On 2024/2/28 12:33, Sergey Senozhatsky wrote: > On (24/02/27 03:02), Chengming Zhou wrote: > [..] >> @@ -978,10 +974,11 @@ static struct zspage *alloc_zspage(struct zs_pool *pool, >> pages[i] = page; >> } >> >> - create_page_chain(class, zspage, pages); >> init_zspage(class, zspage); >> zspage->pool = pool; >> zspage->class = class->index; >> + /* RCU set_zspage() after zspage initialized. */ >> + create_page_chain(class, zspage, pages); > > So this hasn't been tested, has it? I have tested it in my test vm, but it hasn't KASAN enabled. I tested the kernel build in tmpfs with zswap enabled using zsmalloc pool, not sure why the kernel didn't crash then... > > init_zspage() does not like to be invoked before create_page_chain(), > because we haven't setup required pointers yet. You're right, I can reproduce the problem with KASAN enabled this time, create_page_chain() should be put before init_zspage(), which will iterate over the pages to create free objects list. > > So when init_zspage() calls get_first_page() it gets NULL zspage->first_page > which we then use in is_first_page(first_page)->PagePrivate(page). As far as > I can tell. Thanks! I will fix it and test throughly before send an update.
