On Sun, 16 Feb 2020 02:49:16 -0800
> syzbot found the following crash on:
>
> HEAD commit: 2019fc96 Merge git://git.kernel.org/pub/scm/linux/kernel/g..
> git tree: upstream
> console output: https://syzkaller.appspot.com/x/log.txt?x=16ebaae6e00000
> kernel config: https://syzkaller.appspot.com/x/.config?x=735296e4dd620b10
> dashboard link: https://syzkaller.appspot.com/bug?extid=a98f2016f40b9cd3818a
> compiler: gcc (GCC) 9.0.0 20181231 (experimental)
>
> 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+a98f2016f40b9cd38...@syzkaller.appspotmail.com
>
> general protection fault, probably for non-canonical address
> 0xdffffc0000000002: 0000 [#1] PREEMPT SMP KASAN
> KASAN: null-ptr-deref in range [0x0000000000000010-0x0000000000000017]
> CPU: 0 PID: 21 Comm: kworker/u4:1 Not tainted 5.6.0-rc1-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+0x3f4/0x12d0
> net/batman-adv/bat_iv_ogm.c:814
> Code: c1 ea 03 80 3c 02 00 0f 85 e5 0d 00 00 4d 8b a7 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 b8
> RSP: 0018:ffffc90000dd7bb8 EFLAGS: 00010203
> RAX: dffffc0000000000 RBX: 0000000000000000 RCX: 1ffff1101537d9c1
> RDX: 0000000000000002 RSI: ffffffff87cc2c28 RDI: 0000000000000016
> RBP: ffffc90000dd7ca8 R08: 0000000000000004 R09: ffff8880a9bece10
> R10: fffffbfff154b460 R11: ffffffff8aa5a307 R12: 0000000000000000
> R13: 0000000000000001 R14: ffffc90000dd7c40 R15: ffff8880a9aa0800
> FS: 0000000000000000(0000) GS:ffff8880ae800000(0000) knlGS:0000000000000000
> CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> CR2: ffffffffff600400 CR3: 000000008f5a3000 CR4: 00000000001406f0
> 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+0xa05/0x17a0 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
--- a/net/batman-adv/bat_iv_ogm.c
+++ b/net/batman-adv/bat_iv_ogm.c
@@ -811,6 +811,8 @@ static void batadv_iv_ogm_schedule_buff(
}
batadv_ogm_packet = (struct batadv_ogm_packet *)(*ogm_buff);
+ if (!batadv_ogm_packet)
+ goto out;
batadv_ogm_packet->tvlv_len = htons(tvlv_len);
/* change sequence number to network order */
