On Fri, 19 Nov 2021 23:12:55 +0800 Kuan-Ying Lee [off-list ref] wrote:

quoted

quoted

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Call sequence:
ptr = kmalloc(size, GFP_KERNEL);
page = virt_to_page(ptr);
kfree(page_address(page));
ptr = kmalloc(size, GFP_KERNEL);

How is this call sequence valid? page_address returns the address of
the start of the page, while kmalloced object could have been located
in the middle of it.

Thanks for pointing out. I miss the offset.

It should be listed as below.

ptr = kmalloc(size, GFP_KERNEL);
page = virt_to_page(ptr);
offset = offset_in_page(ptr);
kfree(page_address(page) + offset);
ptr = kmalloc(size, GFP_KERNEL);

I updated the changelog to reflect this.

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