From: Masami Hiramatsu <mhiramat@kernel.org>
To: Arnaldo Carvalho de Melo <acme@kernel.org>,
Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Oleg Nesterov <oleg@redhat.com>,
Srikar Dronamraju <srikar@linux.vnet.ibm.com>,
linux-kernel@vger.kernel.org, mhiramat@kernel.org,
Andi Kleen <andi@firstfloor.org>, Andi Kleen <ak@linux.intel.com>
Subject: [PATCH v2 2/4] perf-probe: Fix wrong variable warning when the probe point is not found
Date: Fri, 10 Jul 2020 22:11:13 +0900 [thread overview]
Message-ID: <159438667364.62703.2200642186798763202.stgit@devnote2> (raw)
In-Reply-To: <159438665389.62703.13848613271334658629.stgit@devnote2>
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 warn 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
Reported-by: Andi Kleen <andi@firstfloor.org>
Fixes: cb4027308570 ("perf probe: Trace a magic number if variable is not found")
Cc: stable@vger.kernel.org
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Tested-by: Andi Kleen <ak@linux.intel.com>
Reviewed-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
---
tools/perf/util/probe-finder.c | 3 +++
1 file changed, 3 insertions(+)
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++) {
next prev parent reply other threads:[~2020-07-10 13:11 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-07-10 13:10 [PATCH v2 0/4] perf-probe: Fix GNU IFUNC probe issue etc Masami Hiramatsu
2020-07-10 13:11 ` [PATCH v2 1/4] perf-probe: Avoid setting probes on same address on same event Masami Hiramatsu
2020-07-16 21:47 ` Arnaldo Carvalho de Melo
2020-07-20 12:01 ` Masami Hiramatsu
2020-07-10 13:11 ` Masami Hiramatsu [this message]
2020-07-10 13:11 ` [PATCH v2 3/4] perf-probe: Fix memory leakage when the probe point is not found Masami Hiramatsu
2020-07-10 13:11 ` [PATCH v2 4/4] perf-probe: Warn if the target function is GNU Indirect function Masami Hiramatsu
2020-07-10 13:57 ` Srikar Dronamraju
2020-07-10 17:25 ` Arnaldo Carvalho de Melo
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