X-Git-Url: http://git.lttng.org./?a=blobdiff_plain;f=probes%2Flttng-probe-user.c;h=099a66b229a46fcc90f7b5fd7e504a3806d7d0e6;hb=12d4702757b86de457904f6e344b4f412cef611a;hp=94ecf2f1cffb339d53d9c1dc4d62f58a13dc9ece;hpb=7b8ea3a503536c9d00f8bb14958a150cbf7370c0;p=lttng-modules.git

diff --git a/probes/lttng-probe-user.c b/probes/lttng-probe-user.c
index 94ecf2f1..099a66b2 100644
--- a/probes/lttng-probe-user.c
+++ b/probes/lttng-probe-user.c
@@ -19,7 +19,8 @@
  */
 
 #include <linux/uaccess.h>
-#include "lttng-probe-user.h"
+#include <linux/module.h>
+#include <probes/lttng-probe-user.h>
 
 /*
  * Calculate string length. Include final null terminating character if there is
@@ -30,18 +31,26 @@
 long lttng_strlen_user_inatomic(const char *addr)
 {
 	long count = 0;
-	mm_segment_t old_fs = get_fs();
+	mm_segment_t old_fs;
 
+	if (!addr)
+		return 0;
+
+	old_fs = get_fs();
 	set_fs(KERNEL_DS);
 	pagefault_disable();
 	for (;;) {
 		char v;
-		long ret;
+		unsigned long ret;
 
+		if (unlikely(!access_ok(VERIFY_READ,
+				(__force const char __user *) addr,
+				sizeof(v))))
+			break;
 		ret = __copy_from_user_inatomic(&v,
 			(__force const char __user *)(addr),
 			sizeof(v));
-		if (unlikely(ret == -EFAULT))
+		if (unlikely(ret > 0))
 			break;
 		count++;
 		if (unlikely(!v))
@@ -52,3 +61,4 @@ long lttng_strlen_user_inatomic(const char *addr)
 	set_fs(old_fs);
 	return count;
 }
+EXPORT_SYMBOL_GPL(lttng_strlen_user_inatomic);