| From 9297ebf29ad9118edd6c0fedc84f03e35028827d Mon Sep 17 00:00:00 2001 |
| From: Steven Rostedt <rostedt@goodmis.org> |
| Date: Tue, 18 Mar 2014 11:27:37 -0400 |
| Subject: drm/i915: Do not dereference pointers from ring buffer in evict event |
| |
| From: Steven Rostedt <rostedt@goodmis.org> |
| |
| commit 9297ebf29ad9118edd6c0fedc84f03e35028827d upstream. |
| |
| 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> |
| Fixes: bcccff847d1f "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> |
| Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| |
| --- |
| drivers/gpu/drm/i915/i915_trace.h | 4 +++- |
| 1 file changed, 3 insertions(+), 1 deletion(-) |
| |
| --- a/drivers/gpu/drm/i915/i915_trace.h |
| +++ b/drivers/gpu/drm/i915/i915_trace.h |
| @@ -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, |
