diff options
author | Hangliang Lai <laihangliang1@huawei.com> | 2023-04-11 04:32:24 +0300 |
---|---|---|
committer | Arnaldo Carvalho de Melo <acme@redhat.com> | 2023-04-12 16:36:14 +0300 |
commit | eab5051788f6111adb88268a784af0c981616579 (patch) | |
tree | 8b340c7a1a117c8bac17f69112e560d076ff59b1 /tools/perf/builtin-top.c | |
parent | ed4da0d3de1e1781f8fbdc9cf1028b39cc658c7f (diff) | |
download | linux-eab5051788f6111adb88268a784af0c981616579.tar.xz |
perf top: Expand the range of multithreaded phase
In __cmd_top(), perf_set_multithreaded() is used to enable
pthread_rwlock, thus down_read() and down_write () are not nops,
handling concurrency problems
Then 'perf top' uses perf_set_singlethreaded(), switching to the single
threaded phase, assuming that no thread concurrency will happen later.
However, a use after free problem could occur in the single threaded
phase, the concurrent procedure is this:
display_thread process_thread
-------------- --------------
thread__comm_len
-> thread__comm_str
-> __thread__comm_str(thread)
thread__delete
-> comm__free
-> comm_str__put
-> zfree(&cs->str)
-> thread->comm_len = strlen(comm);
Since in single thread phase, perf_singlethreaded is true, down_read()
and down_write() do nothing to avoid concurrency problems.
This patch moves the perf_set_singlethreaded() call to the function tail
to expand the multithreaded phase range, making display_thread() and
process_thread() concurrency safe.
Reviewed-by: Yunfeng Ye <yeyunfeng@huawei.com>
Signed-off-by: Hangliang Lai <laihangliang1@huawei.com>
Co-developed-by: Wenyu Liu <liuwenyu7@huawei.com>
Acked-by: Namhyung Kim <namhyung@kernel.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Feilong Lin <linfeilong@huawei.com>
Cc: Hewenliang <hewenliang4@huawei.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Link: https://lore.kernel.org/r/20230411013224.2079-1-laihangliang1@huawei.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Diffstat (limited to 'tools/perf/builtin-top.c')
-rw-r--r-- | tools/perf/builtin-top.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/tools/perf/builtin-top.c b/tools/perf/builtin-top.c index 3162bad0d17d..5d448c36ed22 100644 --- a/tools/perf/builtin-top.c +++ b/tools/perf/builtin-top.c @@ -1276,8 +1276,7 @@ static int __cmd_top(struct perf_top *top) top->evlist->core.threads, true, false, top->nr_threads_synthesize); - if (top->nr_threads_synthesize > 1) - perf_set_singlethreaded(); + perf_set_multithreaded(); if (perf_hpp_list.socket) { ret = perf_env__read_cpu_topology_map(&perf_env); @@ -1355,6 +1354,7 @@ out_join: out_join_thread: cond_signal(&top->qe.cond); pthread_join(thread_process, NULL); + perf_set_singlethreaded(); return ret; } |