[PATCH v1 net-next 02/15] ipmr: Annotate access to mrt->mroute_do_{pim,assert,wrvifwhole}.
From: Kuniyuki Iwashima <kuniyu@google.com>
Date: 2026-02-26 02:36:44
Subsystem:
networking [general], networking [ipv4/ipv6], the rest · Maintainers:
"David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, David Ahern, Ido Schimmel, Linus Torvalds
These fields in struct mr_table are updated in ip_mroute_setsockopt() under RTNL: * mroute_do_pim * mroute_do_assert * mroute_do_wrvifwhole However, ip_mroute_getsockopt() does not hold RTNL and read the first two fields locklessly, and ip_mr_forward() reads the latter two under RCU. Let's use WRITE_ONCE() and READ_ONCE() for them. Signed-off-by: Kuniyuki Iwashima <kuniyu@google.com> --- net/ipv4/ipmr.c | 16 ++++++++-------- 1 file changed, 8 insertions(+), 8 deletions(-)
diff --git a/net/ipv4/ipmr.c b/net/ipv4/ipmr.c
index 131382c388e9..377b5848f99c 100644
--- a/net/ipv4/ipmr.c
+++ b/net/ipv4/ipmr.c@@ -1506,7 +1506,7 @@ int ip_mroute_setsockopt(struct sock *sk, int optname, sockptr_t optval, ret = -EFAULT; break; } - mrt->mroute_do_assert = val; + WRITE_ONCE(mrt->mroute_do_assert, val); break; case MRT_PIM: if (!ipmr_pimsm_enabled()) {
@@ -1525,9 +1525,9 @@ int ip_mroute_setsockopt(struct sock *sk, int optname, sockptr_t optval, do_wrvifwhole = (val == IGMPMSG_WRVIFWHOLE); val = !!val; if (val != mrt->mroute_do_pim) { - mrt->mroute_do_pim = val; - mrt->mroute_do_assert = val; - mrt->mroute_do_wrvifwhole = do_wrvifwhole; + WRITE_ONCE(mrt->mroute_do_pim, val); + WRITE_ONCE(mrt->mroute_do_assert, val); + WRITE_ONCE(mrt->mroute_do_wrvifwhole, do_wrvifwhole); } break; case MRT_TABLE:
@@ -1610,10 +1610,10 @@ int ip_mroute_getsockopt(struct sock *sk, int optname, sockptr_t optval, case MRT_PIM: if (!ipmr_pimsm_enabled()) return -ENOPROTOOPT; - val = mrt->mroute_do_pim; + val = READ_ONCE(mrt->mroute_do_pim); break; case MRT_ASSERT: - val = mrt->mroute_do_assert; + val = READ_ONCE(mrt->mroute_do_assert); break; default: return -ENOPROTOOPT;
@@ -2037,7 +2037,7 @@ static void ip_mr_forward(struct net *net, struct mr_table *mrt, atomic_long_inc(&c->_c.mfc_un.res.wrong_if); - if (true_vifi >= 0 && mrt->mroute_do_assert && + if (true_vifi >= 0 && READ_ONCE(mrt->mroute_do_assert) && /* pimsm uses asserts, when switching from RPT to SPT, * so that we cannot check that packet arrived on an oif. * It is bad, but otherwise we would need to move pretty
@@ -2050,7 +2050,7 @@ static void ip_mr_forward(struct net *net, struct mr_table *mrt, MFC_ASSERT_THRESH)) { c->_c.mfc_un.res.last_assert = jiffies; ipmr_cache_report(mrt, skb, true_vifi, IGMPMSG_WRONGVIF); - if (mrt->mroute_do_wrvifwhole) + if (READ_ONCE(mrt->mroute_do_wrvifwhole)) ipmr_cache_report(mrt, skb, true_vifi, IGMPMSG_WRVIFWHOLE); }
--
2.53.0.414.gf7e9f6c205-goog