From: Al Viro <viro@zeniv.linux.org.uk>
Date: Fri, 18 Mar 2011 12:29:36 +0000 (-0400)
Subject: fix deadlock in pivot_root()
X-Git-Tag: v2.6.39-rc1~419^2~4
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=27cb1572e3e6bb1f8cf6bb3d74c914a87b131792;p=pandora-kernel.git

fix deadlock in pivot_root()

Don't hold vfsmount_lock over the loop traversing ->mnt_parent;
do check_mnt(new.mnt) under namespace_sem instead; combined with
namespace_sem held over all that code it'll guarantee the stability
of ->mnt_parent chain all the way to the root.

Doing check_mnt() outside of namespace_sem in case of pivot_root()
is wrong anyway.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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