general protection fault in dst_dev_put (2)

[syzbot]

Hello,

syzbot found the following crash on:

HEAD commit:    290974d43478 nfp: flower: ensure TCP flags can be placed i..
git tree:       net
console output: https://syzkaller.appspot.com/x/log.txt?x=16132705400000
kernel config:  https://syzkaller.appspot.com/x/.config?x=c8970c89a0efbb23
dashboard link: https://syzkaller.appspot.com/bug?extid=9d4c12bfd45a58738d0a
compiler:       gcc (GCC) 8.0.1 20180413 (experimental)
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=17a9d525400000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=13ed7c8b400000

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+9d4c12bfd45a58738d0a@xxxxxxxxxxxxxxxxxxxxxxxxx

New replicast peer: 255.255.255.255
Enabled bearer <udp:syz1>, priority 10
Enabling of bearer <udp:syz1> rejected, already enabled
kasan: CONFIG_KASAN_INLINE enabled
kasan: GPF could be caused by NULL-ptr deref or user memory access
general protection fault: 0000 [#1] PREEMPT SMP KASAN
CPU: 1 PID: 0 Comm: swapper/1 Not tainted 4.20.0-rc6+ #225
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS  
Google 01/01/2011
RIP: 0010:dst_dev_put+0x24/0x290 net/core/dst.c:168
Code: 90 90 90 90 90 90 55 48 89 e5 41 56 41 55 41 54 53 48 89 fb e8 fd ed  
4d fb 48 89 da 48 b8 00 00 00 00 00 fc ff df 48 c1 ea 03 <80> 3c 02 00 0f  
85 e3 01 00 00 48 8d 7b 3a 4c 8b 23 48 b8 00 00 00
RSP: 0018:ffff8881daf07658 EFLAGS: 00010202
RAX: dffffc0000000000 RBX: 00000000000001b8 RCX: ffffffff86b6790f
RDX: 0000000000000037 RSI: ffffffff86319673 RDI: 00000000000001b8
RBP: ffff8881daf07678 R08: ffff8881d9b14340 R09: 0000000000000008
R10: 0000000000000000 R11: ffff8881d9b14340 R12: dffffc0000000000
R13: 0000000000000000 R14: 00000000000001b8 R15: 0000607e24e2ca08
FS:  0000000000000000(0000) GS:ffff8881daf00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f955571ce78 CR3: 00000001cea15000 CR4: 00000000001406e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <IRQ>
 rt_fibinfo_free_cpus net/ipv4/fib_semantics.c:200 [inline]
 free_fib_info_rcu+0x2e1/0x490 net/ipv4/fib_semantics.c:217
 __rcu_reclaim kernel/rcu/rcu.h:240 [inline]
 rcu_do_batch kernel/rcu/tree.c:2437 [inline]
 invoke_rcu_callbacks kernel/rcu/tree.c:2716 [inline]
 rcu_process_callbacks+0x100a/0x1ac0 kernel/rcu/tree.c:2697
 __do_softirq+0x308/0xb7e kernel/softirq.c:292
 invoke_softirq kernel/softirq.c:373 [inline]
 irq_exit+0x17f/0x1c0 kernel/softirq.c:413
 exiting_irq arch/x86/include/asm/apic.h:536 [inline]
 smp_apic_timer_interrupt+0x1cb/0x760 arch/x86/kernel/apic/apic.c:1061
 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:807
 </IRQ>
RIP: 0010:native_safe_halt+0x6/0x10 arch/x86/include/asm/irqflags.h:57
Code: e9 2c ff ff ff 48 89 c7 48 89 45 d8 e8 c3 ef e7 f9 48 8b 45 d8 e9 ca  
fe ff ff 48 89 df e8 b2 ef e7 f9 eb 82 55 48 89 e5 fb f4 <5d> c3 0f 1f 84  
00 00 00 00 00 55 48 89 e5 f4 5d c3 90 90 90 90 90
RSP: 0018:ffff8881d9b27cb8 EFLAGS: 00000282 ORIG_RAX: ffffffffffffff13
RAX: dffffc0000000000 RBX: 1ffff1103b364f9b RCX: 0000000000000000
RDX: 1ffffffff12a4021 RSI: 0000000000000001 RDI: ffffffff89520108
RBP: ffff8881d9b27cb8 R08: ffff8881d9b14340 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: ffff8881d9b27d78
R13: ffffffff8a163e20 R14: 0000000000000000 R15: 0000000000000001
 arch_safe_halt arch/x86/include/asm/paravirt.h:151 [inline]
 default_idle+0xbf/0x490 arch/x86/kernel/process.c:561
 arch_cpu_idle+0x10/0x20 arch/x86/kernel/process.c:552
 default_idle_call+0x6d/0x90 kernel/sched/idle.c:93
 cpuidle_idle_call kernel/sched/idle.c:153 [inline]
 do_idle+0x49b/0x5c0 kernel/sched/idle.c:262
 cpu_startup_entry+0x18/0x20 kernel/sched/idle.c:353
 start_secondary+0x487/0x5f0 arch/x86/kernel/smpboot.c:271
 secondary_startup_64+0xa4/0xb0 arch/x86/kernel/head_64.S:243
Modules linked in:
---[ end trace d0be650c8601c1dd ]---
RIP: 0010:dst_dev_put+0x24/0x290 net/core/dst.c:168
Code: 90 90 90 90 90 90 55 48 89 e5 41 56 41 55 41 54 53 48 89 fb e8 fd ed  
4d fb 48 89 da 48 b8 00 00 00 00 00 fc ff df 48 c1 ea 03 <80> 3c 02 00 0f  
85 e3 01 00 00 48 8d 7b 3a 4c 8b 23 48 b8 00 00 00
RSP: 0018:ffff8881daf07658 EFLAGS: 00010202
RAX: dffffc0000000000 RBX: 00000000000001b8 RCX: ffffffff86b6790f
RDX: 0000000000000037 RSI: ffffffff86319673 RDI: 00000000000001b8
RBP: ffff8881daf07678 R08: ffff8881d9b14340 R09: 0000000000000008
R10: 0000000000000000 R11: ffff8881d9b14340 R12: dffffc0000000000
R13: 0000000000000000 R14: 00000000000001b8 R15: 0000607e24e2ca08
FS:  0000000000000000(0000) GS:ffff8881daf00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f955571ce78 CR3: 00000001cea15000 CR4: 00000000001406e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400


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