From ff29a6cf6e84f4ccbab2d0853cf20e6c2821ef38 Mon Sep 17 00:00:00 2001 From: Greg Kroah-Hartman Date: Sat, 1 Jun 2024 09:33:51 +0000 Subject: [PATCH] ANDROID: ABI fixup for abi break in struct dst_ops In commit 92f1655aa2b2 ("net: fix __dst_negative_advice() race") the struct dst_ops callback negative_advice is callback changes function parameters. But as this pointer is part of a structure that is tracked in the ABI checker, the tool triggers when this is changed. However, the callback pointer is internal to the networking stack, so changing the function type is safe, so needing to preserve this is not required. To do so, switch the function pointer type back to the old one so that the checking tools pass, AND then do a hard cast of the function pointer to the new type when assigning and calling the function. Bug: 343727534 Fixes: 92f1655aa2b2 ("net: fix __dst_negative_advice() race") Change-Id: I48d4ab4bbd29f8edc8fbd7923828b7f78a23e12e Signed-off-by: Greg Kroah-Hartman --- include/net/dst_ops.h | 12 +++++++++++- include/net/sock.h | 12 ++++++++++-- net/ipv4/route.c | 2 +- net/ipv6/route.c | 2 +- net/xfrm/xfrm_policy.c | 2 +- 5 files changed, 24 insertions(+), 6 deletions(-) diff --git a/include/net/dst_ops.h b/include/net/dst_ops.h index dd7c0b37da38..382af5f36e7f 100644 --- a/include/net/dst_ops.h +++ b/include/net/dst_ops.h @@ -12,6 +12,16 @@ struct sk_buff; struct sock; struct net; +/* *** ANDROID FIXUP *** + * These typedefs are used to help fixup the ABI break caused by commit + * 92f1655aa2b2 ("net: fix __dst_negative_advice() race") where the + * negative_advice callback changed function signatures. + * See b/343727534 for more details. + * *** ANDROID FIXUP *** + */ +typedef void (*android_dst_ops_negative_advice_new_t)(struct sock *sk, struct dst_entry *); +typedef struct dst_entry * (*android_dst_ops_negative_advice_old_t)(struct dst_entry *); + struct dst_ops { unsigned short family; unsigned int gc_thresh; @@ -24,7 +34,7 @@ struct dst_ops { void (*destroy)(struct dst_entry *); void (*ifdown)(struct dst_entry *, struct net_device *dev, int how); - void (*negative_advice)(struct sock *sk, struct dst_entry *); + struct dst_entry * (*negative_advice)(struct dst_entry *); void (*link_failure)(struct sk_buff *); void (*update_pmtu)(struct dst_entry *dst, struct sock *sk, struct sk_buff *skb, u32 mtu, diff --git a/include/net/sock.h b/include/net/sock.h index b101012a348f..7189de533bd4 100644 --- a/include/net/sock.h +++ b/include/net/sock.h @@ -1955,12 +1955,20 @@ sk_dst_get(struct sock *sk) static inline void dst_negative_advice(struct sock *sk) { + /* *** ANDROID FIXUP *** + * See b/343727534 for more details why this typedef is needed here. + * *** ANDROID FIXUP *** + */ + android_dst_ops_negative_advice_new_t negative_advice; + struct dst_entry *dst = __sk_dst_get(sk); sk_rethink_txhash(sk); - if (dst && dst->ops->negative_advice) - dst->ops->negative_advice(sk, dst); + if (dst && dst->ops->negative_advice) { + negative_advice = (android_dst_ops_negative_advice_new_t)dst->ops->negative_advice; + negative_advice(sk, dst); + } } static inline void diff --git a/net/ipv4/route.c b/net/ipv4/route.c index 63453c254dcb..0cf4c49b1150 100644 --- a/net/ipv4/route.c +++ b/net/ipv4/route.c @@ -165,7 +165,7 @@ static struct dst_ops ipv4_dst_ops = { .mtu = ipv4_mtu, .cow_metrics = ipv4_cow_metrics, .destroy = ipv4_dst_destroy, - .negative_advice = ipv4_negative_advice, + .negative_advice = (android_dst_ops_negative_advice_old_t)ipv4_negative_advice, .link_failure = ipv4_link_failure, .update_pmtu = ip_rt_update_pmtu, .redirect = ip_do_redirect, diff --git a/net/ipv6/route.c b/net/ipv6/route.c index 23cfce690345..379b62d87bc1 100644 --- a/net/ipv6/route.c +++ b/net/ipv6/route.c @@ -250,7 +250,7 @@ static struct dst_ops ip6_dst_ops_template = { .cow_metrics = dst_cow_metrics_generic, .destroy = ip6_dst_destroy, .ifdown = ip6_dst_ifdown, - .negative_advice = ip6_negative_advice, + .negative_advice = (android_dst_ops_negative_advice_old_t)ip6_negative_advice, .link_failure = ip6_link_failure, .update_pmtu = ip6_rt_update_pmtu, .redirect = rt6_do_redirect, diff --git a/net/xfrm/xfrm_policy.c b/net/xfrm/xfrm_policy.c index cbf9387b1650..0fe167dca7c2 100644 --- a/net/xfrm/xfrm_policy.c +++ b/net/xfrm/xfrm_policy.c @@ -3949,7 +3949,7 @@ int xfrm_policy_register_afinfo(const struct xfrm_policy_afinfo *afinfo, int fam if (likely(dst_ops->mtu == NULL)) dst_ops->mtu = xfrm_mtu; if (likely(dst_ops->negative_advice == NULL)) - dst_ops->negative_advice = xfrm_negative_advice; + dst_ops->negative_advice = (android_dst_ops_negative_advice_old_t)xfrm_negative_advice; if (likely(dst_ops->link_failure == NULL)) dst_ops->link_failure = xfrm_link_failure; if (likely(dst_ops->neigh_lookup == NULL))