Hello, When using Healer to fuzz the latest Linux kernel, the following crash was triggered. HEAD commit: 0513e464f900 Merge tag 'perf-tools-fixes-for-v5.15-2021-09-27' git tree: upstream console output: https://drive.google.com/file/d/1xw1nX3KSXOI0GzbKjGw5c0C14We3e0R3/view?usp=sharing kernel config: https://drive.google.com/file/d/1Jqhc4DpCVE8X7d-XBdQnrMoQzifTG5ho/view?usp=sharing Sorry, I don't have a reproducer for this crash, hope the symbolized report can help. If you fix this issue, please add the following tag to the commit: Reported-by: Hao Sun <sunhao.th@xxxxxxxxx> rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: 1-....: (1 ticks this GP) idle=e03/1/0x4000000000000000 softirq=19163/19163 fqs=3 (detected by 0, t=10635 jiffies, g=32217, q=314) Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 PID: 11958 Comm: kworker/1:5 Not tainted 5.15.0-rc3+ #21 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.12.0-59-gc9ba5276e321-prebuilt.qemu.org 04/01/2014 Workqueue: mld mld_ifc_work RIP: 0010:console_trylock_spinning kernel/printk/printk.c:1874 [inline] RIP: 0010:vprintk_emit+0x1c3/0x340 kernel/printk/printk.c:2243 Code: 0f 2d 81 31 f6 41 b8 01 00 00 00 48 c7 c7 c0 9d 93 85 e8 30 9e fe ff 0f b6 05 d1 a1 3a 07 5a 84 c0 74 10 e8 5f 81 0a 00 f3 90 <41> 0f b6 04 24 84 c0 75 f0 e8 4f 81 0a 00 48 c7 c6 0c 10 2d 81 48 RSP: 0018:ffffc90000708e18 EFLAGS: 00010046 RAX: 0000000000010001 RBX: 000000000000002a RCX: 0000000000000000 RDX: ffff888104d7a280 RSI: ffffffff812d1001 RDI: ffffffff853ccbb6 RBP: ffffc90000708e50 R08: 0000000000000000 R09: 0000000000000001 R10: ffffc90000708ce0 R11: 0000000000000005 R12: ffffffff8867b1c8 R13: 0000000000000000 R14: 0000000000000000 R15: ffffc90000708e78 FS: 0000000000000000(0000) GS:ffff88813dc00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f404556e4a0 CR3: 000000010f89d000 CR4: 0000000000750ee0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 PKRU: 55555554 Call Trace: <IRQ> vprintk+0x65/0x80 kernel/printk/printk_safe.c:50 _printk+0x5e/0x7d kernel/printk/printk.c:2265 vkms_vblank_simulate+0x187/0x190 drivers/gpu/drm/vkms/vkms_crtc.c:26 __run_hrtimer kernel/time/hrtimer.c:1685 [inline] __hrtimer_run_queues+0xb8/0x610 kernel/time/hrtimer.c:1749 hrtimer_interrupt+0xfe/0x280 kernel/time/hrtimer.c:1811 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1086 [inline] __sysvec_apic_timer_interrupt+0x9c/0x2c0 arch/x86/kernel/apic/apic.c:1103 sysvec_apic_timer_interrupt+0x99/0xc0 arch/x86/kernel/apic/apic.c:1097 </IRQ> asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:638 RIP: 0010:ip6mr_get_table net/ipv6/ip6mr.c:126 [inline] RIP: 0010:ip6mr_rule_action+0x78/0xe0 net/ipv6/ip6mr.c:173 Code: 5e e8 8c ee 7e fd 45 89 66 20 48 8b 6d 40 4d 8b 6e 10 48 8b 9d 88 0b 00 00 48 81 c5 88 0b 00 00 48 39 dd 74 25 e8 68 ee 7e fd <44> 3b 63 28 75 0d eb 38 e8 5b ee 7e fd 44 39 63 28 74 2d e8 50 ee RSP: 0018:ffffc900036efa50 EFLAGS: 00010293 RAX: 0000000000000000 RBX: ffff888010f38000 RCX: 0000000000000000 RDX: ffff888104d7a280 RSI: ffffffff83b8a2f8 RDI: ffff88800fa94300 RBP: ffff888015ee3e08 R08: 0000000000000000 R09: 0000000000000000 R10: ffffc900036ef948 R11: 0000000000000004 R12: 00000000000000fe R13: ffffc900036efad0 R14: ffffc900036efad8 R15: ffffc900036efad8 fib_rules_lookup+0x2ba/0x460 net/core/fib_rules.c:318 ip6mr_fib_lookup+0x77/0xc0 net/ipv6/ip6mr.c:145 mroute6_is_socket+0x7b/0xc0 net/ipv6/ip6mr.c:1617 ip6_finish_output2+0x60c/0xcc0 net/ipv6/ip6_output.c:83 __ip6_finish_output+0x143/0x520 net/ipv6/ip6_output.c:191 ip6_finish_output+0x30/0x110 net/ipv6/ip6_output.c:201 NF_HOOK_COND include/linux/netfilter.h:296 [inline] ip6_output+0xa8/0x3a0 net/ipv6/ip6_output.c:224 dst_output include/net/dst.h:450 [inline] NF_HOOK include/linux/netfilter.h:307 [inline] mld_sendpack+0x231/0x4a0 net/ipv6/mcast.c:1826 mld_send_cr net/ipv6/mcast.c:2127 [inline] mld_ifc_work+0x2f9/0x5d0 net/ipv6/mcast.c:2659 process_one_work+0x359/0x850 kernel/workqueue.c:2297 worker_thread+0x41/0x4d0 kernel/workqueue.c:2444 kthread+0x178/0x1b0 kernel/kthread.c:319 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295 vkms_vblank_simulate: vblank timer overrun vkms_vblank_simulate: vblank timer overrun vkms_vblank_simulate: vblank timer overrun vkms_vblank_simulate: vblank timer overrun vkms_vblank_simulate: vblank timer overrun vkms_vblank_simulate: vblank timer overrun vkms_vblank_simulate: vblank timer overrun vkms_vblank_simulate: vblank timer overrun vkms_vblank_simulate: vblank timer overrun vkms_vblank_simulate: vblank timer overrun vkms_vblank_simulate: vblank timer overrun vkms_vblank_simulate: vblank timer overrun vkms_vblank_simulate: vblank timer overrun vkms_vblank_simulate: vblank timer overrun vkms_vblank_simulate: vblank timer overrun vkms_vblank_simulate: vblank timer overrun vkms_vblank_simulate: vblank timer overrun vkms_vblank_simulate: vblank timer overrun vkms_vblank_simulate: vblank timer overrun NMI backtrace for cpu 3 skipped: idling at native_safe_halt arch/x86/include/asm/irqflags.h:51 [inline] NMI backtrace for cpu 3 skipped: idling at arch_safe_halt arch/x86/include/asm/irqflags.h:89 [inline] NMI backtrace for cpu 3 skipped: idling at default_idle+0xb/0x10 arch/x86/kernel/process.c:716 NMI backtrace for cpu 0 CPU: 0 PID: 1284 Comm: kworker/u9:4 Not tainted 5.15.0-rc3+ #21 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.12.0-59-gc9ba5276e321-prebuilt.qemu.org 04/01/2014 Workqueue: events_unbound toggle_allocation_gate RIP: 0010:preempt_count arch/x86/include/asm/preempt.h:27 [inline] RIP: 0010:check_kcov_mode kernel/kcov.c:163 [inline] RIP: 0010:__sanitizer_cov_trace_pc+0x0/0x60 kernel/kcov.c:197 Code: 7e 31 c0 81 e2 00 01 ff 00 75 10 65 48 8b 04 25 40 70 01 00 48 8b 80 28 15 00 00 c3 0f 1f 40 00 66 2e 0f 1f 84 00 00 00 00 00 <65> 8b 05 99 de c9 7e 89 c1 48 8b 34 24 65 48 8b 14 25 40 70 01 00 RSP: 0018:ffffc90005c67c78 EFLAGS: 00000202 RAX: 0000000000000011 RBX: ffff88813dc2f9c0 RCX: 0000000000000000 RDX: ffff88800d8bc500 RSI: ffffffff8132ec00 RDI: 00000000ffffffff RBP: 0000000000000001 R08: 0000000000000001 R09: 0000000000000001 R10: ffffc90005c67c28 R11: 0000000000000005 R12: ffff88807dc2a900 R13: ffff88807dc2a908 R14: ffffffff85a27660 R15: 0000000000000001 FS: 0000000000000000(0000) GS:ffff88807dc00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fbc80015228 CR3: 000000000588a000 CR4: 0000000000750ef0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 PKRU: 55555554 Call Trace: rep_nop arch/x86/include/asm/vdso/processor.h:13 [inline] cpu_relax arch/x86/include/asm/vdso/processor.h:18 [inline] csd_lock_wait kernel/smp.c:440 [inline] smp_call_function_many_cond+0x1d0/0x550 kernel/smp.c:969 on_each_cpu_cond_mask+0x48/0x90 kernel/smp.c:1135 on_each_cpu include/linux/smp.h:71 [inline] text_poke_sync arch/x86/kernel/alternative.c:929 [inline] text_poke_bp_batch+0x255/0x2c0 arch/x86/kernel/alternative.c:1183 text_poke_flush arch/x86/kernel/alternative.c:1268 [inline] text_poke_finish+0x16/0x30 arch/x86/kernel/alternative.c:1275 arch_jump_label_transform_apply+0x13/0x20 arch/x86/kernel/jump_label.c:146 jump_label_update+0xbc/0x190 kernel/jump_label.c:830 static_key_enable_cpuslocked+0x77/0xb0 kernel/jump_label.c:177 static_key_enable+0x16/0x20 kernel/jump_label.c:190 toggle_allocation_gate+0x71/0x240 mm/kfence/core.c:626 process_one_work+0x359/0x850 kernel/workqueue.c:2297 worker_thread+0x41/0x4d0 kernel/workqueue.c:2444 kthread+0x178/0x1b0 kernel/kthread.c:319 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295 NMI backtrace for cpu 1 CPU: 1 PID: 7811 Comm: kworker/u8:4 Not tainted 5.15.0-rc3+ #21 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.12.0-59-gc9ba5276e321-prebuilt.qemu.org 04/01/2014 Workqueue: netns cleanup_net RIP: 0010:neigh_flush_dev+0xd1/0x360 net/core/neighbour.c:307 Code: 00 85 c0 0f 84 55 01 00 00 e8 db c7 c9 fd 48 8b 5d 00 48 85 db 0f 84 9d 01 00 00 e8 c9 c7 c9 fd 4d 85 f6 74 18 e8 bf c7 c9 fd <4c> 39 b3 f8 02 00 00 74 0a e8 b1 c7 c9 fd 48 89 dd eb b2 e8 a7 c7 RSP: 0018:ffffc90001e07b68 EFLAGS: 00010293 RAX: 0000000000000000 RBX: ffff8881000bec00 RCX: 0000000000000000 RDX: ffff88810bd4c500 RSI: ffffffff836dc9a1 RDI: ffffffff853ccbb6 RBP: ffff88811289c2b0 R08: 0000000000000001 R09: 0000000000000001 R10: ffffc90001e07aa8 R11: 0000000000000005 R12: ffff88800e677000 R13: ffffffff85edcbf0 R14: ffff88800e677000 R15: ffffffff85edc960 FS: 0000000000000000(0000) GS:ffff88813dc00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fcb831b5000 CR3: 000000010738c000 CR4: 0000000000750ee0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 PKRU: 55555554 Call Trace: __neigh_ifdown+0x42/0x180 net/core/neighbour.c:358 neigh_ifdown+0x1a/0x20 net/core/neighbour.c:375 ndisc_netdev_event+0x211/0x380 net/ipv6/ndisc.c:1820 notifier_call_chain+0x3b/0xc0 kernel/notifier.c:83 call_netdevice_notifiers_info+0x58/0xa0 net/core/dev.c:1996 call_netdevice_notifiers_extack net/core/dev.c:2008 [inline] call_netdevice_notifiers net/core/dev.c:2022 [inline] dev_close_many+0x116/0x180 net/core/dev.c:1597 unregister_netdevice_many+0x1c8/0x8f0 net/core/dev.c:11020 default_device_exit_batch+0x196/0x1c0 net/core/dev.c:11573 ops_exit_list.isra.8+0x73/0x80 net/core/net_namespace.c:171 cleanup_net+0x2e6/0x4e0 net/core/net_namespace.c:591 process_one_work+0x359/0x850 kernel/workqueue.c:2297 worker_thread+0x41/0x4d0 kernel/workqueue.c:2444 kthread+0x178/0x1b0 kernel/kthread.c:319 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295 vkms_vblank_simulate: vblank timer overrun vkms_vblank_simulate: vblank timer overrun ---------------- Code disassembly (best guess): 0: 0f 2d 81 31 f6 41 b8 cvtps2pi -0x47be09cf(%rcx),%mm0 7: 01 00 add %eax,(%rax) 9: 00 00 add %al,(%rax) b: 48 c7 c7 c0 9d 93 85 mov $0xffffffff85939dc0,%rdi 12: e8 30 9e fe ff callq 0xfffe9e47 17: 0f b6 05 d1 a1 3a 07 movzbl 0x73aa1d1(%rip),%eax # 0x73aa1ef 1e: 5a pop %rdx 1f: 84 c0 test %al,%al 21: 74 10 je 0x33 23: e8 5f 81 0a 00 callq 0xa8187 28: f3 90 pause * 2a: 41 0f b6 04 24 movzbl (%r12),%eax <-- trapping instruction 2f: 84 c0 test %al,%al 31: 75 f0 jne 0x23 33: e8 4f 81 0a 00 callq 0xa8187 38: 48 c7 c6 0c 10 2d 81 mov $0xffffffff812d100c,%rsi 3f: 48 rex.W
