kernel/linux.git/tools/perf/util/jitdump.c, branch v7.2-rc2

perf jitdump: Fix a build error with ASAN

2026-06-10T21:55:49+00:00

I found this error when I pass EXTRA_CFLAGS=-fsanitize=address on Fedora 44 with GCC 16. Fix it by copying one less byte. CC util/jitdump.o util/jitdump.c: In function ‘jit_process’: util/jitdump.c:237:9: error: ‘__builtin_strncpy’ specified bound 4096 equals destination size [-Werror=stringop-truncation] 237 | strncpy(jd->dir, name, PATH_MAX); | ^ cc1: all warnings being treated as errors make[4]: *** [tools/build/Makefile.build:95: util/jitdump.o] Error 1 make[4]: *** Waiting for unfinished jobs.... make[3]: *** [tools/build/Makefile.build:158: util] Error 2 make[2]: *** [Makefile.perf:578: perf-util-in.o] Error 2 make[1]: *** [Makefile.perf:288: sub-make] Error 2 make: *** [Makefile:76: all] Error 2 Signed-off-by: Namhyung Kim Cc: Adrian Hunter Cc: Ian Rogers Cc: Ingo Molnar Cc: James Clark Cc: Jiri Olsa Cc: Peter Zijlstra Signed-off-by: Arnaldo Carvalho de Melo

perf tools: Fix event_contains() macro to verify full field extent

2026-05-29T14:44:19+00:00

event_contains() checked whether a field's start offset was within the event (header.size > offsetof), but not whether the full field fit. A crafted event with header.size = offsetof(field) + 1 would pass the check, but an 8-byte access (bswap_64, direct read) would overrun the event boundary by up to 7 bytes. Fix the macro to verify the complete field: header.size >= offsetof(field) + sizeof(field) Also update all callers that check event_contains(time_cycles) but access later fields (time_mask, cap_user_time_zero, cap_user_time_short) to check for cap_user_time_short — the last field accessed — so the entire extended block is verified: tsc.c, arm-spe.c, cs-etm.c, jitdump.c. Note: session.c's perf_event__time_conv_swap() also guards on time_cycles but accesses time_mask — a pre-existing issue not introduced by this macro change. It is fixed by a later patch in this series ("perf session: Add validated swap infrastructure with null-termination checks"), which decouples time_cycles and time_mask into independent per-field event_contains() checks. The struct assignment overread (session->time_conv = event->time_conv copies sizeof on a potentially shorter event) is separately fixed by "perf session: Use bounded copy for PERF_RECORD_TIME_CONV". Reported-by: sashiko-bot@kernel.org # Running on a local machine Reviewed-by: Ian Rogers Cc: Adrian Hunter Cc: Jiri Olsa Cc: Namhyung Kim Assisted-by: Claude:claude-opus-4.6-1m Signed-off-by: Arnaldo Carvalho de Melo

perf tool: Remove evsel from tool APIs that pass the sample

2026-05-20T19:34:23+00:00

As struct perf_sample now directly contains its own resolved evsel pointer, passing the evsel separately is redundant and clutters the interface. Remove the redundant evsel parameter from tool-specific handlers and structures, ensuring the tool always directly accesses the evsel bound to the sample. This simplifies the API signatures and eliminates the risk of passing an inconsistent evsel. Signed-off-by: Ian Rogers Acked-by: Namhyung Kim Cc: Adrian Hunter Cc: Albert Ou Cc: Alexander Shishkin Cc: Alexandre Ghiti Cc: Andi Kleen Cc: Andrew Jones Cc: Anup Patel Cc: Athira Rajeev Cc: Blake Jones Cc: Chen Ni Cc: Chun-Tse Shao Cc: Dapeng Mi Cc: Derek Foreman Cc: Dmitriy Vyukov Cc: Dr. David Alan Gilbert Cc: Howard Chu Cc: Hrishikesh Suresh Cc: Ingo Molnar Cc: James Clark Cc: Jiri Olsa Cc: Krzysztof Łopatowski Cc: Leo Yan Cc: Palmer Dabbelt Cc: Paul Walmsley Cc: Peter Zijlstra Cc: Quan Zhou Cc: Ravi Bangoria Cc: Swapnil Sapkal Cc: Thomas Falcon Cc: Tianyou Li Cc: Yujie Liu Cc: tanze [ Fixed up conflict with "perf inject: Fix itrace branch stack synthesis" series ] Signed-off-by: Arnaldo Carvalho de Melo

perf jitdump: Constify variables storing the result of strchr() on const tables

2026-01-27T05:36:24+00:00

As newer glibcs will propagate the const attribute of the searched table to its return. Signed-off-by: Arnaldo Carvalho de Melo

perf tools: Switch printf("...%s", strerror(errno)) to printf("...%m")

2026-01-14T20:22:50+00:00

strerror() has thread safety issues, strerror_r() requires stack allocated buffers. Code in perf has already been using the "%m" formatting flag that is a widely support glibc extension to print the current errno's description. Expand the usage of this formatting flag and remove usage of strerror()/strerror_r(). Signed-off-by: Ian Rogers Acked-by: Namhyung Kim Cc: Adrian Hunter Cc: Alexander Shishkin Cc: Alexandre Ghiti Cc: Blake Jones Cc: Chun-Tse Shao Cc: Dmitriy Vyukov Cc: Dr. David Alan Gilbert Cc: Haibo Xu Cc: Howard Chu Cc: Ingo Molnar Cc: Jiri Olsa Cc: Leo Yan Cc: Peter Zijlstra Cc: Stephen Brennan Cc: Thomas Falcon Cc: Yunseong Kim Cc: Zhongqiu Han Signed-off-by: Arnaldo Carvalho de Melo

perf jitdump: Fix missed dso__put

2025-12-03T19:07:46+00:00

Reference count checking caught a missing dso__put following a machine__findnew_dso_id. Signed-off-by: Ian Rogers Reviewed-by: Arnaldo Carvalho de Melo Signed-off-by: Namhyung Kim

perf: replace strcpy() with strncpy() in util/jitdump.c

2025-11-20T19:13:04+00:00

Usage of strcpy() can lead to buffer overflows. Therefore, it has been replaced with strncpy(). The output file path is provided as a parameter and might be restricted by command-line by default. But this defensive patch will prevent any potential overflow, making the code more robust against future changes in input handling. Testing: - ran perf test from tools/perf and did not observe any regression with the earlier code Signed-off-by: Hrishikesh Suresh Signed-off-by: Namhyung Kim

perf jitdump: Directly mark the jitdump DSO

2025-07-25T17:37:56+00:00

The DSO being generated was being accessed through a thread's maps, this is unnecessary as the dso can just be directly found. This avoids problems with passing a NULL evsel which may be inspected to determine properties of a callchain when using the buildid DSO marking code. Signed-off-by: Ian Rogers Link: https://lore.kernel.org/r/20250724163302.596743-8-irogers@google.com Signed-off-by: Namhyung Kim

perf sample: Make user_regs and intr_regs optional

2025-02-13T04:06:11+00:00

The struct dump_regs contains 512 bytes of cache_regs, meaning the two values in perf_sample contribute 1088 bytes of its total 1384 bytes size. Initializing this much memory has a cost reported by Tavian Barnes as about 2.5% when running `perf script --itrace=i0`: https://lore.kernel.org/lkml/d841b97b3ad2ca8bcab07e4293375fb7c32dfce7.1736618095.git.tavianator@tavianator.com/ Adrian Hunter replied that the zero initialization was necessary and couldn't simply be removed. This patch aims to strike a middle ground of still zeroing the perf_sample, but removing 79% of its size by make user_regs and intr_regs optional pointers to zalloc-ed memory. To support the allocation accessors are created for user_regs and intr_regs. To support correct cleanup perf_sample__init and perf_sample__exit functions are created and added throughout the code base. Signed-off-by: Ian Rogers Link: https://lore.kernel.org/r/20250113194345.1537821-1-irogers@google.com Signed-off-by: Namhyung Kim

perf jitdump: Fixup in_pidns member when java agent and 'perf record' are not in the same pidns

2025-01-08T20:30:50+00:00

When running 'perf record' outside a container and the java agent inside a container the jit_repipe_code_load() and friends will emit PERF_RECORD_MMAP2 entries for the jitdump records and will check if we need to fixup the pid/tid: nspid = jr->load.pid; pid = jr_entry_pid(jd, jr); tid = jr_entry_tid(jd, jr); The jr_entry_pid() function looks if we're in the same pidns: static pid_t jr_entry_pid(struct jit_buf_desc *jd, union jr_entry *jr) { if (jd->nsi && nsinfo__in_pidns(jd->nsi)) return nsinfo__tgid(jd->nsi); return jr->load.pid; } But since the thread, populated from perf.data records, try to figure out if in the same pidns by actually trying, on the system where 'perf inject' is running to open a procfs file (a bug that remains to be fixed), assuming that if it is not possible that is because that thread terminated and thus we can't get its namespace info and tolerates nsinfo__init() failing, noting only that that namespace can't be entered, so don't even try. But we can kinda get at least that info (thread->nsinfo->in_pidns) from the data in the perf.data file, namely the pid and tid in the PERF_RECORD_MMAP2 for the jit-.dump file generated from the java agent, if the PERF_RECORD_MMAP2->pid is the same as what is in the jitdump file, then we're in the same namespace, otherwise we need to use the PERF_RECORD_MMAP2->pid. This all has to be revamped for this jitdump + running perf from outside, as the meaning of in_pidns is being abused, the initialization of nsinfo->pid with the value coming from the PERF_RECORD_MMAP2 data is wrong as it is the pid _outside_ the container since perf was running there. The hack in this patch at least produces the expected result in this scenario by following the assumptions in the current codebase for finding maps and for generating the PERF_RECORD_MMAP2 for the ELF files synthesized from the jitdump records in jit_repipe_code_load(), etc.s Reported-by: Francesco Nigro Reported-by: Ilan Green Cc: Adrian Hunter Cc: Clark Williams Cc: Ian Rogers Cc: Ingo Molnar Cc: James Clark Cc: Jiri Olsa Cc: Kan Liang Cc: Namhyung Kim Cc: Stephane Eranian Cc: Thomas Gleixner Cc: Yonatan Goldschmidt Link: https://lore.kernel.org/r/20241206204828.507527-5-acme@kernel.org Signed-off-by: Arnaldo Carvalho de Melo