]> git.proxmox.com Git - mirror_ubuntu-disco-kernel.git/commit
mm: bootmem: fix checking the bitmap when finally freeing bootmem
authorGavin Shan <shangw@linux.vnet.ibm.com>
Tue, 29 May 2012 22:06:32 +0000 (15:06 -0700)
committerLinus Torvalds <torvalds@linux-foundation.org>
Tue, 29 May 2012 23:22:21 +0000 (16:22 -0700)
commit6dccdcbe2c3ebe152847ac8507e7bded4e3f4546
tree32d748a8b981e98b64547ab8a7064453b7686334
parent955c1cd7401565671b064e499115344ec8067dfd
mm: bootmem: fix checking the bitmap when finally freeing bootmem

When bootmem releases an unaligned chunk of memory at the beginning of a
node to the page allocator, it iterates from that unaligned PFN but
checks an aligned word of the page bitmap.  The checked bits do not
correspond to the PFNs and, as a result, reserved pages can be freed.

Properly shift the bitmap word so that the lowest bit corresponds to the
starting PFN before entering the freeing loop.

This bug has been around since commit 41546c17418f ("bootmem: clean up
free_all_bootmem_core") (2.6.27) without known reports.

Signed-off-by: Gavin Shan <shangw@linux.vnet.ibm.com>
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Tejun Heo <tj@kernel.org>
Acked-by: David S. Miller <davem@davemloft.net>
Cc: Yinghai Lu <yinghai@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
mm/bootmem.c