Commit 9297ebf2 authored Mar 18, 2014 by Steven Rostedt Committed by Daniel Vetter Mar 19, 2014

drm/i915: Do not dereference pointers from ring buffer in evict event

The TP_printk() should never dereference any pointers, because the ring
buffer can be read at some unknown time in the future. If a device no
longer exists, it can cause a kernel oops. This also makes this
event useless when saving the ring buffer in userspaces tools such as
perf and trace-cmd.

The i915_gem_evict_vm dereferences the vm pointer which may also not
exist when the ring buffer is read sometime in the future.

Link: http://lkml.kernel.org/r/1395095198-20034-3-git-send-email-artagnon@gmail.com


Reported-by: Ramkumar Ramachandra <artagnon@gmail.com>
Cc: stable@vger.kernel.org # 3.13+
Fixes: bcccff84 "drm/i915: trace vm eviction instead of everything"
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
[danvet: Try to make it actually compile]
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

parent e5081a53

drivers/gpu/drm/i915/i915_trace.h

+3 −1

Original line number	Diff line number	Diff line
		@@ -238,14 +238,16 @@ TRACE_EVENT(i915_gem_evict_vm,
		TP_ARGS(vm),

		TP_STRUCT__entry(
		__field(u32, dev)
		__field(struct i915_address_space *, vm)
		),

		TP_fast_assign(
		__entry->dev = vm->dev->primary->index;
		__entry->vm = vm;
		),

		TP_printk("dev=%d, vm=%p", __entry->vm->dev->primary->index, __entry->vm)
		TP_printk("dev=%d, vm=%p", __entry->dev, __entry->vm)
		);

		TRACE_EVENT(i915_gem_ring_sync_to,