On Wed, Jul 24, 2019 at 10:57:24AM +0800, Qu Wenruo wrote: > On 2019/7/24 上午10:33, Jia-Ju Bai wrote: > > On 2019/7/24 10:21, Qu Wenruo wrote: > >> On 2019/7/24 上午10:11, 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)"? > > My suggestion is, ASSERT((compressed_size >0 && compressed_pages) || > (compressed_size == 0 && !compressed_pages)) > > And keeps the original checks. > > Anyway, just a suggestion.
Agreed, the assertion would be good, covering both cases in one statement at the beginning of the function.
