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| author | Masami Hiramatsu <mhiramat@kernel.org> | 2020-07-10 22:11:13 +0900 |
|---|---|---|
| committer | Arnaldo Carvalho de Melo <acme@redhat.com> | 2020-07-17 09:09:37 -0300 |
| commit | 11fd3eb874e73ee8069bcfd54e3c16fa7ce56fe6 (patch) | |
| tree | a47c95c5131d003dd00cc4f4566a13405a73d34e | |
| parent | 26bbf45fc81dc1bcb29a9b4721d3ec6c3804003d (diff) | |
| download | lwn-11fd3eb874e73ee8069bcfd54e3c16fa7ce56fe6.tar.gz lwn-11fd3eb874e73ee8069bcfd54e3c16fa7ce56fe6.zip | |
perf probe: Fix wrong variable warning when the probe point is not found
Fix a wrong "variable not found" warning when the probe point is not
found in the debuginfo.
Since the debuginfo__find_probes() can return 0 even if it does not find
given probe point in the debuginfo, fill_empty_trace_arg() can be called
with tf.ntevs == 0 and it can emit a wrong warning. To fix this, reject
ntevs == 0 in fill_empty_trace_arg().
E.g. without this patch;
# perf probe -x /lib64/libc-2.30.so -a "memcpy arg1=%di"
Failed to find the location of the '%di' variable at this address.
Perhaps it has been optimized out.
Use -V with the --range option to show '%di' location range.
Added new events:
probe_libc:memcpy (on memcpy in /usr/lib64/libc-2.30.so with arg1=%di)
probe_libc:memcpy (on memcpy in /usr/lib64/libc-2.30.so with arg1=%di)
You can now use it in all perf tools, such as:
perf record -e probe_libc:memcpy -aR sleep 1
With this;
# perf probe -x /lib64/libc-2.30.so -a "memcpy arg1=%di"
Added new events:
probe_libc:memcpy (on memcpy in /usr/lib64/libc-2.30.so with arg1=%di)
probe_libc:memcpy (on memcpy in /usr/lib64/libc-2.30.so with arg1=%di)
You can now use it in all perf tools, such as:
perf record -e probe_libc:memcpy -aR sleep 1
Fixes: cb4027308570 ("perf probe: Trace a magic number if variable is not found")
Reported-by: Andi Kleen <andi@firstfloor.org>
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Reviewed-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Tested-by: Andi Kleen <ak@linux.intel.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: stable@vger.kernel.org
Link: http://lore.kernel.org/lkml/159438667364.62703.2200642186798763202.stgit@devnote2
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
| -rw-r--r-- | tools/perf/util/probe-finder.c | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/tools/perf/util/probe-finder.c b/tools/perf/util/probe-finder.c index 55924255c535..9963e4e8ea20 100644 --- a/tools/perf/util/probe-finder.c +++ b/tools/perf/util/probe-finder.c @@ -1408,6 +1408,9 @@ static int fill_empty_trace_arg(struct perf_probe_event *pev, char *type; int i, j, ret; + if (!ntevs) + return -ENOENT; + for (i = 0; i < pev->nargs; i++) { type = NULL; for (j = 0; j < ntevs; j++) { |