On 6/2/24 00:34, Jakub Kicinski wrote:

On Thu, 30 May 2024 17:24:10 +0300 Ofir Gal wrote:

quoted

skbuff: before sendpage_ok - i: 0. page: 0x654eccd7 (pfn: 120755)
skbuff: before sendpage_ok - i: 1. page: 0x1666a4da (pfn: 120756)
skbuff: before sendpage_ok - i: 2. page: 0x54f9f140 (pfn: 120757)

noob question, how do you get 3 contiguous pages, the third of which
is slab? is_slab doesn't mean what I think it does, or we got extremely
lucky with kmalloc?

I guess it's not slab which triggered; the actual code is:

static inline bool sendpage_ok(struct page *page)
{
         return !PageSlab(page) && page_count(page) >= 1;
}

My bet is on 'page_count()' triggering.

Cheers,

Hannes