Re: [PATCH v4 1/9] brcmsmac: make some local variables 'static const' to reduce stack size

From: Kalle Valo
Date: Mon Sep 25 2017 - 00:34:05 EST


Arnd Bergmann <arnd@xxxxxxxx> writes:

> With KASAN and a couple of other patches applied, this driver is one
> of the few remaining ones that actually use more than 2048 bytes of
> kernel stack:
>
> broadcom/brcm80211/brcmsmac/phy/phy_n.c: In function 'wlc_phy_workarounds_nphy_gainctrl':
> broadcom/brcm80211/brcmsmac/phy/phy_n.c:16065:1: warning: the frame size of 3264 bytes is larger than 2048 bytes [-Wframe-larger-than=]
> broadcom/brcm80211/brcmsmac/phy/phy_n.c: In function 'wlc_phy_workarounds_nphy':
> broadcom/brcm80211/brcmsmac/phy/phy_n.c:17138:1: warning: the frame size of 2864 bytes is larger than 2048 bytes [-Wframe-larger-than=]
>
> Here, I'm reducing the stack size by marking as many local variables as
> 'static const' as I can without changing the actual code.
>
> This is the first of three patches to improve the stack usage in this
> driver. It would be good to have this backported to stabl kernels
> to get all drivers in 'allmodconfig' below the 2048 byte limit so
> we can turn on the frame warning again globally, but I realize that
> the patch is larger than the normal limit for stable backports.
>
> The other two patches do not need to be backported.
>
> Acked-by: Arend van Spriel <arend.vanspriel@xxxxxxxxxxxx>
> Signed-off-by: Arnd Bergmann <arnd@xxxxxxxx>

I'll queue this and the two following brcmsmac patches for 4.14.

Also I'll add (only for this patch):

Cc: <stable@xxxxxxxxxxxxxxx>

--
Kalle Valo