[PATCH] resource: Use 2-factor allocator calls

[PATCH] resource: Use 2-factor allocator calls

[Kees Cook]

As already done treewide, switch from open-coded multiplication to using
2-factor allocation helpers.

Signed-off-by: Kees Cook <keescook@chromium.org>
---
 kernel/resource.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/kernel/resource.c b/kernel/resource.c
index d717acd12bf4..16debbf2d24c 100644
--- a/kernel/resource.c
+++ b/kernel/resource.c
@@ -453,7 +453,7 @@ int walk_system_ram_res_rev(u64 start, u64 end, void *arg,
 	int ret = -1;
 
 	/* create a list */
-	rams = vmalloc(sizeof(struct resource) * rams_size);
+	rams = vmalloc(array_size(rams_size, sizeof(struct resource)));
 	if (!rams)
 		return ret;
 
@@ -469,8 +469,8 @@ int walk_system_ram_res_rev(u64 start, u64 end, void *arg,
 			int rams_new_size;
 
 			rams_new_size = rams_size + 16;
-			rams_new = vmalloc(sizeof(struct resource)
-							* rams_new_size);
+			rams_new = vmalloc(array_size(rams_new_size,
+						      sizeof(struct resource)));
 			if (!rams_new)
 				goto out;
 
-- 
2.17.1


-- 
Kees Cook
Pixel Security

Re: [PATCH] resource: Use 2-factor allocator calls

[Andrew Morton]

On Wed, 4 Jul 2018 10:31:53 -0700 Kees Cook <keescook@chromium.org> wrote:

> As already done treewide, switch from open-coded multiplication to using
> 2-factor allocation helpers.
> 

This is against resource-add-walk_system_ram_res_rev.patch
(http://lkml.kernel.org/r/20180322033722.9279-2-bhe@redhat.com).

That patch is awaiting (for several months!) a v2.  Will this be happening?

Re: [PATCH] resource: Use 2-factor allocator calls

[Baoquan He]

Hi Andrew, Kees, 

About the implemention of walk_system_ram_res_rev(), it was posted by
AKASHI firstly for his arm kexec_file adding, later he dropped it
because he took other way and doesn't need walk_system_ram_res_rev() any
more in his patchset.

Then I found my below patch needs a walk_system_ram_res_rev(), 

	kernel/kexec_file.c: load kernel at top of system RAM if required

so I took AKASHI's patch and posted a patchset including above patch,
and AKASHI's patch, it can be seen here:
http://lkml.kernel.org/r/20180322033722.9279-1-bhe@redhat.com

Then Andrew reviewed and added comment to say this
walk_system_ram_res_rev() is not good, and suggested me to change the
singly linked list of child resource to standard list_head which is
doubly linked list, then walk_system_ram_res_rev() can be implemented
very easily to do reversed searching. So I posted v2:
http://lkml.kernel.org/r/20180408024724.16812-1-bhe@redhat.com

Now the latest post is v6:
http://lkml.kernel.org/r/20180704041038.8190-1-bhe@redhat.com


Since changing resource child tree to take doubly linked list list_head
impacts all ARCH and many components, I am still fixing issues test
robot reported since I can only test on x86. Now I plan to ask intel
0day team to tell how I can run scripts locally for all ARCH to find out
all codes impacted and fix them all at one time.

So I think we can drop the old walk_system_ram_res_rev() in v1, I am
still working on this issue. Sorry for the confusion I made because of
my mistakes.

Thanks
Baoquan

On 07/05/18 at 03:07pm, Andrew Morton wrote:
> On Wed, 4 Jul 2018 10:31:53 -0700 Kees Cook <keescook@chromium.org> wrote:
> 
> > As already done treewide, switch from open-coded multiplication to using
> > 2-factor allocation helpers.
> > 
> 
> This is against resource-add-walk_system_ram_res_rev.patch
> (http://lkml.kernel.org/r/20180322033722.9279-2-bhe@redhat.com).
> 
> That patch is awaiting (for several months!) a v2.  Will this be happening?