On Thu, Jan 26, 2017 at 05:32:11PM +0300, Andrey Ryabinin wrote:
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>
That's old, and indeed does seem to be present from that commit and not
exposed by something later.
Cc: <
stable@vger.kernel.org> # v2.6.36+
Reviewed-by: Chris Wilson <
chris@chris-wilson.co.uk>
-Chris
--
Chris Wilson, Intel Open Source Technology Centre
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