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| author | Matthew Wilcox <[email protected]> | 2016-02-03 00:57:52 +0000 |
|---|---|---|
| committer | Linus Torvalds <[email protected]> | 2016-02-03 16:28:43 +0000 |
| commit | 46437f9a554fbe3e110580ca08ab703b59f2f95a (patch) | |
| tree | 826c5a8180792c3c68f57686d41bf69f01b2985d /lib/dump_stack.c | |
| parent | mm/vmpressure.c: fix subtree pressure detection (diff) | |
| download | kernel-46437f9a554fbe3e110580ca08ab703b59f2f95a.tar.gz kernel-46437f9a554fbe3e110580ca08ab703b59f2f95a.zip | |
radix-tree: fix race in gang lookup
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 <[email protected]>
Cc: Hugh Dickins <[email protected]>
Cc: Ohad Ben-Cohen <[email protected]>
Cc: Konstantin Khlebnikov <[email protected]>
Cc: <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
Diffstat (limited to 'lib/dump_stack.c')
0 files changed, 0 insertions, 0 deletions