Re: general protection fault in pipe_write

[Dmitry Vyukov]

On Fri, Jun 8, 2018 at 3:11 PM, syzbot
<syzbot+772c951c5f15d2f1df03@xxxxxxxxxxxxxxxxxxxxxxxxx> wrote:
> Hello,
>
> syzbot found the following crash on:
>
> HEAD commit:    7170e6045a6a strparser: Add __strp_unpause and use it in k..
> git tree:       net-next
> console output: https://syzkaller.appspot.com/x/log.txt?x=15b5c8cf800000
> kernel config:  https://syzkaller.appspot.com/x/.config?x=a601a80fec461d44
> dashboard link: https://syzkaller.appspot.com/bug?extid=772c951c5f15d2f1df03
> compiler:       gcc (GCC) 8.0.1 20180413 (experimental)
> syzkaller repro:https://syzkaller.appspot.com/x/repro.syz?x=13ad0b6f800000
>
> IMPORTANT: if you fix the bug, please add the following tag to the commit:
> Reported-by: syzbot+772c951c5f15d2f1df03@xxxxxxxxxxxxxxxxxxxxxxxxx

This seems to be same as the splash of other crashes in bpfilter:

#syz fix: bpfilter: fix race in pipe access


> 8021q: adding VLAN 0 to HW filter on device team0
> 8021q: adding VLAN 0 to HW filter on device team0
> bpfilter: read fail -512
> kasan: CONFIG_KASAN_INLINE enabled
> kasan: GPF could be caused by NULL-ptr deref or user memory access
> general protection fault: 0000 [#1] SMP KASAN
> Dumping ftrace buffer:
>    (ftrace buffer empty)
> Modules linked in:
> CPU: 1 PID: 6572 Comm: syz-executor5 Not tainted 4.17.0-rc7+ #82
> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
> Google 01/01/2011
> RIP: 0010:pipe_write+0xa49/0xeb0 fs/pipe.c:480
> RSP: 0000:ffff8801ac6b7858 EFLAGS: 00010206
> RAX: dffffc0000000000 RBX: 0000000000000000 RCX: ffffffff81c22b3b
> RDX: 0000000000000005 RSI: ffffffff81c22b49 RDI: 0000000000000028
> RBP: ffff8801ac6b78d8 R08: ffff8801b3796080 R09: 0000000000000006
> R10: ffff8801b3796080 R11: 0000000000000000 R12: ffff8801cdbaa820
> R13: ffff8801cdb31a40 R14: 0000000000000000 R15: dffffc0000000000
> FS:  00007fe12b0e9700(0000) GS:ffff8801daf00000(0000) knlGS:0000000000000000
> CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> CR2: 00007fe01b0f9af0 CR3: 00000001c43e7000 CR4: 00000000001406e0
> DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
> DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
> Call Trace:
>  call_write_iter include/linux/fs.h:1784 [inline]
>  new_sync_write fs/read_write.c:474 [inline]
>  __vfs_write+0x64d/0x960 fs/read_write.c:487
>  __kernel_write+0x10c/0x380 fs/read_write.c:506
>  __bpfilter_process_sockopt+0x1d8/0x35b net/bpfilter/bpfilter_kern.c:66
>  bpfilter_mbox_request+0x4d/0xb0 net/ipv4/bpfilter/sockopt.c:25
>  bpfilter_ip_set_sockopt+0x33/0x40 net/ipv4/bpfilter/sockopt.c:31
>  ip_setsockopt+0x124/0x140 net/ipv4/ip_sockglue.c:1250
>  raw_setsockopt+0xe2/0x100 net/ipv4/raw.c:868
>  sock_common_setsockopt+0x9a/0xe0 net/core/sock.c:3059
>  __sys_setsockopt+0x1bd/0x390 net/socket.c:1903
>  __do_sys_setsockopt net/socket.c:1914 [inline]
>  __se_sys_setsockopt net/socket.c:1911 [inline]
>  __x64_sys_setsockopt+0xbe/0x150 net/socket.c:1911
>  do_syscall_64+0x1b1/0x800 arch/x86/entry/common.c:287
>  entry_SYSCALL_64_after_hwframe+0x49/0xbe
> RIP: 0033:0x4559f9
> RSP: 002b:00007fe12b0e8c68 EFLAGS: 00000246 ORIG_RAX: 0000000000000036
> RAX: ffffffffffffffda RBX: 00007fe12b0e96d4 RCX: 00000000004559f9
> RDX: 0000000000000040 RSI: 0000000000000000 RDI: 0000000000000004
> RBP: 000000000072bf50 R08: 0000000000000370 R09: 0000000000000000
> R10: 00000000200003c0 R11: 0000000000000246 R12: 00000000ffffffff
> R13: 00000000004c0d8b R14: 00000000004d0828 R15: 0000000000000001
> Code: 48 c1 ea 03 80 3c 02 00 0f 85 fc 03 00 00 48 8b 45 c8 48 8b 58 20 48
> b8 00 00 00 00 00 fc ff df 48 8d 7b 28 48 89 fa 48 c1 ea 03 <80> 3c 02 00 0f
> 85 ef 03 00 00 48 8b 7b 28 31 d2 be 01 00 00 00
> RIP: pipe_write+0xa49/0xeb0 fs/pipe.c:480 RSP: ffff8801ac6b7858
> ---[ end trace 7e44f4b8135e2e72 ]---
>
>
> ---
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