| From 5351fbb1bf1413f6024892093528280769ca852f Mon Sep 17 00:00:00 2001 |
| From: Andrey Ryabinin <aryabinin@virtuozzo.com> |
| Date: Thu, 26 Jan 2017 17:32:11 +0300 |
| Subject: drm/i915: fix use-after-free in page_flip_completed() |
| |
| From: Andrey Ryabinin <aryabinin@virtuozzo.com> |
| |
| commit 5351fbb1bf1413f6024892093528280769ca852f upstream. |
| |
| page_flip_completed() dereferences 'work' variable after executing |
| queue_work(). This is not safe as the 'work' item might be already freed |
| by queued work: |
| |
| BUG: KASAN: use-after-free in page_flip_completed+0x3ff/0x490 at addr ffff8803dc010f90 |
| Call Trace: |
| __asan_report_load8_noabort+0x59/0x80 |
| page_flip_completed+0x3ff/0x490 |
| intel_finish_page_flip_mmio+0xe3/0x130 |
| intel_pipe_handle_vblank+0x2d/0x40 |
| gen8_irq_handler+0x4a7/0xed0 |
| __handle_irq_event_percpu+0xf6/0x860 |
| handle_irq_event_percpu+0x6b/0x160 |
| handle_irq_event+0xc7/0x1b0 |
| handle_edge_irq+0x1f4/0xa50 |
| handle_irq+0x41/0x70 |
| do_IRQ+0x9a/0x200 |
| common_interrupt+0x89/0x89 |
| |
| Freed: |
| kfree+0x113/0x4d0 |
| intel_unpin_work_fn+0x29a/0x3b0 |
| process_one_work+0x79e/0x1b70 |
| worker_thread+0x611/0x1460 |
| kthread+0x241/0x3a0 |
| ret_from_fork+0x27/0x40 |
| |
| Move queue_work() after trace_i915_flip_complete() to fix this. |
| |
| Fixes: e5510fac98a7 ("drm/i915: add tracepoints for flip requests & completions") |
| Signed-off-by: Andrey Ryabinin <aryabinin@virtuozzo.com> |
| Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk> |
| Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch> |
| Link: http://patchwork.freedesktop.org/patch/msgid/20170126143211.24013-1-aryabinin@virtuozzo.com |
| (cherry picked from commit 05c41f926fcc7ef838c80a6a99d84f67b4e0b824) |
| Signed-off-by: Jani Nikula <jani.nikula@intel.com> |
| Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| |
| --- |
| drivers/gpu/drm/i915/intel_display.c | 4 ++-- |
| 1 file changed, 2 insertions(+), 2 deletions(-) |
| |
| --- a/drivers/gpu/drm/i915/intel_display.c |
| +++ b/drivers/gpu/drm/i915/intel_display.c |
| @@ -4280,10 +4280,10 @@ static void page_flip_completed(struct i |
| drm_crtc_vblank_put(&intel_crtc->base); |
| |
| wake_up_all(&dev_priv->pending_flip_queue); |
| - queue_work(dev_priv->wq, &work->unpin_work); |
| - |
| trace_i915_flip_complete(intel_crtc->plane, |
| work->pending_flip_obj); |
| + |
| + queue_work(dev_priv->wq, &work->unpin_work); |
| } |
| |
| static int intel_crtc_wait_for_pending_flips(struct drm_crtc *crtc) |