https://bugs.kde.org/show_bug.cgi?id=201742
Alicia Boya García (ntrrgc) <ntr...@gmail.com> changed:
What |Removed |Added
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CC| |ntr...@gmail.com
--- Comment #2 from Alicia Boya García (ntrrgc) <ntr...@gmail.com> ---
I would suggest renaming the title of this bug to "Expectation rules are
silently cropped to --num-callers", as this bug applies as well to suppressions
rules that don't contain "...".
Recently I've been in a goose chase in GStreamer as a certain leak was being
reported but only in certain configurations.
When running valgrind with the default arguments plus some suppression files I
found a leak that should be reported wasn't being reported. Eventually I
tracked it down to an old suppression rule that looked like this:
{
<One time init in ALSA>
Memcheck:Leak
fun:calloc
obj:*
obj:*
obj:*
obj:*
obj:*
obj:*
obj:*
obj:*
obj:*
obj:*
obj:*
obj:/usr/lib/libasound.so.*
fun:snd_config_searcha_hooks
fun:snd_config_searchva_hooks
obj:/usr/lib/libasound.so.*
fun:snd_config_search_definition
obj:/usr/lib/libasound.so.*
fun:gst_alsa_device_property_probe_get_values
}
`--num-callers` defaults to 12, which caused that rule to be effectively
cropped, functionally becoming this:
{
<One time init in ALSA>
Memcheck:Leak
fun:calloc
obj:*
obj:*
obj:*
obj:*
obj:*
obj:*
obj:*
obj:*
obj:*
obj:*
obj:*
}
In other words, any call to calloc() with a stack trace that has 12 or more
frames is suppressed for memcheck, which is very much not what the original
rule was intended to filter.
Here is a minimal repro without GStreamer:
$ cat > leak.c
#include <stdlib.h>
void* do_allocation() {
return malloc(256);
}
void func1() { do_allocation(); }
void func2() { func1(); }
void func3() { func2(); }
void func4() { func3(); }
void func5() { func4(); }
void func6() { func5(); }
void func7() { func6(); }
void func8() { func7(); }
void func9() { func8(); }
void func10() { func9(); }
void func11() { func10(); }
void func12() { func11(); }
int main() {
func12();
}
$ cat > a.supp
{
<supression that matches what it shouldn't>
Memcheck:Leak
fun:malloc
obj:*
obj:*
obj:*
obj:*
obj:*
obj:*
obj:*
obj:*
obj:*
obj:*
obj:*
fun:non_existing_function
}
$ gcc leak.c
$ valgrind --leak-check=full --suppressions=a.supp ./a.out
[...]
==1539875== LEAK SUMMARY:
==1539875== definitely lost: 0 bytes in 0 blocks
==1539875== indirectly lost: 0 bytes in 0 blocks
==1539875== possibly lost: 0 bytes in 0 blocks
==1539875== still reachable: 0 bytes in 0 blocks
==1539875== suppressed: 256 bytes in 1 blocks
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