Re: [PATCH 4.9 090/105] netlink: fix nla_put_{u8,u16,u32} for KASAN

[Arnd Bergmann]

On Tue, Oct 10, 2017 at 9:51 PM, Greg Kroah-Hartman
<gregkh@xxxxxxxxxxxxxxxxxxx> wrote:
> 4.9-stable review patch.  If anyone has any objections, please let me know.
>
> ------------------
>
> From: Arnd Bergmann <arnd@xxxxxxxx>
>
> commit b4391db42308c9940944b5d7be5ca4b78fb88dd0 upstream.
>
> When CONFIG_KASAN is enabled, the "--param asan-stack=1" causes rather large
> stack frames in some functions. This goes unnoticed normally because
> CONFIG_FRAME_WARN is disabled with CONFIG_KASAN by default as of commit
> 3f181b4d8652 ("lib/Kconfig.debug: disable -Wframe-larger-than warnings with
> KASAN=y").
>
> The kernelci.org build bot however has the warning enabled and that led
> me to investigate it a little further, as every build produces these warnings:
>
> net/wireless/nl80211.c:4389:1: warning: the frame size of 2240 bytes is larger than 2048 bytes [-Wframe-larger-than=]
> net/wireless/nl80211.c:1895:1: warning: the frame size of 3776 bytes is larger than 2048 bytes [-Wframe-larger-than=]
> net/wireless/nl80211.c:1410:1: warning: the frame size of 2208 bytes is larger than 2048 bytes [-Wframe-larger-than=]
> net/bridge/br_netlink.c:1282:1: warning: the frame size of 2544 bytes is larger than 2048 bytes [-Wframe-larger-than=]

Finally a clean build with kernelci again after a year of seeing this
warning, thanks
for the backport!

Now I just need to find a fix for the spurious build failure when
building objtool.

       Arnd