This is a note to let you know that I've just added the patch titled
rbtree: fix rbtree_postorder_for_each_entry_safe() iterator
to the 3.12-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
rbtree-fix-rbtree_postorder_for_each_entry_safe-iterator.patch
and it can be found in the queue-3.12 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 1310a5a99d900ee30b9f171146406bde0c6c2bd4 Mon Sep 17 00:00:00 2001
From: Jan Kara <jack@xxxxxxx>
Date: Tue, 12 Nov 2013 15:11:19 -0800
Subject: rbtree: fix rbtree_postorder_for_each_entry_safe() iterator
From: Jan Kara <jack@xxxxxxx>
commit 1310a5a99d900ee30b9f171146406bde0c6c2bd4 upstream.
The iterator rbtree_postorder_for_each_entry_safe() relies on pointer
underflow behavior when testing for loop termination. In particular it
expects that
&rb_entry(NULL, type, field)->field
is NULL. But the result of this expression is not defined by a C standard
and some gcc versions (e.g. 4.3.4) assume the above expression can never
be equal to NULL. The net result is an oops because the iteration is not
properly terminated.
Fix the problem by modifying the iterator to avoid pointer underflows.
Signed-off-by: Jan Kara <jack@xxxxxxx>
Signed-off-by: Cody P Schafer <cody@xxxxxxxxxxxxxxxxxx>
Cc: Michel Lespinasse <walken@xxxxxxxxxx>
Cc: "David S. Miller" <davem@xxxxxxxxxxxxx>
Cc: Adrian Hunter <adrian.hunter@xxxxxxxxx>
Cc: Artem Bityutskiy <dedekind1@xxxxxxxxx>
Cc: David Woodhouse <dwmw2@xxxxxxxxxxxxx>
Cc: Jozsef Kadlecsik <kadlec@xxxxxxxxxxxxxxxxx>
Cc: Pablo Neira Ayuso <pablo@xxxxxxxxxxxxx>
Cc: Patrick McHardy <kaber@xxxxxxxxx>
Cc: Paul Mundt <lethal@xxxxxxxxxxxx>
Cc: Theodore Ts'o <tytso@xxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
include/linux/rbtree.h | 16 +++++++++-------
1 file changed, 9 insertions(+), 7 deletions(-)
--- a/include/linux/rbtree.h
+++ b/include/linux/rbtree.h
@@ -85,6 +85,11 @@ static inline void rb_link_node(struct r
*rb_link = node;
}
+#define rb_entry_safe(ptr, type, member) \
+ ({ typeof(ptr) ____ptr = (ptr); \
+ ____ptr ? rb_entry(____ptr, type, member) : NULL; \
+ })
+
/**
* rbtree_postorder_for_each_entry_safe - iterate over rb_root in post order of
* given type safe against removal of rb_node entry
@@ -95,12 +100,9 @@ static inline void rb_link_node(struct r
* @field: the name of the rb_node field within 'type'.
*/
#define rbtree_postorder_for_each_entry_safe(pos, n, root, field) \
- for (pos = rb_entry(rb_first_postorder(root), typeof(*pos), field),\
- n = rb_entry(rb_next_postorder(&pos->field), \
- typeof(*pos), field); \
- &pos->field; \
- pos = n, \
- n = rb_entry(rb_next_postorder(&pos->field), \
- typeof(*pos), field))
+ for (pos = rb_entry_safe(rb_first_postorder(root), typeof(*pos), field); \
+ pos && ({ n = rb_entry_safe(rb_next_postorder(&pos->field), \
+ typeof(*pos), field); 1; }); \
+ pos = n)
#endif /* _LINUX_RBTREE_H */
Patches currently in stable-queue which might be from jack@xxxxxxx are
queue-3.12/rbtree-fix-rbtree_postorder_for_each_entry_safe-iterator.patch
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