On Mon, Jun 20, 2016 at 05:42:46PM +0100, Matthew Auld wrote: > The drm_pending_event can be freed by drm_send_event_locked, as a > result we should call trace_drm_vblank_event_delivered before this > to avoid hitting a user-after-free error when accessing the pid member: > > [ 378.438497] BUG: KASAN: use-after-free in send_vblank_event+0xf0/0x310 [drm] at addr ffff8801ac7e50a0 > [ 378.438500] Read of size 4 by task Xorg/1562 > [ 378.438501] ============================================================================= > [ 378.438504] BUG kmalloc-128 (Tainted: G B ): kasan: bad access detected > [ 378.438506] ----------------------------------------------------------------------------- > > [ 378.438509] INFO: Freed in 0x10001309c age=18446737369265680575 cpu=0 pid=0 > [ 378.438541] drm_send_event_locked+0x207/0x2f0 [drm] > [ 378.438544] __slab_free+0x24c/0x650 > [ 378.438546] kfree+0x3a2/0x760 > [ 378.438578] drm_send_event_locked+0x207/0x2f0 [drm] > [ 378.438610] send_vblank_event+0xb7/0x310 [drm] > [ 378.438643] drm_crtc_send_vblank_event+0x130/0x1f0 [drm] > [ 378.438722] intel_atomic_commit_tail+0x23b5/0x53f0 [i915] > [ 378.438802] intel_atomic_commit+0xbae/0x12f0 [i915] > [ 378.438839] drm_atomic_commit+0xb0/0x120 [drm] > [ 378.438855] drm_atomic_helper_connector_dpms+0x339/0x5d0 [drm_kms_helper] > [ 378.438891] drm_mode_obj_set_property_ioctl+0x8f1/0xcc0 [drm] > [ 378.438927] drm_mode_connector_property_set_ioctl+0xf3/0x170 [drm] > [ 378.438959] drm_ioctl+0x2d7/0xae0 [drm] > [ 378.438962] do_vfs_ioctl+0x1c9/0x1280 > [ 378.438964] SyS_ioctl+0x79/0x90 > [ 378.438967] entry_SYSCALL_64_fastpath+0x1a/0xa4 > > Cc: dri-devel@xxxxxxxxxxxxxxxxxxxxx > Cc: Daniel Vetter <daniel.vetter@xxxxxxxxx> > Signed-off-by: Matthew Auld <matthew.auld@xxxxxxxxx> Nice catch, applied to drm-misc. Thanks, Daniel > --- > drivers/gpu/drm/drm_irq.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/drivers/gpu/drm/drm_irq.c b/drivers/gpu/drm/drm_irq.c > index 76e39c5..8ca3d2b 100644 > --- a/drivers/gpu/drm/drm_irq.c > +++ b/drivers/gpu/drm/drm_irq.c > @@ -994,10 +994,10 @@ static void send_vblank_event(struct drm_device *dev, > e->event.tv_sec = now->tv_sec; > e->event.tv_usec = now->tv_usec; > > - drm_send_event_locked(dev, &e->base); > - > trace_drm_vblank_event_delivered(e->base.pid, e->pipe, > e->event.sequence); > + > + drm_send_event_locked(dev, &e->base); > } > > /** > -- > 2.5.5 > > _______________________________________________ > Intel-gfx mailing list > Intel-gfx@xxxxxxxxxxxxxxxxxxxxx > https://lists.freedesktop.org/mailman/listinfo/intel-gfx -- Daniel Vetter Software Engineer, Intel Corporation http://blog.ffwll.ch _______________________________________________ Intel-gfx mailing list Intel-gfx@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/intel-gfx
