2020-04-30 21:37:09

by Arnd Bergmann

Subject: [PATCH 12/15] media: s5k5baf: avoid gcc-10 zero-length-bounds warning

gcc-10 warns about accessing a zero-length struct member:

drivers/media/i2c/s5k5baf.c: In function 's5k5baf_load_setfile':
drivers/media/i2c/s5k5baf.c:390:13: warning: array subscript 65535 is outside the bounds of an interior zero-length array 'struct <anonymous>[0]' [-Wzero-length-bounds]
390 | if (f->seq[i].offset + d <= end)
| ~~~~~~^~~

This should really be a flexible-array member, but the structure
already has one. I experimentally confirmed that swapping the two
avoids the warning, as the 'data[]' array is not accessed like this.

Fixes: 3ba225b506a2 ("treewide: Replace zero-length array with flexible-array member")
Fixes: 7d459937dc09 ("[media] Add driver for Samsung S5K5BAF camera sensor")
Signed-off-by: Arnd Bergmann <[email protected]>
---
drivers/media/i2c/s5k5baf.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/media/i2c/s5k5baf.c b/drivers/media/i2c/s5k5baf.c
index 42584a088273..0b1ddedcf7dc 100644
--- a/drivers/media/i2c/s5k5baf.c
+++ b/drivers/media/i2c/s5k5baf.c
@@ -277,11 +277,11 @@ enum {

struct s5k5baf_fw {
u16 count;
+ u16 data[0];
struct {
u16 id;
u16 offset;
- } seq[0];
- u16 data[];
+ } seq[];
};

struct s5k5baf {
--
2.26.0

2020-04-30 21:44:53

by Gustavo A. R. Silva

Subject: Re: [PATCH 12/15] media: s5k5baf: avoid gcc-10 zero-length-bounds warning

Hi Arnd,

On 4/30/20 16:30, Arnd Bergmann wrote:
> gcc-10 warns about accessing a zero-length struct member:
>
> drivers/media/i2c/s5k5baf.c: In function 's5k5baf_load_setfile':
> drivers/media/i2c/s5k5baf.c:390:13: warning: array subscript 65535 is outside the bounds of an interior zero-length array 'struct <anonymous>[0]' [-Wzero-length-bounds]
> 390 | if (f->seq[i].offset + d <= end)
> | ~~~~~~^~~
>
> This should really be a flexible-array member, but the structure
> already has one. I experimentally confirmed that swapping the two
> avoids the warning, as the 'data[]' array is not accessed like this.
>
> Fixes: 3ba225b506a2 ("treewide: Replace zero-length array with flexible-array member")
> Fixes: 7d459937dc09 ("[media] Add driver for Samsung S5K5BAF camera sensor")
> Signed-off-by: Arnd Bergmann <[email protected]>
> ---
> drivers/media/i2c/s5k5baf.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/media/i2c/s5k5baf.c b/drivers/media/i2c/s5k5baf.c
> index 42584a088273..0b1ddedcf7dc 100644
> --- a/drivers/media/i2c/s5k5baf.c
> +++ b/drivers/media/i2c/s5k5baf.c
> @@ -277,11 +277,11 @@ enum {
>
> struct s5k5baf_fw {
> u16 count;
> + u16 data[0];
> struct {
> u16 id;
> u16 offset;
> - } seq[0];
> - u16 data[];
> + } seq[];
> };
>
> struct s5k5baf {
>

The treewide patch is an experimental change and, as this change only applies
to my -next tree, I will carry this patch in it, so other people don't have
to worry about this at all.

Thank you
--
Gustavo