Changes in usdt_1.c

f5ad4101009e7f5f5984ffea6923d4fcd470932a - Merge tag 'bpf-next-7.1' of git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next

Wed, 15 Apr 2026 03:04:04 +0200

Merge tag 'bpf-next-7.1' of git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-nextPull bpf updates from Alexei Starovoitov: - Welcome new BPF maintainers: Kumar Kartikeya Dwivedi, Eduard Zingerman while Martin KaFai Lau reduced his load to Reviwer. - Lots of fixes everywhere from many first time contributors. Thank you All. - Diff stat is dominated by mechanical split of verifier.c into multiple components: - backtrack.c: backtracking logic and jump history - states.c: state equivalence - cfg.c: control flow graph, postorder, strongly connected components - liveness.c: register and stack liveness - fixups.c: post-verification passes: instruction patching, dead code removal, bpf_loop inlining, finalize fastcall 8k line were moved. verifier.c still stands at 20k lines. Further refactoring is planned for the next release. - Replace dynamic stack liveness with static stack liveness based on data flow analysis. This improved the verification time by 2x for some programs and equally reduced memory consumption. New logic is in liveness.c and supported by constant folding in const_fold.c (Eduard Zingerman, Alexei Starovoitov) - Introduce BTF layout to ease addition of new BTF kinds (Alan Maguire) - Use kmalloc_nolock() universally in BPF local storage (Amery Hung) - Fix several bugs in linked registers delta tracking (Daniel Borkmann) - Improve verifier support of arena pointers (Emil Tsalapatis) - Improve verifier tracking of register bounds in min/max and tnum domains (Harishankar Vishwanathan, Paul Chaignon, Hao Sun) - Further extend support for implicit arguments in the verifier (Ihor Solodrai) - Add support for nop,nop5 instruction combo for USDT probes in libbpf (Jiri Olsa) - Support merging multiple module BTFs (Josef Bacik) - Extend applicability of bpf_kptr_xchg (Kaitao Cheng) - Retire rcu_trace_implies_rcu_gp() (Kumar Kartikeya Dwivedi) - Support variable offset context access for 'syscall' programs (Kumar Kartikeya Dwivedi) - Migrate bpf_task_work and dynptr to kmalloc_nolock() (Mykyta Yatsenko) - Fix UAF in in open-coded task_vma iterator (Puranjay Mohan)* tag 'bpf-next-7.1' of git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next: (241 commits) selftests/bpf: cover short IPv4/IPv6 inputs with adjust_room bpf: reject short IPv4/IPv6 inputs in bpf_prog_test_run_skb selftests/bpf: Use memfd_create instead of shm_open in cgroup_iter_memcg selftests/bpf: Add test for cgroup storage OOB read bpf: Fix OOB in pcpu_init_value selftests/bpf: Fix reg_bounds to match new tnum-based refinement selftests/bpf: Add tests for non-arena/arena operations bpf: Allow instructions with arena source and non-arena dest registers bpftool: add missing fsession to the usage and docs of bpftool docs/bpf: add missing fsession attach type to docs bpf: add missing fsession to the verifier log bpf: Move BTF checking logic into check_btf.c bpf: Move backtracking logic to backtrack.c bpf: Move state equivalence logic to states.c bpf: Move check_cfg() into cfg.c bpf: Move compute_insn_live_regs() into liveness.c bpf: Move fixup/post-processing logic from verifier.c into fixups.c bpf: Simplify do_check_insn() bpf: Move checks for reserved fields out of the main pass bpf: Delete unused variable ... List of files: /linux/tools/testing/selftests/bpf/usdt_1.c

b0cc2e069fae3fba74381609ebc523ceca85cd9a - Merge branch 'libbpf-make-optimized-uprobes-backward-compatible'

Tue, 03 Mar 2026 17:39:22 +0100

Merge branch 'libbpf-make-optimized-uprobes-backward-compatible'Jiri Olsa says:====================libbpf: Make optimized uprobes backward compatiblehi,we can currently optimize uprobes on top of nop5 instructions,so application can define USDT_NOP to nop5 and use USDT macroto define optimized usdt probes.This works fine on new kernels, but could have performance penaltyon older kernels, that do not have the support to optimize and toemulate nop5 instruction.This patchset adds support to workaround the performance penaltyon older kernels that do not support uprobe optimization, pleasesee detailed description in patch 2.v1: https://lore.kernel.org/bpf/20251117083551.517393-1-jolsa@kernel.org/v2: https://lore.kernel.org/bpf/20260210133649.524292-1-jolsa@kernel.org/v3: https://lore.kernel.org/bpf/20260211084858.750950-1-jolsa@kernel.org/T/#tv4: https://lore.kernel.org/bpf/20260220104220.634154-1-jolsa@kernel.org/v5 changes:- keep nop_combo on stack and levae buf uninitialized in has_nop_combo function [David]v4 changes:- rebased on latest bpf-next/master- use pread for nop combo read [Andrii]- renamed usdt triger benchmark names [Andrii]- added more ip address checks to tests [Andrii]v3 changes:- fix __x86_64 define and other typos [CI]- add missing '?' to usdt trigger program [CI]v2 changes:- after more investigation we realized there are some versions of bpftrace and stap that does not work with solution suggested in version 1, so we decided to switch to following solution: - change USDT macro [1] emits nop,nop5 instructions combo by default - libbpf detects nop,nop5 instructions combo for USDT probe, if there is and if uprobe syscall is detected libbpf installs usdt probe on top of nop5 instruction to get it optimized- added usdt trigger benchmarks [Andrii]- several small fixes on uprobe syscall detection, tests and other places [Andrii]- true usdt.h source [1] updated [Andrii]- compile usdt_* objects unconditionally [Andrii]thanks,jirka[1] https://github.com/libbpf/usdt---====================Link: https://patch.msgid.link/20260224103915.1369690-1-jolsa@kernel.orgSigned-off-by: Alexei Starovoitov List of files: /linux/tools/testing/selftests/bpf/usdt_1.c

304841967c5574fec9307a2c1cdfa8abf30a29fc - selftests/bpf: Add test for checking correct nop of optimized usdt

Tue, 24 Feb 2026 11:39:14 +0100

selftests/bpf: Add test for checking correct nop of optimized usdtAdding test that attaches bpf program on usdt probe in 2 scenarios;- attach program on top of usdt_1, which is single nop instruction, so the probe stays on nop instruction and is not optimized.- attach program on top of usdt_2 which is probe defined on top of nop,nop5 combo, so the probe is placed on top of nop5 and is optimized.Signed-off-by: Jiri Olsa Link: https://lore.kernel.org/r/20260224103915.1369690-5-jolsa@kernel.orgSigned-off-by: Alexei Starovoitov List of files: /linux/tools/testing/selftests/bpf/usdt_1.c