percpu: fix pcpu_alloc_pages() failure path
authorTejun Heo <tj@kernel.org>
Fri, 15 Aug 2014 20:06:06 +0000 (16:06 -0400)
committerTejun Heo <tj@kernel.org>
Fri, 15 Aug 2014 20:06:06 +0000 (16:06 -0400)
commitf0d279654dea22b7a6ad34b9334aee80cda62cde
treea4f81f1c04ffced7ac5a5630487d27d575a181c8
parentc9d26423e56ce1ab4d786f92aebecf859d419293
percpu: fix pcpu_alloc_pages() failure path

When pcpu_alloc_pages() fails midway, pcpu_free_pages() is invoked to
free what has already been allocated.  The invocation is across the
whole requested range and pcpu_free_pages() will try to free all
non-NULL pages; unfortunately, this is incorrect as
pcpu_get_pages_and_bitmap(), unlike what its comment suggests, doesn't
clear the pages array and thus the array may have entries from the
previous invocations making the partial failure path free incorrect
pages.

Fix it by open-coding the partial freeing of the already allocated
pages.

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: stable@vger.kernel.org
mm/percpu-vm.c