Linux Virtualization - Mar 2014 - [PATCH] virtio-blk: make the queue depth configurable

On Fri, Mar 14, 2014 at 10:38:40AM -0700, Joe Perches
wrote:
> > +static int queue_depth = 64;
> > +module_param(queue_depth, int, 444);
> 
> 444?  Really Ted?
Oops, *blush*.   Thanks for catching that.

					- Ted

Theodore Ts'o <tytso at mit.edu> writes:
> On Fri, Mar 14, 2014 at 10:38:40AM -0700, Joe Perches wrote:
>> > +static int queue_depth = 64;
>> > +module_param(queue_depth, int, 444);
>> 
>> 444?  Really Ted?
>
> Oops, *blush*.   Thanks for catching that.
Erk, our tests are insufficient.  Testbuilding an allmodconfig with this
now:

diff --git a/include/linux/moduleparam.h b/include/linux/moduleparam.h
index 175f6995d1af..626b85888a6b 100644
--- a/include/linux/moduleparam.h
+++ b/include/linux/moduleparam.h
@@ -188,6 +188,9 @@ struct kparam_array
 	/* Default value instead of permissions? */			\
 	static int __param_perm_check_##name __attribute__((unused)) =	\
 	BUILD_BUG_ON_ZERO((perm) < 0 || (perm) > 0777 || ((perm) & 2))	\
+	/* User perms >= group perms >= other perms. */			\
+	+ BUILD_BUG_ON_ZERO(((perm) >> 6) < (((perm) >> 3) & 7))	\
+	+ BUILD_BUG_ON_ZERO((((perm) >> 3) & 7) < ((perm) & 7))		\
 	+ BUILD_BUG_ON_ZERO(sizeof(""prefix) > MAX_PARAM_PREFIX_LEN);	\
 	static const char __param_str_##name[] = prefix #name;		\
 	static struct kernel_param __moduleparam_const __param_##name	\

On Mon, 2014-03-17 at 14:25 +1030, Rusty Russell wrote:
> Erk, our tests are insufficient.  Testbuilding an allmodconfig with this
> now:
Good idea.
> diff --git a/include/linux/moduleparam.h b/include/linux/moduleparam.h
[]
> @@ -188,6 +188,9 @@ struct kparam_array
>  	/* Default value instead of permissions? */			\
>  	static int __param_perm_check_##name __attribute__((unused)) =	\
>  	BUILD_BUG_ON_ZERO((perm) < 0 || (perm) > 0777 || ((perm) & 2))
\
> +	/* User perms >= group perms >= other perms. */			\
> +	+ BUILD_BUG_ON_ZERO(((perm) >> 6) < (((perm) >> 3) &
7))	\
> +	+ BUILD_BUG_ON_ZERO((((perm) >> 3) & 7) < ((perm) & 7))	
\
>  	+ BUILD_BUG_ON_ZERO(sizeof(""prefix) >
MAX_PARAM_PREFIX_LEN);	\
>  	static const char __param_str_##name[] = prefix #name;		\
>  	static struct kernel_param __moduleparam_const __param_##name	\
It might make sense to separate this octal permissions
test into a new macro for other checks in macros like
CLASS_ATTR, DEVICE_ATTR, SENSOR_ATTR and SENSOR_ATTR_2.

Maybe something like:

#define VERIFY_OCTAL_PERMISSIONS(perm)					\
	static int __param_perm_check_##name __attribute__((unused)) =	\
	BUILD_BUG_ON_ZERO((perm) < 0 || (perm) > 0777 || ((perm) & 2))	\
	/* User perms >= group perms >= other perms. */			\
	+ BUILD_BUG_ON_ZERO(((perm) >> 6) < (((perm) >> 3) & 7))	\
	+ BUILD_BUG_ON_ZERO((((perm) >> 3) & 7) < ((perm) & 7));	\