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-rw-r--r--kernel/trace/trace.c8
-rw-r--r--kernel/trace/trace_probe.c17
-rw-r--r--kernel/trace/trace_stack.c6
3 files changed, 18 insertions, 13 deletions
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index eac2824a18ab..18b86c3974e1 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -4408,13 +4408,15 @@ static int trace_set_options(struct trace_array *tr, char *option)
int neg = 0;
int ret;
size_t orig_len = strlen(option);
+ int len;
cmp = strstrip(option);
- if (str_has_prefix(cmp, "no")) {
+ len = str_has_prefix(cmp, "no");
+ if (len)
neg = 1;
- cmp += 2;
- }
+
+ cmp += len;
mutex_lock(&trace_types_lock);
diff --git a/kernel/trace/trace_probe.c b/kernel/trace/trace_probe.c
index 541375737403..9962cb5da8ac 100644
--- a/kernel/trace/trace_probe.c
+++ b/kernel/trace/trace_probe.c
@@ -186,19 +186,20 @@ int traceprobe_parse_event_name(const char **pevent, const char **pgroup,
static int parse_probe_vars(char *arg, const struct fetch_type *t,
struct fetch_insn *code, unsigned int flags)
{
- int ret = 0;
unsigned long param;
+ int ret = 0;
+ int len;
if (strcmp(arg, "retval") == 0) {
if (flags & TPARG_FL_RETURN)
code->op = FETCH_OP_RETVAL;
else
ret = -EINVAL;
- } else if (str_has_prefix(arg, "stack")) {
- if (arg[5] == '\0') {
+ } else if ((len = str_has_prefix(arg, "stack"))) {
+ if (arg[len] == '\0') {
code->op = FETCH_OP_STACKP;
- } else if (isdigit(arg[5])) {
- ret = kstrtoul(arg + 5, 10, &param);
+ } else if (isdigit(arg[len])) {
+ ret = kstrtoul(arg + len, 10, &param);
if (ret || ((flags & TPARG_FL_KERNEL) &&
param > PARAM_MAX_STACK))
ret = -EINVAL;
@@ -213,10 +214,10 @@ static int parse_probe_vars(char *arg, const struct fetch_type *t,
#ifdef CONFIG_HAVE_FUNCTION_ARG_ACCESS_API
} else if (((flags & TPARG_FL_MASK) ==
(TPARG_FL_KERNEL | TPARG_FL_FENTRY)) &&
- str_has_prefix(arg, "arg")) {
- if (!isdigit(arg[3]))
+ (len = str_has_prefix(arg, "arg"))) {
+ if (!isdigit(arg[len]))
return -EINVAL;
- ret = kstrtoul(arg + 3, 10, &param);
+ ret = kstrtoul(arg + len, 10, &param);
if (ret || !param || param > PARAM_MAX_STACK)
return -EINVAL;
code->op = FETCH_OP_ARG;
diff --git a/kernel/trace/trace_stack.c b/kernel/trace/trace_stack.c
index 3641f28c343f..eec648a0d673 100644
--- a/kernel/trace/trace_stack.c
+++ b/kernel/trace/trace_stack.c
@@ -448,8 +448,10 @@ static char stack_trace_filter_buf[COMMAND_LINE_SIZE+1] __initdata;
static __init int enable_stacktrace(char *str)
{
- if (str_has_prefix(str, "_filter="))
- strncpy(stack_trace_filter_buf, str+8, COMMAND_LINE_SIZE);
+ int len;
+
+ if ((len = str_has_prefix(str, "_filter=")))
+ strncpy(stack_trace_filter_buf, str + len, COMMAND_LINE_SIZE);
stack_tracer_enabled = 1;
last_stack_tracer_enabled = 1;