From 00bf2032e97691c4b53427b33a85b134324e2a94 Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Tue, 10 Dec 2024 18:33:52 +0000 Subject: [PATCH] ipv6: mcast: annotate data-race around psf->sf_count[MCAST_XXX] psf->sf_count[MCAST_XXX] fields are read locklessly from ipv6_chk_mcast_addr() and igmp6_mcf_seq_show(). Add READ_ONCE() and WRITE_ONCE() annotations accordingly. Signed-off-by: Eric Dumazet Reviewed-by: David Ahern Link: https://patch.msgid.link/20241210183352.86530-4-edumazet@google.com Signed-off-by: Jakub Kicinski --- net/ipv6/mcast.c | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-) diff --git a/net/ipv6/mcast.c b/net/ipv6/mcast.c index 09622142b070..5ca8692d565d 100644 --- a/net/ipv6/mcast.c +++ b/net/ipv6/mcast.c @@ -1037,8 +1037,8 @@ bool ipv6_chk_mcast_addr(struct net_device *dev, const struct in6_addr *group, break; } if (psf) - rv = psf->sf_count[MCAST_INCLUDE] || - psf->sf_count[MCAST_EXCLUDE] != + rv = READ_ONCE(psf->sf_count[MCAST_INCLUDE]) || + READ_ONCE(psf->sf_count[MCAST_EXCLUDE]) != READ_ONCE(mc->mca_sfcount[MCAST_EXCLUDE]); else rv = READ_ONCE(mc->mca_sfcount[MCAST_EXCLUDE]) != 0; @@ -2287,7 +2287,7 @@ static int ip6_mc_del1_src(struct ifmcaddr6 *pmc, int sfmode, /* source filter not found, or count wrong => bug */ return -ESRCH; } - psf->sf_count[sfmode]--; + WRITE_ONCE(psf->sf_count[sfmode], psf->sf_count[sfmode] - 1); if (!psf->sf_count[MCAST_INCLUDE] && !psf->sf_count[MCAST_EXCLUDE]) { struct inet6_dev *idev = pmc->idev; @@ -2393,7 +2393,7 @@ static int ip6_mc_add1_src(struct ifmcaddr6 *pmc, int sfmode, rcu_assign_pointer(pmc->mca_sources, psf); } } - psf->sf_count[sfmode]++; + WRITE_ONCE(psf->sf_count[sfmode], psf->sf_count[sfmode] + 1); return 0; } @@ -3079,8 +3079,8 @@ static int igmp6_mcf_seq_show(struct seq_file *seq, void *v) state->dev->ifindex, state->dev->name, &state->im->mca_addr, &psf->sf_addr, - psf->sf_count[MCAST_INCLUDE], - psf->sf_count[MCAST_EXCLUDE]); + READ_ONCE(psf->sf_count[MCAST_INCLUDE]), + READ_ONCE(psf->sf_count[MCAST_EXCLUDE])); } return 0; } -- 2.50.1