[ltt-dev] net extended trace openin error with LTTV (without attachment)
Mathieu Desnoyers
compudj at krystal.dyndns.org
Mon Feb 8 15:32:09 EST 2010
* Benjamin Poirier (benjamin.poirier at polymtl.ca) wrote:
> paljak at mit.bme.hu wrote:
> >
> > -----Mathieu Desnoyers <compudj at krystal.dyndns.org> wrote: -----
> >
> > To: paljak at mit.bme.hu
> > From: Mathieu Desnoyers <compudj at krystal.dyndns.org>
> > Date: 2010/02/08 16:36
> > cc: benjamin.poirier at polymtl.ca, ltt-dev at lists.casi.polymtl.ca
> > Subject: Re: [ltt-dev] net extended trace openin error with LTTV
> > (without attachment)
> >
> > * paljak at mit.bme.hu (paljak at mit.bme.hu) wrote:
> > > Hi Ben,
> > >
> > > I have been working with LTTng lately and the more I know it, the
> > more I
> > > like it!
> > >
> > > I've also been able to open and examine traces, and it looks very
> > > interesting.
> > >
> > > I've also tried to create my own, but I've ran into an error,
> > could you
> > > take a look?
> > >
> > > Basically, I receive an error
> > > (ERROR:tracefile.c:1582:ltt_update_event_size: assertion failed:
> > (info !=
> > > NULL)) every time i try to open a net_extended trace with LTTV.
> > >
> > > Here's what i've done:
> > >
> > > 1. Downloaded the patched kernel: git clone
> > >
> > git://git.kernel.org/pub/scm/linux/kernel/git/compudj/linux-2.6-lttng.git
> > > 2. Compiled the kernel with these options (.config):
> > > #
> > > # GCOV-based kernel profiling
> > > #
> > > # CONFIG_GCOV_KERNEL is not set
> > > CONFIG_SLOW_WORK=y
> > > # CONFIG_SLOW_WORK_DEBUG is not set
> > > CONFIG_LTT=y
> > > CONFIG_LTT_FILTER=m
> > > CONFIG_HAVE_LTT_DUMP_TABLES=y
> > > CONFIG_LTT_RELAY=y
> > > CONFIG_LTT_RELAY_LOCKLESS=y
> > > # CONFIG_LTT_RELAY_IRQOFF is not set
> > > # CONFIG_LTT_RELAY_LOCKED is not set
> > > CONFIG_LTT_SERIALIZE=y
> > > CONFIG_LTT_FAST_SERIALIZE=y
> > > CONFIG_LTT_TRACEPROBES=m
> > > CONFIG_LTT_TRACE_CONTROL=y
> > > CONFIG_LTT_TRACER=y
> > > CONFIG_LTT_ALIGNMENT=y
> > > CONFIG_LTT_CHECK_ARCH_EFFICIENT_UNALIGNED_ACCESS=y
> > > # CONFIG_LTT_DEBUG_EVENT_SIZE is not set
> > > CONFIG_LTT_USERSPACE_EVENT=m
> > > CONFIG_LTT_VMCORE=y
> > > CONFIG_LTT_STATEDUMP=m
> > > CONFIG_LTT_KPROBES=m
> > > # CONFIG_LTT_ASCII is not set
> > > 3. Install the kernel and boot it up
> > > 4. Load all the modules
> > > modprobe -v ltt-trace-control
> > > modprobe -v ltt-marker-control
> > > modprobe -v ltt-tracer
> > > modprobe -v ltt-serialize
> > > modprobe -v ltt-relay
> > > modprobe -v ipc-trace
> > > modprobe -v kernel-trace
> > > modprobe -v mm-trace
> > > modprobe -v net-trace
> > > modprobe -v fs-trace
> > > modprobe -v jbd2-trace
> > > modprobe -v ext4-trace
> > > modprobe -v syscall-trace
> > > modprobe -v trap-trace
> > > modprobe -v ltt-statedump
> > > #extended trace
> > > modprobe -v net-extended-trace
> > > 5. ltt-armall -n
> > > 6. lttctl -C -w /tmp/tr1 tr1
> > > 7. wget http://google.com
> > > 8. lttctl -D tr1
> > > 9. lttv -m textDump -t tr1
> > > **
> > > ERROR:tracefile.c:1582:ltt_update_event_size: assertion failed:
> > (info !=
> > > NULL)
> > > /usr/local/bin/lttv: line 15: 2083 Aborted $0.real $*
> > > 10. lttv -m textDump -t tr1 --verbose --debug --edebug
> > > net.udpv4_rcv_extended: 1003.743082325 (/tmp/tr1/net_0), 1878, 1878,
> > > gnome-terminal, , 1, 0x0, SOFTIRQ { skb = 0xC4BBC240, saddr =
> > 3576624693,
> > > daddr = 3232235780, unicast = 1, ulen = 110, source = 53, dest =
> > 39087,
> > > data_start = a299884901000100 }
> > > Event header (tracefile /tmp/tr1/net_0 offset bb8):
> > > bb8 40 C2 BB C4
> > > **
> > > ERROR:tracefile.c:1582:ltt_update_event_size: assertion failed:
> > (info !=
> > > NULL)
> > > /usr/local/bin/lttv: line 15: 2104 Aborted $0.real $*
> > >
> > > The installed versions are:
> > > Linux Trace Toolkit Visualizer 0.12.29-02022010
> > > Linux Trace Toolkit Trace Control 0.79-01022010
> > >
> > > Here's the created trace for reference:
> > > http://www.mit.bme.hu/~paljak/trace.tgz
> > <http://www.mit.bme.hu/%7Epaljak/trace.tgz>
> > >
> > > If I don't use net extended, than it works just fine. And I've
> > also had
> > > success open your example trace.
> > >
> > > Do you have any idea why do I get this error and how could I
> > correct it?
> >
> > That looks like a field type error in the net extended event. Can you
> > tell us what LTTng version you use ? (git branch should tell you)
> >
> > Is your traced machine 32 or 64 bits ? And what about the machine
> > running lttv ?
> >
> > Reviewing ltt/probes/net-extended-trace.c might help.
> >
> > Thanks,
> >
> > Mathieu
> >
> > I use lttng-0.188. And I run lttng and lttv on the same, 32 bit machine.
> >
> > I'm checking net-extended-trace.c but reason I could think of to cause
> > this error...
> >
>
> I can't reproduce the problem, but looking at the traces, I notice the alignment is different:
>
> your trace:
> metadata.core_marker_id: 994.751622140 (/tmp/trace/tr1/metadata_0), 0, 0, , , 0, 0x0, MODE_UNKNOWN { channel = "net", name = "udpv4_rcv_extended", event_id = 2, int = 4, long = 4, pointer = 4, size_t = 4, alignment = 4 }
>
> my trace:
> metadata.core_marker_id: 193.282545152 (/tmp/tr1/metadata_0), 0, 0, , , 0, 0x0, MODE_UNKNOWN { channel = "net", name = "udpv4_rcv_extended", event_id = 2, int = 4, long = 4, pointer = 4, size_t = 4, alignment = 0 }
>
> Could you apply the following patch over the git kernel, build and test? Thanks.
Seem like my LTTng patch:
lttng-trace-format-allow-large-alignment.patch
"lttng trace format allow large alignment
Do not limit alignment on architecture size anymore, because uint64_t
types are
aligned on 64-bit even on 32-bit archs. It's a waste of space for 32-bit
architectures, but makes our format compatible with gcc."
does not do everything it needs to do. Or maybe LTTV still do an
alignment on min(arch size, data size) somewhere.
A way to "just amke it work" is to disable alignment in LTTng. But it
would be good to find the culprit.
Thanks,
Mathieu
>
> diff --git a/ltt/probes/net-extended-trace.c b/ltt/probes/net-extended-trace.c
> index 074bfec..88410f8 100644
> --- a/ltt/probes/net-extended-trace.c
> +++ b/ltt/probes/net-extended-trace.c
> @@ -130,14 +130,14 @@ notrace void probe_udpv4_rcv_extended(struct sk_buff *skb)
> * bytes of UDP data if they are not in a fragment*/
> data.f8 = 0;
> if (skb_headlen(skb) >= sizeof(struct udphdr) + 8)
> - data.f8 = *(unsigned long long *)(skb->data + sizeof(*uh));
> + data.f8 = *(uint64_t *)(skb->data + sizeof(*uh));
> else if (skb_headlen(skb) >= sizeof(struct udphdr))
> memcpy(&data.f8, skb->data + sizeof(struct udphdr),
> skb_headlen(skb) - sizeof(struct udphdr));
>
> marker = &GET_MARKER(net, udpv4_rcv_extended);
> ltt_specialized_trace(marker, marker->single.probe_private,
> - &data, serialize_sizeof(data), sizeof(unsigned long long));
> + &data, serialize_sizeof(data), sizeof(uint64_t));
> }
>
> MODULE_LICENSE("GPL and additional rights");
>
> > Thanks,
> > Gergely
> >
> >
> > ------------------------------------------------------------------------
> >
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--
Mathieu Desnoyers
OpenPGP key fingerprint: 8CD5 52C3 8E3C 4140 715F BA06 3F25 A8FE 3BAE 9A68
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