Hi, I've got the following error report while running the syzkaller fuzzer:
------------[ cut here ]------------ WARNING: CPU: 1 PID: 0 at net/ipv4/af_inet.c:153[< none >] inet_sock_destruct+0x64d/0x810 net/ipv4/af_inet.c:153 Modules linked in: CPU: 1 PID: 0 Comm: swapper/1 Not tainted 4.9.0-rc2+ #301 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011 ffff88006cd07d88 ffffffff81b47264 0000000000000000 0000000000000000 ffffffff84465d80 0000000000000000 ffff88006cd07dd0 ffffffff81111237 ffff88006cd19100[ 60.531224] 0000000000000099 ffffffff84465d80 0000000000000099 Call Trace: <IRQ> [ 60.531224] [<ffffffff81b47264>] dump_stack+0xb3/0x10f [<ffffffff81111237>] __warn+0x1a7/0x1f0 kernel/panic.c:550 [<ffffffff8111144c>] warn_slowpath_null+0x2c/0x40 kernel/panic.c:585 [<ffffffff8316e64d>] inet_sock_destruct+0x64d/0x810 net/ipv4/af_inet.c:153 [<ffffffff82b7c3a1>] __sk_destruct+0x51/0x480 net/core/sock.c:1422 [< inline >] __rcu_reclaim kernel/rcu/rcu.h:118 [< inline >] rcu_do_batch kernel/rcu/tree.c:2776 [< inline >] invoke_rcu_callbacks kernel/rcu/tree.c:3040 [< inline >] __rcu_process_callbacks kernel/rcu/tree.c:3007 [<ffffffff8125e090>] rcu_process_callbacks+0xa40/0x1190 kernel/rcu/tree.c:3024 [<ffffffff83fc376f>] __do_softirq+0x23f/0x8e5 kernel/softirq.c:284 [< inline >] invoke_softirq kernel/softirq.c:364 [<ffffffff811262b7>] irq_exit+0x1a7/0x1e0 kernel/softirq.c:405 [< inline >] exiting_irq ./arch/x86/include/asm/apic.h:659 [<ffffffff83fc309b>] smp_apic_timer_interrupt+0x7b/0xa0 arch/x86/kernel/apic/apic.c:960 [<ffffffff83fc214c>] apic_timer_interrupt+0x8c/0xa0 <EOI> [ 60.531224] [<ffffffff83fbf866>] ? native_safe_halt+0x6/0x10 [< inline >] arch_safe_halt ./arch/x86/include/asm/paravirt.h:103 [<ffffffff83fbef92>] default_idle+0x22/0x2d0 arch/x86/kernel/process.c:308 [<ffffffff8106ef6a>] arch_cpu_idle+0xa/0x10 arch/x86/kernel/process.c:299 [<ffffffff83fbfc16>] default_idle_call+0x36/0x60 kernel/sched/idle.c:96 [< inline >] cpuidle_idle_call kernel/sched/idle.c:154 [< inline >] cpu_idle_loop kernel/sched/idle.c:247 [<ffffffff811f8024>] cpu_startup_entry+0x244/0x300 kernel/sched/idle.c:302 [<ffffffff810b3ec0>] start_secondary+0x250/0x2d0 arch/x86/kernel/smpboot.c:263 ---[ end trace 3cd7480984cd70d8 ]--- =============================== [ INFO: suspicious RCU usage. ] 4.9.0-rc2+ #301 Tainted: G W ------------------------------- net/core/sock.c:1425 suspicious rcu_dereference_check() usage! other info that might help us debug this: rcu_scheduler_active = 1, debug_locks = 0 1 lock held by swapper/1/0: #0: [ 60.560631] ( rcu_callback[ 60.560930] ){......} , at: [ 60.561271] [<ffffffff8125e03b>] rcu_process_callbacks+0x9eb/0x1190 stack backtrace: CPU: 1 PID: 0 Comm: swapper/1 Tainted: G W 4.9.0-rc2+ #301 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011 ffff88006cd07e20 ffffffff81b47264 ffff88006c180000 0000000000000000 0000000000000001 ffffffff843fe660 ffff88006cd07e50 ffffffff81204a4f ffff880066438440 ffff880066438000 ffff8800664381b0 0000000000000000 Call Trace: <IRQ> [ 60.563304] [<ffffffff81b47264>] dump_stack+0xb3/0x10f [<ffffffff81204a4f>] lockdep_rcu_suspicious+0x13f/0x190 kernel/locking/lockdep.c:4445 [<ffffffff82b7c710>] __sk_destruct+0x3c0/0x480 net/core/sock.c:1424 [< inline >] __rcu_reclaim kernel/rcu/rcu.h:118 [< inline >] rcu_do_batch kernel/rcu/tree.c:2776 [< inline >] invoke_rcu_callbacks kernel/rcu/tree.c:3040 [< inline >] __rcu_process_callbacks kernel/rcu/tree.c:3007 [<ffffffff8125e090>] rcu_process_callbacks+0xa40/0x1190 kernel/rcu/tree.c:3024 [<ffffffff83fc376f>] __do_softirq+0x23f/0x8e5 kernel/softirq.c:284 [< inline >] invoke_softirq kernel/softirq.c:364 [<ffffffff811262b7>] irq_exit+0x1a7/0x1e0 kernel/softirq.c:405 [< inline >] exiting_irq ./arch/x86/include/asm/apic.h:659 [<ffffffff83fc309b>] smp_apic_timer_interrupt+0x7b/0xa0 arch/x86/kernel/apic/apic.c:960 [<ffffffff83fc214c>] apic_timer_interrupt+0x8c/0xa0 <EOI> [ 60.563304] [<ffffffff83fbf866>] ? native_safe_halt+0x6/0x10 [< inline >] arch_safe_halt ./arch/x86/include/asm/paravirt.h:103 [<ffffffff83fbef92>] default_idle+0x22/0x2d0 arch/x86/kernel/process.c:308 [<ffffffff8106ef6a>] arch_cpu_idle+0xa/0x10 arch/x86/kernel/process.c:299 [<ffffffff83fbfc16>] default_idle_call+0x36/0x60 kernel/sched/idle.c:96 [< inline >] cpuidle_idle_call kernel/sched/idle.c:154 [< inline >] cpu_idle_loop kernel/sched/idle.c:247 [<ffffffff811f8024>] cpu_startup_entry+0x244/0x300 kernel/sched/idle.c:302 [<ffffffff810b3ec0>] start_secondary+0x250/0x2d0 arch/x86/kernel/smpboot.c:263 On commit 07d9a380680d1c0eb51ef87ff2eab5c994949e69 (Oct 23).