Release Notes for DTrace 2.0.3

New features:

• USDT probes in executables and shared libraries that are compiled with LTO is now supported. USDT probe definitions are now recorded in .note.usdt ELF notes.

• The pr_psargs member of the psinfo_t < struct task_struct *T > translator is now implemented. It used the new execargs builtin variable.

• The pid provider now supports offset-based instruction probes.

Bugfixes:

• Automatic selection of fprobe vs kprobe based FBT probes has been corrected.

• Trampoline use of the BPF stack for scratch space has been corrected.

• The rawfbt provider has been fixed to perform symbol lookups on the actual true symbol name.

• BPF attach type detection has been fixed.

• The probeprov, probemod, probefunc, and probename builtin variables now report the correct values for late USDT processes.

• The value of arg3 for sched:::enqueue and sched:::dequeue has been corrected.

• No longer register fbt and rawfbt twice.

• Discovery of new probes now correctly loops through all registered providers rather than just the initial providers.

User-visible changes:

• The kernel symbol name filter has been made less strict.

• Failures in enabling a probe now report the probe name.

Internal changes:

• Builtin variables are now implemented with individual functions rather than a single large function, reducing compiled BPF program size.

• Relocation types R_BPF_64_ABS64 and R_BPF_64_ABS32 are now supported.

• The proc provider has been implemented using the standard SDT provider implementation.

• The fbt and rawfbt providers have been consolidated, and significan performance improvements have been applied.

• The hashtable implementation has been moved to libcommon. It is now used by dtprobed and libdtrace.

Testsuite changes:

• Many testcases have been improved.

• Use of bash and gawk throughout the testsuite has been made more consistent.

• Tests can now use CC, OBJCOPY, OBJDUMP, NM, ... as shell variables in scripts to allow setting values that apply to all tests.