Skip to contentSkip to conversation

Fix module.c pointer arithmetics

PATCH In review Carl-Daniel Hailfinger 2 participants 3 messages Jan 31, 2004

lore
Share & tools
lore

Carl-Daniel Hailfinger

author
#0 lore raw

PATCH 1/1 Fix module.c pointer arithmetics

Linus,
Rusty,

while studying the module code closely, I found a problem in kernel/module.c:153ff.

for (i = 0; __start___ksymtab+i < __stop___ksymtab; i++)

In combination with __start___ksymtab[i].name this will go eight times too far. Proposed fix is attached.

Please apply before 2.6.2. If you think this makes the code too slow, I can offer an alternative which will even speed up the current code.

Thanks,
Carl-Daniel

===== kernel/module.c 1.99 vs edited =====

kernel/module.c +3 -3
@@ -150,14 +150,14 @@
 
 	/* Core kernel first. */ 
 	*owner = NULL;
-	for (i = 0; __start___ksymtab+i < __stop___ksymtab; i++) {
+	for (i = 0; __start___ksymtab+i*sizeof(struct kernel_symbol) < __stop___ksymtab; i++) {
 		if (strcmp(__start___ksymtab[i].name, name) == 0) {
 			*crc = symversion(__start___kcrctab, i);
 			return __start___ksymtab[i].value;
 		}
 	}
 	if (gplok) {
-		for (i = 0; __start___ksymtab_gpl+i<__stop___ksymtab_gpl; i++)
+		for (i = 0; __start___ksymtab_gpl+i*sizeof(struct kernel_symbol) < __stop___ksymtab_gpl; i++)
 			if (strcmp(__start___ksymtab_gpl[i].name, name) == 0) {
 				*crc = symversion(__start___kcrctab_gpl, i);
 				return __start___ksymtab_gpl[i].value;

@@ -1308,7 +1308,7 @@
 	unsigned int i;
 
 	if (!mod) {
-		for (i = 0; __start___ksymtab+i < __stop___ksymtab; i++)
+		for (i = 0; __start___ksymtab+i*sizeof(struct kernel_symbol) < __stop___ksymtab; i++)
 			if (strcmp(__start___ksymtab[i].name, name) == 0)
 				return 1;
 		return 0;
#1 lore raw

In message <[email protected]> you write:

kernel/module.c line 153

Quoted 2 lines
kernel/module.c +1 -1
-	for (i = 0; __start___ksymtab+i < __stop___ksymtab; i++) {
+	for (i = 0; __start___ksymtab+i*sizeof(struct kernel_symbol) < __stop___ksymtab; i++) {

Above in this file, there is the declaration:

extern const struct kernel_symbol __start___ksymtab[];

What makes you think you need to multiply here?

Puzzled,
Rusty.
--
Anyone who quotes me in their sig is an idiot. -- Rusty Russell.

author
#2 lore raw
Quoted 11 lines · Rusty Russell

In message <[email protected]> you write:

kernel/module.c line 153

Quoted 2 lines
kernel/module.c +1 -1
-	for (i = 0; __start___ksymtab+i < __stop___ksymtab; i++) {
+	for (i = 0; __start___ksymtab+i*sizeof(struct kernel_symbol) < __stop___ksymtab; i++) {

Above in this file, there is the declaration:

extern const struct kernel_symbol __start___ksymtab[];

What makes you think you need to multiply here?

-ENOCAFFEINE. (Note to self: Never send patches while asleep) Now that I'm awake again, I feel ashamed.

Quoted 2 lines

Puzzled,
Rusty.

Sorry for the confusion,
Carl-Daniel.