kernel/git/stable/linux.git/tools/perf/util/session.c, branch master

perf python: Refactor and add accessors to sample event

2026-06-30T17:17:14+00:00

Add common evsel field for events and move sample specific fields to only be present in sample events. Add accessors for sample events. Ensure offsets are within the bounds of the event. Allocate just enough memory for the copied event, don't make the maximum event size each time. Assisted-by: Gemini:gemini-3.1-pro-preview Signed-off-by: Ian Rogers Cc: Adrian Hunter Cc: Alice Rogers Cc: Dapeng Mi Cc: Ingo Molnar Cc: James Clark Cc: Leo Yan Cc: Namhyung Kim Cc: Peter Zijlstra Cc: Thomas Richter Signed-off-by: Arnaldo Carvalho de Melo Signed-off-by: Namhyung Kim

perf python: Use evsel in sample in pyrf_event

2026-06-30T17:17:12+00:00

Avoid a duplicated evsel by using the one in sample. Add evsel__get/put to the evsel in perf_sample. Signed-off-by: Ian Rogers Cc: Adrian Hunter Cc: Alice Rogers Cc: Dapeng Mi Cc: Ingo Molnar Cc: James Clark Cc: Leo Yan Cc: Namhyung Kim Cc: Peter Zijlstra Cc: Thomas Richter Signed-off-by: Arnaldo Carvalho de Melo Signed-off-by: Namhyung Kim

perf evlist: Add reference count checking

2026-06-30T17:17:11+00:00

Now the evlist is reference counted, add reference count checking so that gets and puts are paired and easy to debug. Reference count checking is documented here: https://perfwiki.github.io/main/reference-count-checking/ This large patch is adding accessors to evlist functions and switching to their use. There was some minor renaming as evlist__mmap is now an accessor to the mmap variable, and the original evlist__mmap is renamed to evlist__do_mmap. Signed-off-by: Ian Rogers Cc: Adrian Hunter Cc: Alice Rogers Cc: Dapeng Mi Cc: Ingo Molnar Cc: James Clark Cc: Leo Yan Cc: Namhyung Kim Cc: Peter Zijlstra Cc: Thomas Richter Signed-off-by: Arnaldo Carvalho de Melo Signed-off-by: Namhyung Kim

perf evsel: Add reference count

2026-06-30T17:17:11+00:00

As with evlist this a no-op for most of the perf tool. The reference count is set to 1 at allocation, the put will see the 1, decrement it and perform the delete. The purpose for adding the reference count is for the python code. Prior to this change the python code would clone evsels, but this has issues if events are opened, etc. leading to assertion failures. With a reference count the same evsel can be used and the reference count incremented for the python usage. To not change the python evsel API getset functions are added for the evsel members, no set function is provided for size as it doesn't make sense to alter this. Signed-off-by: Ian Rogers Cc: Adrian Hunter Cc: Alice Rogers Cc: Dapeng Mi Cc: Ingo Molnar Cc: James Clark Cc: Leo Yan Cc: Namhyung Kim Cc: Peter Zijlstra Cc: Thomas Richter Signed-off-by: Arnaldo Carvalho de Melo Signed-off-by: Namhyung Kim

perf evlist: Add reference count

2026-06-30T17:17:10+00:00

This a no-op for most of the perf tool. The reference count is set to 1 at allocation, the put will see the 1, decrement it and perform the delete. The purpose for adding the reference count is for the python code. Prior to this change the python code would clone evlists, but this has issues if events are opened, etc. This change adds a reference count for the evlists and a later change will add it to evsels. The combination is needed for the python code to operate correctly (not hit asserts in the evsel clone), but the changes are broken apart for the sake of smaller patches. Assisted-by: Gemini:gemini-3.1-pro-preview Signed-off-by: Ian Rogers Cc: Adrian Hunter Cc: Alice Rogers Cc: Dapeng Mi Cc: Ingo Molnar Cc: James Clark Cc: Leo Yan Cc: Namhyung Kim Cc: Peter Zijlstra Cc: Thomas Richter Signed-off-by: Arnaldo Carvalho de Melo Signed-off-by: Namhyung Kim

perf machine: Propagate machine__init() error to callers

2026-06-17T12:21:03+00:00

machine__init() always returns 0 even when memory allocation fails, because commit 81f981d7ec43ed93 ("perf machine: Free root_dir in machine__init() error path") introduced 'int err = -ENOMEM' and an error cleanup path but left the final 'return 0' instead of 'return err'. Fix by returning err, check the return value in __machine__new_host() which was ignoring it, and change machines__init() from void to int so it too can propagate the error to perf_session__new(), aslr_tool__init() and test callers. The error cleanup also used zfree(&machine->kmaps), but kmaps is a refcounted maps structure — use maps__zput() to properly drop the reference, matching machine__exit(). Move dsos__init() and threads__init() before the first fallible allocation (maps__new) so that machine__exit() is safe to call on any machine struct that machine__init() touched, even on early failure. Fixes: 81f981d7ec43ed93 ("perf machine: Free root_dir in machine__init() error path") Reported-by: sashiko-bot Cc: Ian Rogers Cc: Jiri Olsa Assisted-by: Claude:claude-opus-4.6 Signed-off-by: Arnaldo Carvalho de Melo

perf env: Add perf_env__e_machine helper and use in perf_env__arch

2026-06-03T19:42:52+00:00

Add a helper that lazily computes the e_machine and falls back to EM_HOST. Use the perf_env's arch to compute the e_machine if available, using a binary search for efficiency while handling duplicate rules. Switch perf_env__arch to be derived from e_machine for consistency. To support 32-bit compat binaries on 64-bit hosts during dynamic local or live operations, unpopulated arch fallback paths query uname() at runtime to dynamically resolve the correct host e_machine, safely preventing bitness misclassification regressions. Update session and header to use the helper to safely record e_machine and flags without forcing premature thread scanning. Signed-off-by: Ian Rogers Acked-by: Namhyung Kim Cc: Alexander Gordeev Cc: Heiko Carstens Cc: Honglei Wang Cc: Jan Polensky Cc: Sumanth Korikkar Cc: Thomas Richter Cc: Vasily Gorbik Signed-off-by: Arnaldo Carvalho de Melo

perf session: Include file offset in event skip/stop messages

2026-06-03T19:31:03+00:00

Add 'at offset %#' to all warning and error messages in session.c that fire when events are skipped or processing stops due to validation failures. This lets users cross-reference with 'perf report -D' output to inspect the surrounding records and understand the corruption context. Covers messages in perf_session__process_event() (alignment, min size, swap failure), perf_session__deliver_event() (no evsel, parse failure, CPU clamping), machines__deliver_event() (NAMESPACES, TEXT_POKE, null-terminated string checks for MMAP/MMAP2/COMM/CGROUP/KSYMBOL), and perf_session__process_user_event() (THREAD_MAP, CPU_MAP, STAT_CONFIG, BPF_METADATA, HEADER_BUILD_ID). Reviewed-by: Ian Rogers Assisted-by: Claude:claude-opus-4.6 Signed-off-by: Arnaldo Carvalho de Melo

perf sample: Add file_offset field to struct perf_sample

2026-06-03T19:31:03+00:00

Add a file_offset field to struct perf_sample so that event processing callbacks can report the byte offset of the problematic event in perf.data, letting users cross-reference with 'perf report -D' output. Set sample.file_offset in perf_session__deliver_event(), which is the common entry point for both file mode (mmap'd offset) and pipe mode (running byte counter from __perf_session__process_pipe_events). The assignment is placed after evsel__parse_sample(), which zeroes the struct via memset. Preserve file_offset through the deferred callchain delivery path by storing it in struct deferred_event and restoring it after evlist__parse_sample() in both evlist__deliver_deferred_callchain() and session__flush_deferred_samples(). Subsequent patches will use this field in skip/stop warning messages. Reviewed-by: Ian Rogers Assisted-by: Claude:claude-opus-4.6 Signed-off-by: Arnaldo Carvalho de Melo

perf session: Snapshot event->header.size in process_user_event()

2026-05-29T14:44:35+00:00

On native-endian files, events are read from MAP_SHARED memory. Multiple reads of event->header.size can return different values if the file is concurrently modified, allowing an attacker to bypass bounds checks performed on an earlier read. Snapshot header.size into a local variable at function entry using READ_ONCE() to prevent compiler rematerialization, and use it for all size-dependent arithmetic within the function. This ensures every bounds calculation uses the same value that was validated by the reader. Reported-by: sashiko-bot@kernel.org # Running on a local machine Reviewed-by: Ian Rogers Cc: Jiri Olsa Cc: Namhyung Kim Assisted-by: Claude:claude-opus-4.6-1m Signed-off-by: Arnaldo Carvalho de Melo