bisecting fixing commit since f40ddce88593482919761f74910f42f4b84c004b building syzkaller on 98682e5e2aefc9aad61354f4f3ac93be96002a2a testing commit f40ddce88593482919761f74910f42f4b84c004b compiler: gcc (GCC) 10.2.1 20210217, GNU ld (GNU Binutils for Debian) 2.35.2 kernel signature: 75aa9f71120e043efd6a24f768214c8b6ceb616bd7b5f0fdc4fe26875c203e96 run #0: crashed: INFO: rcu detected stall in mac80211_hwsim_beacon run #1: crashed: INFO: rcu detected stall in addrconf_rs_timer run #2: crashed: INFO: rcu detected stall in corrupted run #3: crashed: INFO: rcu detected stall in mac80211_hwsim_beacon run #4: crashed: INFO: rcu detected stall in mac80211_hwsim_beacon run #5: crashed: INFO: rcu detected stall in mac80211_hwsim_beacon run #6: crashed: INFO: rcu detected stall in mac80211_hwsim_beacon run #7: crashed: BUG: soft lockup in addrconf_rs_timer run #8: crashed: BUG: soft lockup in mac80211_hwsim_beacon run #9: crashed: BUG: soft lockup in mac80211_hwsim_beacon run #10: crashed: INFO: rcu detected stall in mac80211_hwsim_beacon run #11: crashed: BUG: soft lockup in mac80211_hwsim_beacon run #12: crashed: INFO: rcu detected stall in mac80211_hwsim_beacon run #13: crashed: INFO: rcu detected stall in mac80211_hwsim_beacon run #14: crashed: INFO: rcu detected stall in addrconf_rs_timer run #15: crashed: INFO: rcu detected stall in mac80211_hwsim_beacon run #16: crashed: INFO: rcu detected stall in mac80211_hwsim_beacon run #17: crashed: INFO: rcu detected stall in mac80211_hwsim_beacon run #18: crashed: INFO: rcu detected stall in mac80211_hwsim_beacon run #19: OK testing current HEAD d999ade1cc86cd2951d41c11ea769cb4452c8811 testing commit d999ade1cc86cd2951d41c11ea769cb4452c8811 compiler: gcc (GCC) 10.2.1 20210217, GNU ld (GNU Binutils for Debian) 2.35.2 kernel signature: 3abddb02f77c97a1cb813867edeb66972b9ab4a2e03dfa0cbd82c736b8b90ca2 run #0: crashed: INFO: rcu detected stall in addrconf_rs_timer run #1: basic kernel testing failed: failed to copy test binary to VM: failed to run ["scp" "-P" "22" "-F" "/dev/null" "-o" "UserKnownHostsFile=/dev/null" "-o" "BatchMode=yes" "-o" "IdentitiesOnly=yes" "-o" "StrictHostKeyChecking=no" "-o" "ConnectTimeout=10" "/tmp/syz-executor516411069" "root@10.128.10.26:./syz-executor516411069"]: exit status 1 Connection timed out during banner exchange Connection to 10.128.10.26 port 22 timed out lost connection run #2: OK run #3: OK run #4: OK run #5: OK run #6: OK run #7: OK run #8: OK run #9: OK reproducer seems to be flaky Reproducer flagged being flaky revisions tested: 2, total time: 36m12.022543596s (build: 13m3.244981189s, test: 22m16.938080486s) the crash still happens on HEAD commit msg: Merge tag 'perf-tools-fixes-for-v5.15-2021-10-16' of git://git.kernel.org/pub/scm/linux/kernel/git/acme/linux crash: INFO: rcu detected stall in addrconf_rs_timer rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: (detected by 1, t=10502 jiffies, g=9261, q=2907) rcu: All QSes seen, last rcu_preempt kthread activity 10371 (4294961750-4294951379), jiffies_till_next_fqs=1, root ->qsmask 0x0 rcu: rcu_preempt kthread starved for 10371 jiffies! g9261 f0x2 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=1 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:R running task stack:29136 pid: 13 ppid: 2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:4940 [inline] __schedule+0x908/0x26a0 kernel/sched/core.c:6287 schedule+0xd3/0x270 kernel/sched/core.c:6366 schedule_timeout+0x11d/0x250 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+0x38b/0x460 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 1 CPU: 1 PID: 12122 Comm: syz-executor.5 Not tainted 5.15.0-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+0x45/0x59 lib/dump_stack.c:106 nmi_cpu_backtrace.cold+0x30/0xac lib/nmi_backtrace.c:105 nmi_trigger_cpumask_backtrace+0x11a/0x160 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+0x13b/0x1c0 kernel/time/timer.c:1785 tick_sched_handle+0x6f/0x130 kernel/time/tick-sched.c:226 tick_sched_timer+0x132/0x210 kernel/time/tick-sched.c:1421 __run_hrtimer kernel/time/hrtimer.c:1685 [inline] __hrtimer_run_queues+0x18a/0xb00 kernel/time/hrtimer.c:1749 hrtimer_interrupt+0x2f5/0x780 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+0x40/0xc0 arch/x86/kernel/apic/apic.c:1097 asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:638 RIP: 0010:unwind_next_frame+0xca5/0x1ce0 arch/x86/kernel/unwind_orc.c:534 Code: 28 f5 ff ff 4c 89 ff 4c 89 44 24 20 e8 44 48 7a 00 4c 8b 44 24 20 e9 cb f6 ff ff e8 2c f6 d2 ff e9 49 f7 ff ff 48 8b 44 24 60 <4c> 89 e2 4c 89 f7 48 89 4c 24 30 4c 89 44 24 28 48 8d 70 f8 48 89 RSP: 0018:ffffc90000db04b0 EFLAGS: 00000246 RAX: ffffc90000db0ff8 RBX: 1ffff920001b609e RCX: ffffffff8cfa5e17 RDX: ffffc90000db0ff0 RSI: 0000000000000000 RDI: 0000000000000001 RBP: 0000000000000002 R08: ffffffff8cfa5e12 R09: 0000000000000001 R10: fffff520001b60bc R11: 000000000007a089 R12: ffffc90000db05d0 R13: ffffc90000db05bd R14: ffffc90000db0588 R15: ffffffff8cfa5e16 arch_stack_walk+0x7d/0xe0 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0x8c/0xc0 kernel/stacktrace.c:121 kasan_save_stack+0x1b/0x40 mm/kasan/common.c:38 kasan_set_track+0x1c/0x30 mm/kasan/common.c:46 kasan_set_free_info+0x20/0x30 mm/kasan/generic.c:360 ____kasan_slab_free mm/kasan/common.c:366 [inline] ____kasan_slab_free mm/kasan/common.c:328 [inline] __kasan_slab_free+0xe0/0x110 mm/kasan/common.c:374 kasan_slab_free include/linux/kasan.h:230 [inline] slab_free_hook mm/slub.c:1700 [inline] slab_free_freelist_hook mm/slub.c:1725 [inline] slab_free mm/slub.c:3483 [inline] kfree+0xd9/0x570 mm/slub.c:4543 skb_free_head net/core/skbuff.c:654 [inline] skb_release_data+0x500/0x640 net/core/skbuff.c:676 skb_release_all net/core/skbuff.c:741 [inline] __kfree_skb net/core/skbuff.c:755 [inline] kfree_skb net/core/skbuff.c:773 [inline] kfree_skb+0xe0/0x2c0 net/core/skbuff.c:767 neigh_connected_output+0x330/0x470 net/core/neighbour.c:1524 neigh_output include/net/neighbour.h:510 [inline] ip6_finish_output2+0x54a/0x1250 net/ipv6/ip6_output.c:126 dst_output include/net/dst.h:450 [inline] NF_HOOK include/linux/netfilter.h:307 [inline] ndisc_send_skb+0x97e/0x1520 net/ipv6/ndisc.c:508 addrconf_rs_timer+0x24b/0x710 net/ipv6/addrconf.c:3893 call_timer_fn+0x163/0x4a0 kernel/time/timer.c:1421 expire_timers kernel/time/timer.c:1466 [inline] __run_timers.part.0+0x524/0x890 kernel/time/timer.c:1734 __run_timers kernel/time/timer.c:1715 [inline] run_timer_softirq+0x9c/0x190 kernel/time/timer.c:1747 __do_softirq+0x29b/0x9c2 kernel/softirq.c:558 invoke_softirq kernel/softirq.c:432 [inline] __irq_exit_rcu+0x123/0x180 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:1097 asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:638 RIP: 0010:ima_file_free+0x7/0x370 security/integrity/ima/ima_main.c:187 Code: 44 8b 0c 24 eb a3 e8 78 18 0b 05 0f 1f 84 00 00 00 00 00 8b 05 3a a1 07 07 c3 66 0f 1f 84 00 00 00 00 00 48 c7 c0 40 0a bb 8e <41> 57 48 ba 00 00 00 00 00 fc ff df 48 89 c1 41 56 83 e0 07 41 55 RSP: 0018:ffffc9000b327c38 EFLAGS: 00000282 RAX: ffffffff8ebb0a40 RBX: ffff888142354a20 RCX: 1ffff1102822b4fa RDX: 1ffff1102846a988 RSI: 0000000000000000 RDI: ffff8880161c7180 RBP: ffff8880161c7204 R08: ffff88806e4dfa70 R09: ffff888142354a20 R10: ffffed102822b4fa R11: 0000000000000008 R12: 00000000000a0003 R13: ffff8880161c7190 R14: ffff8881409f84a0 R15: ffff8880161c7180 __fput+0x173/0x8d0 fs/file_table.c:274 task_work_run+0xc0/0x160 kernel/task_work.c:164 get_signal+0x1529/0x1c80 kernel/signal.c:2641 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:207 __syscall_exit_to_user_mode_work kernel/entry/common.c:289 [inline] syscall_exit_to_user_mode+0x19/0x50 kernel/entry/common.c:300 do_syscall_64+0x42/0xb0 arch/x86/entry/common.c:86 entry_SYSCALL_64_after_hwframe+0x44/0xae RIP: 0033:0x465d99 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:00007faddf05f188 EFLAGS: 00000246 ORIG_RAX: 0000000000000048 RAX: 0000000000000000 RBX: 000000000056bf60 RCX: 0000000000465d99 RDX: 0000000000042000 RSI: 0000000000000004 RDI: 0000000000000003 RBP: 00000000004bcf27 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000056bf60 R13: 00007ffda8528fcf R14: 00007faddf05f300 R15: 0000000000022000 ---------------- Code disassembly (best guess), 3 bytes skipped: 0: ff 4c 89 ff decl -0x1(%rcx,%rcx,4) 4: 4c 89 44 24 20 mov %r8,0x20(%rsp) 9: e8 44 48 7a 00 callq 0x7a4852 e: 4c 8b 44 24 20 mov 0x20(%rsp),%r8 13: e9 cb f6 ff ff jmpq 0xfffff6e3 18: e8 2c f6 d2 ff callq 0xffd2f649 1d: e9 49 f7 ff ff jmpq 0xfffff76b 22: 48 8b 44 24 60 mov 0x60(%rsp),%rax * 27: 4c 89 e2 mov %r12,%rdx <-- trapping instruction 2a: 4c 89 f7 mov %r14,%rdi 2d: 48 89 4c 24 30 mov %rcx,0x30(%rsp) 32: 4c 89 44 24 28 mov %r8,0x28(%rsp) 37: 48 8d 70 f8 lea -0x8(%rax),%rsi 3b: 48 rex.W 3c: 89 .byte 0x89