Re: [PATCH 1/1] fs/omfs/inode.c: replace count*size kzalloc by kcalloc

From: Bob Copeland
Date: Wed Jun 25 2014 - 15:03:05 EST


On Wed, Jun 25, 2014 at 11:27:21AM -0700, Linus Torvalds wrote:
> On Wed, Jun 25, 2014 at 11:17 AM, Fabian Frederick <fabf@xxxxxxxxx> wrote:
> > kcalloc manages count*sizeof overflow.
>
> As far as I can tell, any overflow has happened long before, in
>
> bitmap_size = DIV_ROUND_UP(sbi->s_num_blocks, 8);
>
> where 'sbi->s_num_blocks' i san u64, and 'bitmap_size' is an 'int'.
>
> I don't think the patch is necessarily a bad thing, but I think it
> might be more important to sanity-check that part instead.

Agreed - even though the FS data structures support 64-bit block
count, I've never seen an OMFS fs with more than about 2M blocks
(typical device had 20 gigs w/ 8k blocks). So it would make
sense to bail in omfs_fill_super if that number is greater than
2^31 or so.

(I am fine with the kcalloc patch too, though.)

--
Bob Copeland %% www.bobcopeland.com
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