2.0.0-1.13 (May 26th, 2023)

New features:

Full support for is-enabled USDT probes.
An error will be reported when a tracing script requires more space to store aggregation data than is available per the aggsize option value.
An error will be reported when a tracing script requires more space to store dynamic variables than is available per the dynvarsize option value.
Support for data drop counters for principal buffers, speculation buffers, aggregations, and dynamic variables.
The proc:::signal-clear probe has been implemented.
The sched provider has been implemented for a limited set of probes (and with some limitations). Available probes are: dequeue, enqueue, off-cpu, on-cpu (limited trigger locations), surrender, tick, and wakeup. Note that the cpuinfo argument for dequeue and enqueue (arg1) is NULL due to system limitations. Future releases will incrementally expand this provider.
The lockstat provider has been implemented. All lockstat probes are implemented, but depending on the runtime kernel configuration, some probe may not trigger in all cases (particularly for lock operations that are forced to be inlined). Also, kernels prior to 5.10.0 contain a bug that can cause kernel deadlock when a kretprobe is used on spinlock functions. The lockstat provider is not enabled for such kernels for safety.
True NULL strings are now supported.
The uregs built-in variable is now supported on older kernels as well.
New option 'linknommap' has been added as a workaround for elfutils bugs related to mmap() usage.

Bugfixes:

The error message issued by dtprobed to report incorrect helper data size was reporting the expected and received values backwards.
USDT probes in programs that live in different fs namespaces are now fully supported.
When multiple USDT probes were specified, only the first one would get provided properly.
Properly recognize all forms of the 'char' datatype as equivalent.
Do not allow iregs to be increased beyond its default value (the number of BPF registers).
The uaddr handling has been fixed to not trigger a segmentation fault for pid 0.
Tracepoint argument datatypes that are expressed by the kernel using symbolic array size specifiers are now handled correctly.
The established behaviour of DTrace when storing data in a speculation has been to abort clause execution at any statement that would cause a speculation buffer overflow. Code to perform overflow checks when storing data in a speculation are now generated correctly.
Some faults were not reporting the PC of the fault location.
FBT probes are no longer provided for compiler-generated internal symbols. Such symbols cannot be probed anyway.
Multiple memory leaks were resolved.
Integers loaded from an associative array are now promoted to 64 bits.
Failure to allocate a dynamic variable now reports a dynamic variable drop warning, and aborts the clause execution.
DOF parser crash causes were fixed in dtprobed.
USDT probes in non-PIE executables are now fully supported.
Multiple programs providing their DOF to dtprobed simultaneously could cause some of their probes to not get created.
Support for shared libraries and executables with very large numbers of USDT probes (500+) has been improved.

Internal changes:

DOF_VERSION_3 has been added for the new-style USDT is-enabled probe mechanism that is not compatible with the previous versions.
Userspace probe scanning was reworked to resolve performance issues.
The 'cpuinfo' BPF map can now support configurations where CPU ids are not strictly sequential.
The GCC BPF support in some gcc/binutils releases did not offer a way to express an atomic add operation. As a workaround, the DTrace source code provides its own atomic_add() construct.
The handling of associative arrays and TLS variables has been consolidated because they are both implemented using dynamic variables.

Testsuite changes:

The testsuite can now specify kernel modules that are needed for tests.
A test has been added to verify whether libctf bug #30264 is present on the system. The libctf bug breaks offsetof() for members of unnamed structs and unions at non-zero offsets.
A test has been added to test multiple simultaneous dtrace instances tracing multiple processes,
Various tests using tick-* probes without actually requiring them have been reworked using non-timer based probes for efficiency and stability.
Test have been added for many dtrace options.
The testsuite can now support interpreter-style executable .d files using #!dtrace (the actual pathname for dtrace will be substituted during test execution).

Known problems:

Programs and shared libraries that make use of is-enabled USDT probes and were built using a previous version of dtrace will need to be rebuilt for is-enabled probes to work.