Commit-ID: b8f2ed538477d9ab803c6458f497df1b1c6cf4ce
Gitweb: http://git.kernel.org/tip/b8f2ed538477d9ab803c6458f497df1b1c6cf4ce
Author: Paul E. McKenney <paulmck@xxxxxxxxxxxxxxxxxx>
AuthorDate: Tue, 23 Aug 2016 06:51:47 -0700
Committer: Paul E. McKenney <paulmck@xxxxxxxxxxxxxxxxxx>
CommitDate: Mon, 14 Nov 2016 10:46:08 -0800
rcu: Tighten up __call_rcu() rcu_head alignment check
Commit 720abae3d68ae ("rcu: force alignment on struct
callback_head/rcu_head") forced the rcu_head (AKA callback_head)
structure's alignment to pointer size, that is, to 4-byte boundaries on
32-bit systems and to 8-byte boundaries on 64-bit systems. This
commit therefore checks for this same alignment in __call_rcu(),
which used to contain a looser check for two-byte alignment.
Signed-off-by: Paul E. McKenney <paulmck@xxxxxxxxxxxxxxxxxx>
Tested-by: Geert Uytterhoeven <geert@xxxxxxxxxxxxxx>
Acked-by: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
Reviewed-by: Josh Triplett <josh@xxxxxxxxxxxxxxxx>
---
kernel/rcu/tree.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c
index 69a5611..37e4f7d 100644
--- a/kernel/rcu/tree.c
+++ b/kernel/rcu/tree.c
@@ -3121,7 +3121,9 @@ __call_rcu(struct rcu_head *head, rcu_callback_t func,
unsigned long flags;
struct rcu_data *rdp;
- WARN_ON_ONCE((unsigned long)head & 0x1); /* Misaligned rcu_head! */
+ /* Misaligned rcu_head! */
+ WARN_ON_ONCE((unsigned long)head & (sizeof(void *) - 1));
+
if (debug_rcu_head_queue(head)) {
/* Probable double call_rcu(), so leak the callback. */
WRITE_ONCE(head->func, rcu_leak_callback);
--
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