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Michel Dänzer
9be8dc35bc
commit 7f43ef9f0d upstream.
Fixes the BUG_ON spuriously triggering under the following
circumstances:
* reservation_object_reserve_shared is called with shared_count ==
shared_max - 1, so obj->staged is freed in preparation of an in-place
update.
* reservation_object_add_shared_fence is called with the first fence,
after which shared_count == shared_max.
* reservation_object_add_shared_fence is called with a follow-up fence
from the same context.
In the second reservation_object_add_shared_fence call, the BUG_ON
triggers. However, nothing bad would happen in
reservation_object_add_shared_inplace, since both fences are from the
same context, so they only occupy a single slot.
Prevent this by moving the BUG_ON to where an overflow would actually
happen (e.g. if a buggy caller didn't call
reservation_object_reserve_shared before).
v2:
* Fix description of breaking scenario (Christian König)
* Add bugzilla reference
Cc: stable@vger.kernel.org
Bugzilla: https://bugs.freedesktop.org/106418
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk> # v1
Reviewed-by: Christian König <christian.koenig@amd.com> # v1
Signed-off-by: Michel Dänzer <michel.daenzer@amd.com>
Signed-off-by: Sumit Semwal <sumit.semwal@linaro.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20180704151405.10357-1-michel@daenzer.net
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Linux kernel
============
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https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
See Documentation/00-INDEX for a list of what is contained in each file.
Please read the Documentation/process/changes.rst file, as it contains the
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the problems which may result by upgrading your kernel.