Subject: Re: [PATCH] bpf: fix possible uninitialized access in inactive rotation

From: Daniel Borkmann <[email-masked]>
Date: Wed, 16 Nov 2016 17:00:10 +0100

On 11/16/2016 03:38 PM, Arnd Bergmann wrote:
> This newly added code causes a build warning:
>
> kernel/bpf/bpf_lru_list.c: In function '__bpf_lru_list_rotate_inactive':
> kernel/bpf/bpf_lru_list.c:201:28: error: 'next' may be used uninitialized in this function [-Werror=maybe-uninitialized]
>
> The warning is plausible from looking at the code, though there might
> be non-obvious external constraints that ensure it always works.
>
> Moving the assignment of ->next_inactive_rotation inside of the
> loop makes it obvious to the reader and the compiler when we
> actually want to update ->next.
>
> Fixes: 3a08c2fd7634 ("bpf: LRU List")
> Signed-off-by: Arnd Bergmann <[email-masked]>

Thanks a lot, Arnd, patch was already sent here though:

http://patchwork.ozlabs.org/patch/695202/