kernel/linux.git/tools/perf/util/thread.c, branch v7.2-rc1

perf tools: Fix thread__set_comm_from_proc() on empty comm file

2026-06-10T21:56:01+00:00

thread__set_comm_from_proc() calls procfs__read_str() then strips the trailing newline via comm[sz - 1] = '\0'. procfs__read_str() allocates the buffer before reading, so on an empty /proc/pid/comm (reachable during late exit teardown) it returns success with sz = 0 and an unterminated heap buffer. The sz - 1 underflow was the original sashiko finding: it writes a null byte before the allocation. But even with a sz > 0 guard on the newline strip, the unterminated buffer would still be passed to thread__set_comm() which calls strlen() — an unbounded heap read. Fix by treating sz == 0 as failure: free the buffer and return -1. This is consistent with pmu.c's perf_pmu__parse_scale/unit which already treat len == 0 from filename__read_str as an error. Fixes: 2f3027ac28bf6bc3 ("perf thread: Introduce method to set comm from /proc/pid/self") Reported-by: sashiko-bot Assisted-by: Claude:claude-opus-4.6 Signed-off-by: Arnaldo Carvalho de Melo

perf env, dso, thread: Add _endian variants for e_machine helpers

2026-06-03T19:45:21+00:00

Add perf_arch_is_big_endian(), dso__read_e_machine_endian(), dso__e_machine_endian(), and thread__e_machine_endian() to support bi-endianness and cross-architecture analysis without breaking the existing API. These helpers allow querying the absolute endianness of a DSO or thread, which is required for tools like Capstone that need to set the correct disassembly mode. Assisted-by: Gemini:gemini-3.1-pro-preview 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 unwind-libunwind: Move flush/finish access out of local

2026-05-15T19:19:50+00:00

Flush and finish access are relatively simple calls into libunwind, move them out struct unwind_libunwind_ops. So that the correct version can be called, add an e_machine variable to maps. This size regression will go away when the unwind_libunwind_ops no longer need stashing in the maps. To set the e_machine up pass it into unwind__prepare_access, which no longer needs to determine the unwind operations based on a map dso because of this. This also means the maps copying code can call unwind__prepare_access once for the e_machine rather than once per map. Signed-off-by: Ian Rogers Cc: Adrian Hunter Cc: Albert Ou Cc: Alexander Shishkin Cc: Alexandre Ghiti Cc: Andrew Jones Cc: Athira Rajeev Cc: Dapeng Mi Cc: Dmitrii Dolgov <9erthalion6@gmail.com> Cc: Florian Fainelli Cc: Howard Chu Cc: Ingo Molnar Cc: James Clark Cc: Jiri Olsa Cc: John Garry Cc: Leo Yan Cc: Li Guan Cc: Namhyung Kim Cc: Palmer Dabbelt Cc: Paul Walmsley Cc: Peter Zijlstra Cc: Shimin Guo Cc: Thomas Richter Cc: Tomas Glozar Cc: Will Deacon Signed-off-by: Arnaldo Carvalho de Melo

perf thread: Don't require machine to compute the e_machine

2026-02-03T21:01:27+00:00

The machine can be calculated from a thread via its maps. Don't require the machine argument to simplify callers and also to delay computing the machine until a little later. Signed-off-by: Ian Rogers Cc: Aditya Bodkhe Cc: Adrian Hunter Cc: Albert Ou Cc: Alexander Shishkin Cc: Alexandre Ghiti Cc: Andi Kleen Cc: Andrew Jones Cc: Anubhav Shelat Cc: Anup Patel Cc: Athira Rajeev Cc: Blake Jones Cc: Chun-Tse Shao Cc: Dapeng Mi Cc: Dmitriy Vyukov Cc: Howard Chu Cc: Ingo Molnar Cc: James Clark Cc: Jiri Olsa Cc: John Garry Cc: Leo Yan Cc: Namhyung Kim Cc: Palmer Dabbelt Cc: Paul Walmsley Cc: Peter Zijlstra Cc: Quan Zhou Cc: Shimin Guo Cc: Swapnil Sapkal Cc: Thomas Falcon Cc: Will Deacon Cc: Yunseong Kim Signed-off-by: Arnaldo Carvalho de Melo

perf thread: Add optional e_flags output argument to thread__e_machine

2026-01-26T21:21:20+00:00

The e_flags are needed to accurately compute complete perf register information for CSKY. Add the ability to read and have this value associated with a thread. This change doesn't wire up the use of the e_flags except in disasm where use already exists but just wasn't set up yet. Signed-off-by: Ian Rogers Cc: Aditya Bodkhe Cc: Adrian Hunter Cc: Alexander Shishkin Cc: Athira Rajeev Cc: Chun-Tse Shao Cc: Guo Ren Cc: Howard Chu Cc: Ingo Molnar Cc: James Clark Cc: Jiri Olsa Cc: Namhyung Kim Cc: Peter Zijlstra Cc: Sergei Trofimovich Cc: Shimin Guo Cc: Stephen Brennan Cc: Swapnil Sapkal Cc: Tianyou Li Signed-off-by: Arnaldo Carvalho de Melo

perf dso: Factor out e_machine reading for use in thread

2026-01-26T21:21:20+00:00

Factor out the resilient e_machine reading code in dso so that it may be used in thread. As there is no dso in that case, make the dso optional. This makes some minor other changes as the swap type from the dso cannot be ascertained. Signed-off-by: Ian Rogers Cc: Aditya Bodkhe Cc: Adrian Hunter Cc: Alexander Shishkin Cc: Athira Rajeev Cc: Chun-Tse Shao Cc: Guo Ren Cc: Howard Chu Cc: Ingo Molnar Cc: James Clark Cc: Jiri Olsa Cc: Namhyung Kim Cc: Peter Zijlstra Cc: Sergei Trofimovich Cc: Shimin Guo Cc: Stephen Brennan Cc: Swapnil Sapkal Cc: Tianyou Li Signed-off-by: Arnaldo Carvalho de Melo

perf thread: Ensure comm_lock held for comm_list

2025-06-11T20:40:31+00:00

perf callchain: Always populate the addr_location map when adding IP

2025-05-31T11:58:30+00:00

Dropping symbols also meant the callchain maps wasn't populated, but the callchain map is needed to find the DSO. Plumb the symbols option better, falling back to thread__find_map() rather than thread__find_symbol() when symbols are disabled. Fixes: 02b2705017d2e5ad ("perf callchain: Allow symbols to be optional when resolving a callchain") Signed-off-by: Ian Rogers Cc: Adrian Hunter Cc: Alexander Shishkin Cc: Andi Kleen Cc: Athira Rajeev Cc: Ben Gainey Cc: Chaitanya S Prakash Cc: Charlie Jenkins Cc: Chun-Tse Shao Cc: Colin Ian King Cc: Dmitriy Vyukov Cc: Dr. David Alan Gilbert Cc: Graham Woodward Cc: Howard Chu Cc: Ilkka Koskinen Cc: Ingo Molnar Cc: James Clark Cc: Jiri Olsa Cc: John Garry Cc: Kajol Jain Cc: Kan Liang Cc: Krzysztof Łopatowski Cc: Leo Yan Cc: Levi Yun Cc: Li Huafei Cc: linux-arm-kernel@lists.infradead.org Cc: Mark Rutland Cc: Martin Liška Cc: Masami Hiramatsu Cc: Matt Fleming Cc: Mike Leach Cc: Namhyung Kim Cc: Peter Zijlstra Cc: Ravi Bangoria Cc: Song Liu Cc: Steinar H. Gunderson Cc: Stephen Brennan Cc: Steve Clevenger Cc: Thomas Falcon Cc: Veronika Molnarova Cc: Weilin Wang Cc: Will Deacon Cc: Yicong Yang Cc: Yujie Liu Cc: Zhongqiu Han Cc: Zixian Cai Link: https://lore.kernel.org/r/20250529044000.759937-2-irogers@google.com Signed-off-by: Arnaldo Carvalho de Melo

Revert "perf thread: Ensure comm_lock held for comm_list"

2025-05-28T15:59:17+00:00

This reverts commit 8f454c95817d15ee529d58389612ea4b34f5ffb3. 'perf top' is freezing on exit sometimes, bisected to this one, revert. Cc: Adrian Hunter Cc: Alexander Shishkin Cc: Athira Rajeev Cc: Bill Wendling Cc: Chaitanya S Prakash Cc: Fei Lang Cc: Howard Chu Cc: Ian Rogers Cc: Ingo Molnar Cc: James Clark Cc: Jiri Olsa Cc: Justin Stitt Cc: Kan Liang Cc: Mark Rutland Cc: Namhyung Kim Cc: Nathan Chancellor Cc: Nick Desaulniers Cc: Peter Zijlstra Cc: Stephen Brennan Link: https://lore.kernel.org/r/aDcyvvOKZkRYbjul@x1 Signed-off-by: Arnaldo Carvalho de Melo

perf thread: Ensure comm_lock held for comm_list

2025-05-21T18:07:13+00:00

Add thread safety annotations for comm_list and add locking for two instances where the list is accessed without the lock held (in contradiction to ____thread__set_comm()). Signed-off-by: Ian Rogers Cc: Adrian Hunter Cc: Alexander Shishkin Cc: Athira Rajeev Cc: Bill Wendling Cc: Chaitanya S Prakash Cc: Fei Lang Cc: Howard Chu Cc: Ingo Molnar Cc: James Clark Cc: Jiri Olsa Cc: Justin Stitt Cc: Kan Liang Cc: Mark Rutland Cc: Namhyung Kim Cc: Nathan Chancellor Cc: Nick Desaulniers Cc: Peter Zijlstra Cc: Stephen Brennan Link: https://lore.kernel.org/r/20250519224645.1810891-3-irogers@google.com Signed-off-by: Arnaldo Carvalho de Melo