kernel/linux.git/tools/perf/builtin-record.c, branch v6.18.42

powerpc tools perf: Initialize error code in auxtrace_record_init function

2026-07-24T14:16:18+00:00

[ Upstream commit 789d22d77879eabb042627f6627cdb62787bc142 ] perf trace record fails some cases in powerpc # perf test "perf trace record and replay" 128: perf trace record and replay : FAILED! # perf trace record sleep 1 # echo $? 32 This is happening because of non-zero err value from auxtrace_record__init() function. static int record__auxtrace_init(struct record *rec) { int err; if ((rec->opts.auxtrace_snapshot_opts || rec->opts.auxtrace_sample_opts) && record__threads_enabled(rec)) { pr_err("AUX area tracing options are not available in parallel streaming mode.\n"); return -EINVAL; } if (!rec->itr) { rec->itr = auxtrace_record__init(rec->evlist, &err); if (err) return err; } Here "int err" is not initialised. The code expects "err" to be set from auxtrace_record__init() function. Update auxtrace_record__init() in arch/powerpc/util/auxtrace.c to clear err value in the beginning. - Clear err value in beginning of function. Any fail later will set appropriate return code to err. - Even if we haven't found any event for auxtrace, perf record should continue for other events. NULL return will indicate that there is no auxtrace record initialized. - Not having "err" set here will affect monitoring of other events also because perf record will fail seeing random value in err. Set err to -EINVAL before invoking auxtrace_record__init() in builtin-record.c With the fix, # perf trace record sleep 1 [ perf record: Woken up 2 times to write data ] [ perf record: Captured and wrote 0.033 MB perf.data (228 samples) ] Fixes: 1dbfaf94cf66ec4b ("perf powerpc: Add basic CONFIG_AUXTRACE support for VPA pmu on powerpc") Reviewed-by: Adrian Hunter Signed-off-by: Athira Rajeev Acked-by: Namhyung Kim Cc: Athira Rajeev Cc: Hari Bathini Cc: Ian Rogers Cc: Jiri Olsa Cc: linuxppc-dev@lists.ozlabs.org Cc: Madhavan Srinivasan Cc: Michael Petlan Cc: Shivani Nittor Cc: Tanushree Shah Cc: Tejas Manhas Cc: Thomas Richter Signed-off-by: Arnaldo Carvalho de Melo Signed-off-by: Sasha Levin

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

2026-07-24T14:15:38+00:00

commit bac74dcbd48b5b441e47841fd0fe507c7b0bcbaf upstream. 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 Signed-off-by: Greg Kroah-Hartman

perf record: skip synthesize event when open evsel failed

2025-12-18T13:02:46+00:00

[ Upstream commit 163e5f2b96632b7fb2eaa965562aca0dbdf9f996 ] When using perf record with the `--overwrite` option, a segmentation fault occurs if an event fails to open. For example: perf record -e cycles-ct -F 1000 -a --overwrite Error: cycles-ct:H: PMU Hardware doesn't support sampling/overflow-interrupts. Try 'perf stat' perf: Segmentation fault #0 0x6466b6 in dump_stack debug.c:366 #1 0x646729 in sighandler_dump_stack debug.c:378 #2 0x453fd1 in sigsegv_handler builtin-record.c:722 #3 0x7f8454e65090 in __restore_rt libc-2.32.so[54090] #4 0x6c5671 in __perf_event__synthesize_id_index synthetic-events.c:1862 #5 0x6c5ac0 in perf_event__synthesize_id_index synthetic-events.c:1943 #6 0x458090 in record__synthesize builtin-record.c:2075 #7 0x45a85a in __cmd_record builtin-record.c:2888 #8 0x45deb6 in cmd_record builtin-record.c:4374 #9 0x4e5e33 in run_builtin perf.c:349 #10 0x4e60bf in handle_internal_command perf.c:401 #11 0x4e6215 in run_argv perf.c:448 #12 0x4e653a in main perf.c:555 #13 0x7f8454e4fa72 in __libc_start_main libc-2.32.so[3ea72] #14 0x43a3ee in _start ??:0 The --overwrite option implies --tail-synthesize, which collects non-sample events reflecting the system status when recording finishes. However, when evsel opening fails (e.g., unsupported event 'cycles-ct'), session->evlist is not initialized and remains NULL. The code unconditionally calls record__synthesize() in the error path, which iterates through the NULL evlist pointer and causes a segfault. To fix it, move the record__synthesize() call inside the error check block, so it's only called when there was no error during recording, ensuring that evlist is properly initialized. Fixes: 4ea648aec019 ("perf record: Add --tail-synthesize option") Signed-off-by: Shuai Xue Signed-off-by: Namhyung Kim Signed-off-by: Sasha Levin

perf stat: Refactor retry/skip/fatal error handling

2025-10-03T19:49:51+00:00

For the sake of Intel topdown events commit 9eac5612da1c9102 ("perf stat: Don't skip failing group events") changed 'perf stat' error handling making it so that more errors were fatal and didn't report "" events. The change outside of topdown events was unintentional. The notion of "fatal" error handling was introduced in commit e0e6a6ca3ac211cc ("perf stat: Factor out open error handling") and refined in commits like commit cb5ef60067c11cc8 ("perf stat: Error out unsupported group leader immediately") to be an approach for avoiding later assertion failures in the code base. This change fixes those issues and removes the notion of a fatal error on an event. If all events fail to open then a fatal error occurs with the previous fatal error message. This seems to best match the notion of supported events and allowing some errors not to stop 'perf stat', while allowing the truly fatal no event case to terminate the tool early. The evsel->errored flag is only used in the stat code but always just meaning !evsel->supported although there is a comment about it being sticky. Force all evsels to be supported in evsel__init and then clear this when evsel__open fails. When an event is tried the supported is set to true again. This simplifies the notion of whether an evsel is broken. In the get_group_fd code, fail to get a group fd when the evsel isn't supported. If the leader isn't supported then it is also expected that there is no group_fd as the leader will have been skipped. Therefore change the BUG_ON test to be on supported rather than skippable. This corrects the assertion errors that were the reason for the previous fatal error handling. Fixes: 9eac5612da1c9102 ("perf stat: Don't skip failing group events") Reviewed-by: James Clark Signed-off-by: Ian Rogers Cc: Adrian Hunter Cc: Alexander Shishkin Cc: Chun-Tse Shao Cc: Dapeng Mi Cc: Howard Chu Cc: Ian Rogers Cc: Ingo Molnar Cc: Jiri Olsa Cc: Kan Liang Cc: Namhyung Kim Cc: Peter Zijlstra Cc: Thomas Falcon Link: https://lore.kernel.org/r/20251002220727.1889799-2-irogers@google.com Signed-off-by: Arnaldo Carvalho de Melo

perf auxtrace: Pass perf_env from session through to mmap read

2025-07-25T17:37:58+00:00

auxtrace_mmap__read and auxtrace_mmap__read_snapshot end up calling `evsel__env(NULL)` which returns the global perf_env variable for the host. Their only call is in perf record. Rather than use the global variable pass through the perf_env for `perf record`. Signed-off-by: Ian Rogers Link: https://lore.kernel.org/r/20250724163302.596743-18-irogers@google.com Signed-off-by: Namhyung Kim

perf session: Add accessor for session->header.env

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

The perf_env from the header in the session is frequently accessed, add an accessor function rather than access directly. Cache the value to avoid repeated calls. No behavioral change. Signed-off-by: Ian Rogers Link: https://lore.kernel.org/r/20250724163302.596743-10-irogers@google.com Signed-off-by: Namhyung Kim

perf record: Make --buildid-mmap the default

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

Support for build IDs in mmap2 perf events has been present since Linux v5.12: https://lore.kernel.org/lkml/20210219194619.1780437-1-acme@kernel.org/ Build ID mmap events don't avoid the need to inject build IDs for DSO touched by samples as the build ID cache is populated by perf record. They can avoid some cases of symbol mis-resolution caused by the file system changing from when a sample occurred and when the DSO is sought. Unlike the --buildid-mmap option, this chnage doesn't disable the build ID cache but it does disable the processing of samples looking for DSOs to inject build IDs for. To disable the build ID cache the -B (--no-buildid) option should be used. Making this option the default was raised on the list in: https://lore.kernel.org/linux-perf-users/CAP-5=fXP7jN_QrGUcd55_QH5J-Y-FCaJ6=NaHVtyx0oyNh8_-Q@mail.gmail.com/ Signed-off-by: Ian Rogers Link: https://lore.kernel.org/r/20250724163302.596743-9-irogers@google.com Signed-off-by: Namhyung Kim

perf record: collect BPF metadata from new programs

2025-06-20T21:48:49+00:00

This collects metadata for any BPF programs that were loaded during a "perf record" run, and emits it at the end of the run. Signed-off-by: Blake Jones Link: https://lore.kernel.org/r/20250612194939.162730-4-blakejones@google.com Signed-off-by: Namhyung Kim

perf record: Switch user option to use BPF filter

2025-06-09T18:18:17+00:00

Finding user processes by scanning /proc is inherently racy and results in perf_event_open failures. Use a BPF filter to drop samples where the uid doesn't match. Ensure adding the BPF filter forces system-wide. Signed-off-by: Ian Rogers Link: https://lore.kernel.org/r/20250604174545.2853620-5-irogers@google.com Signed-off-by: Namhyung Kim

perf record: Fix incorrect --user-regs comments

2025-05-28T17:10:56+00:00

The comment of "--user-regs" option is not correct, fix it. "on interrupt," -> "in user space," Fixes: 84c417422798c897 ("perf record: Support direct --user-regs arguments") Reviewed-by: Ian Rogers Signed-off-by: Dapeng Mi Cc: Adrian Hunter Cc: Alexander Shishkin Cc: Andi Kleen Cc: Ingo Molnar Cc: Kan Liang Cc: Namhyung Kim Cc: Peter Zijlstra Link: https://lore.kernel.org/r/20250403060810.196028-1-dapeng1.mi@linux.intel.com Signed-off-by: Arnaldo Carvalho de Melo