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From:   Willem de Bruijn <willemdebruijn.kernel@gmail.com>
Date:   Fri, 28 Jun 2019 15:52:03 -0400
Message-ID: <CA+FuTSdL=GwjhbERsePAJfbakgEQZb7X51UHw=+4R9dJD3JD4A@mail.gmail.com>
Subject: Re: [PATCH 3/4] staging: rtl8712: reduce stack usage, again
To:     Arnd Bergmann <arnd@arndb.de>
Cc:     Kees Cook <keescook@chromium.org>,
        Larry Finger <Larry.Finger@lwfinger.net>,
        Florian Schilhabel <florian.c.schilhabel@googlemail.com>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
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        "James E . J . Bottomley" <jejb@linux.ibm.com>,
        "Martin K . Petersen" <martin.petersen@oracle.com>,
        "David S . Miller" <davem@davemloft.net>,
        Wensong Zhang <wensong@linux-vs.org>,
        Simon Horman <horms@verge.net.au>,
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On Fri, Jun 28, 2019 at 8:41 AM Arnd Bergmann <arnd@arndb.de> wrote:
>
> An earlier patch I sent reduced the stack usage enough to get
> below the warning limit, and I could show this was safe, but with
> GCC_PLUGIN_STRUCTLEAK_BYREF_ALL, it gets worse again because large stack
> variables in the same function no longer overlap:
>
> drivers/staging/rtl8712/rtl871x_ioctl_linux.c: In function 'translate_scan.isra.2':
> drivers/staging/rtl8712/rtl871x_ioctl_linux.c:322:1: error: the frame size of 1200 bytes is larger than 1024 bytes [-Werror=frame-larger-than=]
>
> Split out the largest two blocks in the affected function into two
> separate functions and mark those noinline_for_stack.
>
> Fixes: 8c5af16f7953 ("staging: rtl8712: reduce stack usage")
> Fixes: 81a56f6dcd20 ("gcc-plugins: structleak: Generalize to all variable types")
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>

Reviewed-by: Willem de Bruijn <willemb@google.com>