On (10/21/15 06:54), Sowmini Varadhan wrote:
> But __alignof__(*p) is 8 on sparc, and without the patch I get
> all types of unaligned access. So what do you suggest as the fix?
Even though the alignment is, in fact, 8 (and that comes from
struct xfrm_lifetime_cfg), if uspace is firmly attached to the 4 byte
alignment, I think we can retain that behavior and still avoid
unaligned access in the kernel with the following (admittedly ugly hack).
Can you please take a look? I tested it with 'ip x m' and a transport
mode tunnel on my sparc.
diff --git a/net/xfrm/xfrm_user.c b/net/xfrm/xfrm_user.c
index 158ef4a..ca4e7f0 100644
--- a/net/xfrm/xfrm_user.c
+++ b/net/xfrm/xfrm_user.c
@@ -2620,7 +2620,7 @@ static inline size_t xfrm_sa_len(struct xfrm_state *x)
static int xfrm_notify_sa(struct xfrm_state *x, const struct km_event *c)
{
struct net *net = xs_net(x);
- struct xfrm_usersa_info *p;
+ struct xfrm_usersa_info *p, tmp;
struct xfrm_usersa_id *id;
struct nlmsghdr *nlh;
struct sk_buff *skb;
@@ -2659,11 +2659,16 @@ static int xfrm_notify_sa(struct xfrm_state *x, const
struct km_event *c)
if (attr == NULL)
goto out_free_skb;
- p = PTR_ALIGN(nla_data(attr), __alignof__(*p));
+ p = nla_data(attr);
+ err = copy_to_user_state_extra(x, &tmp, skb);
+ if (err)
+ goto out_free_skb;
+ memcpy((u8 *)p, &tmp, sizeof(tmp));
+ } else {
+ err = copy_to_user_state_extra(x, p, skb);
+ if (err)
+ goto out_free_skb;
}
- err = copy_to_user_state_extra(x, p, skb);
- if (err)
- goto out_free_skb;
nlmsg_end(skb, nlh);
--
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