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-Wsometimes-uninitialized in drivers/gpu/drm/omapdrm/omap_fbdev.c #1809

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nathanchance opened this issue Feb 24, 2023 · 2 comments
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-Wsometimes-uninitialized in drivers/gpu/drm/omapdrm/omap_fbdev.c #1809

nathanchance opened this issue Feb 24, 2023 · 2 comments
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@nathanchance
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-Wsometimes-uninitialized [BUG] linux A bug that should be fixed in the mainline kernel. [FIXED][LINUX] development cycle This bug was only present and fixed in a -next or -rc cycle

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@nathanchance
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drivers/gpu/drm/omapdrm/omap_fbdev.c:235:6: error: variable 'helper' is used uninitialized whenever 'if' condition is true [-Werror,-Wsometimes-uninitialized]
        if (!fbdev)
            ^~~~~~
drivers/gpu/drm/omapdrm/omap_fbdev.c:259:26: note: uninitialized use occurs here
        drm_fb_helper_unprepare(helper);
                                ^~~~~~
drivers/gpu/drm/omapdrm/omap_fbdev.c:235:2: note: remove the 'if' if its condition is always false
        if (!fbdev)
        ^~~~~~~~~~~
drivers/gpu/drm/omapdrm/omap_fbdev.c:228:30: note: initialize the variable 'helper' to silence this warning
        struct drm_fb_helper *helper;
                                    ^
                                     = NULL
1 error generated.

Patch submitted: https://lore.kernel.org/20230224-omapdrm-wsometimes-uninitialized-v1-1-3fec8906ee3a@kernel.org/
@nathanchance nathanchance added [BUG] linux A bug that should be fixed in the mainline kernel. [PATCH] Submitted A patch has been submitted for review -Wsometimes-uninitialized labels Feb 24, 2023
@nathanchance nathanchance self-assigned this Feb 24, 2023
intel-lab-lkp pushed a commit to intel-lab-lkp/linux that referenced this issue Feb 24, 2023
@nathanchance @intel-lab-lkp
drm: omapdrm: Do not use helper unininitialized in omap_fbdev_init()
fb3d3f8 
Clang warns (or errors with CONFIG_WERROR):

  ../drivers/gpu/drm/omapdrm/omap_fbdev.c:235:6: error: variable 'helper' is used uninitialized whenever 'if' condition is true [-Werror,-Wsometimes-uninitialized]
          if (!fbdev)
              ^~~~~~
  ../drivers/gpu/drm/omapdrm/omap_fbdev.c:259:26: note: uninitialized use occurs here
          drm_fb_helper_unprepare(helper);
                                  ^~~~~~
  ../drivers/gpu/drm/omapdrm/omap_fbdev.c:235:2: note: remove the 'if' if its condition is always false
          if (!fbdev)
          ^~~~~~~~~~~
  ../drivers/gpu/drm/omapdrm/omap_fbdev.c:228:30: note: initialize the variable 'helper' to silence this warning
          struct drm_fb_helper *helper;
                                      ^
                                       = NULL
  1 error generated.

Return early, as there is nothing for the function to do if memory
cannot be allocated. There is no point in adding another label to just
emit the warning at the end of the function in this case, as memory
allocation failures are already logged.

Fixes: 3fb1f62 ("drm/fb-helper: Remove drm_fb_helper_unprepare() from drm_fb_helper_fini()")
Link: ClangBuiltLinux#1809
Link: https://lore.kernel.org/oe-kbuild-all/202302250058.fYTe9aTP-lkp@intel.com/
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
intel-lab-lkp pushed a commit to intel-lab-lkp/linux that referenced this issue Feb 28, 2023
@nathanchance
drm: omapdrm: Do not use helper unininitialized in omap_fbdev_init()
c176060 
Clang warns (or errors with CONFIG_WERROR):

  ../drivers/gpu/drm/omapdrm/omap_fbdev.c:235:6: error: variable 'helper' is used uninitialized whenever 'if' condition is true [-Werror,-Wsometimes-uninitialized]
          if (!fbdev)
              ^~~~~~
  ../drivers/gpu/drm/omapdrm/omap_fbdev.c:259:26: note: uninitialized use occurs here
          drm_fb_helper_unprepare(helper);
                                  ^~~~~~
  ../drivers/gpu/drm/omapdrm/omap_fbdev.c:235:2: note: remove the 'if' if its condition is always false
          if (!fbdev)
          ^~~~~~~~~~~
  ../drivers/gpu/drm/omapdrm/omap_fbdev.c:228:30: note: initialize the variable 'helper' to silence this warning
          struct drm_fb_helper *helper;
                                      ^
                                       = NULL
  1 error generated.

Return early, as there is nothing for the function to do if memory
cannot be allocated. There is no point in adding another label to just
emit the warning at the end of the function in this case, as memory
allocation failures are already logged.

Fixes: 3fb1f62 ("drm/fb-helper: Remove drm_fb_helper_unprepare() from drm_fb_helper_fini()")
Link: ClangBuiltLinux#1809
Link: https://lore.kernel.org/oe-kbuild-all/202302250058.fYTe9aTP-lkp@intel.com/
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Link: https://patchwork.freedesktop.org/patch/msgid/20230224-omapdrm-wsometimes-uninitialized-v1-1-3fec8906ee3a@kernel.org
@nathanchance
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Patch accepted: https://cgit.freedesktop.org/drm/drm-misc/commit/?id=c176060a4c76ed0043cb9c10435af04ed1ad0560

@nathanchance nathanchance added [PATCH] Accepted A submitted patch has been accepted upstream and removed [PATCH] Submitted A patch has been submitted for review labels Feb 28, 2023
@nathanchance
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This was merged into mainline before 6.3-rc1.

@nathanchance nathanchance added [FIXED][LINUX] development cycle This bug was only present and fixed in a -next or -rc cycle and removed [PATCH] Accepted A submitted patch has been accepted upstream labels Mar 7, 2023
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-Wsometimes-uninitialized [BUG] linux A bug that should be fixed in the mainline kernel. [FIXED][LINUX] development cycle This bug was only present and fixed in a -next or -rc cycle
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