Messages in this thread Patch in this message | | | From | Greg Kroah-Hartman <> | Subject | [PATCH 5.4 12/21] perf ftrace: Fix access to pid in array when setting a pid filter | Date | Wed, 5 May 2021 14:04:26 +0200 |
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From: Thomas Richter <tmricht@linux.ibm.com>
[ Upstream commit 671b60cb6a897a5b3832fe57657152f2c3995e25 ]
Command 'perf ftrace -v -- ls' fails in s390 (at least 5.12.0rc6).
The root cause is a missing pointer dereference which causes an array element address to be used as PID.
Fix this by extracting the PID.
Output before: # ./perf ftrace -v -- ls function_graph tracer is used write '-263732416' to tracing/set_ftrace_pid failed: Invalid argument failed to set ftrace pid #
Output after: ./perf ftrace -v -- ls function_graph tracer is used # tracer: function_graph # # CPU DURATION FUNCTION CALLS # | | | | | | | 4) | rcu_read_lock_sched_held() { 4) 0.552 us | rcu_lockdep_current_cpu_online(); 4) 6.124 us | }
Reported-by: Alexander Schmidt <alexschm@de.ibm.com> Signed-off-by: Thomas Richter <tmricht@linux.ibm.com> Acked-by: Namhyung Kim <namhyung@kernel.org> Cc: Heiko Carstens <hca@linux.ibm.com> Cc: Sumanth Korikkar <sumanthk@linux.ibm.com> Cc: Sven Schnelle <svens@linux.ibm.com> Cc: Vasily Gorbik <gor@linux.ibm.com> Link: http://lore.kernel.org/lkml/20210421120400.2126433-1-tmricht@linux.ibm.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com> Signed-off-by: Sasha Levin <sashal@kernel.org> --- tools/perf/builtin-ftrace.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/tools/perf/builtin-ftrace.c b/tools/perf/builtin-ftrace.c index d5adc417a4ca..40b179f54428 100644 --- a/tools/perf/builtin-ftrace.c +++ b/tools/perf/builtin-ftrace.c @@ -161,7 +161,7 @@ static int set_tracing_pid(struct perf_ftrace *ftrace) for (i = 0; i < perf_thread_map__nr(ftrace->evlist->core.threads); i++) { scnprintf(buf, sizeof(buf), "%d", - ftrace->evlist->core.threads->map[i]); + perf_thread_map__pid(ftrace->evlist->core.threads, i)); if (append_tracing_file("set_ftrace_pid", buf) < 0) return -1; } -- 2.30.2
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