general protection fault in j1939_sk_bind

[syzbot]

Hello,

syzbot found the following crash on:

HEAD commit:    a99d8080 Linux 5.4-rc6
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=12a6b844e00000
kernel config:  https://syzkaller.appspot.com/x/.config?x=896c87b73c6fcda6
dashboard link: https://syzkaller.appspot.com/bug?extid=4857323ec1bb236f6a45
compiler:       clang version 9.0.0 (/home/glider/llvm/clang  
80fee25776c2fb61e74c1ecb1a523375c2500b69)
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=110a8b8ae00000

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+4857323ec1bb236f6a45@xxxxxxxxxxxxxxxxxxxxxxxxx

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: 0 PID: 8341 Comm: syz-executor.0 Not tainted 5.4.0-rc6 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS  
Google 01/01/2011
RIP: 0010:__lock_acquire+0x86/0x1be0 kernel/locking/lockdep.c:3828
Code: 8a 04 30 84 c0 0f 85 66 12 00 00 83 3d 92 24 66 07 00 0f 84 91 12 00  
00 83 3d 35 a6 34 07 00 74 34 48 8b 44 24 10 48 c1 e8 03 <80> 3c 30 00 74  
14 48 8b 7c 24 10 e8 fa 13 54 00 48 be 00 00 00 00
RSP: 0018:ffff88809865fb80 EFLAGS: 00010006
RAX: 0000000000000218 RBX: 0000000000000001 RCX: 0000000000000000
RDX: 0000000000000000 RSI: dffffc0000000000 RDI: 00000000000010c0
RBP: ffff88809865fcd8 R08: 0000000000000001 R09: 0000000000000000
R10: fffffbfff117cc5d R11: 0000000000000000 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: ffff888098654700
FS:  00007f68f3c1c700(0000) GS:ffff8880aea00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000000075c000 CR3: 00000000a96a2000 CR4: 00000000001406f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 lock_acquire+0x158/0x250 kernel/locking/lockdep.c:4487
 __raw_spin_lock_bh include/linux/spinlock_api_smp.h:135 [inline]
 _raw_spin_lock_bh+0x34/0x50 kernel/locking/spinlock.c:175
 spin_lock_bh include/linux/spinlock.h:343 [inline]
 j1939_jsk_del net/can/j1939/socket.c:90 [inline]
 j1939_sk_bind+0x387/0xac0 net/can/j1939/socket.c:421
 __sys_bind+0x2c2/0x3a0 net/socket.c:1647
 __do_sys_bind net/socket.c:1658 [inline]
 __se_sys_bind net/socket.c:1656 [inline]
 __x64_sys_bind+0x7a/0x90 net/socket.c:1656
 do_syscall_64+0xf7/0x1c0 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x45a219
Code: ad b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 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 0f 83 7b b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007f68f3c1bc78 EFLAGS: 00000246 ORIG_RAX: 0000000000000031
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 000000000045a219
RDX: 0000000000000018 RSI: 0000000020000000 RDI: 0000000000000003
RBP: 000000000075bfc8 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f68f3c1c6d4
R13: 00000000004c057e R14: 00000000004d2c50 R15: 00000000ffffffff
Modules linked in:
---[ end trace bc0dd162dace32c7 ]---
RIP: 0010:__lock_acquire+0x86/0x1be0 kernel/locking/lockdep.c:3828
Code: 8a 04 30 84 c0 0f 85 66 12 00 00 83 3d 92 24 66 07 00 0f 84 91 12 00  
00 83 3d 35 a6 34 07 00 74 34 48 8b 44 24 10 48 c1 e8 03 <80> 3c 30 00 74  
14 48 8b 7c 24 10 e8 fa 13 54 00 48 be 00 00 00 00
RSP: 0018:ffff88809865fb80 EFLAGS: 00010006
RAX: 0000000000000218 RBX: 0000000000000001 RCX: 0000000000000000
RDX: 0000000000000000 RSI: dffffc0000000000 RDI: 00000000000010c0
RBP: ffff88809865fcd8 R08: 0000000000000001 R09: 0000000000000000
R10: fffffbfff117cc5d R11: 0000000000000000 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: ffff888098654700
FS:  00007f68f3c1c700(0000) GS:ffff8880aea00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000000075c000 CR3: 00000000a96a2000 CR4: 00000000001406f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400


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