Re: 2.6.17-mm2

Martin J. Bligh
2006-06-28T14:44:21Z

Andrew Morton wrote:
> On Wed, 28 Jun 2006 03:42:15 -0700
> Andrew Morton <akpm@osdl.org> wrote:
>
>
>>his is caused by the vsprintf() changes. Right now, if you do
>>
>> snprintf(buf, 4, "1111111111111");
>>
>>the memory at `buf' gets [31 31 31 31 00], which is not good.
>>
>>This'll plug it, but I didn't check very hard whether it still has any
>>off-by-ones, or if breaks the intent of Jeremy's patch. I think it's OK..

Aha, you're a genius! How the hell did you figure that one out?

Andy / Steve ... any chance one of you could kick this through the
harness? Against -git10 or so, I'd think

Thanks,

M.

> That diff was against an older kernel and doesn't apply. This is against
> mainline:
>
> --- a/lib/vsprintf.c~vsnprintf-fix
> +++ a/lib/vsprintf.c
> @@ -259,7 +259,9 @@ int vsnprintf(char *buf, size_t size, co
> int len;
> unsigned long long num;
> int i, base;
> - char *str, *end, c;
> + char *str; /* Where we're writing to */
> + char *end; /* The last byte we can write to */
> + char c;
> const char *s;
>
> int flags; /* flags to number() */
> @@ -283,12 +285,12 @@ int vsnprintf(char *buf, size_t size, co
> }
>
> str = buf;
> - end = buf + size;
> + end = buf + size - 1;
>
> /* Make sure end is always >= buf */
> - if (end < buf) {
> + if (end < buf - 1) {
> end = ((void *)-1);
> - size = end - buf;
> + size = end - buf + 1;
> }
>
> for (; *fmt ; ++fmt) {
> @@ -494,7 +496,6 @@ int vsnprintf(char *buf, size_t size, co
> /* the trailing null byte doesn't count towards the total */
> return str-buf;
> }
> -
> EXPORT_SYMBOL(vsnprintf);
>
> /**
> _
>