From b8efe48651b88dd4db89d924ad6d3bc8e08f84af Mon Sep 17 00:00:00 2001
From: Jonathan Lebon <jlebon@redhat.com>
Date: Mon, 10 Jun 2013 11:49:29 -0400
Subject: [PATCH] PR15044: keep cute return val and conditional check for
 last_error only

In order to avoid the kernel panic which occurred due to a null pointer
(see previous commit), all patches in PR15044 were rechecked so that
the return value is always valid (by keeping its cute message) and the
conditional version check is done solely for assigning to last_error.
---
 runtime/stp_string.c    | 10 +---------
 tapset/string.stp       |  3 +--
 tapset/uconversions.stp |  7 +++----
 3 files changed, 5 insertions(+), 15 deletions(-)

diff --git a/runtime/stp_string.c b/runtime/stp_string.c
index 875f7961f..a7392782e 100644
--- a/runtime/stp_string.c
+++ b/runtime/stp_string.c
@@ -77,11 +77,7 @@ static int _stp_text_str(char *outstr, char *in, int len, int quoted, int user)
 
 	if (user) {
 		if (_stp_read_address(c, in, USER_DS))
-#if STAP_COMPAT_VERSION < STAP_VERSION(2,3) // PR15044
 			goto bad;
-#else
-			return -1;
-#endif
 	} else
 		c = *in;
 
@@ -151,11 +147,7 @@ static int _stp_text_str(char *outstr, char *in, int len, int quoted, int user)
 		in++;
 		if (user) {
 			if (_stp_read_address(c, in, USER_DS))
-#if STAP_COMPAT_VERSION < STAP_VERSION(2,3) // PR15044
 				goto bad;
-#else
-				return -1;
-#endif
 		} else
 			c = *in;
 	}
@@ -174,7 +166,7 @@ static int _stp_text_str(char *outstr, char *in, int len, int quoted, int user)
 	return 0;
 bad:
 	strlcpy (outstr, "<unknown>", len);
-	return -1;
+	return -1; // PR15044
 }
 
 /**
diff --git a/tapset/string.stp b/tapset/string.stp
index b67485e31..030fa95ef 100644
--- a/tapset/string.stp
+++ b/tapset/string.stp
@@ -50,9 +50,8 @@ function stringat:long(str:string, pos:long) %{ /* pure */ /* unprivileged */
 	if (STAP_ARG_pos >= 0 && STAP_ARG_pos < strlen(STAP_ARG_str))
 		STAP_RETVALUE = STAP_ARG_str[STAP_ARG_pos];
 	else {
-#if STAP_COMPAT_VERSION < STAP_VERSION(2,3) // PR15044
 		STAP_RETVALUE = 0;
-#else
+#if STAP_COMPAT_VERSION >= STAP_VERSION(2,3) // PR15044
 		CONTEXT->last_error = "Position out of bounds";
 #endif
 	}
diff --git a/tapset/uconversions.stp b/tapset/uconversions.stp
index d3593256c..3e418faee 100644
--- a/tapset/uconversions.stp
+++ b/tapset/uconversions.stp
@@ -159,16 +159,15 @@ function user_string_n:string (addr:long, n:long)
 	int64_t len = clamp_t(int64_t, STAP_ARG_n + 1, 1, MAXSTRINGLEN);
 	rc = _stp_strncpy_from_user(STAP_RETVALUE,
 		(char __user *) (uintptr_t) STAP_ARG_addr, len);
-	if (rc < 0)
-#if STAP_COMPAT_VERSION < STAP_VERSION(2,3) // PR15044
+	if (rc < 0) {
 		strlcpy(STAP_RETVALUE, "<unknown>", MAXSTRINGLEN);
-#else
+#if STAP_COMPAT_VERSION >= STAP_VERSION(2,3) // PR15044
 		snprintf (CONTEXT->error_buffer, sizeof(CONTEXT->error_buffer),
 			"user string copy fault %ld at %p", rc,
 			(void *) (uintptr_t) STAP_ARG_addr);
 		CONTEXT->last_error = CONTEXT->error_buffer;
 #endif
-	else
+	} else
 		STAP_RETVALUE[len - 1] = '\0';
 %}
 
-- 
2.43.5