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authorLinus Torvalds <torvalds@linux-foundation.org>2013-03-14 14:53:07 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2013-03-14 14:53:07 -0700
commitf4846e52c51755fe1dd6642a117bc23cd0655c95 (patch)
parent40e4591d949469d089714518385e4a99071a1762 (diff)
parentf65846a1800ef8c48d1ae1973c30dae4c356a800 (diff)
Merge branch 'rcu/urgent' of git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu
Pull fix for hlist_entry_safe() regression from Paul McKenney: "This contains a single commit that fixes a regression in hlist_entry_safe(). This macro references its argument twice, which can cause NULL-pointer errors. This commit applies a gcc statement expression, creating a temporary variable to avoid the double reference. This has been posted to LKML at https://lkml.org/lkml/2013/3/9/75. Kudos to CAI Qian, whose testing uncovered this, to Eric Dumazet, who spotted root cause, and to Li Zefan, who tested this commit." * 'rcu/urgent' of git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu: list: Fix double fetch of pointer in hlist_entry_safe()
1 files changed, 3 insertions, 1 deletions
diff --git a/include/linux/list.h b/include/linux/list.h
index d991cc147c98..6a1f8df9144b 100644
--- a/include/linux/list.h
+++ b/include/linux/list.h
@@ -667,7 +667,9 @@ static inline void hlist_move_list(struct hlist_head *old,
pos = n)
#define hlist_entry_safe(ptr, type, member) \
- (ptr) ? hlist_entry(ptr, type, member) : NULL
+ ({ typeof(ptr) ____ptr = (ptr); \
+ ____ptr ? hlist_entry(____ptr, type, member) : NULL; \
+ })
* hlist_for_each_entry - iterate over list of given type

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