On Wed, Aug 12, 2026 at 06:45:46PM +0200, Melissa Wen wrote: > > > On 29/07/2026 08:10, Thadeu Lima de Souza Cascardo wrote: > > When an out_fence_ptr is provided but DRM_MODE_PAGE_FLIP_EVENT is not > > set, a drm_pending_vblank_event will be allocated. If later, there is an > > allocation failure or another failure at setup_out_fence(), that event > > will not have base.fence set and it will not be released at > > complete_signaling(). > > > > Release the event and set crtc_state->event to NULL just like in the > > DRM_MODE_PAGE_FLIP_EVENT case when there is a failure at > > drm_event_reserve_init(). That is, prepare_signaling() releases the > > event and there is nothing to be done at complete_signaling(). Use > > drm_event_cancel_free() as that will also undo drm_event_reserve_init() > > in case it has been called. > Hey, > > Nice catch! > > Reported-by: [email protected] > > Take this with a grain of salt: I think checkpatch will complain about > reporter > as just an email. I usually use: > `Reported-by: Sashiko <[email protected]>` but not 100% sure.
Neither b4 prep --check or directly calling checkpatch complain about it. And I noticed some other occurences of applied commits with only the email address. > > Closes: > > https://sashiko.dev/#/patchset/20260727-drm_crtc_atomic_commit_leak-v1-1-23d9948a9...@igalia.com?part=1 > > Fixes: 92c715fca907 ("drm/atomic: Fix double free in > > drm_atomic_state_default_clear") > > Signed-off-by: Thadeu Lima de Souza Cascardo <[email protected]> > > --- > > Changes in v2: > > - Fix UAF when DRM_MODE_PAGE_FLIP_EVENT is used. > > - Link to v1: > > https://patch.msgid.link/20260728-drm_pending_vblank_event_leak-v1-1-08429b920...@igalia.com > > --- > > drivers/gpu/drm/drm_atomic_uapi.c | 13 +++++++++++-- > > 1 file changed, 11 insertions(+), 2 deletions(-) > > > > diff --git a/drivers/gpu/drm/drm_atomic_uapi.c > > b/drivers/gpu/drm/drm_atomic_uapi.c > > index 1050dddadb17..aed6040182eb 100644 > > --- a/drivers/gpu/drm/drm_atomic_uapi.c > > +++ b/drivers/gpu/drm/drm_atomic_uapi.c > > @@ -1464,11 +1464,15 @@ static int prepare_signaling(struct drm_device *dev, > > if (fence_ptr) { > > struct dma_fence *fence; > > struct drm_out_fence_state *f; > > + struct drm_pending_vblank_event *e = crtc_state->event; > > f = krealloc(*fence_state, sizeof(**fence_state) * > > (*num_fences + 1), GFP_KERNEL); > > - if (!f) > > + if (!f) { > > + drm_event_cancel_free(dev, &e->base); > > + crtc_state->event = NULL; > > return -ENOMEM; > > + } > > memset(&f[*num_fences], 0, sizeof(*f)); > > @@ -1476,12 +1480,17 @@ static int prepare_signaling(struct drm_device *dev, > > *fence_state = f; > > fence = drm_crtc_create_fence(crtc); > > - if (!fence) > > + if (!fence) { > > + drm_event_cancel_free(dev, &e->base); > > + crtc_state->event = NULL; > > return -ENOMEM; > > + } > > ret = setup_out_fence(&f[(*num_fences)++], fence); > > if (ret) { > > dma_fence_put(fence); > > + drm_event_cancel_free(dev, &e->base); > > + crtc_state->event = NULL; > > How about to goto a single error handle instead of repeating those three > lines > three times? I think it'd be better for maintenance, but the fix looks > correct as is: I have tested a fix with an error label and I am going to send it as a v3. Let me know what you think about it. Thanks. Cascardo. > > Reviewed-by: Melissa Wen <[email protected]> > > > return ret; > > } > > > > --- > > base-commit: df0311845915442ab75d03ee89fb443b444c1370 > > change-id: 20260728-drm_pending_vblank_event_leak-a36cedb296ba > > > > Best regards, > > -- > > Thadeu Lima de Souza Cascardo <[email protected]> > > >
