>>>>> On Wed, 26 Dec 2001 01:32:21 -0200, Ralf Baechle <firstname.lastname@example.org> said:
>> In somewhere between 2.4.6 and 2.4.9, the call to flush_cache_all()
>> disappered from vmalloc_area_pages(). I have a data corruption
>> problem in vmalloc()ed area without this call. I think we still
>> need this call.
ralf> Have you ever resolved this problem? I've just doublechecked
ralf> the vmalloc code and it seems as if it should be entirely safe
ralf> without these two calls. The tlb is flushed on vfree so no
ralf> stale entries for a vmalloc address can ever be in the tlb at
ralf> vmalloc time, so this flush_tlb_all() is just an expensive nop.
ralf> And the same it true for flush_cache_all() no matter if caches
ralf> are physically or virtually indexed.
I am still using the patch and have not tried without the two calls
When I found this problem, I suppose that vmalloc called after
free_pages causes the data corruption. vmalloc can re-use pages freed
by free_pages and it seems free_pages does not flush cache. If
vmalloc is to use a page which is associated with dirty cache and has
different "color", virtual aliasing happens and data may be corrupt.
Is this wrong?