diff mbox series

drm/selftest: plane_helper: Put test structures in static storage

Message ID 20220302235909.784935-1-nathan@kernel.org (mailing list archive)
State New, archived
Headers show
Series drm/selftest: plane_helper: Put test structures in static storage | expand

Commit Message

Nathan Chancellor March 2, 2022, 11:59 p.m. UTC 
Clang warns on certain 32-bit architectures:

  drivers/gpu/drm/selftests/test-drm_plane_helper.c:76:5: warning: stack frame size (1064) exceeds limit (1024) in 'igt_check_plane_state' [-Wframe-larger-than]
  int igt_check_plane_state(void *ignored)
      ^
  1 warning generated.

The structures in igt_check_plane_state() total 1008 bytes, so any small
amount of inlining will cause the stack frame to exceed the 32-bit limit
of 1024, triggering the warning.

Move these structures to static storage, which dramatically reduces the
amount of stack space in igt_check_plane_state(). There is no testing
impact, as igt_check_plane_state() is only called once in the driver.

Fixes: 943e6a8beeac ("mock a drm_plane in igt_check_plane_state to make the test more robust")
Link: https://github.com/ClangBuiltLinux/linux/issues/1600
Reported-by: kernel test robot <lkp@intel.com>
Suggested-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
---
 drivers/gpu/drm/selftests/test-drm_plane_helper.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)


base-commit: 9ae2ac4d31a85ce59cc560d514a31b95f4ace154

Comments

Nick Desaulniers March 8, 2022, 10:47 p.m. UTC | #1 
On Wed, Mar 2, 2022 at 4:00 PM Nathan Chancellor <nathan@kernel.org> wrote:
>
> Clang warns on certain 32-bit architectures:
>
>   drivers/gpu/drm/selftests/test-drm_plane_helper.c:76:5: warning: stack frame size (1064) exceeds limit (1024) in 'igt_check_plane_state' [-Wframe-larger-than]
>   int igt_check_plane_state(void *ignored)
>       ^
>   1 warning generated.
>
> The structures in igt_check_plane_state() total 1008 bytes, so any small
> amount of inlining will cause the stack frame to exceed the 32-bit limit
> of 1024, triggering the warning.
>
> Move these structures to static storage, which dramatically reduces the
> amount of stack space in igt_check_plane_state(). There is no testing
> impact, as igt_check_plane_state() is only called once in the driver.
>
> Fixes: 943e6a8beeac ("mock a drm_plane in igt_check_plane_state to make the test more robust")
> Link: https://github.com/ClangBuiltLinux/linux/issues/1600
> Reported-by: kernel test robot <lkp@intel.com>
> Suggested-by: Nick Desaulniers <ndesaulniers@google.com>
> Signed-off-by: Nathan Chancellor <nathan@kernel.org>

Thanks for the patch!
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>

> ---
>  drivers/gpu/drm/selftests/test-drm_plane_helper.c | 8 ++++----
>  1 file changed, 4 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/gpu/drm/selftests/test-drm_plane_helper.c b/drivers/gpu/drm/selftests/test-drm_plane_helper.c
> index ceebeede55ea..b61273e9c403 100644
> --- a/drivers/gpu/drm/selftests/test-drm_plane_helper.c
> +++ b/drivers/gpu/drm/selftests/test-drm_plane_helper.c
> @@ -77,7 +77,7 @@ int igt_check_plane_state(void *ignored)
>  {
>         int ret;
>
> -       const struct drm_crtc_state crtc_state = {
> +       static const struct drm_crtc_state crtc_state = {
>                 .crtc = ZERO_SIZE_PTR,
>                 .enable = true,
>                 .active = true,
> @@ -87,14 +87,14 @@ int igt_check_plane_state(void *ignored)
>                                 DRM_MODE_FLAG_NHSYNC | DRM_MODE_FLAG_NVSYNC)
>                 },
>         };
> -       struct drm_plane plane = {
> +       static struct drm_plane plane = {
>                 .dev = NULL
>         };
> -       struct drm_framebuffer fb = {
> +       static struct drm_framebuffer fb = {
>                 .width = 2048,
>                 .height = 2048
>         };
> -       struct drm_plane_state plane_state = {
> +       static struct drm_plane_state plane_state = {
>                 .plane = &plane,
>                 .crtc = ZERO_SIZE_PTR,
>                 .fb = &fb,
>
> base-commit: 9ae2ac4d31a85ce59cc560d514a31b95f4ace154
> --
> 2.35.1
>
Nathan Chancellor March 18, 2022, 5:11 p.m. UTC | #2 
Ping, could someone review and/or pick this up? This is going to break a
few builds with CONFIG_WERROR, it would be nice to have it in
drm-misc-next-fixes, as the commit it is fixing is in drm-misc-next.

Cheers,
Nathan

On Wed, Mar 02, 2022 at 04:59:09PM -0700, Nathan Chancellor wrote:
> Clang warns on certain 32-bit architectures:
> 
>   drivers/gpu/drm/selftests/test-drm_plane_helper.c:76:5: warning: stack frame size (1064) exceeds limit (1024) in 'igt_check_plane_state' [-Wframe-larger-than]
>   int igt_check_plane_state(void *ignored)
>       ^
>   1 warning generated.
> 
> The structures in igt_check_plane_state() total 1008 bytes, so any small
> amount of inlining will cause the stack frame to exceed the 32-bit limit
> of 1024, triggering the warning.
> 
> Move these structures to static storage, which dramatically reduces the
> amount of stack space in igt_check_plane_state(). There is no testing
> impact, as igt_check_plane_state() is only called once in the driver.
> 
> Fixes: 943e6a8beeac ("mock a drm_plane in igt_check_plane_state to make the test more robust")
> Link: https://github.com/ClangBuiltLinux/linux/issues/1600
> Reported-by: kernel test robot <lkp@intel.com>
> Suggested-by: Nick Desaulniers <ndesaulniers@google.com>
> Signed-off-by: Nathan Chancellor <nathan@kernel.org>
> ---
>  drivers/gpu/drm/selftests/test-drm_plane_helper.c | 8 ++++----
>  1 file changed, 4 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/gpu/drm/selftests/test-drm_plane_helper.c b/drivers/gpu/drm/selftests/test-drm_plane_helper.c
> index ceebeede55ea..b61273e9c403 100644
> --- a/drivers/gpu/drm/selftests/test-drm_plane_helper.c
> +++ b/drivers/gpu/drm/selftests/test-drm_plane_helper.c
> @@ -77,7 +77,7 @@ int igt_check_plane_state(void *ignored)
>  {
>  	int ret;
>  
> -	const struct drm_crtc_state crtc_state = {
> +	static const struct drm_crtc_state crtc_state = {
>  		.crtc = ZERO_SIZE_PTR,
>  		.enable = true,
>  		.active = true,
> @@ -87,14 +87,14 @@ int igt_check_plane_state(void *ignored)
>  				DRM_MODE_FLAG_NHSYNC | DRM_MODE_FLAG_NVSYNC)
>  		},
>  	};
> -	struct drm_plane plane = {
> +	static struct drm_plane plane = {
>  		.dev = NULL
>  	};
> -	struct drm_framebuffer fb = {
> +	static struct drm_framebuffer fb = {
>  		.width = 2048,
>  		.height = 2048
>  	};
> -	struct drm_plane_state plane_state = {
> +	static struct drm_plane_state plane_state = {
>  		.plane = &plane,
>  		.crtc = ZERO_SIZE_PTR,
>  		.fb = &fb,
> 
> base-commit: 9ae2ac4d31a85ce59cc560d514a31b95f4ace154
> -- 
> 2.35.1
> 
>
Maxime Ripard March 21, 2022, 10:08 a.m. UTC | #3 
On Wed, 2 Mar 2022 16:59:09 -0700, Nathan Chancellor wrote:
> Clang warns on certain 32-bit architectures:
> 
>   drivers/gpu/drm/selftests/test-drm_plane_helper.c:76:5: warning: stack frame size (1064) exceeds limit (1024) in 'igt_check_plane_state' [-Wframe-larger-than]
>   int igt_check_plane_state(void *ignored)
>       ^
>   1 warning generated.
> 
> [...]

Applied to drm/drm-misc (drm-misc-next-fixes).

Thanks!
Maxime
Guenter Roeck March 25, 2022, 6:30 p.m. UTC | #4 
On Wed, Mar 02, 2022 at 04:59:09PM -0700, Nathan Chancellor wrote:
> Clang warns on certain 32-bit architectures:
> 
>   drivers/gpu/drm/selftests/test-drm_plane_helper.c:76:5: warning: stack frame size (1064) exceeds limit (1024) in 'igt_check_plane_state' [-Wframe-larger-than]
>   int igt_check_plane_state(void *ignored)
>       ^
>   1 warning generated.
> 
> The structures in igt_check_plane_state() total 1008 bytes, so any small
> amount of inlining will cause the stack frame to exceed the 32-bit limit
> of 1024, triggering the warning.
> 
> Move these structures to static storage, which dramatically reduces the
> amount of stack space in igt_check_plane_state(). There is no testing
> impact, as igt_check_plane_state() is only called once in the driver.
> 
> Fixes: 943e6a8beeac ("mock a drm_plane in igt_check_plane_state to make the test more robust")
> Link: https://github.com/ClangBuiltLinux/linux/issues/1600
> Reported-by: kernel test robot <lkp@intel.com>
> Suggested-by: Nick Desaulniers <ndesaulniers@google.com>
> Signed-off-by: Nathan Chancellor <nathan@kernel.org>
> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>

Tested-by: Guenter Roeck <linux@roeck-us.net>

Note that the offending patch is now in mainline and results in test build
failures there.

Building csky:allmodconfig ... failed
--------------
Error log:
drivers/gpu/drm/selftests/test-drm_plane_helper.c: In function 'igt_check_plane_state':
drivers/gpu/drm/selftests/test-drm_plane_helper.c:223:1: error: the frame size of 1072 bytes is larger than 1024 bytes

This is with gcc 11.2.

Guenter
diff mbox series

Patch

diff --git a/drivers/gpu/drm/selftests/test-drm_plane_helper.c b/drivers/gpu/drm/selftests/test-drm_plane_helper.c
index ceebeede55ea..b61273e9c403 100644
--- a/drivers/gpu/drm/selftests/test-drm_plane_helper.c
+++ b/drivers/gpu/drm/selftests/test-drm_plane_helper.c
@@ -77,7 +77,7 @@  int igt_check_plane_state(void *ignored)
 {
 	int ret;
 
-	const struct drm_crtc_state crtc_state = {
+	static const struct drm_crtc_state crtc_state = {
 		.crtc = ZERO_SIZE_PTR,
 		.enable = true,
 		.active = true,
@@ -87,14 +87,14 @@  int igt_check_plane_state(void *ignored)
 				DRM_MODE_FLAG_NHSYNC | DRM_MODE_FLAG_NVSYNC)
 		},
 	};
-	struct drm_plane plane = {
+	static struct drm_plane plane = {
 		.dev = NULL
 	};
-	struct drm_framebuffer fb = {
+	static struct drm_framebuffer fb = {
 		.width = 2048,
 		.height = 2048
 	};
-	struct drm_plane_state plane_state = {
+	static struct drm_plane_state plane_state = {
 		.plane = &plane,
 		.crtc = ZERO_SIZE_PTR,
 		.fb = &fb,