linux-kernel - drivers/gpu/drm/vc4/vc4_gem.c:604 vc4_lock_bo_reservations() error: uninitialized symbol 'ret'.

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Message-ID: <f5dd7fb6-6a99-407f-846f-0de2d0abe177@stanley.mountain>
Date: Wed, 2 Apr 2025 11:43:25 +0300
From: Dan Carpenter <dan.carpenter@...aro.org>
To: oe-kbuild@...ts.linux.dev,
	Maíra Canal <mcanal@...lia.com>
Cc: lkp@...el.com, oe-kbuild-all@...ts.linux.dev,
	linux-kernel@...r.kernel.org, Melissa Wen <mwen@...lia.com>
Subject: drivers/gpu/drm/vc4/vc4_gem.c:604 vc4_lock_bo_reservations() error:
 uninitialized symbol 'ret'.

tree:   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
head:   acc4d5ff0b61eb1715c498b6536c38c1feb7f3c1
commit: 04630796c437a9285643097825cbd3cd06603f47 drm/vc4: Use DRM Execution Contexts
date:   2 months ago
config: arm64-randconfig-r073-20250402 (https://download.01.org/0day-ci/archive/20250402/202504021500.3AM1hKKS-lkp@intel.com/config)
compiler: clang version 14.0.6 (https://github.com/llvm/llvm-project f28c006a5895fc0e329fe15fead81e37457cb1d1)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@...el.com>
| Reported-by: Dan Carpenter <dan.carpenter@...aro.org>
| Closes: https://lore.kernel.org/r/202504021500.3AM1hKKS-lkp@intel.com/

smatch warnings:
drivers/gpu/drm/vc4/vc4_gem.c:604 vc4_lock_bo_reservations() error: uninitialized symbol 'ret'.

vim +/ret +604 drivers/gpu/drm/vc4/vc4_gem.c

cdec4d3613230f Eric Anholt 2017-04-12  589  static int
04630796c437a9 Maíra Canal 2024-12-20  590  vc4_lock_bo_reservations(struct vc4_exec_info *exec,
04630796c437a9 Maíra Canal 2024-12-20  591  			 struct drm_exec *exec_ctx)
cdec4d3613230f Eric Anholt 2017-04-12  592  {
04630796c437a9 Maíra Canal 2024-12-20  593  	int ret;
cdec4d3613230f Eric Anholt 2017-04-12  594  
cdec4d3613230f Eric Anholt 2017-04-12  595  	/* Reserve space for our shared (read-only) fence references,
cdec4d3613230f Eric Anholt 2017-04-12  596  	 * before we commit the CL to the hardware.
cdec4d3613230f Eric Anholt 2017-04-12  597  	 */
04630796c437a9 Maíra Canal 2024-12-20  598  	drm_exec_init(exec_ctx, DRM_EXEC_INTERRUPTIBLE_WAIT, exec->bo_count);
04630796c437a9 Maíra Canal 2024-12-20  599  	drm_exec_until_all_locked(exec_ctx) {
04630796c437a9 Maíra Canal 2024-12-20  600  		ret = drm_exec_prepare_array(exec_ctx, exec->bo,
04630796c437a9 Maíra Canal 2024-12-20  601  					     exec->bo_count, 1);

This is a false positive in Smatch.  I can silence the warning on my
end easily enough to say that we always enter the drm_exec_until_all_locked()
loop.  But the question is why do we only test the last "ret" instead of
testing all of them?

04630796c437a9 Maíra Canal 2024-12-20  602  	}
cdec4d3613230f Eric Anholt 2017-04-12  603  
cdec4d3613230f Eric Anholt 2017-04-12 @604  	if (ret) {
04630796c437a9 Maíra Canal 2024-12-20  605  		drm_exec_fini(exec_ctx);
cdec4d3613230f Eric Anholt 2017-04-12  606  		return ret;
7edabee06a5622 Eric Anholt 2016-09-27  607  	}
d5b1a78a772f1e Eric Anholt 2015-11-30  608  
cdec4d3613230f Eric Anholt 2017-04-12  609  	return 0;
cdec4d3613230f Eric Anholt 2017-04-12  610  }

-- 
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki