kernel/linux.git/tools/lib/perf/evlist.c, branch v6.1.168

libperf evlist: Avoid out-of-bounds access

2024-04-13T11:05:12+00:00

[ Upstream commit 1947b92464c3268381604bbe2ac977a3fd78192f ] Parallel testing appears to show a race between allocating and setting evsel ids. As there is a bounds check on the xyarray it yields a segv like: ``` AddressSanitizer:DEADLYSIGNAL ================================================================= ==484408==ERROR: AddressSanitizer: SEGV on unknown address 0x000000000010 ==484408==The signal is caused by a WRITE memory access. ==484408==Hint: address points to the zero page. #0 0x55cef5d4eff4 in perf_evlist__id_hash tools/lib/perf/evlist.c:256 #1 0x55cef5d4f132 in perf_evlist__id_add tools/lib/perf/evlist.c:274 #2 0x55cef5d4f545 in perf_evlist__id_add_fd tools/lib/perf/evlist.c:315 #3 0x55cef5a1923f in store_evsel_ids util/evsel.c:3130 #4 0x55cef5a19400 in evsel__store_ids util/evsel.c:3147 #5 0x55cef5888204 in __run_perf_stat tools/perf/builtin-stat.c:832 #6 0x55cef5888c06 in run_perf_stat tools/perf/builtin-stat.c:960 #7 0x55cef58932db in cmd_stat tools/perf/builtin-stat.c:2878 ... ``` Avoid this crash by early exiting the perf_evlist__id_add_fd and perf_evlist__id_add is the access is out-of-bounds. Signed-off-by: Ian Rogers Cc: Yang Jihong Signed-off-by: Namhyung Kim Link: https://lore.kernel.org/r/20240229070757.796244-1-irogers@google.com Signed-off-by: Sasha Levin

libperf: Propagate maps only if necessary

2022-10-06T11:03:53+00:00

The current code propagate evsel's cpu map settings to evlist when it's added to an evlist. But the evlist->all_cpus and each evsel's cpus will be updated in perf_evlist__set_maps() later. No need to do it before evlist's cpus are set actually. In fact it discards this intermediate all_cpus maps at the beginning of perf_evlist__set_maps(). Let's not do this. It's only needed when an evsel is added after the evlist cpu/thread maps are set. Reviewed-by: Adrian Hunter Signed-off-by: Namhyung Kim Cc: Ian Rogers Cc: Ingo Molnar Cc: Jiri Olsa Cc: Kan Liang Cc: Leo Yan Cc: Peter Zijlstra Link: https://lore.kernel.org/r/20221003204647.1481128-3-namhyung@kernel.org Signed-off-by: Arnaldo Carvalho de Melo

libperf: Populate system-wide evsel maps

2022-10-06T11:03:53+00:00

Setting proper cpu and thread maps for system wide evsels regardless of user requested cpu in __perf_evlist__propagate_maps(). Those evsels need to be active on all cpus always. Do it in the libperf so that we can guarantee it has proper maps. Reviewed-by: Adrian Hunter Signed-off-by: Namhyung Kim Cc: Ian Rogers Cc: Ingo Molnar Cc: Jiri Olsa Cc: Kan Liang Cc: Leo Yan Cc: Peter Zijlstra Link: https://lore.kernel.org/r/20221003204647.1481128-2-namhyung@kernel.org Signed-off-by: Arnaldo Carvalho de Melo

perf tools: Add debug messages and comments for testing

2022-10-04T11:55:23+00:00

Add debug messages to enable scripts to track aspects of 'perf record' behaviour. The messages will be consumed after 'perf record' has run, with the exception of "perf record has started" which is consequently flushed. Put comments so developers know which messages are also being used by test scripts. Signed-off-by: Adrian Hunter Acked-by: Namhyung Kim Cc: Ian Rogers Cc: Jiri Olsa Link: https://lore.kernel.org/r/20220912083412.7058-11-adrian.hunter@intel.com Signed-off-by: Arnaldo Carvalho de Melo

libperf evlist: Fix polling of system-wide events

2022-09-21T19:08:00+00:00

Originally, (refer commit f90d194a867a5a1d ("perf evlist: Do not poll events that use the system_wide flag") there wasn't much reason to poll system-wide events because: 1. The mmaps get "merged" via set-output anyway (the per-cpu case) 2. perf reads all mmaps when any event is woken 3. system-wide mmaps do not fill up as fast as the mmaps for user selected events But there was 1 reason not to poll which was that it prevented correct termination due to POLLHUP on all user selected events. That issue is now easily resolved by using fdarray_flag__nonfilterable. With the advent of commit ae4f8ae16a078964 ("libperf evlist: Allow mixing per-thread and per-cpu mmaps"), system-wide mmaps can be used also in the per-thread case where reason 1 does not apply. Fix the omission of system-wide events from polling by using the fdarray_flag__nonfilterable flag. Example: Before: $ perf record --no-bpf-event -vvv -e intel_pt// --per-thread uname 2>err.txt Linux $ grep 'sys_perf_event_open.*=\|pollfd' err.txt sys_perf_event_open: pid 155076 cpu -1 group_fd -1 flags 0x8 = 5 sys_perf_event_open: pid 155076 cpu -1 group_fd -1 flags 0x8 = 6 sys_perf_event_open: pid -1 cpu 0 group_fd -1 flags 0x8 = 7 sys_perf_event_open: pid -1 cpu 1 group_fd -1 flags 0x8 = 9 sys_perf_event_open: pid -1 cpu 2 group_fd -1 flags 0x8 = 10 sys_perf_event_open: pid -1 cpu 3 group_fd -1 flags 0x8 = 11 sys_perf_event_open: pid -1 cpu 4 group_fd -1 flags 0x8 = 12 sys_perf_event_open: pid -1 cpu 5 group_fd -1 flags 0x8 = 13 sys_perf_event_open: pid -1 cpu 6 group_fd -1 flags 0x8 = 14 sys_perf_event_open: pid -1 cpu 7 group_fd -1 flags 0x8 = 15 thread_data[0x55fb43c29e80]: pollfd[0] <- event_fd=5 thread_data[0x55fb43c29e80]: pollfd[1] <- event_fd=6 thread_data[0x55fb43c29e80]: pollfd[2] <- non_perf_event fd=4 After: $ perf record --no-bpf-event -vvv -e intel_pt// --per-thread uname 2>err.txt Linux $ grep 'sys_perf_event_open.*=\|pollfd' err.txt sys_perf_event_open: pid 156316 cpu -1 group_fd -1 flags 0x8 = 5 sys_perf_event_open: pid 156316 cpu -1 group_fd -1 flags 0x8 = 6 sys_perf_event_open: pid -1 cpu 0 group_fd -1 flags 0x8 = 7 sys_perf_event_open: pid -1 cpu 1 group_fd -1 flags 0x8 = 9 sys_perf_event_open: pid -1 cpu 2 group_fd -1 flags 0x8 = 10 sys_perf_event_open: pid -1 cpu 3 group_fd -1 flags 0x8 = 11 sys_perf_event_open: pid -1 cpu 4 group_fd -1 flags 0x8 = 12 sys_perf_event_open: pid -1 cpu 5 group_fd -1 flags 0x8 = 13 sys_perf_event_open: pid -1 cpu 6 group_fd -1 flags 0x8 = 14 sys_perf_event_open: pid -1 cpu 7 group_fd -1 flags 0x8 = 15 thread_data[0x55cc19e58e80]: pollfd[0] <- event_fd=5 thread_data[0x55cc19e58e80]: pollfd[1] <- event_fd=6 thread_data[0x55cc19e58e80]: pollfd[2] <- event_fd=7 thread_data[0x55cc19e58e80]: pollfd[3] <- event_fd=9 thread_data[0x55cc19e58e80]: pollfd[4] <- event_fd=10 thread_data[0x55cc19e58e80]: pollfd[5] <- event_fd=11 thread_data[0x55cc19e58e80]: pollfd[6] <- event_fd=12 thread_data[0x55cc19e58e80]: pollfd[7] <- event_fd=13 thread_data[0x55cc19e58e80]: pollfd[8] <- event_fd=14 thread_data[0x55cc19e58e80]: pollfd[9] <- event_fd=15 thread_data[0x55cc19e58e80]: pollfd[10] <- non_perf_event fd=4 Fixes: ae4f8ae16a078964 ("libperf evlist: Allow mixing per-thread and per-cpu mmaps") Signed-off-by: Adrian Hunter Acked-by: Namhyung Kim Cc: Ian Rogers Cc: Jiri Olsa Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/20220915122612.81738-3-adrian.hunter@intel.com Signed-off-by: Arnaldo Carvalho de Melo

libperf evlist: Fix per-thread mmaps for multi-threaded targets

2022-09-08T15:17:22+00:00

The offending commit removed mmap_per_thread(), which did not consider the different set-output rules for per-thread mmaps i.e. in the per-thread case set-output is used for file descriptors of the same thread not the same cpu. This was not immediately noticed because it only happens with multi-threaded targets and we do not have a test for that yet. Reinstate mmap_per_thread() expanding it to cover also system-wide per-cpu events i.e. to continue to allow the mixing of per-thread and per-cpu mmaps. Debug messages (with -vv) show the file descriptors that are opened with sys_perf_event_open. New debug messages are added (needs -vvv) that show also which file descriptors are mmapped and which are redirected with set-output. In the per-cpu case (cpu != -1) file descriptors for the same CPU are set-output to the first file descriptor for that CPU. In the per-thread case (cpu == -1) file descriptors for the same thread are set-output to the first file descriptor for that thread. Example (process 17489 has 2 threads): Before (but with new debug prints): $ perf record --no-bpf-event -vvv --per-thread -p 17489 sys_perf_event_open: pid 17489 cpu -1 group_fd -1 flags 0x8 = 5 sys_perf_event_open: pid 17490 cpu -1 group_fd -1 flags 0x8 = 6 libperf: idx 0: mmapping fd 5 libperf: idx 0: set output fd 6 -> 5 failed to mmap with 22 (Invalid argument) After: $ perf record --no-bpf-event -vvv --per-thread -p 17489 sys_perf_event_open: pid 17489 cpu -1 group_fd -1 flags 0x8 = 5 sys_perf_event_open: pid 17490 cpu -1 group_fd -1 flags 0x8 = 6 libperf: mmap_per_thread: nr cpu values (may include -1) 1 nr threads 2 libperf: idx 0: mmapping fd 5 libperf: idx 1: mmapping fd 6 [ perf record: Woken up 2 times to write data ] [ perf record: Captured and wrote 0.018 MB perf.data (15 samples) ] Per-cpu example (process 20341 has 2 threads, same as above): $ perf record --no-bpf-event -vvv -p 20341 sys_perf_event_open: pid 20341 cpu 0 group_fd -1 flags 0x8 = 5 sys_perf_event_open: pid 20342 cpu 0 group_fd -1 flags 0x8 = 6 sys_perf_event_open: pid 20341 cpu 1 group_fd -1 flags 0x8 = 7 sys_perf_event_open: pid 20342 cpu 1 group_fd -1 flags 0x8 = 8 sys_perf_event_open: pid 20341 cpu 2 group_fd -1 flags 0x8 = 9 sys_perf_event_open: pid 20342 cpu 2 group_fd -1 flags 0x8 = 10 sys_perf_event_open: pid 20341 cpu 3 group_fd -1 flags 0x8 = 11 sys_perf_event_open: pid 20342 cpu 3 group_fd -1 flags 0x8 = 12 sys_perf_event_open: pid 20341 cpu 4 group_fd -1 flags 0x8 = 13 sys_perf_event_open: pid 20342 cpu 4 group_fd -1 flags 0x8 = 14 sys_perf_event_open: pid 20341 cpu 5 group_fd -1 flags 0x8 = 15 sys_perf_event_open: pid 20342 cpu 5 group_fd -1 flags 0x8 = 16 sys_perf_event_open: pid 20341 cpu 6 group_fd -1 flags 0x8 = 17 sys_perf_event_open: pid 20342 cpu 6 group_fd -1 flags 0x8 = 18 sys_perf_event_open: pid 20341 cpu 7 group_fd -1 flags 0x8 = 19 sys_perf_event_open: pid 20342 cpu 7 group_fd -1 flags 0x8 = 20 libperf: mmap_per_cpu: nr cpu values 8 nr threads 2 libperf: idx 0: mmapping fd 5 libperf: idx 0: set output fd 6 -> 5 libperf: idx 1: mmapping fd 7 libperf: idx 1: set output fd 8 -> 7 libperf: idx 2: mmapping fd 9 libperf: idx 2: set output fd 10 -> 9 libperf: idx 3: mmapping fd 11 libperf: idx 3: set output fd 12 -> 11 libperf: idx 4: mmapping fd 13 libperf: idx 4: set output fd 14 -> 13 libperf: idx 5: mmapping fd 15 libperf: idx 5: set output fd 16 -> 15 libperf: idx 6: mmapping fd 17 libperf: idx 6: set output fd 18 -> 17 libperf: idx 7: mmapping fd 19 libperf: idx 7: set output fd 20 -> 19 [ perf record: Woken up 7 times to write data ] [ perf record: Captured and wrote 0.020 MB perf.data (17 samples) ] Fixes: ae4f8ae16a078964 ("libperf evlist: Allow mixing per-thread and per-cpu mmaps") Reported-by: Tomáš Trnka Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=216441 Signed-off-by: Adrian Hunter Acked-by: Jiri Olsa Cc: Adrian Hunter Cc: Ian Rogers Cc: Ingo Molnar Cc: Namhyung Kim Cc: Peter Zijlstra Link: https://lore.kernel.org/r/20220905114209.8389-1-adrian.hunter@intel.com Signed-off-by: Arnaldo Carvalho de Melo

perf tools: Allow system-wide events to keep their own threads

2022-05-26T15:36:57+00:00

System-wide events do not have threads, so do not propagate threads to them. Signed-off-by: Adrian Hunter Acked-by: Ian Rogers Acked-by: Namhyung Kim Cc: Alexey Bayduraev Cc: Jiri Olsa Cc: Leo Yan Link: https://lore.kernel.org/r/20220524075436.29144-16-adrian.hunter@intel.com Signed-off-by: Arnaldo Carvalho de Melo

perf tools: Allow system-wide events to keep their own CPUs

2022-05-26T15:36:57+00:00

Currently, user_requested_cpus supplants system-wide CPUs when the evlist has_user_cpus. Change that so that system-wide events retain their own CPUs and they are added to all_cpus. Signed-off-by: Adrian Hunter Acked-by: Ian Rogers Acked-by: Namhyung Kim Cc: Alexey Bayduraev Cc: Jiri Olsa Cc: Leo Yan Link: https://lore.kernel.org/r/20220524075436.29144-15-adrian.hunter@intel.com Signed-off-by: Arnaldo Carvalho de Melo

perf stat: Add requires_cpu flag for uncore

2022-05-26T15:36:57+00:00

Uncore events require a CPU i.e. it cannot be -1. The evsel system_wide flag is intended for events that should be on every CPU, which does not make sense for uncore events because uncore events do not map one-to-one with CPUs. These 2 requirements are not exactly the same, so introduce a new flag 'requires_cpu' for the uncore case. Signed-off-by: Adrian Hunter Acked-by: Ian Rogers Acked-by: Namhyung Kim Cc: Alexey Bayduraev Cc: Jiri Olsa Cc: Leo Yan Link: https://lore.kernel.org/r/20220524075436.29144-13-adrian.hunter@intel.com Signed-off-by: Arnaldo Carvalho de Melo

libperf evlist: Check nr_mmaps is correct

2022-05-26T15:36:57+00:00

Print an error message if the predetermined number of mmaps is incorrect. Signed-off-by: Adrian Hunter Acked-by: Ian Rogers Acked-by: Namhyung Kim Cc: Alexey Bayduraev Cc: Jiri Olsa Cc: Leo Yan Link: https://lore.kernel.org/r/20220524075436.29144-12-adrian.hunter@intel.com Signed-off-by: Arnaldo Carvalho de Melo