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| author | Matthew Wilcox <willy@linux.intel.com> | 2016-02-02 16:57:52 -0800 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2016-02-25 12:01:23 -0800 |
| commit | f4595e0081495b677a98c780e9ec1ab68ce89488 (patch) | |
| tree | 969674b2a1fb46c713b01ead74279c939456c315 /lib/memory-notifier-error-inject.c | |
| parent | 262139f0244b3ade149b785dc820118c4265cdb1 (diff) | |
radix-tree: fix race in gang lookup
commit 46437f9a554fbe3e110580ca08ab703b59f2f95a upstream.
If the indirect_ptr bit is set on a slot, that indicates we need to redo
the lookup. Introduce a new function radix_tree_iter_retry() which
forces the loop to retry the lookup by setting 'slot' to NULL and
turning the iterator back to point at the problematic entry.
This is a pretty rare problem to hit at the moment; the lookup has to
race with a grow of the radix tree from a height of 0. The consequences
of hitting this race are that gang lookup could return a pointer to a
radix_tree_node instead of a pointer to whatever the user had inserted
in the tree.
Fixes: cebbd29e1c2f ("radix-tree: rewrite gang lookup using iterator")
Signed-off-by: Matthew Wilcox <willy@linux.intel.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Ohad Ben-Cohen <ohad@wizery.com>
Cc: Konstantin Khlebnikov <khlebnikov@openvz.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'lib/memory-notifier-error-inject.c')
0 files changed, 0 insertions, 0 deletions