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

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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: bcccff847d "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>
This commit is contained in:
Steven Rostedt 2014-03-18 11:27:37 -04:00 committed by Daniel Vetter
parent e5081a538a
commit 9297ebf29a
1 changed files with 3 additions and 1 deletions
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4
drivers/gpu/drm/i915/i915_trace.h
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@ -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,