Re: ipc/testmsg GPF.

[Peter Hurley <peter@hurleysoftware.com>]

[ +Andrew Morton ]

On Thu, 2013-03-07 at 16:38 -0500, Dave Jones wrote:
> Trying to reproduce that nd_jump_link trace, but I keep hitting other bugs
> instead.  It's like whackamole. Except these are even more annoying
> than moles.

Dave,
I thought I copied you on the 'ipc MSG_COPY fixes' patchset that fixes
this. Or is this gp fault happening with that patchset?

Linus,
The fixes should be in your inbox (from Andrew) titled:
[patch 01/11] ipc: fix potential oops when src msg > 4k w/ MSG_COPY
[patch 02/11] ipc: don't allocate a copy larger than max

> general protection fault: 0000 [#1] PREEMPT SMP 
> Modules linked in: rose ax25 phonet lockd sunrpc ip6t_REJECT nf_conntrack_ipv6 nf_defrag_ipv6 xt_conntrack nf_conntrack ip6table_filter ip6_tables snd_hda_codec_realtek snd_hda_intel btusb snd_hda_codec bluetooth snd_pcm snd_page_alloc snd_timer snd vhost_net rfkill tun macvtap usb_debug macvlan microcode serio_raw pcspkr kvm_amd soundcore edac_core r8169 mii kvm
> CPU 0 
> Pid: 845, comm: trinity-child14 Not tainted 3.9.0-rc1+ #70 Gigabyte Technology Co., Ltd. GA-MA78GM-S2H/GA-MA78GM-S2H
> RIP: 0010:[<ffffffff812b7b00>]  [<ffffffff812b7b00>] testmsg.isra.1+0x40/0x60
> RSP: 0018:ffff880122b0fe78  EFLAGS: 00010246
> RAX: 0000000000000000 RBX: 0000000000000002 RCX: 0000000000000001
> RDX: 0000000000000002 RSI: 000000002c24a9b2 RDI: 697665642d737983
> RBP: ffff880122b0fe78 R08: fffffff3f14b03ae R09: 0000000000000000
> R10: ffff880127bd8000 R11: 0000000000000000 R12: 000000002c24a9b2
> R13: ffff880123360798 R14: ffff8801233606e8 R15: 697665642d737973
> FS:  00007f2672bd3740(0000) GS:ffff88012ae00000(0000) knlGS:0000000000000000
> CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> CR2: 00007f2672b96068 CR3: 0000000127bc1000 CR4: 00000000000007f0
> DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
> DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
> Process trinity-child14 (pid: 845, threadinfo ffff880122b0e000, task ffff880127bd8000)
> Stack:
>  ffff880122b0ff68 ffffffff812b8e7e ffff8801276d5b90 ffff880127bd8000
>  ffff880127bd8000 ffff880127bd8000 0000000000000000 ffffffff812b78c0
>  0000000000000000 ffffffff81c7a260 0000000000000000 0000000000001000
> Call Trace:
>  [<ffffffff812b8e7e>] do_msgrcv+0x1de/0x670
>  [<ffffffff812b78c0>] ? load_msg+0x180/0x180
>  [<ffffffff810b8685>] ? trace_hardirqs_on_caller+0x115/0x1a0
>  [<ffffffff81341aae>] ? trace_hardirqs_on_thunk+0x3a/0x3f
>  [<ffffffff812b9325>] sys_msgrcv+0x15/0x20
>  [<ffffffff816cd982>] system_call_fastpath+0x16/0x1b
> Code: 83 fa 04 74 16 31 c0 5d c3 66 90 ff ca b8 01 00 00 00 74 f3 31 c0 eb ef 0f 1f 00 48 39 37 b8 01 00 00 00 7e e2 31 c0 eb de 66 90 <48> 3b 37 75 d5 b8 01 00 00 00 5d c3 0f 1f 40 00 48 3b 37 74 c5 
> 
> 0000000000000000 <.text>:
>    0:	48 3b 37             	cmp    (%rdi),%rsi
>    3:	75 d5                	jne    0xffffffffffffffda
>    5:	b8 01 00 00 00       	mov    $0x1,%eax
>    a:	5d                   	pop    %rbp
>    b:	c3                   	retq   
>    c:	0f 1f 40 00          	nopl   0x0(%rax)
>   10:	48 3b 37             	cmp    (%rdi),%rsi
>   13:	74 c5                	je     0xffffffffffffffda
> 
> rdi is ascii. "ived-sy�" Curious.
> 
> EIP is here in testmsg.
> 
>                 case SEARCH_EQUAL:
>                         if (msg->m_type == type)
>      240:       48 3b 37                cmp    (%rdi),%rsi
>      243:       75 d5                   jne    21a <testmsg.isra.1+0x1a>
>         {
> 
> 
> --
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