Re: [PATCH] MM, NUMA : sys_set_mempolicy() doesnt check if mode < 0

[Andi Kleen]

On Tue, Aug 02, 2005 at 12:07:23AM +0200, Eric Dumazet wrote:
> MM, NUMA : sys_set_mempolicy() doesnt check if mode < 0
> 
> A kernel BUG() is triggered by a call to set_mempolicy() with a negative 
> first argument.
> This is because the mode is declared as an int, and the validity check 
> doesnt check < 0 values.
> Alternatively, mode could be declared as unsigned int or unsigned long.

Thanks looks good. Andrew, can you apply that one?

-Andi

> 
> Thank you
> Eric
> ---------------------------------
> Test program for x86_64:
> ---------------------------------
> #include <unistd.h>
> #include <stdio.h>
> #include <errno.h>
> #include <linux/unistd.h>
> 
> #define __NR_set_mempolicy      238
> #define __sys_set_mempolicy(mode, nmask, maxnode) _syscall3(int, 
> set_mempolicy, int, mode, unsigned long *, nmask, unsigned long, maxnode)
> static __sys_set_mempolicy(mode, nmask, maxnode)
> 
> unsigned long nodes = 3;
> 
> int main()
> {
> int ret = set_mempolicy(-6, &nodes, 2);
> printf("result=%d errno=%d\n", ret, errno);
> return 0;
> }
> 
> 
> Signed-off-by: Eric Dumazet <dada1@xxxxxxxxxxxxx>
> 

> --- linux-2.6.13-rc4/mm/mempolicy.c	2005-07-29 00:44:44.000000000 +0200
> +++ linux-2.6.13-rc4-ed/mm/mempolicy.c	2005-08-01 23:52:43.000000000 +0200
> @@ -443,7 +443,7 @@
>  	struct mempolicy *new;
>  	DECLARE_BITMAP(nodes, MAX_NUMNODES);
>  
> -	if (mode > MPOL_MAX)
> +	if ((unsigned int)mode > MPOL_MAX)
>  		return -EINVAL;
>  	err = get_nodes(nodes, nmask, maxnode, mode);
>  	if (err)

-
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