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tracing/kprobes: Avoid field name confliction
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Check whether the argument name is in conflict with other field names
while creating a kprobe through the debugfs interface.

Changes in v3:
 - Check strcmp() == 0 instead of !strcmp().

Changes in v2:
 - Add common_lock_depth to reserved name list.

Signed-off-by: Masami Hiramatsu <mhiramat@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Jim Keniston <jkenisto@us.ibm.com>
Cc: Frank Ch. Eigler <fche@redhat.com>
LKML-Reference: <20091007222807.1684.26880.stgit@dhcp-100-2-132.bos.redhat.com>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
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Masami Hiramatsu authored and Frederic Weisbecker committed Oct 12, 2009
1 parent 2e06ff6 commit a703d94
Showing 1 changed file with 53 additions and 12 deletions.
65 changes: 53 additions & 12 deletions kernel/trace/trace_kprobe.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -38,6 +38,25 @@
#define MAX_EVENT_NAME_LEN 64
#define KPROBE_EVENT_SYSTEM "kprobes"

/* Reserved field names */
#define FIELD_STRING_IP "ip"
#define FIELD_STRING_NARGS "nargs"
#define FIELD_STRING_RETIP "ret_ip"
#define FIELD_STRING_FUNC "func"

const char *reserved_field_names[] = {
"common_type",
"common_flags",
"common_preempt_count",
"common_pid",
"common_tgid",
"common_lock_depth",
FIELD_STRING_IP,
FIELD_STRING_NARGS,
FIELD_STRING_RETIP,
FIELD_STRING_FUNC,
};

/* currently, trace_kprobe only supports X86. */

struct fetch_func {
Expand Down Expand Up @@ -537,6 +556,20 @@ static int parse_probe_arg(char *arg, struct fetch_func *ff, int is_return)
return ret;
}

/* 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)
{
int i;
for (i = 0; i < ARRAY_SIZE(reserved_field_names); i++)
if (strcmp(reserved_field_names[i], name) == 0)
return 1;
for (i = 0; i < narg; i++)
if (strcmp(args[i].name, name) == 0)
return 1;
return 0;
}

static int create_trace_probe(int argc, char **argv)
{
/*
Expand Down Expand Up @@ -637,6 +670,12 @@ static int create_trace_probe(int argc, char **argv)
*arg++ = '\0';
else
arg = argv[i];

if (conflict_field_name(argv[i], tp->args, i)) {
ret = -EINVAL;
goto error;
}

tp->args[i].name = kstrdup(argv[i], GFP_KERNEL);

/* Parse fetch argument */
Expand Down Expand Up @@ -1039,8 +1078,8 @@ static int kprobe_event_define_fields(struct ftrace_event_call *event_call)
if (!ret)
return ret;

DEFINE_FIELD(unsigned long, ip, "ip", 0);
DEFINE_FIELD(int, nargs, "nargs", 1);
DEFINE_FIELD(unsigned long, ip, FIELD_STRING_IP, 0);
DEFINE_FIELD(int, nargs, FIELD_STRING_NARGS, 1);
/* Set argument names as fields */
for (i = 0; i < tp->nr_args; i++)
DEFINE_FIELD(unsigned long, args[i], tp->args[i].name, 0);
Expand All @@ -1057,9 +1096,9 @@ static int kretprobe_event_define_fields(struct ftrace_event_call *event_call)
if (!ret)
return ret;

DEFINE_FIELD(unsigned long, func, "func", 0);
DEFINE_FIELD(unsigned long, ret_ip, "ret_ip", 0);
DEFINE_FIELD(int, nargs, "nargs", 1);
DEFINE_FIELD(unsigned long, func, FIELD_STRING_FUNC, 0);
DEFINE_FIELD(unsigned long, ret_ip, FIELD_STRING_RETIP, 0);
DEFINE_FIELD(int, nargs, FIELD_STRING_NARGS, 1);
/* Set argument names as fields */
for (i = 0; i < tp->nr_args; i++)
DEFINE_FIELD(unsigned long, args[i], tp->args[i].name, 0);
Expand Down Expand Up @@ -1108,15 +1147,16 @@ static int kprobe_event_show_format(struct ftrace_event_call *call,
int ret, i;
struct trace_probe *tp = (struct trace_probe *)call->data;

SHOW_FIELD(unsigned long, ip, "ip");
SHOW_FIELD(int, nargs, "nargs");
SHOW_FIELD(unsigned long, ip, FIELD_STRING_IP);
SHOW_FIELD(int, nargs, FIELD_STRING_NARGS);

/* Show fields */
for (i = 0; i < tp->nr_args; i++)
SHOW_FIELD(unsigned long, args[i], tp->args[i].name);
trace_seq_puts(s, "\n");

return __probe_event_show_format(s, tp, "(%lx)", "REC->ip");
return __probe_event_show_format(s, tp, "(%lx)",
"REC->" FIELD_STRING_IP);
}

static int kretprobe_event_show_format(struct ftrace_event_call *call,
Expand All @@ -1126,17 +1166,18 @@ static int kretprobe_event_show_format(struct ftrace_event_call *call,
int ret, i;
struct trace_probe *tp = (struct trace_probe *)call->data;

SHOW_FIELD(unsigned long, func, "func");
SHOW_FIELD(unsigned long, ret_ip, "ret_ip");
SHOW_FIELD(int, nargs, "nargs");
SHOW_FIELD(unsigned long, func, FIELD_STRING_FUNC);
SHOW_FIELD(unsigned long, ret_ip, FIELD_STRING_RETIP);
SHOW_FIELD(int, nargs, FIELD_STRING_NARGS);

/* Show fields */
for (i = 0; i < tp->nr_args; i++)
SHOW_FIELD(unsigned long, args[i], tp->args[i].name);
trace_seq_puts(s, "\n");

return __probe_event_show_format(s, tp, "(%lx <- %lx)",
"REC->func, REC->ret_ip");
"REC->" FIELD_STRING_FUNC
", REC->" FIELD_STRING_RETIP);
}

#ifdef CONFIG_EVENT_PROFILE
Expand Down

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