From: Daniel Vetter <daniel.vetter@ffwll.ch>
To: DRI Development <dri-devel@lists.freedesktop.org>
Cc: Sean Paul <sean@poorly.run>,
Daniel Vetter <daniel.vetter@ffwll.ch>,
linux-arm-msm@vger.kernel.org,
Daniel Vetter <daniel.vetter@intel.com>,
freedreno@lists.freedesktop.org
Subject: [PATCH] drm/msm: Don't call dma_buf_vunmap without _vmap
Date: Thu, 14 May 2020 22:11:17 +0200 [thread overview]
Message-ID: <20200514201117.465146-1-daniel.vetter@ffwll.ch> (raw)
In-Reply-To: <20200511093554.211493-2-daniel.vetter@ffwll.ch>
I honestly don't exactly understand what's going on here, but the
current code is wrong for sure: It calls dma_buf_vunmap without ever
calling dma_buf_vmap.
What I'm not sure about is whether the WARN_ON is correct:
- msm imports dma-buf using drm_prime_sg_to_page_addr_arrays. Which is
a pretty neat layering violation of how you shouldn't peek behind
the curtain of the dma-buf exporter, but par for course. Note that
all the nice new helpers don't (and we should probably have a bit a
warning about this in the kerneldoc).
- but then in the get_vaddr() in msm_gem.c, we seems to happily wrap a
vmap() around any object with ->pages set (so including imported
dma-buf).
- I'm not seeing any guarantees that userspace can't use an imported
dma-buf for e.g. MSM_SUBMIT_CMD_BUF in a5xx_submit_in_rb, so no
guarantees that an imported dma-buf won't end up with a ->vaddr set.
But even if that WARN_ON is wrong, cleaning up a vmap() done by msm by
calling dma_buf_vunmap is the wrong thing to do.
v2: Rob said in review that we do indeed have a gap in get_vaddr() that
needs to be plugged. But the users I've found aren't legit users on
imported dma-buf, so we can just reject that.
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Cc: Rob Clark <robdclark@gmail.com>
Cc: Sean Paul <sean@poorly.run>
Cc: linux-arm-msm@vger.kernel.org
Cc: freedreno@lists.freedesktop.org
---
drivers/gpu/drm/msm/msm_gem.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)
diff --git a/drivers/gpu/drm/msm/msm_gem.c b/drivers/gpu/drm/msm/msm_gem.c
index 5a6a79fbc9d6..e70abd1cde43 100644
--- a/drivers/gpu/drm/msm/msm_gem.c
+++ b/drivers/gpu/drm/msm/msm_gem.c
@@ -554,6 +554,9 @@ static void *get_vaddr(struct drm_gem_object *obj, unsigned madv)
struct msm_gem_object *msm_obj = to_msm_bo(obj);
int ret = 0;
+ if (obj->import_attach)
+ return ERR_PTR(-ENODEV);
+
mutex_lock(&msm_obj->lock);
if (WARN_ON(msm_obj->madv > madv)) {
@@ -907,8 +910,7 @@ static void free_object(struct msm_gem_object *msm_obj)
put_iova(obj);
if (obj->import_attach) {
- if (msm_obj->vaddr)
- dma_buf_vunmap(obj->import_attach->dmabuf, msm_obj->vaddr);
+ WARN_ON(msm_obj->vaddr);
/* Don't drop the pages for imported dmabuf, as they are not
* ours, just free the array we allocated:
--
2.26.2
_______________________________________________
dri-devel mailing list
dri-devel@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/dri-devel
next prev parent reply other threads:[~2020-05-14 20:11 UTC|newest]
Thread overview: 51+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-05-11 9:35 [PATCH 0/9] shmem helper untangling Daniel Vetter
2020-05-11 9:35 ` [PATCH 1/9] drm/msm: Don't call dma_buf_vunmap without _vmap Daniel Vetter
2020-05-11 15:24 ` Rob Clark
2020-05-11 15:28 ` Daniel Vetter
2020-05-11 20:36 ` Rob Clark
2020-05-14 20:11 ` Daniel Vetter [this message]
2020-05-28 8:29 ` [PATCH] " Daniel Vetter
2020-05-31 16:02 ` Rob Clark
2020-06-03 12:46 ` Daniel Vetter
2020-05-11 9:35 ` [PATCH 2/9] drm/gem: WARN if drm_gem_get_pages is called on a private obj Daniel Vetter
2020-05-14 7:45 ` Thomas Zimmermann
2020-05-11 9:35 ` [PATCH 3/9] drm/doc: Some polish for shmem helpers Daniel Vetter
2020-05-11 11:12 ` Thomas Zimmermann
2020-05-14 20:05 ` Daniel Vetter
2020-05-15 6:26 ` Thomas Zimmermann
2020-05-11 9:35 ` [PATCH 4/9] drm/virtio: Call the right " Daniel Vetter
2020-05-14 7:46 ` Thomas Zimmermann
2020-05-11 9:35 ` [PATCH 5/9] drm/udl: Don't call get/put_pages on imported dma-buf Daniel Vetter
2020-05-11 11:23 ` Thomas Zimmermann
2020-05-11 11:37 ` Daniel Vetter
2020-05-11 12:04 ` Thomas Zimmermann
2020-05-14 7:25 ` Thomas Zimmermann
2020-05-14 12:47 ` Daniel Vetter
2020-06-03 12:57 ` Daniel Vetter
2020-05-11 9:35 ` [PATCH 6/9] drm/shmem-helpers: Don't call get/put_pages on imported dma-buf in vmap Daniel Vetter
2020-05-14 7:16 ` Thomas Zimmermann
2020-05-14 12:49 ` Daniel Vetter
2020-05-14 20:22 ` [PATCH] " Daniel Vetter
2020-05-11 9:35 ` [PATCH 7/9] drm/shmem-helpers: Redirect mmap for imported dma-buf Daniel Vetter
2020-05-14 7:23 ` Thomas Zimmermann
2020-05-14 12:47 ` Daniel Vetter
2020-05-27 18:32 ` Thomas Zimmermann
2020-05-27 19:34 ` Daniel Vetter
2020-05-28 12:53 ` Thomas Zimmermann
2020-05-11 9:35 ` [PATCH 8/9] drm/shmem-helpers: Ensure get_pages is not called on " Daniel Vetter
2020-05-14 7:30 ` Thomas Zimmermann
2020-06-03 13:12 ` Daniel Vetter
2020-06-08 14:40 ` Thomas Zimmermann
2020-06-08 15:04 ` Daniel Vetter
2020-05-11 9:35 ` [PATCH 9/9] drm/shmem-helpers: Simplify dma-buf importing Daniel Vetter
2020-05-14 7:44 ` Thomas Zimmermann
2020-05-14 12:55 ` Daniel Vetter
2020-05-14 15:26 ` Thomas Zimmermann
2020-05-20 18:02 ` [PATCH] " Daniel Vetter
2020-05-29 13:34 ` Boris Brezillon
2020-05-29 13:35 ` Boris Brezillon
2020-05-29 13:49 ` Boris Brezillon
2020-05-29 14:05 ` Daniel Vetter
2020-05-29 14:36 ` Boris Brezillon
2020-06-15 8:23 ` [PATCH 9/9] " Thomas Zimmermann
2020-05-29 13:52 ` [PATCH 0/9] shmem helper untangling Boris Brezillon
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20200514201117.465146-1-daniel.vetter@ffwll.ch \
--to=daniel.vetter@ffwll.ch \
--cc=daniel.vetter@intel.com \
--cc=dri-devel@lists.freedesktop.org \
--cc=freedreno@lists.freedesktop.org \
--cc=linux-arm-msm@vger.kernel.org \
--cc=sean@poorly.run \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).