general protection fault in batadv_iv_ogm_schedule_buff

[syzbot]

Hello,

syzbot found the following crash on:

HEAD commit: b9d3d014 Add linux-next specific files for 20191122
git tree: linux-next
console output: https://syzkaller.appspot.com/x/log.txt?x=137f1bd2e00000
kernel config: https://syzkaller.appspot.com/x/.config?x=6c24c45ce29b175c
dashboard link: https://syzkaller.appspot.com/bug?extid=79ce6b21f6cda6dd39f3
compiler: gcc (GCC) 9.0.0 20181231 (experimental)
CC: [a...@unstable.cc b.a.t...@lists.open-mesh.org
da...@davemloft.net linux-...@vger.kernel.org marekl...@neomailbox.ch
net...@vger.kernel.org sv...@narfation.org s...@simonwunderlich.de]

Unfortunately, I don't have any reproducer for this crash yet.

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+79ce6b...@syzkaller.appspotmail.com

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: 9301 Comm: kworker/u4:11 Not tainted
5.4.0-rc8-next-20191122-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
Google 01/01/2011
Workqueue: bat_events batadv_iv_send_outstanding_bat_ogm_packet
RIP: 0010:batadv_iv_ogm_schedule_buff+0x295/0xea0
net/batman-adv/bat_iv_ogm.c:814
Code: c1 ea 03 80 3c 02 00 0f 85 13 0c 00 00 4d 8b a6 88 00 00 00 48 b8 00
00 00 00 00 fc ff df 49 8d 7c 24 16 48 89 fa 48 c1 ea 03 <0f> b6 14 02 48
89 f8 83 e0 07 83 c0 01 38 d0 7c 08 84 d2 0f 85 c3
RSP: 0000:ffff88805468fc30 EFLAGS: 00010203
RAX: dffffc0000000000 RBX: 0000000000000000 RCX: 1ffff1100a8cf9d2
RDX: 0000000000000002 RSI: ffffffff873aac69 RDI: 0000000000000016
RBP: ffff88805468fcb8 R08: 0000000000000004 R09: ffff88805467ce98
R10: fffffbfff139e730 R11: ffffffff89cf3987 R12: 0000000000000000
R13: 0000000000000000 R14: ffff88808de21800 R15: ffff88808de21800
FS: 0000000000000000(0000) GS:ffff8880ae900000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f121bbf8028 CR3: 00000000a0847000 CR4: 00000000001406e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
batadv_iv_ogm_schedule net/batman-adv/bat_iv_ogm.c:865 [inline]
batadv_iv_ogm_schedule net/batman-adv/bat_iv_ogm.c:858 [inline]
batadv_iv_send_outstanding_bat_ogm_packet+0x5da/0x7c0
net/batman-adv/bat_iv_ogm.c:1718
process_one_work+0x9af/0x1740 kernel/workqueue.c:2264
worker_thread+0x98/0xe40 kernel/workqueue.c:2410
kthread+0x361/0x430 kernel/kthread.c:255
ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352
Modules linked in:
---[ end trace d9c28670d04eb403 ]---
RIP: 0010:batadv_iv_ogm_schedule_buff+0x295/0xea0
net/batman-adv/bat_iv_ogm.c:814
Code: c1 ea 03 80 3c 02 00 0f 85 13 0c 00 00 4d 8b a6 88 00 00 00 48 b8 00
00 00 00 00 fc ff df 49 8d 7c 24 16 48 89 fa 48 c1 ea 03 <0f> b6 14 02 48
89 f8 83 e0 07 83 c0 01 38 d0 7c 08 84 d2 0f 85 c3
RSP: 0000:ffff88805468fc30 EFLAGS: 00010203
RAX: dffffc0000000000 RBX: 0000000000000000 RCX: 1ffff1100a8cf9d2
RDX: 0000000000000002 RSI: ffffffff873aac69 RDI: 0000000000000016
RBP: ffff88805468fcb8 R08: 0000000000000004 R09: ffff88805467ce98
R10: fffffbfff139e730 R11: ffffffff89cf3987 R12: 0000000000000000
R13: 0000000000000000 R14: ffff88808de21800 R15: ffff88808de21800
FS: 0000000000000000(0000) GS:ffff8880ae800000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000c4295b9010 CR3: 00000000a7b77000 CR4: 00000000001406f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400


---
This bug is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
syzbot engineers can be reached at syzk...@googlegroups.com.

syzbot will keep track of this bug report. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.

[Dmitry Vyukov]

#syz upstream

> --
> You received this message because you are subscribed to the Google Groups "syzkaller-upstream-moderation" group.
> To unsubscribe from this group and stop receiving emails from it, send an email to syzkaller-upstream-m...@googlegroups.com.
> To view this discussion on the web visit https://groups.google.com/d/msgid/syzkaller-upstream-moderation/000000000000156e100598075f4f%40google.com.