From: Benjamin LaHaise Date: Mon, 9 Sep 2013 15:57:59 +0000 (-0400) Subject: aio: fix race in ring buffer page lookup introduced by page migration support X-Git-Tag: v3.12-rc1~16^2~1 X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=d6c355c7dabcd753a75bc77d150d36328a355267;p=pandora-kernel.git aio: fix race in ring buffer page lookup introduced by page migration support Prior to the introduction of page migration support in "fs/aio: Add support to aio ring pages migration" / 36bc08cc01709b4a9bb563b35aa530241ddc63e3, mapping of the ring buffer pages was done via get_user_pages() while retaining mmap_sem held for write. This avoided possible races with userland racing an munmap() or mremap(). The page migration patch, however, switched to using mm_populate() to prime the page mapping. mm_populate() cannot be called with mmap_sem held. Instead of dropping the mmap_sem, revert to the old behaviour and simply drop the use of mm_populate() since get_user_pages() will cause the pages to get mapped anyways. Thanks to Al Viro for spotting this issue. Signed-off-by: Benjamin LaHaise --- Reading git-diff-tree failed