Clang warns a couple of times:

drivers/gpu/drm/i915/gem/selftests/i915_gem_dmabuf.c:63:6: warning: variable 'import_obj' is used uninitialized whenever 'if' condition is true [-Wsometimes-uninitialized] if (import != &obj->base) { ^~~~~~~~~~~~~~~~~~~~ drivers/gpu/drm/i915/gem/selftests/i915_gem_dmabuf.c:80:22: note: uninitialized use occurs here i915_gem_object_put(import_obj); ^~~~~~~~~~ drivers/gpu/drm/i915/gem/selftests/i915_gem_dmabuf.c:63:2: note: remove the 'if' if its condition is always false if (import != &obj->base) { ^~~~~~~~~~~~~~~~~~~~~~~~~~~ drivers/gpu/drm/i915/gem/selftests/i915_gem_dmabuf.c:38:46: note: initialize the variable 'import_obj' to silence this warning struct drm_i915_gem_object *obj, *import_obj; ^ = NULL

Shuffle the import_obj initialization above these if statements so that it is not used uninitialized.

Fixes: d7b2cb380b3a ("drm/i915/gem: Correct the locking and pin pattern for dma-buf (v8)") Reported-by: Dan Carpenter dan.carpenter@oracle.com Signed-off-by: Nathan Chancellor nathan@kernel.org --- drivers/gpu/drm/i915/gem/selftests/i915_gem_dmabuf.c | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/i915/gem/selftests/i915_gem_dmabuf.c b/drivers/gpu/drm/i915/gem/selftests/i915_gem_dmabuf.c index ffae7df5e4d7..532c7955b300 100644 --- a/drivers/gpu/drm/i915/gem/selftests/i915_gem_dmabuf.c +++ b/drivers/gpu/drm/i915/gem/selftests/i915_gem_dmabuf.c @@ -59,13 +59,13 @@ static int igt_dmabuf_import_self(void *arg) err = PTR_ERR(import); goto out_dmabuf; } + import_obj = to_intel_bo(import);

if (import != &obj->base) { pr_err("i915_gem_prime_import created a new object!\n"); err = -EINVAL; goto out_import; } - import_obj = to_intel_bo(import);

i915_gem_object_lock(import_obj, NULL); err = __i915_gem_object_get_pages(import_obj); @@ -176,6 +176,7 @@ static int igt_dmabuf_import_same_driver(struct drm_i915_private *i915, err = PTR_ERR(import); goto out_dmabuf; } + import_obj = to_intel_bo(import);

if (import == &obj->base) { pr_err("i915_gem_prime_import reused gem object!\n"); @@ -183,8 +184,6 @@ static int igt_dmabuf_import_same_driver(struct drm_i915_private *i915, goto out_import; }

- import_obj = to_intel_bo(import); - i915_gem_object_lock(import_obj, NULL); err = __i915_gem_object_get_pages(import_obj); if (err) {

Clang warns:

drivers/gpu/drm/i915/gem/selftests/i915_gem_dmabuf.c:127:13: warning: variable 'err' is used uninitialized whenever 'if' condition is false [-Wsometimes-uninitialized] } else if (PTR_ERR(import) != -EOPNOTSUPP) { ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ drivers/gpu/drm/i915/gem/selftests/i915_gem_dmabuf.c:138:9: note: uninitialized use occurs here return err; ^~~ drivers/gpu/drm/i915/gem/selftests/i915_gem_dmabuf.c:127:9: note: remove the 'if' if its condition is always true } else if (PTR_ERR(import) != -EOPNOTSUPP) { ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ drivers/gpu/drm/i915/gem/selftests/i915_gem_dmabuf.c:95:9: note: initialize the variable 'err' to silence this warning int err; ^ = 0

The test is expected to pass if i915_gem_prime_import() returns -EOPNOTSUPP so initialize err to zero in this case.

Fixes: cdb35d1ed6d2 ("drm/i915/gem: Migrate to system at dma-buf attach time (v7)") Reported-by: Dan Carpenter dan.carpenter@oracle.com Signed-off-by: Nathan Chancellor nathan@kernel.org --- drivers/gpu/drm/i915/gem/selftests/i915_gem_dmabuf.c | 2 ++ 1 file changed, 2 insertions(+)

diff --git a/drivers/gpu/drm/i915/gem/selftests/i915_gem_dmabuf.c b/drivers/gpu/drm/i915/gem/selftests/i915_gem_dmabuf.c index 532c7955b300..4a6bb64c3a35 100644 --- a/drivers/gpu/drm/i915/gem/selftests/i915_gem_dmabuf.c +++ b/drivers/gpu/drm/i915/gem/selftests/i915_gem_dmabuf.c @@ -128,6 +128,8 @@ static int igt_dmabuf_import_same_driver_lmem(void *arg) pr_err("i915_gem_prime_import failed with the wrong err=%ld\n", PTR_ERR(import)); err = PTR_ERR(import); + } else { + err = 0; }

dma_buf_put(dmabuf);

This warning helps catch uninitialized variables. It should have been enabled at the same time as commit b2423184ac33 ("drm/i915: Enable -Wuninitialized") but I did not realize they were disabled separately. Enable it now that i915 is clean so that it stays that way.

Signed-off-by: Nathan Chancellor nathan@kernel.org --- drivers/gpu/drm/i915/Makefile | 1 - 1 file changed, 1 deletion(-)

diff --git a/drivers/gpu/drm/i915/Makefile b/drivers/gpu/drm/i915/Makefile index 642a5b5a1b81..335ba9f43d8f 100644 --- a/drivers/gpu/drm/i915/Makefile +++ b/drivers/gpu/drm/i915/Makefile @@ -19,7 +19,6 @@ subdir-ccflags-y += $(call cc-disable-warning, missing-field-initializers) subdir-ccflags-y += $(call cc-disable-warning, unused-but-set-variable) # clang warnings subdir-ccflags-y += $(call cc-disable-warning, sign-compare) -subdir-ccflags-y += $(call cc-disable-warning, sometimes-uninitialized) subdir-ccflags-y += $(call cc-disable-warning, initializer-overrides) subdir-ccflags-y += $(call cc-disable-warning, frame-address) subdir-ccflags-$(CONFIG_DRM_I915_WERROR) += -Werror