kprobes: Return -ENOENT if probe point doesn't exist

Return -ENOENT if probe point doesn't exist, but still returns -EINVAL if both of kprobe->addr and kprobe->symbol_name are specified or both are not specified. Acked-by: Ananth N Mavinakayanahalli <ananth@in.ibm.com> Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com> Cc: "David S. Miller" <davem@davemloft.net> Link: http://lkml.kernel.org/r/20110627072650.6528.67329.stgit@fedora15 Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

kprobes: Return -ENOENT if probe point doesn't exist
Return -ENOENT if probe point doesn't exist, but still returns -EINVAL if both of kprobe->addr and kprobe->symbol_name are specified or both are not specified. Acked-by: Ananth N Mavinakayanahalli <ananth@in.ibm.com> Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com> Cc: "David S. Miller" <davem@davemloft.net> Link: http://lkml.kernel.org/r/20110627072650.6528.67329.stgit@fedora15 Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Masami Hiramatsu · Steven Rostedt
1 parent 1538f888f1
Showing 1 changed file with 23 additions and 10 deletions Side-by-side Diff
kernel/kprobes.c
@@ -1255,19 +1255,29 @@
 /*
  * If we have a symbol_name argument, look it up and add the offset field
  * to it. This way, we can specify a relative address to a symbol.
+ * This returns encoded errors if it fails to look up symbol or invalid
+ * combination of parameters.
  */
 static kprobe_opcode_t __kprobes *kprobe_addr(struct kprobe *p)
 {
 	kprobe_opcode_t *addr = p->addr;
+
+	if ((p->symbol_name && p->addr) ||
+	    (!p->symbol_name && !p->addr))
+		goto invalid;
+
 	if (p->symbol_name) {
-		if (addr)
-			return NULL;
 		kprobe_lookup_name(p->symbol_name, addr);
+		if (!addr)
+			return ERR_PTR(-ENOENT);
 	}
  
-	if (!addr)
-		return NULL;
-	return (kprobe_opcode_t *)(((char *)addr) + p->offset);
+	addr = (kprobe_opcode_t *)(((char *)addr) + p->offset);
+	if (addr)
+		return addr;
+
+invalid:
+	return ERR_PTR(-EINVAL);
 }
  
 /* Check passed kprobe is valid and return kprobe in kprobe_table. */
@@ -1311,8 +1321,8 @@
 	kprobe_opcode_t *addr;
  
 	addr = kprobe_addr(p);
-	if (!addr)
-		return -EINVAL;
+	if (IS_ERR(addr))
+		return PTR_ERR(addr);
 	p->addr = addr;
  
 	ret = check_kprobe_rereg(p);
@@ -1335,6 +1345,8 @@
 	 */
 	probed_mod = __module_text_address((unsigned long) p->addr);
 	if (probed_mod) {
+		/* Return -ENOENT if fail. */
+		ret = -ENOENT;
 		/*
 		 * We must hold a refcount of the probed module while updating
 		 * its code to prohibit unexpected unloading.
@@ -1351,6 +1363,7 @@
 			module_put(probed_mod);
 			goto fail_with_jump_label;
 		}
+		/* ret will be updated by following code */
 	}
 	preempt_enable();
 	jump_label_unlock();
@@ -1399,7 +1412,7 @@
 fail_with_jump_label:
 	preempt_enable();
 	jump_label_unlock();
-	return -EINVAL;
+	return ret;
 }
 EXPORT_SYMBOL_GPL(register_kprobe);
  
@@ -1686,8 +1699,8 @@
  
 	if (kretprobe_blacklist_size) {
 		addr = kprobe_addr(&rp->kp);
-		if (!addr)
-			return -EINVAL;
+		if (IS_ERR(addr))
+			return PTR_ERR(addr);
  
 		for (i = 0; kretprobe_blacklist[i].name != NULL; i++) {
 			if (kretprobe_blacklist[i].addr == addr)
...	...	@@ -1255,19 +1255,29 @@
1255	1255	/*
1256	1256	* If we have a symbol_name argument, look it up and add the offset field
1257	1257	* to it. This way, we can specify a relative address to a symbol.
	1258	+ * This returns encoded errors if it fails to look up symbol or invalid
	1259	+ * combination of parameters.
1258	1260	*/
1259	1261	static kprobe_opcode_t __kprobes kprobe_addr(struct kprobe p)
1260	1262	{
1261	1263	kprobe_opcode_t *addr = p->addr;
	1264	+
	1265	+ if ((p->symbol_name && p->addr) \|\|
	1266	+ (!p->symbol_name && !p->addr))
	1267	+ goto invalid;
	1268	+
1262	1269	if (p->symbol_name) {
1263		- if (addr)
1264		- return NULL;
1265	1270	kprobe_lookup_name(p->symbol_name, addr);
	1271	+ if (!addr)
	1272	+ return ERR_PTR(-ENOENT);
1266	1273	}
1267	1274
1268		- if (!addr)
1269		- return NULL;
1270		- return (kprobe_opcode_t )(((char )addr) + p->offset);
	1275	+ addr = (kprobe_opcode_t )(((char )addr) + p->offset);
	1276	+ if (addr)
	1277	+ return addr;
	1278	+
	1279	+invalid:
	1280	+ return ERR_PTR(-EINVAL);
1271	1281	}
1272	1282
1273	1283	/* Check passed kprobe is valid and return kprobe in kprobe_table. */
...	...	@@ -1311,8 +1321,8 @@
1311	1321	kprobe_opcode_t *addr;
1312	1322
1313	1323	addr = kprobe_addr(p);
1314		- if (!addr)
1315		- return -EINVAL;
	1324	+ if (IS_ERR(addr))
	1325	+ return PTR_ERR(addr);
1316	1326	p->addr = addr;
1317	1327
1318	1328	ret = check_kprobe_rereg(p);
...	...	@@ -1335,6 +1345,8 @@
1335	1345	*/
1336	1346	probed_mod = __module_text_address((unsigned long) p->addr);
1337	1347	if (probed_mod) {
	1348	+ /* Return -ENOENT if fail. */
	1349	+ ret = -ENOENT;
1338	1350	/*
1339	1351	* We must hold a refcount of the probed module while updating
1340	1352	* its code to prohibit unexpected unloading.
...	...	@@ -1351,6 +1363,7 @@
1351	1363	module_put(probed_mod);
1352	1364	goto fail_with_jump_label;
1353	1365	}
	1366	+ /* ret will be updated by following code */
1354	1367	}
1355	1368	preempt_enable();
1356	1369	jump_label_unlock();
...	...	@@ -1399,7 +1412,7 @@
1399	1412	fail_with_jump_label:
1400	1413	preempt_enable();
1401	1414	jump_label_unlock();
1402		- return -EINVAL;
	1415	+ return ret;
1403	1416	}
1404	1417	EXPORT_SYMBOL_GPL(register_kprobe);
1405	1418
...	...	@@ -1686,8 +1699,8 @@
1686	1699
1687	1700	if (kretprobe_blacklist_size) {
1688	1701	addr = kprobe_addr(&rp->kp);
1689		- if (!addr)
1690		- return -EINVAL;
	1702	+ if (IS_ERR(addr))
	1703	+ return PTR_ERR(addr);
1691	1704
1692	1705	for (i = 0; kretprobe_blacklist[i].name != NULL; i++) {
1693	1706	if (kretprobe_blacklist[i].addr == addr)