From: Sasha Levin <sashal@kernel.org>
To: stable@vger.kernel.org
Cc: Eric Dumazet <edumazet@google.com>, Jiri Pirko <jiri@nvidia.com>,
"David S. Miller" <davem@davemloft.net>,
Sasha Levin <sashal@kernel.org>
Subject: [PATCH 5.10.y 1/2] ipv6/addrconf: annotate data-races around devconf fields (II)
Date: Tue, 8 Sep 2026 20:25:22 -0400 [thread overview]
Message-ID: <20260909002523.727517-1-sashal@kernel.org> (raw)
In-Reply-To: <2026090351-marbling-tiny-a334@gregkh>
From: Eric Dumazet <edumazet@google.com>
[ Upstream commit 2f0ff05a44302c91af54a5f9efe1b65b7681540e ]
Final (?) round of this series.
Annotate lockless reads on following devconf fields,
because they be changed concurrently from /proc/net/ipv6/conf.
- accept_dad
- optimistic_dad
- use_optimistic
- use_oif_addrs_only
- ra_honor_pio_life
- keep_addr_on_down
- ndisc_notify
- ndisc_evict_nocarrier
- suppress_frag_ndisc
- addr_gen_mode
- seg6_enabled
- ioam6_enabled
- ioam6_id
- ioam6_id_wide
- drop_unicast_in_l2_multicast
- mldv[12]_unsolicited_report_interval
- force_mld_version
- force_tllao
- accept_untracked_na
- drop_unsolicited_na
- accept_source_route
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Jiri Pirko <jiri@nvidia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
[ Backport to 5.10: omit ioam6.c and annotations for fields and control
flow only present in newer kernels. Preserve the applicable data-race
annotations, and annotate rpl_seg_enabled as well so the dependent IPv6
RPL fix applies against its expected context. ]
[ sashal: Reduced backport -- upstream 2f0ff05a44302 touches 7 file(s), this
backport carries 6. Not backported here:
net/ipv6/ioam6.c
This note is generated from the file lists only; see the resolution record
for the reasoning. ]
Stable-dep-of: f826df95332c ("ipv6: rpl: fix NULL dereference of idev in ipv6_rpl_srh_rcv()")
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
net/ipv6/addrconf.c | 47 +++++++++++++++++++++++---------------------
net/ipv6/exthdrs.c | 20 +++++++++----------
net/ipv6/ip6_input.c | 2 +-
net/ipv6/mcast.c | 14 ++++++-------
net/ipv6/ndisc.c | 12 +++++------
net/ipv6/seg6_hmac.c | 8 +++++---
6 files changed, 54 insertions(+), 49 deletions(-)
diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c
index 3bb1855cdcb87..6d5a4a7fb18fe 100644
--- a/net/ipv6/addrconf.c
+++ b/net/ipv6/addrconf.c
@@ -1492,15 +1492,17 @@ static inline int ipv6_saddr_preferred(int type)
return 0;
}
-static bool ipv6_use_optimistic_addr(struct net *net,
- struct inet6_dev *idev)
+static bool ipv6_use_optimistic_addr(const struct net *net,
+ const struct inet6_dev *idev)
{
#ifdef CONFIG_IPV6_OPTIMISTIC_DAD
if (!idev)
return false;
- if (!net->ipv6.devconf_all->optimistic_dad && !idev->cnf.optimistic_dad)
+ if (!READ_ONCE(net->ipv6.devconf_all->optimistic_dad) &&
+ !READ_ONCE(idev->cnf.optimistic_dad))
return false;
- if (!net->ipv6.devconf_all->use_optimistic && !idev->cnf.use_optimistic)
+ if (!READ_ONCE(net->ipv6.devconf_all->use_optimistic) &&
+ !READ_ONCE(idev->cnf.use_optimistic))
return false;
return true;
@@ -1509,13 +1511,14 @@ static bool ipv6_use_optimistic_addr(struct net *net,
#endif
}
-static bool ipv6_allow_optimistic_dad(struct net *net,
- struct inet6_dev *idev)
+static bool ipv6_allow_optimistic_dad(const struct net *net,
+ const struct inet6_dev *idev)
{
#ifdef CONFIG_IPV6_OPTIMISTIC_DAD
if (!idev)
return false;
- if (!net->ipv6.devconf_all->optimistic_dad && !idev->cnf.optimistic_dad)
+ if (!READ_ONCE(net->ipv6.devconf_all->optimistic_dad) &&
+ !READ_ONCE(idev->cnf.optimistic_dad))
return false;
return true;
@@ -1797,7 +1800,7 @@ int ipv6_dev_get_saddr(struct net *net, const struct net_device *dst_dev,
idev = __in6_dev_get(dst_dev);
if ((dst_type & IPV6_ADDR_MULTICAST) ||
dst.scope <= IPV6_ADDR_SCOPE_LINKLOCAL ||
- (idev && idev->cnf.use_oif_addrs_only)) {
+ (idev && READ_ONCE(idev->cnf.use_oif_addrs_only))) {
use_oif_addr = true;
}
}
@@ -2628,8 +2631,8 @@ int addrconf_prefix_rcv_add_addr(struct net *net, struct net_device *dev,
};
#ifdef CONFIG_IPV6_OPTIMISTIC_DAD
- if ((net->ipv6.devconf_all->optimistic_dad ||
- in6_dev->cnf.optimistic_dad) &&
+ if ((READ_ONCE(net->ipv6.devconf_all->optimistic_dad) ||
+ READ_ONCE(in6_dev->cnf.optimistic_dad)) &&
!net->ipv6.devconf_all->forwarding && sllao)
cfg.ifa_flags |= IFA_F_OPTIMISTIC;
#endif
@@ -3226,8 +3229,8 @@ void addrconf_add_linklocal(struct inet6_dev *idev,
struct inet6_ifaddr *ifp;
#ifdef CONFIG_IPV6_OPTIMISTIC_DAD
- if ((dev_net(idev->dev)->ipv6.devconf_all->optimistic_dad ||
- idev->cnf.optimistic_dad) &&
+ if ((READ_ONCE(dev_net(idev->dev)->ipv6.devconf_all->optimistic_dad) ||
+ READ_ONCE(idev->cnf.optimistic_dad)) &&
!dev_net(idev->dev)->ipv6.devconf_all->forwarding)
cfg.ifa_flags |= IFA_F_OPTIMISTIC;
#endif
@@ -3784,10 +3787,10 @@ static int addrconf_ifdown(struct net_device *dev, bool unregister)
*/
if (!unregister && !idev->cnf.disable_ipv6) {
/* aggregate the system setting and interface setting */
- int _keep_addr = net->ipv6.devconf_all->keep_addr_on_down;
+ int _keep_addr = READ_ONCE(net->ipv6.devconf_all->keep_addr_on_down);
if (!_keep_addr)
- _keep_addr = idev->cnf.keep_addr_on_down;
+ _keep_addr = READ_ONCE(idev->cnf.keep_addr_on_down);
keep_addr = (_keep_addr > 0);
}
@@ -4009,8 +4012,8 @@ static void addrconf_dad_begin(struct inet6_ifaddr *ifp)
net = dev_net(dev);
if (dev->flags&(IFF_NOARP|IFF_LOOPBACK) ||
- (net->ipv6.devconf_all->accept_dad < 1 &&
- idev->cnf.accept_dad < 1) ||
+ (READ_ONCE(net->ipv6.devconf_all->accept_dad) < 1 &&
+ READ_ONCE(idev->cnf.accept_dad) < 1) ||
!(ifp->flags&IFA_F_TENTATIVE) ||
ifp->flags & IFA_F_NODAD) {
bool send_na = false;
@@ -4102,8 +4105,8 @@ static void addrconf_dad_work(struct work_struct *w)
action = DAD_ABORT;
ifp->state = INET6_IFADDR_STATE_POSTDAD;
- if ((dev_net(idev->dev)->ipv6.devconf_all->accept_dad > 1 ||
- idev->cnf.accept_dad > 1) &&
+ if ((READ_ONCE(dev_net(idev->dev)->ipv6.devconf_all->accept_dad) > 1 ||
+ READ_ONCE(idev->cnf.accept_dad) > 1) &&
!idev->cnf.disable_ipv6 &&
!(ifp->flags & IFA_F_STABLE_PRIVACY)) {
struct in6_addr addr;
@@ -4241,8 +4244,8 @@ static void addrconf_dad_completed(struct inet6_ifaddr *ifp, bool bump_id,
/* send unsolicited NA if enabled */
if (send_na &&
- (ifp->idev->cnf.ndisc_notify ||
- dev_net(dev)->ipv6.devconf_all->ndisc_notify)) {
+ (READ_ONCE(ifp->idev->cnf.ndisc_notify) ||
+ READ_ONCE(dev_net(dev)->ipv6.devconf_all->ndisc_notify))) {
ndisc_send_na(dev, &in6addr_linklocal_allnodes, &ifp->addr,
/*router=*/ !!ifp->idev->cnf.forwarding,
/*solicited=*/ false, /*override=*/ true,
@@ -6389,7 +6392,7 @@ static int addrconf_sysctl_addr_gen_mode(struct ctl_table *ctl, int write,
} else if (&net->ipv6.devconf_all->addr_gen_mode == ctl->data) {
struct net_device *dev;
- net->ipv6.devconf_dflt->addr_gen_mode = new_val;
+ WRITE_ONCE(net->ipv6.devconf_dflt->addr_gen_mode, new_val);
for_each_netdev(net, dev) {
idev = __in6_dev_get(dev);
if (idev &&
@@ -6400,7 +6403,7 @@ static int addrconf_sysctl_addr_gen_mode(struct ctl_table *ctl, int write,
}
}
- *((u32 *)ctl->data) = new_val;
+ WRITE_ONCE(*((u32 *)ctl->data), new_val);
}
out:
diff --git a/net/ipv6/exthdrs.c b/net/ipv6/exthdrs.c
index 0230fa98a3482..bc01761844194 100644
--- a/net/ipv6/exthdrs.c
+++ b/net/ipv6/exthdrs.c
@@ -368,9 +368,8 @@ static int ipv6_srh_rcv(struct sk_buff *skb)
return -1;
}
- accept_seg6 = net->ipv6.devconf_all->seg6_enabled;
- if (accept_seg6 > idev->cnf.seg6_enabled)
- accept_seg6 = idev->cnf.seg6_enabled;
+ accept_seg6 = min(READ_ONCE(net->ipv6.devconf_all->seg6_enabled),
+ READ_ONCE(idev->cnf.seg6_enabled));
if (!accept_seg6) {
kfree_skb(skb);
@@ -491,9 +490,8 @@ static int ipv6_rpl_srh_rcv(struct sk_buff *skb)
idev = __in6_dev_get(skb->dev);
- accept_rpl_seg = net->ipv6.devconf_all->rpl_seg_enabled;
- if (accept_rpl_seg > idev->cnf.rpl_seg_enabled)
- accept_rpl_seg = idev->cnf.rpl_seg_enabled;
+ accept_rpl_seg = min(READ_ONCE(net->ipv6.devconf_all->rpl_seg_enabled),
+ READ_ONCE(idev->cnf.rpl_seg_enabled));
if (!accept_rpl_seg) {
kfree_skb(skb);
@@ -674,11 +672,13 @@ static int ipv6_rthdr_rcv(struct sk_buff *skb)
struct ipv6_rt_hdr *hdr;
struct rt0_hdr *rthdr;
struct net *net = dev_net(skb->dev);
- int accept_source_route = net->ipv6.devconf_all->accept_source_route;
+ int accept_source_route;
- idev = __in6_dev_get(skb->dev);
- if (idev && accept_source_route > idev->cnf.accept_source_route)
- accept_source_route = idev->cnf.accept_source_route;
+ accept_source_route = READ_ONCE(net->ipv6.devconf_all->accept_source_route);
+
+ if (idev)
+ accept_source_route = min(accept_source_route,
+ READ_ONCE(idev->cnf.accept_source_route));
if (!pskb_may_pull(skb, skb_transport_offset(skb) + 8) ||
!pskb_may_pull(skb, (skb_transport_offset(skb) +
diff --git a/net/ipv6/ip6_input.c b/net/ipv6/ip6_input.c
index 8cf5b10eee695..85e14f9df3a63 100644
--- a/net/ipv6/ip6_input.c
+++ b/net/ipv6/ip6_input.c
@@ -229,7 +229,7 @@ static struct sk_buff *ip6_rcv_core(struct sk_buff *skb, struct net_device *dev,
if (!ipv6_addr_is_multicast(&hdr->daddr) &&
(skb->pkt_type == PACKET_BROADCAST ||
skb->pkt_type == PACKET_MULTICAST) &&
- idev->cnf.drop_unicast_in_l2_multicast)
+ READ_ONCE(idev->cnf.drop_unicast_in_l2_multicast))
goto err;
/* RFC4291 2.7
diff --git a/net/ipv6/mcast.c b/net/ipv6/mcast.c
index c4a9866ea45b6..cdbff3dc89ced 100644
--- a/net/ipv6/mcast.c
+++ b/net/ipv6/mcast.c
@@ -162,9 +162,9 @@ static int unsolicited_report_interval(struct inet6_dev *idev)
int iv;
if (mld_in_v1_mode(idev))
- iv = idev->cnf.mldv1_unsolicited_report_interval;
+ iv = READ_ONCE(idev->cnf.mldv1_unsolicited_report_interval);
else
- iv = idev->cnf.mldv2_unsolicited_report_interval;
+ iv = READ_ONCE(idev->cnf.mldv2_unsolicited_report_interval);
return iv > 0 ? iv : 1;
}
@@ -1218,15 +1218,15 @@ static bool mld_marksources(struct ifmcaddr6 *pmc, int nsrcs,
static int mld_force_mld_version(const struct inet6_dev *idev)
{
+ const struct net *net = dev_net(idev->dev);
+ int all_force;
+
+ all_force = READ_ONCE(net->ipv6.devconf_all->force_mld_version);
/* Normally, both are 0 here. If enforcement to a particular is
* being used, individual device enforcement will have a lower
* precedence over 'all' device (.../conf/all/force_mld_version).
*/
-
- if (dev_net(idev->dev)->ipv6.devconf_all->force_mld_version != 0)
- return dev_net(idev->dev)->ipv6.devconf_all->force_mld_version;
- else
- return idev->cnf.force_mld_version;
+ return all_force ?: READ_ONCE(idev->cnf.force_mld_version);
}
static bool mld_in_v2_mode_only(const struct inet6_dev *idev)
diff --git a/net/ipv6/ndisc.c b/net/ipv6/ndisc.c
index de389b519700d..e8e3ea61e0623 100644
--- a/net/ipv6/ndisc.c
+++ b/net/ipv6/ndisc.c
@@ -450,7 +450,7 @@ static void ip6_nd_hdr(struct sk_buff *skb,
rcu_read_lock();
idev = __in6_dev_get(skb->dev);
- tclass = idev ? idev->cnf.ndisc_tclass : 0;
+ tclass = idev ? READ_ONCE(idev->cnf.ndisc_tclass) : 0;
rcu_read_unlock();
skb_push(skb, sizeof(*hdr));
@@ -538,7 +538,7 @@ void ndisc_send_na(struct net_device *dev, const struct in6_addr *daddr,
src_addr = solicited_addr;
if (ifp->flags & IFA_F_OPTIMISTIC)
override = false;
- inc_opt |= ifp->idev->cnf.force_tllao;
+ inc_opt |= READ_ONCE(ifp->idev->cnf.force_tllao);
in6_ifa_put(ifp);
} else {
if (ipv6_dev_get_saddr(dev_net(dev), dev, daddr,
@@ -991,7 +991,7 @@ static void ndisc_recv_na(struct sk_buff *skb)
* and thus should not be accepted.
*/
if (!msg->icmph.icmp6_solicited && idev &&
- idev->cnf.drop_unsolicited_na)
+ READ_ONCE(idev->cnf.drop_unsolicited_na))
return;
if (!ndisc_parse_options(dev, msg->opt, ndoptlen, &ndopts)) {
@@ -1737,7 +1737,7 @@ static bool ndisc_suppress_frag_ndisc(struct sk_buff *skb)
if (!idev)
return true;
if (IP6CB(skb)->flags & IP6SKB_FRAGMENTED &&
- idev->cnf.suppress_frag_ndisc) {
+ READ_ONCE(idev->cnf.suppress_frag_ndisc)) {
net_warn_ratelimited("Received fragmented ndisc packet. Carefully consider disabling suppress_frag_ndisc.\n");
return true;
}
@@ -1812,8 +1812,8 @@ static int ndisc_netdev_event(struct notifier_block *this, unsigned long event,
idev = in6_dev_get(dev);
if (!idev)
break;
- if (idev->cnf.ndisc_notify ||
- net->ipv6.devconf_all->ndisc_notify)
+ if (READ_ONCE(idev->cnf.ndisc_notify) ||
+ READ_ONCE(net->ipv6.devconf_all->ndisc_notify))
ndisc_send_unsol_na(dev);
in6_dev_put(idev);
break;
diff --git a/net/ipv6/seg6_hmac.c b/net/ipv6/seg6_hmac.c
index b52985c867c29..abccc86990c1a 100644
--- a/net/ipv6/seg6_hmac.c
+++ b/net/ipv6/seg6_hmac.c
@@ -243,6 +243,7 @@ bool seg6_hmac_validate_skb(struct sk_buff *skb)
struct sr6_tlv_hmac *tlv;
struct ipv6_sr_hdr *srh;
struct inet6_dev *idev;
+ int require_hmac;
idev = __in6_dev_get(skb->dev);
if (!idev)
@@ -252,16 +253,17 @@ bool seg6_hmac_validate_skb(struct sk_buff *skb)
tlv = seg6_get_tlv_hmac(srh);
+ require_hmac = READ_ONCE(idev->cnf.seg6_require_hmac);
/* mandatory check but no tlv */
- if (idev->cnf.seg6_require_hmac > 0 && !tlv)
+ if (require_hmac > 0 && !tlv)
return false;
/* no check */
- if (idev->cnf.seg6_require_hmac < 0)
+ if (require_hmac < 0)
return true;
/* check only if present */
- if (idev->cnf.seg6_require_hmac == 0 && !tlv)
+ if (require_hmac == 0 && !tlv)
return true;
/* now, seg6_require_hmac >= 0 && tlv */
--
2.53.0
next prev parent reply other threads:[~2026-09-09 0:25 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-09-03 14:00 FAILED: patch "[PATCH] ipv6: rpl: fix NULL dereference of idev in ipv6_rpl_srh_rcv()" failed to apply to 5.10-stable tree gregkh
2026-09-09 0:25 ` Sasha Levin [this message]
2026-09-09 0:25 ` [PATCH 5.10.y 2/2] ipv6: rpl: fix NULL dereference of idev in ipv6_rpl_srh_rcv() Sasha Levin
2026-09-09 1:31 ` [PATCH 5.10.y 1/2] ipv6/addrconf: annotate data-races around devconf fields (II) Sasha Levin
2026-09-09 1:31 ` [PATCH 5.10.y 2/2] ipv6: rpl: fix NULL dereference of idev in ipv6_rpl_srh_rcv() Sasha Levin
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