======================================
| [ 1257.800337][    C2] ==================================================================
| [ 1257.800615][ C2] BUG: KASAN: null-ptr-deref in sock_def_write_space_wfree (./arch/x86/include/asm/bitops.h:206 ./arch/x86/include/asm/bitops.h:238 ./include/asm-generic/bitops/instrumented-non-atomic.h:142 net/core/sock.c:3397) 
| [ 1257.800855][    C2] Read of size 8 at addr 0000000000000008 by task swapper/2/0
| [ 1257.801086][    C2]
[ 1257.801409][    C2] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.16.3-0-ga6ed6b701f0a-prebuilt.qemu.org 04/01/2014
[ 1257.801754][    C2] Call Trace:
[ 1257.801871][    C2]  <IRQ>
[ 1257.801951][ C2] dump_stack_lvl (lib/dump_stack.c:117) 
[ 1257.802119][ C2] kasan_report (mm/kasan/report.c:603) 
[ 1257.802238][ C2] ? sock_def_write_space_wfree (./arch/x86/include/asm/bitops.h:206 ./arch/x86/include/asm/bitops.h:238 ./include/asm-generic/bitops/instrumented-non-atomic.h:142 net/core/sock.c:3397) 
[ 1257.802452][ C2] kasan_check_range (mm/kasan/generic.c:183 mm/kasan/generic.c:189) 
[ 1257.802603][ C2] sock_def_write_space_wfree (./arch/x86/include/asm/bitops.h:206 ./arch/x86/include/asm/bitops.h:238 ./include/asm-generic/bitops/instrumented-non-atomic.h:142 net/core/sock.c:3397) 
[ 1257.802752][ C2] sock_wfree (./include/linux/rcupdate.h:810 net/core/sock.c:2471) 
[ 1257.802868][ C2] skb_release_head_state (net/core/skbuff.c:1162 (discriminator 3)) 
[ 1257.803018][ C2] consume_skb (net/core/skbuff.c:1174 net/core/skbuff.c:1189 net/core/skbuff.c:1405 net/core/skbuff.c:1399) 
[ 1257.803130][ C2] dummy_xmit (drivers/net/dummy.c:66) 
[ 1257.803245][ C2] ? trace_net_dev_start_xmit (./include/trace/events/net.h:14 (discriminator 52)) 
[ 1257.803394][ C2] dev_hard_start_xmit (./include/linux/netdevice.h:4875 ./include/linux/netdevice.h:4889 net/core/dev.c:3563 net/core/dev.c:3579) 
[ 1257.803551][ C2] sch_direct_xmit (net/sched/sch_generic.c:343) 
[ 1257.803713][ C2] ? __pfx_sch_direct_xmit (net/sched/sch_generic.c:318) 
[ 1257.803864][ C2] __qdisc_run (net/sched/sch_generic.c:416) 
[ 1257.804016][ C2] ? __pfx_lock_acquire.part.0 (kernel/locking/lockdep.c:5719) 
[ 1257.804170][ C2] ? __pfx___qdisc_run (net/sched/sch_generic.c:412) 
[ 1257.804338][ C2] ? do_raw_spin_lock (./arch/x86/include/asm/atomic.h:115 ./include/linux/atomic/atomic-arch-fallback.h:2170 ./include/linux/atomic/atomic-instrumented.h:1302 ./include/asm-generic/qspinlock.h:111 kernel/locking/spinlock_debug.c:116) 
[ 1257.804486][ C2] ? __pfx_do_raw_spin_lock (kernel/locking/spinlock_debug.c:114) 
[ 1257.804652][ C2] ? lock_acquire (kernel/locking/lockdep.c:5727) 
[ 1257.804808][ C2] ? net_tx_action (./include/linux/spinlock.h:352 net/core/dev.c:5250) 
[ 1257.804957][ C2] net_tx_action (./include/net/sch_generic.h:217 ./include/net/pkt_sched.h:128 ./include/net/pkt_sched.h:124 net/core/dev.c:5266) 
[ 1257.805108][ C2] __do_softirq (kernel/softirq.c:554) 
[ 1257.805261][ C2] irq_exit_rcu (kernel/softirq.c:428 kernel/softirq.c:633 kernel/softirq.c:645) 
[ 1257.805376][ C2] sysvec_apic_timer_interrupt (arch/x86/kernel/apic/apic.c:1043 arch/x86/kernel/apic/apic.c:1043) 
[ 1257.805525][    C2]  </IRQ>
[ 1257.805618][    C2]  <TASK>
[ 1257.805701][ C2] asm_sysvec_apic_timer_interrupt (./arch/x86/include/asm/idtentry.h:702) 
[ 1257.805886][ C2] RIP: 0010:default_idle (./arch/x86/include/asm/irqflags.h:37 ./arch/x86/include/asm/irqflags.h:72 arch/x86/kernel/process.c:743) 
[ 1257.806055][ C2] Code: 4c 01 c7 4c 29 c2 e9 72 ff ff ff 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 66 90 0f 00 2d e3 cc 32 00 fb f4 <fa> c3 cc cc cc cc 66 66 2e 0f 1f 84 00 00 00 00 00 90 90 90 90 90
All code
========
   0:	4c 01 c7             	add    %r8,%rdi
   3:	4c 29 c2             	sub    %r8,%rdx
   6:	e9 72 ff ff ff       	jmp    0xffffffffffffff7d
   b:	90                   	nop
   c:	90                   	nop
   d:	90                   	nop
   e:	90                   	nop
   f:	90                   	nop
  10:	90                   	nop
  11:	90                   	nop
  12:	90                   	nop
  13:	90                   	nop
  14:	90                   	nop
  15:	90                   	nop
  16:	90                   	nop
  17:	90                   	nop
  18:	90                   	nop
  19:	90                   	nop
  1a:	90                   	nop
  1b:	f3 0f 1e fa          	endbr64
  1f:	66 90                	xchg   %ax,%ax
  21:	0f 00 2d e3 cc 32 00 	verw   0x32cce3(%rip)        # 0x32cd0b
  28:	fb                   	sti
  29:	f4                   	hlt
  2a:*	fa                   	cli		<-- trapping instruction
  2b:	c3                   	ret
  2c:	cc                   	int3
  2d:	cc                   	int3
  2e:	cc                   	int3
  2f:	cc                   	int3
  30:	66 66 2e 0f 1f 84 00 	data16 cs nopw 0x0(%rax,%rax,1)
  37:	00 00 00 00 
  3b:	90                   	nop
  3c:	90                   	nop
  3d:	90                   	nop
  3e:	90                   	nop
  3f:	90                   	nop

Code starting with the faulting instruction
===========================================
   0:	fa                   	cli
   1:	c3                   	ret
   2:	cc                   	int3
   3:	cc                   	int3
   4:	cc                   	int3
   5:	cc                   	int3
   6:	66 66 2e 0f 1f 84 00 	data16 cs nopw 0x0(%rax,%rax,1)
   d:	00 00 00 00 
  11:	90                   	nop
  12:	90                   	nop
  13:	90                   	nop
  14:	90                   	nop
  15:	90                   	nop
[ 1257.806582][    C2] RSP: 0018:ffffc9000015fdf8 EFLAGS: 00000246
[ 1257.806771][    C2] RAX: 000000000291e109 RBX: 1ffff9200002bfc1 RCX: ffffffff8eb34e95
[ 1257.806997][    C2] RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffffffff8c2ac0e4
[ 1257.807222][    C2] RBP: 0000000000000000 R08: 0000000000000001 R09: ffffed1006c2709c
[ 1257.807445][    C2] R10: ffff8880361384e3 R11: ffff88803613de40 R12: 0000000000000000
[ 1257.807667][    C2] R13: ffff888001b8c5c0 R14: dffffc0000000000 R15: 0000000000000000
[ 1257.807891][ C2] ? ct_kernel_exit.constprop.0 (kernel/context_tracking.c:147) 
[ 1257.808039][ C2] ? cpuidle_idle_call (kernel/sched/idle.c:192) 
[ 1257.808198][ C2] default_idle_call (./include/linux/cpuidle.h:143 kernel/sched/idle.c:118) 
[ 1257.808350][ C2] cpuidle_idle_call (kernel/sched/idle.c:192) 
[ 1257.808501][ C2] ? __pfx_cpuidle_idle_call (kernel/sched/idle.c:168) 
[ 1257.808648][ C2] ? tsc_verify_tsc_adjust (arch/x86/kernel/tsc_sync.c:59) 
[ 1257.808798][ C2] do_idle (kernel/sched/idle.c:332) 
[ 1257.808912][ C2] cpu_startup_entry (kernel/sched/idle.c:429 (discriminator 1)) 
[ 1257.809058][ C2] start_secondary (arch/x86/kernel/smpboot.c:201 arch/x86/kernel/smpboot.c:281) 
[ 1257.809207][ C2] ? __pfx_start_secondary (arch/x86/kernel/smpboot.c:231) 
[ 1257.809354][ C2] common_startup_64 (arch/x86/kernel/head_64.S:421) 
| [ 1257.809626][    C2] ==================================================================
| [ 1257.809879][    C2] Disabling lock debugging due to kernel taint
| [ 1257.810109][    C2] general protection fault, probably for non-canonical address 0xdffffc0000000001: 0000 [#1] PREEMPT SMP KASAN NOPTI
| [ 1257.810446][    C2] KASAN: null-ptr-deref in range [0x0000000000000008-0x000000000000000f]
[ 1257.810943][    C2] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.16.3-0-ga6ed6b701f0a-prebuilt.qemu.org 04/01/2014
[ 1257.811272][ C2] RIP: 0010:sock_def_write_space_wfree (./arch/x86/include/asm/bitops.h:206 ./arch/x86/include/asm/bitops.h:238 ./include/asm-generic/bitops/instrumented-non-atomic.h:142 net/core/sock.c:3397) 
[ 1257.811471][ C2] Code: 00 4c 8b bb a0 01 00 00 be 08 00 00 00 4d 8d 77 08 4c 89 f7 e8 e0 0e 8b fe 4c 89 f2 48 b8 00 00 00 00 00 fc ff df 48 c1 ea 03 <80> 3c 02 00 0f 85 fe 00 00 00 49 8b 47 08 a8 04 0f 85 dc fe ff ff
All code
========
   0:	00 4c 8b bb          	add    %cl,-0x45(%rbx,%rcx,4)
   4:	a0 01 00 00 be 08 00 	movabs 0x8be000001,%al
   b:	00 00 
   d:	4d 8d 77 08          	lea    0x8(%r15),%r14
  11:	4c 89 f7             	mov    %r14,%rdi
  14:	e8 e0 0e 8b fe       	call   0xfffffffffe8b0ef9
  19:	4c 89 f2             	mov    %r14,%rdx
  1c:	48 b8 00 00 00 00 00 	movabs $0xdffffc0000000000,%rax
  23:	fc ff df 
  26:	48 c1 ea 03          	shr    $0x3,%rdx
  2a:*	80 3c 02 00          	cmpb   $0x0,(%rdx,%rax,1)		<-- trapping instruction
  2e:	0f 85 fe 00 00 00    	jne    0x132
  34:	49 8b 47 08          	mov    0x8(%r15),%rax
  38:	a8 04                	test   $0x4,%al
  3a:	0f 85 dc fe ff ff    	jne    0xffffffffffffff1c

Code starting with the faulting instruction
===========================================
   0:	80 3c 02 00          	cmpb   $0x0,(%rdx,%rax,1)
   4:	0f 85 fe 00 00 00    	jne    0x108
   a:	49 8b 47 08          	mov    0x8(%r15),%rax
   e:	a8 04                	test   $0x4,%al
  10:	0f 85 dc fe ff ff    	jne    0xfffffffffffffef2
[ 1257.811997][    C2] RSP: 0018:ffffc90000230c30 EFLAGS: 00010202
[ 1257.812187][    C2] RAX: dffffc0000000000 RBX: ffff88800a785dc0 RCX: ffffffff8c19564a
[ 1257.812408][    C2] RDX: 0000000000000001 RSI: 0000000000000008 RDI: ffffffff916fda00
[ 1257.812626][    C2] RBP: ffff88800a785e20 R08: 0000000000000001 R09: fffffbfff22dfb40
[ 1257.812854][    C2] R10: ffffffff916fda07 R11: 205d324320202020 R12: 0000000000000000
[ 1257.813073][    C2] R13: ffff88800a785f40 R14: 0000000000000008 R15: 0000000000000000
[ 1257.813290][    C2] FS:  0000000000000000(0000) GS:ffff888036100000(0000) knlGS:0000000000000000
[ 1257.813558][    C2] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 1257.813745][    C2] CR2: 00007faa550f7ac0 CR3: 000000002e938002 CR4: 0000000000770ef0
[ 1257.813973][    C2] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[ 1257.814196][    C2] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[ 1257.814429][    C2] PKRU: 55555554
[ 1257.814562][    C2] Call Trace:
[ 1257.814701][    C2]  <IRQ>
[ 1257.814781][ C2] ? die_addr (arch/x86/kernel/dumpstack.c:421 arch/x86/kernel/dumpstack.c:460) 
[ 1257.814900][ C2] ? exc_general_protection (arch/x86/kernel/traps.c:702 arch/x86/kernel/traps.c:644) 
[ 1257.815055][ C2] ? asm_exc_general_protection (./arch/x86/include/asm/idtentry.h:617) 
[ 1257.815204][ C2] ? add_taint (./arch/x86/include/asm/bitops.h:60 ./include/asm-generic/bitops/instrumented-atomic.h:29 kernel/panic.c:555) 
[ 1257.815316][ C2] ? sock_def_write_space_wfree (./arch/x86/include/asm/bitops.h:206 ./arch/x86/include/asm/bitops.h:238 ./include/asm-generic/bitops/instrumented-non-atomic.h:142 net/core/sock.c:3397) 
[ 1257.815503][ C2] sock_wfree (./include/linux/rcupdate.h:810 net/core/sock.c:2471) 
[ 1257.815617][ C2] skb_release_head_state (net/core/skbuff.c:1162 (discriminator 3)) 
[ 1257.815773][ C2] consume_skb (net/core/skbuff.c:1174 net/core/skbuff.c:1189 net/core/skbuff.c:1405 net/core/skbuff.c:1399) 
[ 1257.815883][ C2] dummy_xmit (drivers/net/dummy.c:66) 
[ 1257.816001][ C2] ? trace_net_dev_start_xmit (./include/trace/events/net.h:14 (discriminator 52)) 
[ 1257.816161][ C2] dev_hard_start_xmit (./include/linux/netdevice.h:4875 ./include/linux/netdevice.h:4889 net/core/dev.c:3563 net/core/dev.c:3579) 
[ 1257.816314][ C2] sch_direct_xmit (net/sched/sch_generic.c:343) 
[ 1257.816466][ C2] ? __pfx_sch_direct_xmit (net/sched/sch_generic.c:318) 
[ 1257.816614][ C2] __qdisc_run (net/sched/sch_generic.c:416) 
[ 1257.816767][ C2] ? __pfx_lock_acquire.part.0 (kernel/locking/lockdep.c:5719) 
[ 1257.816918][ C2] ? __pfx___qdisc_run (net/sched/sch_generic.c:412) 
[ 1257.817069][ C2] ? do_raw_spin_lock (./arch/x86/include/asm/atomic.h:115 ./include/linux/atomic/atomic-arch-fallback.h:2170 ./include/linux/atomic/atomic-instrumented.h:1302 ./include/asm-generic/qspinlock.h:111 kernel/locking/spinlock_debug.c:116) 
[ 1257.817220][ C2] ? __pfx_do_raw_spin_lock (kernel/locking/spinlock_debug.c:114) 
[ 1257.817372][ C2] ? lock_acquire (kernel/locking/lockdep.c:5727) 
[ 1257.817517][ C2] ? net_tx_action (./include/linux/spinlock.h:352 net/core/dev.c:5250) 
[ 1257.817663][ C2] net_tx_action (./include/net/sch_generic.h:217 ./include/net/pkt_sched.h:128 ./include/net/pkt_sched.h:124 net/core/dev.c:5266) 
[ 1257.817809][ C2] __do_softirq (kernel/softirq.c:554) 
[ 1257.817962][ C2] irq_exit_rcu (kernel/softirq.c:428 kernel/softirq.c:633 kernel/softirq.c:645) 
[ 1257.818073][ C2] sysvec_apic_timer_interrupt (arch/x86/kernel/apic/apic.c:1043 arch/x86/kernel/apic/apic.c:1043) 
[ 1257.818221][    C2]  </IRQ>
[ 1257.818300][    C2]  <TASK>
[ 1257.818375][ C2] asm_sysvec_apic_timer_interrupt (./arch/x86/include/asm/idtentry.h:702) 
[ 1257.818561][ C2] RIP: 0010:default_idle (./arch/x86/include/asm/irqflags.h:37 ./arch/x86/include/asm/irqflags.h:72 arch/x86/kernel/process.c:743) 
[ 1257.818731][ C2] Code: 4c 01 c7 4c 29 c2 e9 72 ff ff ff 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 66 90 0f 00 2d e3 cc 32 00 fb f4 <fa> c3 cc cc cc cc 66 66 2e 0f 1f 84 00 00 00 00 00 90 90 90 90 90
All code
========
   0:	4c 01 c7             	add    %r8,%rdi
   3:	4c 29 c2             	sub    %r8,%rdx
   6:	e9 72 ff ff ff       	jmp    0xffffffffffffff7d
   b:	90                   	nop
   c:	90                   	nop
   d:	90                   	nop
   e:	90                   	nop
   f:	90                   	nop
  10:	90                   	nop
  11:	90                   	nop
  12:	90                   	nop
  13:	90                   	nop
  14:	90                   	nop
  15:	90                   	nop
  16:	90                   	nop
  17:	90                   	nop
  18:	90                   	nop
  19:	90                   	nop
  1a:	90                   	nop
  1b:	f3 0f 1e fa          	endbr64
  1f:	66 90                	xchg   %ax,%ax
  21:	0f 00 2d e3 cc 32 00 	verw   0x32cce3(%rip)        # 0x32cd0b
  28:	fb                   	sti
  29:	f4                   	hlt
  2a:*	fa                   	cli		<-- trapping instruction
  2b:	c3                   	ret
  2c:	cc                   	int3
  2d:	cc                   	int3
  2e:	cc                   	int3
  2f:	cc                   	int3
  30:	66 66 2e 0f 1f 84 00 	data16 cs nopw 0x0(%rax,%rax,1)
  37:	00 00 00 00 
  3b:	90                   	nop
  3c:	90                   	nop
  3d:	90                   	nop
  3e:	90                   	nop
  3f:	90                   	nop

Code starting with the faulting instruction
===========================================
   0:	fa                   	cli
   1:	c3                   	ret
   2:	cc                   	int3
   3:	cc                   	int3
   4:	cc                   	int3
   5:	cc                   	int3
   6:	66 66 2e 0f 1f 84 00 	data16 cs nopw 0x0(%rax,%rax,1)
   d:	00 00 00 00 
  11:	90                   	nop
  12:	90                   	nop
  13:	90                   	nop
  14:	90                   	nop
  15:	90                   	nop
[ 1257.819246][    C2] RSP: 0018:ffffc9000015fdf8 EFLAGS: 00000246
[ 1257.819438][    C2] RAX: 000000000291e109 RBX: 1ffff9200002bfc1 RCX: ffffffff8eb34e95
[ 1257.819665][    C2] RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffffffff8c2ac0e4
[ 1257.819898][    C2] RBP: 0000000000000000 R08: 0000000000000001 R09: ffffed1006c2709c
[ 1257.820120][    C2] R10: ffff8880361384e3 R11: ffff88803613de40 R12: 0000000000000000
[ 1257.820338][    C2] R13: ffff888001b8c5c0 R14: dffffc0000000000 R15: 0000000000000000
[ 1257.820559][ C2] ? ct_kernel_exit.constprop.0 (kernel/context_tracking.c:147) 
[ 1257.820702][ C2] ? cpuidle_idle_call (kernel/sched/idle.c:192) 
[ 1257.820853][ C2] default_idle_call (./include/linux/cpuidle.h:143 kernel/sched/idle.c:118) 
[ 1257.820998][ C2] cpuidle_idle_call (kernel/sched/idle.c:192) 
[ 1257.821146][ C2] ? __pfx_cpuidle_idle_call (kernel/sched/idle.c:168) 
[ 1257.821292][ C2] ? tsc_verify_tsc_adjust (arch/x86/kernel/tsc_sync.c:59) 
[ 1257.821441][ C2] do_idle (kernel/sched/idle.c:332) 
[ 1257.821550][ C2] cpu_startup_entry (kernel/sched/idle.c:429 (discriminator 1)) 
[ 1257.821698][ C2] start_secondary (arch/x86/kernel/smpboot.c:201 arch/x86/kernel/smpboot.c:281) 
[ 1257.821854][ C2] ? __pfx_start_secondary (arch/x86/kernel/smpboot.c:231) 


Finger prints:
dump_stack_lvl:kasan_report:kasan_check_range:sock_def_write_space_wfree
sock_def_write_space_wfree:sock_wfree:skb_release_head_state:consume_skb