1. 10 7月, 2012 38 次提交
  2. 09 7月, 2012 2 次提交
    • M
      virtio-balloon: fix add/get API use · 9c378abc
      Michael S. Tsirkin 提交于
      Since ee7cd898 'virtio: expose added
      descriptors immediately.', in virtio balloon virtqueue_get_buf might
      now run concurrently with virtqueue_kick.  I audited both and this
      seems safe in practice but this is not guaranteed by the API.
      Additionally, a spurious interrupt might in theory make
      virtqueue_get_buf run in parallel with virtqueue_add_buf, which is
      racy.
      
      While we might try to protect against spurious callbacks it's
      easier to fix the driver: balloon seems to be the only one
      (mis)using the API like this, so let's just fix balloon.
      Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>
      Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> (removed unused var)
      9c378abc
    • L
      Merge branch 'for-3.5-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup · 8c84bf41
      Linus Torvalds 提交于
      Pull cgroup fixes from Tejun Heo:
       "The previous cgroup pull request contained a patch to fix a race
        condition during cgroup hierarchy umount.  Unfortunately, while the
        patch reduced the race window such that the test case I and Sasha were
        using didn't trigger it anymore, it wasn't complete - Shyju and Li
        could reliably trigger the race condition using a different test case.
      
        The problem wasn't the gap between dentry deletion and release which
        the previous patch tried to fix.  The window was between the last
        dput() of a root's child and the resulting dput() of the root.  For
        cgroup dentries, the deletion and release always happen synchronously.
        As this releases the s_active ref, the refcnt of the root dentry,
        which doesn't hold s_active, stays above zero without the
        corresponding s_active.  If umount was in progress, the last
        deactivate_super() proceeds to destory the superblock and triggers
        BUG() on the non-zero root dentry refcnt after shrinking.
      
        This issue surfaced because cgroup dentries are now allowed to linger
        after rmdir(2) since 3.5-rc1.  Before, rmdir synchronously drained the
        dentry refcnt and the s_active acquired by rmdir from vfs layer
        protected the whole thing.  After 3.5-rc1, cgroup may internally hold
        and put dentry refs after rmdir finishes and the delayed dput()
        doesn't have surrounding s_active ref exposing this issue.
      
        This pull request contains two patches - one reverting the previous
        incorrect fix and the other adding the surrounding s_active ref around
        the delayed dput().
      
        This is quite late in the release cycle but the change is on the safer
        side and fixes the test cases reliably, so I don't think it's too
        crazy."
      
      * 'for-3.5-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup:
        cgroup: fix cgroup hierarchy umount race
        Revert "cgroup: superblock can't be released with active dentries"
      8c84bf41