Re: [PATCH] ext4: fix null pointer deref on mount

[Thiemo Nagel <thiemo.nagel@ph.tum.de>]

Theodore Tso wrote:
> On Tue, Jan 06, 2009 at 01:46:23PM +0100, Thiemo Nagel wrote:
>>>> @@ -2160,6 +2162,15 @@
>>>>  			EXT4_BLOCKS_PER_GROUP(sb) - 1);
>>>>  	do_div(blocks_count, EXT4_BLOCKS_PER_GROUP(sb));
>>>>  	sbi->s_groups_count = blocks_count;
>>>> +	if (sbi->s_groups_count > ((uint64_t)1<<32) - EXT4_DESC_PER_BLOCK(sb)) {
>>> This can't possibly work, given that s_groups_count is an unsigned
>>> int.
>> I'm casting to uint64_t, so in my opinion it should work on all  
>> architectures.
> ... which doesn't help given that sbi->s_groups_count is 32 bits on
> x86_32 machines if it is unsigned long, and always 32 bits once
> ext4_group_t was changed to be an unsigned int.

You're right.

Thiemo