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Subject[PATCH -tip 1/9] trace_kprobes: Fix a memory leak bug and check kstrdup return value
Date
Fix a memory leak case in create_trace_probe(). When an argument is
too long (> MAX_ARGSTR_LEN), it just jumps to error path. In that case
tp->args[i].name is not released.
This also fixes a bug to check kstrdup()'s return value.

Signed-off-by: Masami Hiramatsu <mhiramat@redhat.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Jim Keniston <jkenisto@us.ibm.com>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Frank Ch. Eigler <fche@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jason Baron <jbaron@redhat.com>
Cc: K.Prasad <prasad@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
---

kernel/trace/trace_kprobe.c | 26 +++++++++++++++++++-------
1 files changed, 19 insertions(+), 7 deletions(-)

diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c
index 72d0c65..aff5f80 100644
--- a/kernel/trace/trace_kprobe.c
+++ b/kernel/trace/trace_kprobe.c
@@ -483,7 +483,8 @@ static int parse_probe_vars(char *arg, struct fetch_func *ff, int is_return)
return ret;
}

-static int parse_probe_arg(char *arg, struct fetch_func *ff, int is_return)
+/* Recursive argument parser */
+static int __parse_probe_arg(char *arg, struct fetch_func *ff, int is_return)
{
int ret = 0;
unsigned long param;
@@ -543,7 +544,7 @@ static int parse_probe_arg(char *arg, struct fetch_func *ff, int is_return)
if (!id)
return -ENOMEM;
id->offset = offset;
- ret = parse_probe_arg(arg, &id->orig, is_return);
+ ret = __parse_probe_arg(arg, &id->orig, is_return);
if (ret)
kfree(id);
else {
@@ -560,6 +561,16 @@ static int parse_probe_arg(char *arg, struct fetch_func *ff, int is_return)
return ret;
}

+/* String length checking wrapper */
+static int parse_probe_arg(char *arg, struct fetch_func *ff, int is_return)
+{
+ if (strlen(arg) > MAX_ARGSTR_LEN) {
+ pr_info("Argument is too long.: %s\n", arg);
+ return -ENOSPC;
+ }
+ return __parse_probe_arg(arg, ff, is_return);
+}
+
/* Return 1 if name is reserved or already used by another argument */
static int conflict_field_name(const char *name,
struct probe_arg *args, int narg)
@@ -698,13 +709,14 @@ static int create_trace_probe(int argc, char **argv)
}

tp->args[i].name = kstrdup(argv[i], GFP_KERNEL);
-
- /* Parse fetch argument */
- if (strlen(arg) > MAX_ARGSTR_LEN) {
- pr_info("Argument%d(%s) is too long.\n", i, arg);
- ret = -ENOSPC;
+ if (!tp->args[i].name) {
+ pr_info("Failed to allocate argument%d name '%s'.\n",
+ i, argv[i]);
+ ret = -ENOMEM;
goto error;
}
+
+ /* Parse fetch argument */
ret = parse_probe_arg(arg, &tp->args[i].fetch, is_return);
if (ret) {
pr_info("Parse error at argument%d. (%d)\n", i, ret);

--
Masami Hiramatsu

Software Engineer
Hitachi Computer Products (America), Inc.
Software Solutions Division

e-mail: mhiramat@redhat.com


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