 copy_user_generic arch/x86/include/asm/uaccess_64.h:37 [inline] raw_copy_from_user arch/x86/include/asm/uaccess_64.h:52 [inline] copyin.part.0+0xe4/0x110 lib/iov_iter.c:168 copyin lib/iov_iter.c:718 [inline] _copy_from_iter+0x2a3/0x1320 lib/iov_iter.c:718 copy_from_iter include/linux/uio.h:148 [inline] copy_from_iter_full include/linux/uio.h:154 [inline] skb_do_copy_data_nocache+0x145/0x310 include/net/sock.h:2080 skb_copy_to_page_nocache include/net/sock.h:2106 [inline] tcp_sendmsg_locked+0x1239/0x2f10 net/ipv4/tcp.c:1361 tcp_sendmsg+0x2b/0x40 net/ipv4/tcp.c:1461 inet_sendmsg+0x99/0xe0 net/ipv4/af_inet.c:821 sock_sendmsg_nosec net/socket.c:704 [inline] sock_sendmsg+0xcf/0x120 net/socket.c:724 __sys_sendto+0x21c/0x320 net/socket.c:2036 __do_sys_sendto net/socket.c:2048 [inline] __se_sys_sendto net/socket.c:2044 [inline] __x64_sys_sendto+0xdd/0x1b0 net/socket.c:2044 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:00007f100ecd6188 EFLAGS: 00000246 ORIG_RAX: 000000000000002c RAX: ffffffffffffffda RBX: 000000000056bf80 RCX: 00000000004665f9 RDX: ffffffffffffffef RSI: 0000000020d7cfcb RDI: 0000000000000007 RBP: 00000000004bfcc4 R08: 0000000000000000 R09: 0000000000000053 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000056bf80 R13: 00007fffb02195df R14: 00007f100ecd6300 R15: 0000000000022000 ---------------- Code disassembly (best guess): 0: 00 00 add %al,(%rax) 2: 48 89 f8 mov %rdi,%rax 5: 48 c1 e8 03 shr $0x3,%rax 9: 42 0f b6 04 28 movzbl (%rax,%r13,1),%eax e: 84 c0 test %al,%al 10: 74 08 je 0x1a 12: 3c 03 cmp $0x3,%al 14: 0f 8e b3 05 00 00 jle 0x5cd 1a: 48 8b 44 24 10 mov 0x10(%rsp),%rax 1f: bf 01 00 00 00 mov $0x1,%edi 24: 8b a8 a8 00 00 00 mov 0xa8(%rax),%ebp * 2a: 89 ee mov %ebp,%esi <-- trapping instruction 2c: e8 9f 5e e2 ff callq 0xffe25ed0 31: 83 fd 01 cmp $0x1,%ebp 34: 0f 84 a5 02 00 00 je 0x2df 3a: e8 e1 55 e2 ff callq 0xffe25620 3f: 48 rex.W