Re: [PATCH] fs: btrfs: Fix a possible null-pointer dereference in insert_inline_extent()

[Jia-Ju Bai]

On 2019/7/24 10:21, Qu Wenruo wrote:
> On 2019/7/24 äå10:11, Jia-Ju Bai wrote:
> > In insert_inline_extent(), there is an if statement on line 181 to check
> > whether compressed_pages is NULL:
> >      if (compressed_size && compressed_pages)
> >
> > When compressed_pages is NULL, compressed_pages is used on line 215:
> >      cpage = compressed_pages[i];
> >
> > Thus, a possible null-pointer dereference may occur.
> >
> > To fix this possible bug, compressed_pages is checked on line 214.
> This can only be hit with compressed_size > 0 and compressed_pages != NULL.
>
> It would be better to have an extra ASSERT() to warn developers about
> the impossible case.

Thanks for the reply :)
So I should add ASSERT(compressed_size > 0 & compressed_pages) at the 
beginning of the function, and remove "if (compressed_size && 
compressed_pages)"?


Best wishes,
Jia-Ju Bai