Re: [PATCH 7/9] net: macb: avoid uninitialized variables

From: Sergei Shtylyov
Date: Thu Jan 28 2016 - 08:27:50 EST


Hello.

On 1/27/2016 5:04 PM, Arnd Bergmann wrote:

The macb_clk_init function returns three clock pointers, unless
the it fails to get the first ones. We correctly handle the

s/the//.

failure case by propagating the error from macb_probe, but
gcc does not realize this and incorrectly warns about a later
use of those:

In file included from /git/arm-soc/drivers/net/ethernet/cadence/macb.c:12:0:
drivers/net/ethernet/cadence/macb.c: In function 'macb_probe':

Hm, didn't these 2 lines get swapped by chance?

include/linux/clk.h:484:2: error: 'tx_clk' may be used uninitialized in this function [-Werror=maybe-uninitialized]
clk_disable(clk);
^
drivers/net/ethernet/cadence/macb.c:2822:28: note: 'tx_clk' was declared here
struct clk *pclk, *hclk, *tx_clk;
^
In file included from /git/arm-soc/drivers/net/ethernet/cadence/macb.c:12:0:
include/linux/clk.h:484:2: error: 'hclk' may be used uninitialized in this function [-Werror=maybe-uninitialized]
clk_disable(clk);
^
drivers/net/ethernet/cadence/macb.c:2822:21: note: 'hclk' was declared here
struct clk *pclk, *hclk, *tx_clk;
^

This shuts up the misleading warnings by ensuring that the
macb_clk_init() always stores something into all three pointers.

Signed-off-by: Arnd Bergmann <arnd@xxxxxxxx>

[...]

MBR, Sergei