From 0da57e88074840bdb692e7c9ef936b0e000e4c79 Mon Sep 17 00:00:00 2001
From: Josh Poimboeuf <jpoimboe@redhat.com>
Date: Wed, 10 Sep 2014 20:22:27 -0500
Subject: [PATCH] fix the mangled function strcmp

Fix the mangled function strcmp so that it compares all of the string
except for the numbered parts.  foo.isra.35 should match foo.isra.1, but
not foo.isra.35.part.36.

Fixes #352.
---
 kpatch-build/create-diff-object.c    | 56 +++++++++++++++++-----------
 test/integration/gcc-mangled-3.patch | 14 +++++++
 2 files changed, 48 insertions(+), 22 deletions(-)
 create mode 100644 test/integration/gcc-mangled-3.patch

diff --git a/kpatch-build/create-diff-object.c b/kpatch-build/create-diff-object.c
index dc7c681..29bacd0 100644
--- a/kpatch-build/create-diff-object.c
+++ b/kpatch-build/create-diff-object.c
@@ -236,19 +236,6 @@ struct symbol *find_symbol_by_name(struct list_head *list, const char *name)
 	return NULL;
 }
 
-struct symbol *find_symbol_by_name_prefix(struct list_head *list,
-					  const char *name)
-{
-	struct symbol *sym;
-	int namelen = strlen(name);
-
-	list_for_each_entry(sym, list, list)
-		if (!strncmp(sym->name, name, namelen))
-			return sym;
-
-	return NULL;
-}
-
 #define ALLOC_LINK(_new, _list) \
 { \
 	(_new) = malloc(sizeof(*(_new))); \
@@ -785,6 +772,30 @@ void kpatch_mark_grouped_sections(struct kpatch_elf *kelf)
 	}
 }
 
+/*
+ * This is like strcmp, but for gcc-mangled function names.  It skips the
+ * comparison of any substring which consists of '.' followed by any number of
+ * digits.
+ */
+static int kpatch_mangled_strcmp(char *s1, char *s2)
+{
+	while (*s1 == *s2) {
+		if (!*s1)
+			return 0;
+		if (*s1 == '.' && isdigit(s1[1])) {
+			if (!isdigit(s2[1]))
+				return 1;
+			while (isdigit(*++s1))
+				;
+			while (isdigit(*++s2))
+				;
+		} else {
+			s1++;
+			s2++;
+		}
+	}
+	return 1;
+}
 
 /*
  * When gcc makes compiler optimizations which affect a function's calling
@@ -798,8 +809,9 @@ void kpatch_rename_mangled_functions(struct kpatch_elf *base,
 				     struct kpatch_elf *patched)
 {
 	struct symbol *sym, *basesym;
-	char *prefix, *dot, name[256], *origname;
+	char name[256], *origname;
 	struct section *sec, *basesec;
+	int found;
 
 	list_for_each_entry(sym, &patched->symbols, list) {
 		if (sym->type != STT_FUNC)
@@ -810,15 +822,15 @@ void kpatch_rename_mangled_functions(struct kpatch_elf *base,
 		    !strstr(sym->name, ".part."))
 			continue;
 
-		/* prefix of foo.isra.1.constprop.2 is foo.isra */
-		prefix = strdup(sym->name);
-		dot = strchr(prefix, '.');
-		dot = strchr(dot+1, '.');
-		*dot = '\0';
+		found = 0;
+		list_for_each_entry(basesym, &base->symbols, list) {
+			if (!kpatch_mangled_strcmp(basesym->name, sym->name)) {
+				found = 1;
+				break;
+			}
+		}
 
-		basesym = find_symbol_by_name_prefix(&base->symbols, prefix);
-		free(prefix);
-		if (!basesym)
+		if (!found)
 			continue;
 
 		if (!strcmp(sym->name, basesym->name))
diff --git a/test/integration/gcc-mangled-3.patch b/test/integration/gcc-mangled-3.patch
new file mode 100644
index 0000000..9e8225e
--- /dev/null
+++ b/test/integration/gcc-mangled-3.patch
@@ -0,0 +1,14 @@
+Index: src/mm/slub.c
+===================================================================
+--- src.orig/mm/slub.c
++++ src/mm/slub.c
+@@ -5346,6 +5346,9 @@ void get_slabinfo(struct kmem_cache *s,
+ 	unsigned long nr_free = 0;
+ 	int node;
+ 
++	if (!jiffies)
++		printk("slabinfo\n");
++
+ 	for_each_online_node(node) {
+ 		struct kmem_cache_node *n = get_node(s, node);
+