Hi Joe,
Thanks for the good test case.
Yes, this seems to be a bug. It appears that we end up generating
malformed DOF when unreferenced providers are included as in your
example. This will mean that we reject the DOF when it's loaded
into the kernel and you therefore don't get any probes. I've logged:
6918387: DOF rejected if unreferenced USDT providers are included
I'm a bit short of time at the minute to look at this but let
me know if it's causing major problems.
Thanks.
Jon.
This drove me nuts until a colleague helped me nail down a small test case.
I'm posting here before filing a bug in case I'm somehow overlooking something
that would justify what I'm seeing. This is on Solaris, both S10 and
OpenSolaris (whatever release is snv_111b), by the way.
I have defined two providers, named A and B, and I have a program that uses either a
probe from each or only from one. If it uses both, everything works as expected. If it
uses only one, that probe disappears. Somehow, adding the second, unused provider to the
"dtrace -G" seems to make the probe for the first provider go away.
Here's the test program, main.c:
#include "providerA.h"
#include "providerB.h"
int main() {
A_HELLO();
#ifdef USE_B
B_BYE();
#endif
return 0;
}
With both probes in place, I get this:
$ dtrace -h -s providerA.d
$ dtrace -h -s providerB.d
$ cc -o main.o -c -DUSE_B main.c
$ dtrace -G -s providerA.d -s providerB.d -o providers.o main.o
$ cc -o program main.o providers.o
$ dtrace -l -P 'A$target' -P 'B$target' -c ./program
ID PROVIDER MODULE FUNCTION NAME
63692 A12109 program main hello
63693 B12109 program main bye
Just as expected. With only one probe in place, I get this:
$ dtrace -h -s providerA.d
$ dtrace -h -s providerB.d
$ cc -o main.o -c main.c
$ dtrace -G -s providerA.d -s providerB.d -o providers.o main.o
$ cc -o program main.o providers.o
$ dtrace -l -P 'A$target' -P 'B$target' -c ./program
ID PROVIDER MODULE FUNCTION NAME
dtrace: failed to match A12161:::: No probe matches description
dtrace: failed to match B12161:::: No probe matches description
I expect the B probe to be missing, but what happened to the A probe?
The providers are trivial:
$ cat providerA.d providerB.d
provider A {
probe hello();
};
provider B {
probe bye();
};
Any clues?
Thanks.
joe
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