general protection fault in skb_put

From: syzbot <syzbot+65788f9af9d54844389e@syzkaller.appspotmail.com>
To: johan.hedberg@gmail.com, linux-bluetooth@vger.kernel.org,
	linux-kernel@vger.kernel.org, marcel@holtmann.org,
	syzkaller-bugs@googlegroups.com
Subject: general protection fault in skb_put
Date: Mon, 04 Feb 2019 08:43:03 -0800	[thread overview]
Message-ID: <000000000000b9e68e0581142f19@google.com> (raw)

Hello,

syzbot found the following crash on:

HEAD commit:    dc4c89997735 Add linux-next specific files for 20190201
git tree:       linux-next
console output: https://syzkaller.appspot.com/x/log.txt?x=120a50b0c00000
kernel config:  https://syzkaller.appspot.com/x/.config?x=59aefae07c771af6
dashboard link: https://syzkaller.appspot.com/bug?extid=65788f9af9d54844389e
compiler:       gcc (GCC) 9.0.0 20181231 (experimental)
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=178e0798c00000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=11b4f0b0c00000

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+65788f9af9d54844389e@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: 21 Comm: kworker/u4:1 Not tainted 5.0.0-rc4-next-20190201 #25
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS  
Google 01/01/2011
Workqueue: events_unbound flush_to_ldisc
RIP: 0010:skb_put+0x35/0x1d0 net/core/skbuff.c:1698
Code: 89 f5 41 54 49 89 fc 53 4d 8d b4 24 b8 00 00 00 48 83 ec 08 e8 2c 6a  
01 fc 4c 89 f2 48 b8 00 00 00 00 00 fc ff df 48 c1 ea 03 <0f> b6 14 02 4c  
89 f0 83 e0 07 83 c0 03 38 d0 7c 08 84 d2 0f 85 4c
RSP: 0018:ffff8880a99cfb28 EFLAGS: 00010206
RAX: dffffc0000000000 RBX: ffff8880969a9280 RCX: ffffffff84ef8fa3
RDX: 0000000000000017 RSI: ffffffff856e9164 RDI: 0000000000000000
RBP: ffff8880a99cfb58 R08: ffff8880a99c0580 R09: ffffed1015d25bc0
R10: ffffed1015d25bbf R11: ffff8880ae92ddfb R12: 0000000000000000
R13: 0000000000000001 R14: 00000000000000b8 R15: 0000000000000000
FS:  0000000000000000(0000) GS:ffff8880ae900000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00000000004b4adc CR3: 000000008e053000 CR4: 00000000001406e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
  skb_put_data include/linux/skbuff.h:2138 [inline]
  bcsp_unslip_one_byte drivers/bluetooth/hci_bcsp.c:451 [inline]
  bcsp_recv+0x98f/0x13a0 drivers/bluetooth/hci_bcsp.c:612
  hci_uart_tty_receive+0x22b/0x530 drivers/bluetooth/hci_ldisc.c:607
  tty_ldisc_receive_buf+0x164/0x1c0 drivers/tty/tty_buffer.c:465
  tty_port_default_receive_buf+0x7d/0xb0 drivers/tty/tty_port.c:38
  receive_buf drivers/tty/tty_buffer.c:481 [inline]
  flush_to_ldisc+0x228/0x390 drivers/tty/tty_buffer.c:533
  process_one_work+0x98e/0x1790 kernel/workqueue.c:2257
  worker_thread+0x98/0xe40 kernel/workqueue.c:2403
  kthread+0x357/0x430 kernel/kthread.c:247
  ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:352
Modules linked in:
---[ end trace 6643b2336de1f8b1 ]---
RIP: 0010:skb_put+0x35/0x1d0 net/core/skbuff.c:1698
Code: 89 f5 41 54 49 89 fc 53 4d 8d b4 24 b8 00 00 00 48 83 ec 08 e8 2c 6a  
01 fc 4c 89 f2 48 b8 00 00 00 00 00 fc ff df 48 c1 ea 03 <0f> b6 14 02 4c  
89 f0 83 e0 07 83 c0 03 38 d0 7c 08 84 d2 0f 85 4c
RSP: 0018:ffff8880a99cfb28 EFLAGS: 00010206
RAX: dffffc0000000000 RBX: ffff8880969a9280 RCX: ffffffff84ef8fa3
RDX: 0000000000000017 RSI: ffffffff856e9164 RDI: 0000000000000000
RBP: ffff8880a99cfb58 R08: ffff8880a99c0580 R09: ffffed1015d25bc0
R10: ffffed1015d25bbf R11: ffff8880ae92ddfb R12: 0000000000000000
R13: 0000000000000001 R14: 00000000000000b8 R15: 0000000000000000
FS:  0000000000000000(0000) GS:ffff8880ae900000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00000000004b4adc CR3: 000000008e053000 CR4: 00000000001406e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400

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