The patch below does not apply to the 6.1-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.1.y git checkout FETCH_HEAD git cherry-pick -x f9e96bf1905479f18e83a3a4c314a8dfa56ede2c # <resolve conflicts, build, test, etc.> git commit -s git send-email --to 'stable@vger.kernel.org' --in-reply-to '2023082736-canal-swimsuit-6b7b@gregkh' --subject-prefix 'PATCH 6.1.y' HEAD^..

Possible dependencies:

f9e96bf19054 ("drm/vmwgfx: Fix possible invalid drm gem put calls") 9ef8d83e8e25 ("drm/vmwgfx: Do not drop the reference to the handle too soon") 668b206601c5 ("drm/vmwgfx: Stop using raw ttm_buffer_object's") 39985eea5a6d ("drm/vmwgfx: Abstract placement selection") e0029da927fa ("drm/vmwgfx: Rename dummy to is_iomem") cb8097a45da1 ("drm/vmwgfx: Cleanup the vmw bo usage in the cursor paths") 6703e28f976d ("drm/vmwgfx: Simplify fb pinning") 09881d2940bb ("drm/vmwgfx: Rename vmw_buffer_object to vmw_bo") 6b2e8aa45126 ("drm/vmwgfx: Remove the duplicate bo_free function") f87c1f0b7b79 ("drm/ttm: prevent moving of pinned BOs") aebd8f0c6f82 ("Merge v6.2-rc6 into drm-next")

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From f9e96bf1905479f18e83a3a4c314a8dfa56ede2c Mon Sep 17 00:00:00 2001 From: Zack Rusin zackr@vmware.com Date: Fri, 18 Aug 2023 00:13:01 -0400 Subject: [PATCH] drm/vmwgfx: Fix possible invalid drm gem put calls

vmw_bo_unreference sets the input buffer to null on exit, resulting in null ptr deref's on the subsequent drm gem put calls.

This went unnoticed because only very old userspace would be exercising those paths but it wouldn't be hard to hit on old distros with brand new kernels.

Introduce a new function that abstracts unrefing of user bo's to make the code cleaner and more explicit.

Signed-off-by: Zack Rusin zackr@vmware.com Reported-by: Ian Forbes iforbes@vmware.com Fixes: 9ef8d83e8e25 ("drm/vmwgfx: Do not drop the reference to the handle too soon") Cc: stable@vger.kernel.org # v6.4+ Reviewed-by: Maaz Mombasawalamombasawalam@vmware.com Link: https://patchwork.freedesktop.org/patch/msgid/20230818041301.407636-1-zack@k...

diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_bo.c b/drivers/gpu/drm/vmwgfx/vmwgfx_bo.c index 82094c137855..c43853597776 100644 --- a/drivers/gpu/drm/vmwgfx/vmwgfx_bo.c +++ b/drivers/gpu/drm/vmwgfx/vmwgfx_bo.c @@ -497,10 +497,9 @@ static int vmw_user_bo_synccpu_release(struct drm_file *filp, if (!(flags & drm_vmw_synccpu_allow_cs)) { atomic_dec(&vmw_bo->cpu_writers); } - ttm_bo_put(&vmw_bo->tbo); + vmw_user_bo_unref(vmw_bo); }

- drm_gem_object_put(&vmw_bo->tbo.base); return ret; }

@@ -540,8 +539,7 @@ int vmw_user_bo_synccpu_ioctl(struct drm_device *dev, void *data, return ret;

ret = vmw_user_bo_synccpu_grab(vbo, arg->flags); - vmw_bo_unreference(&vbo); - drm_gem_object_put(&vbo->tbo.base); + vmw_user_bo_unref(vbo); if (unlikely(ret != 0)) { if (ret == -ERESTARTSYS || ret == -EBUSY) return -EBUSY; diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_bo.h b/drivers/gpu/drm/vmwgfx/vmwgfx_bo.h index 50a836e70994..1d433fceed3d 100644 --- a/drivers/gpu/drm/vmwgfx/vmwgfx_bo.h +++ b/drivers/gpu/drm/vmwgfx/vmwgfx_bo.h @@ -195,6 +195,14 @@ static inline struct vmw_bo *vmw_bo_reference(struct vmw_bo *buf) return buf; }

+static inline void vmw_user_bo_unref(struct vmw_bo *vbo) +{ + if (vbo) { + ttm_bo_put(&vbo->tbo); + drm_gem_object_put(&vbo->tbo.base); + } +} + static inline struct vmw_bo *to_vmw_bo(struct drm_gem_object *gobj) { return container_of((gobj), struct vmw_bo, tbo.base); diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_execbuf.c b/drivers/gpu/drm/vmwgfx/vmwgfx_execbuf.c index d30c0e3d3ab7..98e0723ca6f5 100644 --- a/drivers/gpu/drm/vmwgfx/vmwgfx_execbuf.c +++ b/drivers/gpu/drm/vmwgfx/vmwgfx_execbuf.c @@ -1164,8 +1164,7 @@ static int vmw_translate_mob_ptr(struct vmw_private *dev_priv, } vmw_bo_placement_set(vmw_bo, VMW_BO_DOMAIN_MOB, VMW_BO_DOMAIN_MOB); ret = vmw_validation_add_bo(sw_context->ctx, vmw_bo); - ttm_bo_put(&vmw_bo->tbo); - drm_gem_object_put(&vmw_bo->tbo.base); + vmw_user_bo_unref(vmw_bo); if (unlikely(ret != 0)) return ret;

@@ -1221,8 +1220,7 @@ static int vmw_translate_guest_ptr(struct vmw_private *dev_priv, vmw_bo_placement_set(vmw_bo, VMW_BO_DOMAIN_GMR | VMW_BO_DOMAIN_VRAM, VMW_BO_DOMAIN_GMR | VMW_BO_DOMAIN_VRAM); ret = vmw_validation_add_bo(sw_context->ctx, vmw_bo); - ttm_bo_put(&vmw_bo->tbo); - drm_gem_object_put(&vmw_bo->tbo.base); + vmw_user_bo_unref(vmw_bo); if (unlikely(ret != 0)) return ret;

diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_kms.c b/drivers/gpu/drm/vmwgfx/vmwgfx_kms.c index b62207be3363..1489ad73c103 100644 --- a/drivers/gpu/drm/vmwgfx/vmwgfx_kms.c +++ b/drivers/gpu/drm/vmwgfx/vmwgfx_kms.c @@ -1665,10 +1665,8 @@ static struct drm_framebuffer *vmw_kms_fb_create(struct drm_device *dev,

err_out: /* vmw_user_lookup_handle takes one ref so does new_fb */ - if (bo) { - vmw_bo_unreference(&bo); - drm_gem_object_put(&bo->tbo.base); - } + if (bo) + vmw_user_bo_unref(bo); if (surface) vmw_surface_unreference(&surface);

diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_overlay.c b/drivers/gpu/drm/vmwgfx/vmwgfx_overlay.c index 7e112319a23c..fb85f244c3d0 100644 --- a/drivers/gpu/drm/vmwgfx/vmwgfx_overlay.c +++ b/drivers/gpu/drm/vmwgfx/vmwgfx_overlay.c @@ -451,8 +451,7 @@ int vmw_overlay_ioctl(struct drm_device *dev, void *data,

ret = vmw_overlay_update_stream(dev_priv, buf, arg, true);

- vmw_bo_unreference(&buf); - drm_gem_object_put(&buf->tbo.base); + vmw_user_bo_unref(buf);

out_unlock: mutex_unlock(&overlay->mutex); diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_shader.c b/drivers/gpu/drm/vmwgfx/vmwgfx_shader.c index e7226db8b242..1e81ff2422cf 100644 --- a/drivers/gpu/drm/vmwgfx/vmwgfx_shader.c +++ b/drivers/gpu/drm/vmwgfx/vmwgfx_shader.c @@ -809,8 +809,7 @@ static int vmw_shader_define(struct drm_device *dev, struct drm_file *file_priv, shader_type, num_input_sig, num_output_sig, tfile, shader_handle); out_bad_arg: - vmw_bo_unreference(&buffer); - drm_gem_object_put(&buffer->tbo.base); + vmw_user_bo_unref(buffer); return ret; }