]> git.proxmox.com Git - mirror_ubuntu-kernels.git/commit
mm/swap: fix race on swap_info reuse between swapoff and swapon
authorWeijie Yang <weijie.yang@samsung.com>
Thu, 6 Feb 2014 20:04:23 +0000 (12:04 -0800)
committerLinus Torvalds <torvalds@linux-foundation.org>
Thu, 6 Feb 2014 21:48:51 +0000 (13:48 -0800)
commitf893ab41e4dae2fe8991faf5d86d029068d1ef3a
tree6cde60539b7c64f11381a58d8c07112f0e7d5d5f
parent579f82901f6f41256642936d7e632f3979ad76d4
mm/swap: fix race on swap_info reuse between swapoff and swapon

swapoff clear swap_info's SWP_USED flag prematurely and free its
resources after that.  A concurrent swapon will reuse this swap_info
while its previous resources are not cleared completely.

These late freed resources are:
 - p->percpu_cluster
 - swap_cgroup_ctrl[type]
 - block_device setting
 - inode->i_flags &= ~S_SWAPFILE

This patch clears the SWP_USED flag after all its resources are freed,
so that swapon can reuse this swap_info by alloc_swap_info() safely.

[akpm@linux-foundation.org: tidy up code comment]
Signed-off-by: Weijie Yang <weijie.yang@samsung.com>
Acked-by: Hugh Dickins <hughd@google.com>
Cc: Krzysztof Kozlowski <k.kozlowski@samsung.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
mm/swapfile.c