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From: Masami Hiramatsu <mhiramat@kernel.org>
To: Steven Rostedt <rostedt@goodmis.org>
Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com>,
	Naveen Rao <naveen.n.rao@linux.vnet.ibm.com>,
	Ravi Bangoria <ravi.bangoria@linux.ibm.com>,
	linux-kernel@vger.kernel.org, mhiramat@kernel.org,
	mingo@redhat.com
Subject: [PATCH] tracing/probe: Fix to check the difference of nr_args before adding probe
Date: Sat, 28 Sep 2019 02:59:08 -0700
Message-ID: <156966474783.3478.13217501608215769150.stgit@devnote2> (raw)
In-Reply-To: <20190928011748.599255f6ffc9a4831e1efd2c@kernel.org>

Fix to check the difference of nr_args before adding probe
on existing probes. This also may set the error log index
bigger than the number of command parameters. In that case
it sets the error position is next to the last parameter.

Fixes: ca89bc071d5e ("tracing/kprobe: Add multi-probe per event support")
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
---
 kernel/trace/trace_probe.c |   16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/kernel/trace/trace_probe.c b/kernel/trace/trace_probe.c
index baf58a3612c0..905b10af5d5c 100644
--- a/kernel/trace/trace_probe.c
+++ b/kernel/trace/trace_probe.c
@@ -178,6 +178,16 @@ void __trace_probe_log_err(int offset, int err_type)
 	if (!command)
 		return;
 
+	if (trace_probe_log.index >= trace_probe_log.argc) {
+		/**
+		 * Set the error position is next to the last arg + space.
+		 * Note that len includes the terminal null and the cursor
+		 * appaers at pos + 1.
+		 */
+		pos = len;
+		offset = 0;
+	}
+
 	/* And make a command string from argv array */
 	p = command;
 	for (i = 0; i < trace_probe_log.argc; i++) {
@@ -1084,6 +1094,12 @@ int trace_probe_compare_arg_type(struct trace_probe *a, struct trace_probe *b)
 {
 	int i;
 
+	/* In case of more arguments */
+	if (a->nr_args < b->nr_args)
+		return a->nr_args + 1;
+	if (a->nr_args > b->nr_args)
+		return b->nr_args + 1;
+
 	for (i = 0; i < a->nr_args; i++) {
 		if ((b->nr_args <= i) ||
 		    ((a->args[i].type != b->args[i].type) ||


  parent reply index

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-09-27  9:50 [PATCH] tracing/probe: Test nr_args match in looking for same probe events Steven Rostedt
2019-09-27 13:38 ` Srikar Dronamraju
2019-09-27 15:06   ` Steven Rostedt
2019-09-27 17:54     ` Srikar Dronamraju
2019-09-28  8:17   ` Masami Hiramatsu
2019-09-28  9:56     ` Masami Hiramatsu
2019-09-28  9:59     ` Masami Hiramatsu [this message]
2019-09-28 21:11       ` [PATCH] tracing/probe: Fix to check the difference of nr_args before adding probe Steven Rostedt
2019-09-29  8:14         ` Masami Hiramatsu
2019-09-30 10:28         ` Srikar Dronamraju

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