kernel/linux.git/tools/perf/util/debuginfo.c, branch v6.19.11

perf tools: Don't read build-ids from non-regular files

2025-11-26T18:13:38+00:00

Simplify the build ID reading code by removing the non-blocking option. Having to pass the correct option to this function was fragile and a mistake would result in a hang, see the linked fix. Furthermore, compressed files are always opened blocking anyway, ignoring the non-blocking option. We also don't expect to read build IDs from non-regular files. The only hits to this function that are non-regular are devices that won't be elf files with build IDs, for example "/dev/dri/renderD129". Now instead of opening these as non-blocking and failing to read, we skip them. Even if something like a pipe or character device did have a build ID, I don't think it would have worked because you need to call read() in a loop, check for -EAGAIN and handle timeouts to make non-blocking reads work. Link: https://lore.kernel.org/linux-perf-users/20251022-james-perf-fix-dso-block-v1-1-c4faab150546@linaro.org/ Signed-off-by: James Clark Signed-off-by: Namhyung Kim

perf symbol: Add blocking argument to filename__read_build_id

2025-08-25T22:07:18+00:00

When synthesizing build-ids, for build ID mmap2 events, they will be added for data mmaps if -d/--data is specified. The files opened for their build IDs may block on the open causing perf to hang during synthesis. There is some robustness in existing calls to filename__read_build_id by checking the file path is to a regular file, which unfortunately fails for symlinks. Rather than adding more is_regular_file calls, switch filename__read_build_id to take a "block" argument and specify O_NONBLOCK when this is false. The existing is_regular_file checking callers and the event synthesis callers are made to pass false and thereby avoiding the hang. Fixes: 53b00ff358dc ("perf record: Make --buildid-mmap the default") Signed-off-by: Ian Rogers Link: https://lore.kernel.org/r/20250823000024.724394-3-irogers@google.com Signed-off-by: Namhyung Kim

perf build-id: Ensure struct build_id is empty before use

2025-07-25T17:37:55+00:00

If a build ID is read then not all code paths may ensure it is empty before use. Initialize the build_id to be zero-ed unless there is clear initialization such as a call to build_id__init. Signed-off-by: Ian Rogers Link: https://lore.kernel.org/r/20250724163302.596743-6-irogers@google.com Signed-off-by: Namhyung Kim

perf tools: Use symfs when opening debuginfo by path

2025-02-13T03:44:16+00:00

I found that it failed to load a binary using --symfs option. Say I have a binary in /home/user/prog/xxx and a perf data file with it. If I move them to a different machine and use --symfs, it tries to find the binary in some locations under symfs using dso__read_binary_type_filename(), but not the last one. ${symfs}/usr/lib/debug/home/user/prog/xxx.debug ${symfs}/usr/lib/debug/home/user/prog/xxx ${symfs}/home/user/prog/.debug/xxx /home/user/prog/xxx It should check ${symfs}/home/usr/prog/xxx. Let's fix it. Reviewed-by: Ian Rogers Acked-by: Masami Hiramatsu (Google) Link: https://lore.kernel.org/r/20250212221445.437481-1-namhyung@kernel.org Signed-off-by: Namhyung Kim

perf tools: Add util/debuginfo.[ch] files

2023-11-10T12:03:54+00:00

Split debuginfo data structure and related functions into a separate file so that it can be used by other components than the probe-finder. Signed-off-by: Namhyung Kim Cc: Adrian Hunter Cc: Andi Kleen Cc: Ian Rogers Cc: Ingo Molnar Cc: Jiri Olsa Cc: Linus Torvalds Cc: Masami Hiramatsu (Google) Cc: Peter Zijlstra Cc: Stephane Eranian Cc: linux-toolchains@vger.kernel.org Cc: linux-trace-devel@vger.kernel.org Link: https://lore.kernel.org/r/20231110000012.3538610-4-namhyung@kernel.org Signed-off-by: Arnaldo Carvalho de Melo