kernel/linux.git/tools/perf/util/machine.c, branch linux-6.9.y

perf map: Remove kernel map before updating start and end addresses

2024-06-12T09:39:10+00:00

[ Upstream commit df12e21d4e15e48a5e7d12e58f1a00742c4177d0 ] In a debug build there is validation that mmap lists are sorted when taking a lock. In machine__update_kernel_mmap() the start and end addresses are updated resulting in an unsorted list before the map is removed from the list. When the map is removed, the lock is taken which triggers the validation and the failure: $ perf test "object code reading" --- start --- perf: util/maps.c:88: check_invariants: Assertion `map__start(prev) <= map__start(map)' failed. Aborted Fix it by updating the addresses after removal, but before insertion. The bug depends on the ordering and type of debug info on the system and doesn't reproduce everywhere. Fixes: 659ad3492b913c90 ("perf maps: Switch from rbtree to lazily sorted array for addresses") Reviewed-by: Ian Rogers Signed-off-by: James Clark Acked-by: Namhyung Kim Cc: Adrian Hunter Cc: Alexander Shishkin Cc: Athira Rajeev Cc: Ian Rogers Cc: Ingo Molnar Cc: Jiri Olsa Cc: Kan Liang Cc: Leo Yan Cc: Mark Rutland Cc: Namhyung Kim Cc: Peter Zijlstra Cc: Spoorthy S Link: https://lore.kernel.org/r/20240410103458.813656-4-james.clark@arm.com Signed-off-by: Arnaldo Carvalho de Melo Signed-off-by: Sasha Levin

perf threads: Move threads to its own files

2024-03-04T06:51:55+00:00

Move threads out of machine and into its own file. Signed-off-by: Ian Rogers Acked-by: Namhyung Kim Cc: Yang Jihong Cc: Oliver Upton Signed-off-by: Namhyung Kim Link: https://lore.kernel.org/r/20240301053646.1449657-6-irogers@google.com

perf machine: Move machine's threads into its own abstraction

2024-03-04T06:51:44+00:00

Move thread_rb_node into the machine.c file. This hides the implementation of threads from the rest of the code allowing for it to be refactored. Locking discipline is tightened up in this change. As the lock is now encapsulated in threads, the findnew function requires holding it (as it already did in machine). Rather than do conditionals with locks based on whether the thread should be created (which could potentially be error prone with a read lock match with a write unlock), have a separate threads__find that won't create the thread and only holds the read lock. This effectively duplicates the findnew logic, with the existing findnew logic only operating under a write lock assuming creation is necessary as a previous find failed. The creation may still fail with the write lock due to another thread. The duplication is removed in a later next patch that delegates the implementation to hashtable. Signed-off-by: Ian Rogers Acked-by: Namhyung Kim Cc: Yang Jihong Cc: Oliver Upton Signed-off-by: Namhyung Kim Link: https://lore.kernel.org/r/20240301053646.1449657-5-irogers@google.com

perf machine: Move fprintf to for_each loop and a callback

2024-03-04T06:51:31+00:00

Avoid exposing the threads data structure by switching to the callback machine__for_each_thread approach. machine__fprintf is only used in tests and verbose >3 output so don't turn to list and sort. Add machine__threads_nr to be refactored later. Note, all existing *_fprintf routines ignore fprintf errors. Signed-off-by: Ian Rogers Acked-by: Namhyung Kim Cc: Yang Jihong Cc: Oliver Upton Signed-off-by: Namhyung Kim Link: https://lore.kernel.org/r/20240301053646.1449657-4-irogers@google.com

perf report: Sort child tasks by tid

2024-03-04T06:50:55+00:00

Commit 91e467bc568f ("perf machine: Use hashtable for machine threads") made the iteration of thread tids unordered. The perf report --tasks output now shows child threads in an order determined by the hashing. For example, in this snippet tid 3 appears after tid 256 even though they have the same ppid 2: ``` $ perf report --tasks % pid tid ppid comm 0 0 -1 |swapper 2 2 0 | kthreadd 256 256 2 | kworker/12:1H-k 693761 693761 2 | kworker/10:1-mm 1301762 1301762 2 | kworker/1:1-mm_ 1302530 1302530 2 | kworker/u32:0-k 3 3 2 | rcu_gp ... ``` The output is easier to read if threads appear numerically increasing. To allow for this, read all threads into a list then sort with a comparator that orders by the child task's of the first common parent. The list creation and deletion are created as utilities on machine. The indentation is possible by counting the number of parents a child has. With this change the output for the same data file is now like: ``` $ perf report --tasks % pid tid ppid comm 0 0 -1 |swapper 1 1 0 | systemd 823 823 1 | systemd-journal 853 853 1 | systemd-udevd 3230 3230 1 | systemd-timesyn 3236 3236 1 | auditd 3239 3239 3236 | audisp-syslog 3321 3321 1 | accounts-daemon ... ``` Signed-off-by: Ian Rogers Acked-by: Namhyung Kim Cc: Yang Jihong Cc: Oliver Upton Signed-off-by: Namhyung Kim Link: https://lore.kernel.org/r/20240301053646.1449657-2-irogers@google.com

perf maps: Locking tidy up of nr_maps

2024-02-12T20:35:41+00:00

After this change maps__nr_maps is only used by tests, existing users are migrated to maps__empty. Compute maps__empty under the read lock. Signed-off-by: Ian Rogers Acked-by: Namhyung Kim Cc: K Prateek Nayak Cc: James Clark Cc: Vincent Whitchurch Cc: Alexey Dobriyan Cc: Colin Ian King Cc: Changbin Du Cc: Masami Hiramatsu Cc: Song Liu Cc: Leo Yan Cc: Athira Rajeev Cc: Liam Howlett Cc: Artem Savkov Cc: bpf@vger.kernel.org Signed-off-by: Namhyung Kim Link: https://lore.kernel.org/r/20240210031746.4057262-7-irogers@google.com

perf maps: Get map before returning in maps__find_next_entry

2024-02-12T20:35:41+00:00

Finding a map is done under a lock, returning the map without a reference count means it can be removed without notice and causing uses after free. Grab a reference count to the map within the lock region and return this. Fix up locations that need a map__put following this. Signed-off-by: Ian Rogers Acked-by: Namhyung Kim Cc: K Prateek Nayak Cc: James Clark Cc: Vincent Whitchurch Cc: Alexey Dobriyan Cc: Colin Ian King Cc: Changbin Du Cc: Masami Hiramatsu Cc: Song Liu Cc: Leo Yan Cc: Athira Rajeev Cc: Liam Howlett Cc: Artem Savkov Cc: bpf@vger.kernel.org Signed-off-by: Namhyung Kim Link: https://lore.kernel.org/r/20240210031746.4057262-5-irogers@google.com

perf maps: Get map before returning in maps__find_by_name

2024-02-12T20:35:33+00:00

Finding a map is done under a lock, returning the map without a reference count means it can be removed without notice and causing uses after free. Grab a reference count to the map within the lock region and return this. Fix up locations that need a map__put following this. Also fix some reference counted pointer comparisons. Signed-off-by: Ian Rogers Acked-by: Namhyung Kim Cc: K Prateek Nayak Cc: James Clark Cc: Vincent Whitchurch Cc: Alexey Dobriyan Cc: Colin Ian King Cc: Changbin Du Cc: Masami Hiramatsu Cc: Song Liu Cc: Leo Yan Cc: Athira Rajeev Cc: Liam Howlett Cc: Artem Savkov Cc: bpf@vger.kernel.org Signed-off-by: Namhyung Kim Link: https://lore.kernel.org/r/20240210031746.4057262-4-irogers@google.com

perf maps: Get map before returning in maps__find

2024-02-12T20:35:26+00:00

perf maps: Add find next entry to give entry after the given map

2023-12-20T18:02:02+00:00

Use to remove map_rb_node use from machine.c. Signed-off-by: Ian Rogers Cc: Adrian Hunter Cc: Alexander Shishkin Cc: Andi Kleen Cc: Athira Rajeev Cc: Changbin Du Cc: Colin Ian King Cc: Dmitrii Dolgov <9erthalion6@gmail.com> Cc: German Gomez Cc: Guilherme Amadio Cc: Huacai Chen Cc: Ingo Molnar Cc: James Clark Cc: Jiri Olsa Cc: K Prateek Nayak Cc: Kajol Jain Cc: Kan Liang Cc: Leo Yan Cc: Li Dong Cc: Liam Howlett Cc: Mark Rutland Cc: Masami Hiramatsu Cc: Miguel Ojeda Cc: Ming Wang Cc: Namhyung Kim Cc: Nick Terrell Cc: Paolo Bonzini Cc: Peter Zijlstra Cc: Ravi Bangoria Cc: Sandipan Das Cc: Sean Christopherson Cc: Steinar H. Gunderson Cc: Vincent Whitchurch Cc: Wenyu Liu Cc: Yang Jihong Link: https://lore.kernel.org/r/20231207011722.1220634-21-irogers@google.com Signed-off-by: Arnaldo Carvalho de Melo