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[Bug translator/11089] New: process.mark() probes with same name trigger wrongly
- From: "mjw at redhat dot com" <sourceware-bugzilla at sourceware dot org>
- To: systemtap at sources dot redhat dot com
- Date: 14 Dec 2009 12:30:44 -0000
- Subject: [Bug translator/11089] New: process.mark() probes with same name trigger wrongly
- Reply-to: sourceware-bugzilla at sourceware dot org
When a process.mark() probe is in the .probes section multiple times with
different addresses it looks like only one address is being triggered for a
probe on the mark() for that name (and it is triggered multiple times for that
one address).
One example is the cxxclass.exp test on i386:
> $ stap ./systemtap.base/cxxclass.stp cxxclass.exe -c ./cxxclass.exe
> main_enter
> call: 64
> cons call: 64
> cons call: 64
> meth call: 64 24
> meth call: 64 24
> dest call: 42
> dest call: 42
> call2: 24
> main_exit
>
> Seems there is double call on process.mark.
The issue seems to be that some of the static probe points get
duplicated in the code. This shouldn't be a problem, and the .probes
section does contain both places with different addresses. You can also
see (with enough -vvvvv) that stap finds both locations while resolving
the mark("cons") probe. But, only the first is registered twice, as can
be seen in the generated code:
{ .address=(unsigned
long)0x8048476ULL,
.pp="process(\"/home/mark/src/systemtap/testsuite/cxxclass.exe\").statement(134513782)",
.ph=&probe_1895, },
{ .address=(unsigned
long)0x8048476ULL,
.pp="process(\"/home/mark/src/systemtap/testsuite/cxxclass.exe\").statement(134513782)",
.ph=&probe_1895, },
This means the first call of the constructor is triggered as probe twice
(as is the method, and destructor call) but the second call isn't
triggered as probe at all.
It looks like this is a problem in how sdt_query::convert_location() is
called (it seems to do duplication detection based on probe name, but
not address. I haven't looked very deeply into it yet though.
--
Summary: process.mark() probes with same name trigger wrongly
Product: systemtap
Version: unspecified
Status: NEW
Severity: normal
Priority: P2
Component: translator
AssignedTo: systemtap at sources dot redhat dot com
ReportedBy: mjw at redhat dot com
http://sourceware.org/bugzilla/show_bug.cgi?id=11089
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