[Intel-gfx] [bug report] drm/i915/gem: Correct the locking and pin pattern for dma-buf (v8)

[Nathan Chancellor]

On 8/13/2021 4:31 AM, Dan Carpenter wrote:
> Nathan has probably already sent fixes for these.  Nathan, could you CC
> kernel-janitors on static checker fixes?  That way we wouldn't send so
> many duplicate patches.

Sure. I did not send any fixes prior to this email but I just sent
https://lore.kernel.org/r/20210813171158.2665823-1-nathan@kernel.org/ 
with kernel-janitors and you CC'd.

> Uninitialized variable warnings are really frustrating.  We disabled the
> GCC warning for them because the new GCC is crap.  So now they take up
> a lot of my time.  A few of these are because Smatch doesn't always know
> when we enter loops, but more than half are clear bugs.
> 
> drivers/gpu/drm/i915/gem/i915_gem_dmabuf.c:189 i915_gem_dmabuf_attach() error: uninitialized symbol 'err'.
> drivers/gpu/drm/i915/gem/selftests/i915_gem_dmabuf.c:80 igt_dmabuf_import_self() error: uninitialized symbol 'import_obj'.
> drivers/gpu/drm/i915/gem/selftests/i915_gem_dmabuf.c:104 igt_dmabuf_import_same_driver_lmem() error: uninitialized symbol 'dmabuf'.
> drivers/gpu/drm/i915/gem/selftests/i915_gem_dmabuf.c:138 igt_dmabuf_import_same_driver_lmem() error: uninitialized symbol 'err'.
> drivers/gpu/drm/i915/gem/selftests/i915_gem_dmabuf.c:158 igt_dmabuf_import_same_driver() error: uninitialized symbol 'dmabuf'.
> drivers/gpu/drm/i915/gem/selftests/i915_gem_dmabuf.c:231 igt_dmabuf_import_same_driver() error: uninitialized symbol 'import_obj'.
> drivers/gpu/drm/i915/gem/selftests/i915_gem_migrate.c:197 igt_lmem_pages_migrate() error: uninitialized symbol 'err'.

...

> drivers/gpu/drm/i915/gt/selftest_hangcheck.c:465 igt_reset_nop_engine() error: uninitialized symbol 'err'.
> drivers/gpu/drm/i915/gt/selftest_hangcheck.c:580 igt_reset_fail_engine() error: uninitialized symbol 'err'.

Clang caught these two but none of the rest and it is an obvious fix so 
that is the only one I am going to fix.

> drivers/gpu/drm/i915/gt/selftest_migrate.c:102 copy() error: uninitialized symbol 'rq'.
> drivers/gpu/drm/i915/gt/selftest_migrate.c:113 copy() error: uninitialized symbol 'vaddr'.
> drivers/gpu/drm/i915/gt/selftest_migrate.c:182 clear() error: uninitialized symbol 'rq'.
> drivers/gpu/drm/i915/gt/selftest_migrate.c:193 clear() error: uninitialized symbol 'vaddr'.
> drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c:819 __unwind_incomplete_requests() error: uninitialized symbol 'pl'.

Cheers,
Nathan