drm/i915: Prevent use-after-free in invalidate_range_start callback

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commit 460822b0b1 upstream.

It's possible for invalidate_range_start mmu notifier callback to race
against userptr object release. If the gem object was released prior to
obtaining the spinlock in invalidate_range_start we're hitting null
pointer dereference.

Testcase: igt/gem_userptr_blits/stress-mm-invalidate-close
Testcase: igt/gem_userptr_blits/stress-mm-invalidate-close-overlap
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Michał Winiarski <michal.winiarski@intel.com>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
[Jani: added code comment suggested by Chris]
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Sasha Levin <sasha.levin@oracle.com>

...

This commit is contained in:

Michał Winiarski 2015-02-03 15:48:17 +01:00 • committed by Sasha Levin

parent 4182c01b25

commit 5c8bf2b80c

1 changed files with 18 additions and 2 deletions

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drivers/gpu/drm/i915/i915_gem_userptr.c

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