Re: ipc/testmsg GPF.

From: Peter Hurley
Date: Mon Mar 11 2013 - 15:03:37 EST

On Mon, 2013-03-11 at 14:26 -0400, Dave Jones wrote:
> On Fri, Mar 08, 2013 at 07:27:01PM -0500, Peter Hurley wrote:
>
> > On Thu, 2013-03-07 at 16:38 -0500, Dave Jones wrote:
> > 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-syï" 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>
> > > {
>
> I just hit this again on rc2 which looks like it has the fixes that
> Peter mentions above. This time rdi was 6b6b6b6b6b6b6b7b
>
> Dave

Sorry, Dave. The fix must be in the other 8 patches that Andrew didn't
want to apply. I run trinity 10 or more times a day and can't get this
to trigger with the whole series.

Regards,
Peter Hurley

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