Messages in this thread | | | Date | Tue, 22 Sep 2020 15:35:59 +0100 | From | Matthew Wilcox <> | Subject | Re: [PATCH] page_alloc: Fix freeing non-compound pages |
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On Tue, Sep 22, 2020 at 03:00:17PM +0100, Matthew Wilcox (Oracle) wrote: > void __free_pages(struct page *page, unsigned int order) > { > if (put_page_testzero(page)) > free_the_page(page, order); > + else > + while (order-- > 0) > + free_the_page(page + (1 << order), order); > } > EXPORT_SYMBOL(__free_pages);
... a three line patch and one of them is wrong.
- else + else if (!PageHead(page))
Anyone got a smart idea about how to _test_ this code path? I'm wondering about loading one kernel module which wanders through memmap calling if (page_cache_get_speculative(page)) put_page(page); and another kernel module that calls __free_pages(alloc_page(GFP_KERNEL, 1), 1);
and putting in a printk to let me know when we hit it.
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