bisecting fixing commit since 53bd76690e27f37c9df221a651a52cea04214da9 building syzkaller on 6c236867ce33c0c16b102e02a08226d7eb9b2046 testing commit 53bd76690e27f37c9df221a651a52cea04214da9 compiler: gcc version 8.4.1 20210217 (GCC) kernel signature: 8064d9797e409b482f4e6ed418fdd1cfa83377f6ab538aa918dcc127ad80e491 run #0: crashed: BUG: soft lockup in mld_dad_timer_expire run #1: crashed: BUG: soft lockup in addrconf_dad_work run #2: crashed: BUG: soft lockup in mld_dad_timer_expire run #3: crashed: BUG: soft lockup in mld_dad_timer_expire run #4: crashed: BUG: soft lockup in addrconf_dad_work run #5: crashed: BUG: soft lockup in mld_dad_timer_expire run #6: crashed: BUG: soft lockup in addrconf_dad_work run #7: crashed: BUG: soft lockup in addrconf_dad_work run #8: crashed: BUG: soft lockup in addrconf_dad_work run #9: crashed: BUG: soft lockup in addrconf_dad_work run #10: crashed: BUG: soft lockup in mld_dad_timer_expire run #11: crashed: BUG: soft lockup in addrconf_dad_work run #12: crashed: BUG: soft lockup in addrconf_dad_work run #13: crashed: BUG: soft lockup in mld_dad_timer_expire run #14: crashed: BUG: soft lockup in addrconf_dad_work run #15: crashed: BUG: soft lockup in addrconf_dad_work run #16: crashed: BUG: soft lockup in addrconf_dad_work run #17: crashed: BUG: soft lockup in addrconf_dad_work run #18: crashed: BUG: soft lockup in addrconf_dad_work run #19: crashed: BUG: soft lockup in mld_dad_timer_expire testing current HEAD b172b44fcb1771e083aad806fa96f3f60e2ddfac testing commit b172b44fcb1771e083aad806fa96f3f60e2ddfac compiler: gcc version 8.4.1 20210217 (GCC) kernel signature: a6b48e2b79ce4ceff8b55fd1cbbf606a020d8b66cf581b0823633afb815fa7a9 run #0: crashed: BUG: soft lockup in addrconf_dad_work run #1: crashed: BUG: soft lockup in addrconf_dad_work run #2: crashed: BUG: soft lockup in addrconf_dad_work run #3: crashed: BUG: soft lockup in addrconf_dad_work run #4: crashed: BUG: soft lockup in addrconf_dad_work run #5: crashed: BUG: soft lockup in addrconf_dad_work run #6: crashed: BUG: soft lockup in addrconf_dad_work run #7: crashed: BUG: soft lockup in mld_dad_timer_expire run #8: crashed: BUG: soft lockup in addrconf_dad_work run #9: crashed: BUG: soft lockup in mld_dad_timer_expire revisions tested: 2, total time: 26m3.289807024s (build: 18m16.113996045s, test: 7m24.846761325s) the crash still happens on HEAD commit msg: Linux 4.19.206 crash: BUG: soft lockup in mld_dad_timer_expire Bluetooth: hci3: command 0x0419 tx timeout Bluetooth: hci1: command 0x0419 tx timeout wlan1: Creating new IBSS network, BSSID 50:50:50:50:50:50 ieee802154 phy0 wpan0: encryption failed: -22 ieee802154 phy1 wpan1: encryption failed: -22 watchdog: BUG: soft lockup - CPU#0 stuck for 22s! [swapper/0:0] Modules linked in: irq event stamp: 215733 hardirqs last enabled at (215732): [] trace_hardirqs_on_thunk+0x1a/0x1c hardirqs last disabled at (215733): [] trace_hardirqs_off_thunk+0x1a/0x1c softirqs last enabled at (210336): [] _local_bh_enable+0x1c/0x30 kernel/softirq.c:162 softirqs last disabled at (210337): [] invoke_softirq kernel/softirq.c:372 [inline] softirqs last disabled at (210337): [] irq_exit+0x17f/0x1c0 kernel/softirq.c:412 CPU: 0 PID: 0 Comm: swapper/0 Not tainted 4.19.206-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:__list_add include/linux/list.h:63 [inline] RIP: 0010:list_add_tail include/linux/list.h:93 [inline] RIP: 0010:list_move_tail include/linux/list.h:183 [inline] RIP: 0010:fq_codel_dequeue+0xd7b/0x2e30 net/sched/sch_fq_codel.c:306 Code: f7 48 89 8d 70 ff ff ff 4c 89 fe e8 8f 2b 0e fd 84 c0 0f 84 2b f3 ff ff 48 8b 8d 70 ff ff ff 48 89 c8 48 c1 e8 03 80 3c 18 00 <0f> 85 93 16 00 00 4c 89 f0 4d 89 b5 00 03 00 00 48 c1 e8 03 80 3c RSP: 0018:ffff8880ba206cc0 EFLAGS: 00000246 ORIG_RAX: ffffffffffffff13 RAX: 1ffff110131e04f0 RBX: dffffc0000000000 RCX: ffff888098f02780 RDX: ffff888098f02778 RSI: ffff888098f02778 RDI: ffff888098f02780 RBP: ffff8880ba206e10 R08: ffffffff89877de8 R09: 0000000000000008 R10: ffffffff89877dc8 R11: 0000000000000001 R12: ffff888098f02778 R13: ffff888098f02480 R14: ffff88808d602c50 R15: ffff888098f02778 FS: 0000000000000000(0000) GS:ffff8880ba200000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000055993e50c160 CR3: 000000000986d000 CR4: 00000000001406f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: dequeue_skb net/sched/sch_generic.c:282 [inline] qdisc_restart net/sched/sch_generic.c:385 [inline] __qdisc_run+0x16a/0x1640 net/sched/sch_generic.c:403 __dev_xmit_skb net/core/dev.c:3500 [inline] __dev_queue_xmit+0x116b/0x2900 net/core/dev.c:3807 dev_queue_xmit+0xb/0x10 net/core/dev.c:3871 neigh_hh_output include/net/neighbour.h:491 [inline] neigh_output include/net/neighbour.h:499 [inline] ip_finish_output2+0x948/0x12c0 net/ipv4/ip_output.c:230 ip_finish_output+0x46d/0xe40 net/ipv4/ip_output.c:318 NF_HOOK_COND include/linux/netfilter.h:278 [inline] ip_output+0x1bc/0x530 net/ipv4/ip_output.c:406 dst_output include/net/dst.h:455 [inline] ip_local_out+0x74/0x110 net/ipv4/ip_output.c:125 iptunnel_xmit+0x5ae/0x950 net/ipv4/ip_tunnel_core.c:91 udp_tunnel_xmit_skb+0x23b/0x370 net/ipv4/udp_tunnel.c:182 geneve_xmit_skb drivers/net/geneve.c:867 [inline] geneve_xmit+0x1160/0x3120 drivers/net/geneve.c:943 __netdev_start_xmit include/linux/netdevice.h:4349 [inline] netdev_start_xmit include/linux/netdevice.h:4363 [inline] xmit_one net/core/dev.c:3256 [inline] dev_hard_start_xmit+0x160/0x6e0 net/core/dev.c:3272 __dev_queue_xmit+0x1ca6/0x2900 net/core/dev.c:3838 dev_queue_xmit+0xb/0x10 net/core/dev.c:3871 neigh_hh_output include/net/neighbour.h:491 [inline] neigh_output include/net/neighbour.h:499 [inline] ip6_finish_output2+0xbbc/0x2080 net/ipv6/ip6_output.c:120 ip6_finish_output+0x6db/0xea0 net/ipv6/ip6_output.c:192 NF_HOOK_COND include/linux/netfilter.h:278 [inline] ip6_output+0x1bb/0x610 net/ipv6/ip6_output.c:209 dst_output include/net/dst.h:455 [inline] NF_HOOK include/linux/netfilter.h:289 [inline] mld_sendpack+0x63d/0xe50 net/ipv6/mcast.c:1681 mld_send_initial_cr.part.15+0xd7/0x110 net/ipv6/mcast.c:2098 mld_send_initial_cr net/ipv6/mcast.c:2082 [inline] mld_dad_timer_expire+0x29/0x150 net/ipv6/mcast.c:2117 call_timer_fn+0x14c/0x510 kernel/time/timer.c:1338 expire_timers+0x255/0x3a0 kernel/time/timer.c:1375 __run_timers kernel/time/timer.c:1696 [inline] run_timer_softirq+0x1dc/0x570 kernel/time/timer.c:1709 __do_softirq+0x25f/0x919 kernel/softirq.c:292 invoke_softirq kernel/softirq.c:372 [inline] irq_exit+0x17f/0x1c0 kernel/softirq.c:412 exiting_irq arch/x86/include/asm/apic.h:536 [inline] smp_apic_timer_interrupt+0x13e/0x540 arch/x86/kernel/apic/apic.c:1098 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:894 RIP: 0010:native_safe_halt+0x12/0x20 arch/x86/include/asm/irqflags.h:61 Code: 11 ff ff ff 4c 89 e7 e8 dc 85 e6 f9 eb 97 90 90 90 90 90 90 90 90 90 90 55 48 89 e5 e9 07 00 00 00 0f 00 2d 60 b6 61 00 fb f4 <5d> c3 66 66 2e 0f 1f 84 00 00 00 00 00 90 55 48 89 e5 e9 07 00 00 RSP: 0018:ffffffff89807c80 EFLAGS: 00000282 ORIG_RAX: ffffffffffffff13 RAX: dffffc0000000000 RBX: ffffffff89877400 RCX: 0000000000000000 RDX: 1ffffffff13224ac RSI: 0000000000000001 RDI: ffffffff89912560 RBP: ffffffff89807c80 R08: ffffed101744455b R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000 R13: ffffffff89912550 R14: ffffffff8ab98818 R15: 0000000000000000 arch_safe_halt arch/x86/include/asm/paravirt.h:94 [inline] default_idle+0x51/0x310 arch/x86/kernel/process.c:557 arch_cpu_idle+0xa/0x10 arch/x86/kernel/process.c:548 default_idle_call+0x6d/0x90 kernel/sched/idle.c:93 cpuidle_idle_call kernel/sched/idle.c:153 [inline] do_idle+0x451/0x570 kernel/sched/idle.c:263 cpu_startup_entry+0xc8/0xe0 kernel/sched/idle.c:369 rest_init+0x237/0x23d init/main.c:441 start_kernel+0x648/0x686 init/main.c:736 x86_64_start_reservations+0x29/0x2b arch/x86/kernel/head64.c:490 x86_64_start_kernel+0x76/0x79 arch/x86/kernel/head64.c:471 secondary_startup_64+0xa4/0xb0 arch/x86/kernel/head_64.S:243 Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 PID: 8453 Comm: syz-executor.3 Not tainted 4.19.206-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:native_apic_mem_write+0xc/0x10 arch/x86/include/asm/apic.h:109 Code: 75 13 83 3d f5 e0 c9 09 01 7e 07 89 df e8 d5 7e 5c 06 5b 5d c3 e8 a4 a6 66 00 eb e6 66 90 55 89 ff 48 89 e5 89 b7 00 c0 5f ff <5d> c3 66 90 48 b8 00 00 00 00 00 fc ff df 55 48 89 e5 53 89 fb 48 RSP: 0018:ffff8880ba307e98 EFLAGS: 00000046 RAX: dffffc0000000000 RBX: ffffffff895cb1a0 RCX: 0000000000000020 RDX: 1ffffffff12b9636 RSI: 0000000000096940 RDI: 0000000000000380 RBP: ffff8880ba307e98 R08: ffffffff8aefb058 R09: 0000000000000004 R10: fffffbfff15df609 R11: 000000009501a8a0 R12: 0000000000000000 R13: 0000000000096940 R14: ffff8880ba324e98 R15: ffff8880ba324cc0 FS: 000000000324a400(0000) GS:ffff8880ba300000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fdce846b000 CR3: 00000000b2853000 CR4: 00000000001406e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: apic_write arch/x86/include/asm/apic.h:389 [inline] lapic_next_event+0x54/0x80 arch/x86/kernel/apic/apic.c:460 clockevents_program_event+0x1c2/0x280 kernel/time/clockevents.c:344 tick_program_event+0x6c/0xd0 kernel/time/tick-oneshot.c:48 hrtimer_interrupt+0x336/0x760 kernel/time/hrtimer.c:1552 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1071 [inline] smp_apic_timer_interrupt+0x114/0x540 arch/x86/kernel/apic/apic.c:1096 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:894 RIP: 0010:get_timespec64+0x0/0x110 kernel/time/time.c:858 Code: 88 e8 09 51 34 06 0f 0b eb 93 e8 ab 3e 3e 00 eb a8 89 54 24 04 e8 00 3e 3e 00 8b 54 24 04 e9 51 ff ff ff e8 b2 3f e6 ff 66 90 <55> ba 10 00 00 00 48 89 e5 41 56 41 55 49 89 fd 41 54 48 8d 7d a0 RSP: 0018:ffff8880aa6ffe30 EFLAGS: 00000282 ORIG_RAX: ffffffffffffff13 RAX: 1ffffffff1016a69 RBX: 1ffff110154dffcb RCX: 0000000000000000 RDX: ffff8880aa6ffe78 RSI: 00007ffd0ed6d6f0 RDI: ffff8880aa6ffe78 RBP: ffff8880aa6ffee0 R08: 1ffff110154dfff9 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: ffff8880aa6ffeb8 R13: ffffffff880b5348 R14: dffffc0000000000 R15: ffffffff880b5320 __x64_sys_clock_nanosleep+0x92/0xf0 kernel/time/posix-timers.c:1209 do_syscall_64+0xd0/0x4e0 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x48a7b1 Code: 24 0c 89 3c 24 48 89 4c 24 18 e8 aa e7 ff ff 4c 8b 54 24 18 48 8b 54 24 10 41 89 c0 8b 74 24 0c 8b 3c 24 b8 e6 00 00 00 0f 05 <44> 89 c7 48 89 04 24 e8 e3 e7 ff ff 48 8b 04 24 eb 97 66 2e 0f 1f RSP: 002b:00007ffd0ed6d6b0 EFLAGS: 00000293 ORIG_RAX: 00000000000000e6 RAX: ffffffffffffffda RBX: 0000000000000040 RCX: 000000000048a7b1 RDX: 00007ffd0ed6d6f0 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 0000000000000003 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000001 R13: 00007ffd0ed6d74a R14: 00000000014a4320 R15: 000000000000001e ---------------- Code disassembly (best guess): 0: f7 48 89 8d 70 ff ff testl $0xffff708d,-0x77(%rax) 7: ff 4c 89 fe decl -0x2(%rcx,%rcx,4) b: e8 8f 2b 0e fd callq 0xfd0e2b9f 10: 84 c0 test %al,%al 12: 0f 84 2b f3 ff ff je 0xfffff343 18: 48 8b 8d 70 ff ff ff mov -0x90(%rbp),%rcx 1f: 48 89 c8 mov %rcx,%rax 22: 48 c1 e8 03 shr $0x3,%rax 26: 80 3c 18 00 cmpb $0x0,(%rax,%rbx,1) * 2a: 0f 85 93 16 00 00 jne 0x16c3 <-- trapping instruction 30: 4c 89 f0 mov %r14,%rax 33: 4d 89 b5 00 03 00 00 mov %r14,0x300(%r13) 3a: 48 c1 e8 03 shr $0x3,%rax 3e: 80 .byte 0x80 3f: 3c .byte 0x3c