* [PATCH] ALSA: hda/ca0132 - Replace zero-length array with flexible-array member
@ 2020-02-11 19:44 Gustavo A. R. Silva
2020-02-12 7:16 ` Takashi Iwai
0 siblings, 1 reply; 2+ messages in thread
From: Gustavo A. R. Silva @ 2020-02-11 19:44 UTC (permalink / raw)
To: Jaroslav Kysela, Takashi Iwai
Cc: alsa-devel, linux-kernel, Gustavo A. R. Silva
The current codebase makes use of the zero-length array language
extension to the C90 standard, but the preferred mechanism to declare
variable-length types such as these ones is a flexible array member[1][2],
introduced in C99:
struct foo {
int stuff;
struct boo array[];
};
By making use of the mechanism above, we will get a compiler warning
in case the flexible array does not occur last in the structure, which
will help us prevent some kind of undefined behavior bugs from being
inadvertenly introduced[3] to the codebase from now on.
This issue was found with the help of Coccinelle.
[1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html
[2] https://github.com/KSPP/linux/issues/21
[3] commit 76497732932f ("cxgb3/l2t: Fix undefined behaviour")
Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
---
sound/pci/hda/patch_ca0132.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/sound/pci/hda/patch_ca0132.c b/sound/pci/hda/patch_ca0132.c
index e1ebc6d5f382..ab5632502206 100644
--- a/sound/pci/hda/patch_ca0132.c
+++ b/sound/pci/hda/patch_ca0132.c
@@ -2708,7 +2708,7 @@ struct dsp_image_seg {
u32 magic;
u32 chip_addr;
u32 count;
- u32 data[0];
+ u32 data[];
};
static const u32 g_magic_value = 0x4c46584d;
--
2.25.0
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH] ALSA: hda/ca0132 - Replace zero-length array with flexible-array member
2020-02-11 19:44 [PATCH] ALSA: hda/ca0132 - Replace zero-length array with flexible-array member Gustavo A. R. Silva
@ 2020-02-12 7:16 ` Takashi Iwai
0 siblings, 0 replies; 2+ messages in thread
From: Takashi Iwai @ 2020-02-12 7:16 UTC (permalink / raw)
To: Gustavo A. R. Silva
Cc: Jaroslav Kysela, Takashi Iwai, alsa-devel, linux-kernel
On Tue, 11 Feb 2020 20:44:03 +0100,
Gustavo A. R. Silva wrote:
>
> The current codebase makes use of the zero-length array language
> extension to the C90 standard, but the preferred mechanism to declare
> variable-length types such as these ones is a flexible array member[1][2],
> introduced in C99:
>
> struct foo {
> int stuff;
> struct boo array[];
> };
>
> By making use of the mechanism above, we will get a compiler warning
> in case the flexible array does not occur last in the structure, which
> will help us prevent some kind of undefined behavior bugs from being
> inadvertenly introduced[3] to the codebase from now on.
>
> This issue was found with the help of Coccinelle.
>
> [1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html
> [2] https://github.com/KSPP/linux/issues/21
> [3] commit 76497732932f ("cxgb3/l2t: Fix undefined behaviour")
>
> Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Applied, thanks.
Takashi
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