W dniu 15.04.2020 o 20:33, Daniel Vetter pisze:
On Wed, Apr 15, 2020 at 7:19 PM Andrzej Pietrasiewicz <andrzej.p@xxxxxxxxxxxxx> wrote:drm_gem_fb_init() is passed the fb and never allocates it, so it should be not the one freeing it. As it is now the second call to kfree() is possible with the same fb. Coverity reported the following: *** CID 1492613: Memory - corruptions (USE_AFTER_FREE) /drivers/gpu/drm/drm_gem_framebuffer_helper.c: 230 in drm_gem_fb_create_with_funcs() 224 fb = kzalloc(sizeof(*fb), GFP_KERNEL); 225 if (!fb) 226 return ERR_PTR(-ENOMEM); 227 228 ret = drm_gem_fb_init_with_funcs(dev, fb, file, mode_cmd, funcs); 229 if (ret) { vvv CID 1492613: Memory - corruptions (USE_AFTER_FREE) vvv Calling "kfree" frees pointer "fb" which has already been freed. [Note: The source code implementation of the function has been overridden by a user model.] 230 kfree(fb); 231 return ERR_PTR(ret); 232 } 233 234 return fb; 235 } drm_gem_fb_init_with_funcs() calls drm_gem_fb_init() drm_gem_fb_init() calls kfree(fb) Reported-by: coverity-bot <keescook+coverity-bot@xxxxxxxxxxxx> Addresses-Coverity-ID: 1492613 ("Memory - corruptions") Fixes: f2b816d78a94 ("drm/core: Allow drivers allocate a subclass of struct drm_framebuffer") Signed-off-by: Andrzej Pietrasiewicz <andrzej.p@xxxxxxxxxxxxx>Reviewed-by: Daniel Vetter <daniel.vetter@xxxxxxxx>--- drivers/gpu/drm/drm_gem_framebuffer_helper.c | 4 +--- 1 file changed, 1 insertion(+), 3 deletions(-) diff --git a/drivers/gpu/drm/drm_gem_framebuffer_helper.c b/drivers/gpu/drm/drm_gem_framebuffer_helper.c index cac15294aef6..ccc2c71fa491 100644 --- a/drivers/gpu/drm/drm_gem_framebuffer_helper.c +++ b/drivers/gpu/drm/drm_gem_framebuffer_helper.c @@ -76,10 +76,8 @@ drm_gem_fb_init(struct drm_device *dev, fb->obj[i] = obj[i]; ret = drm_framebuffer_init(dev, fb, funcs); - if (ret) { + if (ret) drm_err(dev, "Failed to init framebuffer: %d\n", ret); - kfree(fb); - } return ret; } -- 2.17.1
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