[PATCH 5/9] staging: media: atomisp: fix stack overflow in init_pipe_defaults()

[Arnd Bergmann]

When building with clang, multiple copies of the structures to be
initialized are passed around on the stack and copied locally, using an
insane amount of stack space:

drivers/staging/media/atomisp/pci/sh_css.c:2371:1: error: stack frame size of 
26864 bytes in function 'create_pipe' [-Werror,-Wframe-larger-than=]

Use constantly-allocated variables plus an explicit memcpy()
to avoid that.

Fixes: 6dc9a2568f84 ("media: atomisp: convert default struct values to use 
compound-literals with designated initializers")
Signed-off-by: Arnd Bergmann <a...@arndb.de>
---
 drivers/staging/media/atomisp/pci/sh_css.c | 16 +++++++++++-----
 1 file changed, 11 insertions(+), 5 deletions(-)

diff --git a/drivers/staging/media/atomisp/pci/sh_css.c 
b/drivers/staging/media/atomisp/pci/sh_css.c
index e91c6029c651..1e8b9d637116 100644
--- a/drivers/staging/media/atomisp/pci/sh_css.c
+++ b/drivers/staging/media/atomisp/pci/sh_css.c
@@ -2264,6 +2264,12 @@ static enum ia_css_err
 init_pipe_defaults(enum ia_css_pipe_mode mode,
                   struct ia_css_pipe *pipe,
                   bool copy_pipe) {
+       static const struct ia_css_pipe default_pipe = IA_CSS_DEFAULT_PIPE;
+       static const struct ia_css_preview_settings preview = 
IA_CSS_DEFAULT_PREVIEW_SETTINGS;
+       static const struct ia_css_capture_settings capture = 
IA_CSS_DEFAULT_CAPTURE_SETTINGS;
+       static const struct ia_css_video_settings video = 
IA_CSS_DEFAULT_VIDEO_SETTINGS;
+       static const struct ia_css_yuvpp_settings yuvpp = 
IA_CSS_DEFAULT_YUVPP_SETTINGS;
+
        if (!pipe)
        {
                IA_CSS_ERROR("NULL pipe parameter");
@@ -2271,14 +2277,14 @@ init_pipe_defaults(enum ia_css_pipe_mode mode,
        }
 
        /* Initialize pipe to pre-defined defaults */
-       *pipe = IA_CSS_DEFAULT_PIPE;
+       memcpy(pipe, &default_pipe, sizeof(default_pipe));
 
        /* TODO: JB should not be needed, but temporary backward reference */
        switch (mode)
        {
        case IA_CSS_PIPE_MODE_PREVIEW:
                pipe->mode = IA_CSS_PIPE_ID_PREVIEW;
-               pipe->pipe_settings.preview = IA_CSS_DEFAULT_PREVIEW_SETTINGS;
+               memcpy(&pipe->pipe_settings.preview, &preview, sizeof(preview));
                break;
        case IA_CSS_PIPE_MODE_CAPTURE:
                if (copy_pipe) {
@@ -2286,11 +2292,11 @@ init_pipe_defaults(enum ia_css_pipe_mode mode,
                } else {
                        pipe->mode = IA_CSS_PIPE_ID_CAPTURE;
                }
-               pipe->pipe_settings.capture = IA_CSS_DEFAULT_CAPTURE_SETTINGS;
+               memcpy(&pipe->pipe_settings.capture, &capture, sizeof(capture));
                break;
        case IA_CSS_PIPE_MODE_VIDEO:
                pipe->mode = IA_CSS_PIPE_ID_VIDEO;
-               pipe->pipe_settings.video = IA_CSS_DEFAULT_VIDEO_SETTINGS;
+               memcpy(&pipe->pipe_settings.video, &video, sizeof(video));
                break;
        case IA_CSS_PIPE_MODE_ACC:
                pipe->mode = IA_CSS_PIPE_ID_ACC;
@@ -2300,7 +2306,7 @@ init_pipe_defaults(enum ia_css_pipe_mode mode,
                break;
        case IA_CSS_PIPE_MODE_YUVPP:
                pipe->mode = IA_CSS_PIPE_ID_YUVPP;
-               pipe->pipe_settings.yuvpp = IA_CSS_DEFAULT_YUVPP_SETTINGS;
+               memcpy(&pipe->pipe_settings.yuvpp, &yuvpp, sizeof(yuvpp));
                break;
        default:
                return IA_CSS_ERR_INVALID_ARGUMENTS;
-- 
2.26.2

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