systemtap 5.5 release

[Frank Ch. Eigler]

The SystemTap team announces release 5.5

Support for new kernel syscalls and memory management primitives.
Numerous stap-serverd security fixes and compatibility updates for GCC
14+.


= Where to get it

https://sourceware.org/systemtap/ - our project page
https://sourceware.org/systemtap/ftp/releases/
https://koji.fedoraproject.org/koji/packageinfo?packageID=615
git tag release-5.5 (commit 90b164cf106e)

There have been around 110 commits since the last release.
There have been around 31 bugs fixed / features added since the last
release.


= SystemTap frontend (stap) changes

- Support for `@enum("name")` has been added.
- The string concatenation operator (`.`) has been generalized to handle
  N operands more efficiently.
- BPF and language-server NULL pointer dereference bugfixes.
- SystemTap now prefers to advertise `dnf debuginfo-install` when
  missing debuginfo is detected.
- The `-p1`, `-p2`, `-p3` frontend passes no longer force server/mok
  mode unnecessarily.


= SystemTap backend changes

- Multiple security and robustness fixes for `stap-serverd`, including
  fixes for TOCTOU races in mountfs and certificate database permission
  checks, CWE-476 NULL pointer dereferences, restricting SSL/TLS cipher
  suites to strong algorithms only, and upgrading module signing to
  SHA256.
- Added a hypothetical emergency experimental band-aid for
  CVE-2026-31431.
- The prototype httpd server code has been removed.
- Compatibility updates for newer compilers including GCC 14+ and GCC
  16.
- Initial support for kernels >= 7.0 (including silencing pahole version
  warnings and testsuite preprocessor tolerance).
- Fixed potential buffer overflows in `sscanf` and module name
  replacements.


= SystemTap tapset changes

- Support for new kernel syscalls: `lsm_get_self_attr`,
  `lsm_set_self_attr`, `sys_file_setattr`, and `sys_file_getattr`.
- Support for memory management primitives `MADV_GUARD_INSTALL` and
  `MADV_GUARD_REMOVE`.
- Adapted to kernel 6.16 `DECLARE_TRACE_EVENT` refactoring.


= SystemTap sample scripts

- All ~200 examples can be found at
  https://sourceware.org/systemtap/examples/


= Examples of tested kernel versions

4.18.0 (RHEL8 + CentOS Stream 8 x86_64, aarch64, ppc64le, s390x)
5.14.0 (RHEL9 + CentOS Stream 9 x86_64, aarch64, ppc64le, s390x)
6.11.0 (RHEL10 + CentOS Stream 10 x86_64, aarch64, ppc64le, s390x)
6.15.9 (Fedora, x86_64)
7.0.0-rc (Fedora rawhide x86_64)

Some test results are stored in bunsen, see
https://sourceware.org/systemtap/links.html


= Contributors for this release

Frank Ch. Eigler, lijunlong, Mark Wielaard, Martin Cermak,
Sergei Trofimovich, T K Sourab*

Special thanks to new contributors, marked with '*' above.


= Bugs fixed for this release <https://sourceware.org/PR#####>
  <issues.redhat.com/browse/RHEL-####>

PR15052  PR15052 related test suite fixes
PR33428  imply kernel<vmlinux.h>, check by file name
PR33782  Fix uprobe RIP check for newer kernels and add backtrace test
         case
PR33925  session.cxx: don't force server/mok mode for stap -p{1,2,3}
PR33932  Handle kernel 6.16 DECLARE_TRACE_EVENT refactor
PR33975  GCC-16 build time issues
PR33976  Support MADV_GUARD_INSTALL and MADV_GUARD_REMOVE
PR33978  fallback to kallsyms for lock_task_sighand
PR34022  Include a central bgerror definition in systemtap.exp
PR34023  correct ubsan on map initialization
PR34027  fix type inference for multiple operands
PR34046  support @enum("name")
PR34055  Fix utf_kernel_trunc.exp and utf_user_trunc.exp
PR34063  remove httpd server prototype code
PR34065  lib/systemtap.exp: get environment_sanity_test to dump
         autoconf-* run internals
PR34089  list.exp fails on rawhide in case glibc-debuginfo is installed
PR34103  PR15052 related test suite fixes
PR34108  Replace 'uname -i' with 'uname -m' elsewhere
PR34109  Fix the caller.exp testcase
PR34110  Fix buildid.exp and make it compatible with modern GCC-16
PR34111  Fix listing_mode_sanity.exp testcase
PR34113  Fix global_var_kernel.exp
PR34115  testsuite: intercept dejagnu record_test to emit TIMESTAMP_MS
PR34119  correct conflict between syscalls/test.tcl bgerror and dmesg-
         consumer
PR34120  Fix buildok/{nested_vars.stp,twentyseven.stp}
BZ2460461  tapset/linux/signal: support posixtimer_send_sigqueue
           fallback
BZ2461617  systemtap.spec: Recommend yama-ptrace-enable for runtime
           package
CVE-2026-31431  hypothetical emergency experimental band-aid for
                CVE-2026-31431
RHEL-134992  prefer to advertise "dnf debuginfo-install"
RHEL-143253  Test cover RHEL-143253
RHEL-149811  tapsets.cxx: tolerate bad address/symbol pairings without
             SEGV