Re: [2.6.12-rc1-mm4] swapped memset arguments

Re: [2.6.12-rc1-mm4] swapped memset arguments

[Jesper Juhl]

On Sat, 2 Apr 2005, Maciej Soltysiak wrote:

> Hi,
> 
> out of boredom I grepped 2.6.12-rc1-mm4 for swapped memset arguments.
> I found one:
> 
> # grep -nr "memset.*\,\(\ \|\)0\(\ \|\));" *
> net/ieee80211/ieee80211_tx.c:226:       memset(txb, sizeof(struct ieee80211_txb), 0);  
> 
And here's a patch : 


Fix swapped memset() arguments in  net/ieee80211/ieee80211_tx.c  
found by Maciej Soltysiak.

Signed-off-by: Jesper Juhl <juhl-lkml@dif.dk>

--- linux-2.6.12-rc1-mm4-orig/net/ieee80211/ieee80211_tx.c	2005-03-31 21:20:08.000000000 +0200
+++ linux-2.6.12-rc1-mm4/net/ieee80211/ieee80211_tx.c	2005-04-03 00:34:22.000000000 +0200
@@ -223,7 +223,7 @@ struct ieee80211_txb *ieee80211_alloc_tx
 	if (!txb)
 		return NULL;
 
-	memset(txb, sizeof(struct ieee80211_txb), 0);
+	memset(txb, 0, sizeof(struct ieee80211_txb));
 	txb->nr_frags = nr_frags;
 	txb->frag_size = txb_size;
 

Re: [2.6.12-rc1-mm4] swapped memset arguments

[Denis Vlasenko]

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On Sunday 03 April 2005 01:38, Jesper Juhl wrote:
> On Sat, 2 Apr 2005, Maciej Soltysiak wrote:
> 
> > Hi,
> > 
> > out of boredom I grepped 2.6.12-rc1-mm4 for swapped memset arguments.
> > I found one:
> > 
> > # grep -nr "memset.*\,\(\ \|\)0\(\ \|\));" *
> > net/ieee80211/ieee80211_tx.c:226:       memset(txb, sizeof(struct ieee80211_txb), 0);  
> > 
> And here's a patch : 
> 
> 
> Fix swapped memset() arguments in  net/ieee80211/ieee80211_tx.c  
> found by Maciej Soltysiak.

This one will stop these from happening again.
(Well, at least on i386)...
--
vda

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--- linux-2.6.11.src/include/asm-i386/string.h.orig	Thu Mar  3 09:31:08 2005
+++ linux-2.6.11.src/include/asm-i386/string.h	Tue Apr  5 18:34:28 2005
@@ -316,8 +345,16 @@ __asm__ __volatile__(
 return s;
 }
 
-/* we might want to write optimized versions of these later */
-#define __constant_count_memset(s,c,count) __memset_generic((s),(c),(count))
+/*
+ * we might want to write optimized versions of this later
+ * for mow, just prevent common mistake of memset(a,c,0)
+ */
+void BUG_memset_with_zero_length(void);
+static inline void * __constant_count_memset(void * s, int c, size_t count)
+{
+	if(!count) BUG_memset_with_zero_length();
+	return __memset_generic(s,c,count);
+}
 
 /*
  * memset(x,0,y) is a reasonably common thing to do, so we want to fill
@@ -376,6 +413,7 @@ static inline void * __constant_c_and_co
 {
 	switch (count) {
 		case 0:
+			BUG_memset_with_zero_length();
 			return s;
 		case 1:
 			*(unsigned char *)s = pattern;