Sebastian Andrzej Siewior
2021-Sep-28 14:10 UTC
[Bridge] [PATCH net] net: bridge: mcast: Associate the seqcount with its protecting lock.
From: Thomas Gleixner <tglx at linutronix.de>
The sequence count bridge_mcast_querier::seq is protected by
net_bridge::multicast_lock but seqcount_init() does not associate the
seqcount with the lock. This leads to a warning on PREEMPT_RT because
preemption is still enabled.
Let seqcount_init() associate the seqcount with lock that protects the
write section. Remove lockdep_assert_held_once() because lockdep already checks
whether the associated lock is held.
Fixes: 67b746f94ff39 ("net: bridge: mcast: make sure querier port/address
updates are consistent")
Reported-by: Mike Galbraith <efault at gmx.de>
Signed-off-by: Thomas Gleixner <tglx at linutronix.de>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy at linutronix.de>
Tested-by: Mike Galbraith <efault at gmx.de>
---
net/bridge/br_multicast.c | 6 ++----
net/bridge/br_private.h | 2 +-
2 files changed, 3 insertions(+), 5 deletions(-)
--- a/net/bridge/br_multicast.c
+++ b/net/bridge/br_multicast.c
@@ -1677,8 +1677,6 @@ static void br_multicast_update_querier(
int ifindex,
struct br_ip *saddr)
{
- lockdep_assert_held_once(&brmctx->br->multicast_lock);
-
write_seqcount_begin(&querier->seq);
querier->port_ifidx = ifindex;
memcpy(&querier->addr, saddr, sizeof(*saddr));
@@ -3867,13 +3865,13 @@ void br_multicast_ctx_init(struct net_br
brmctx->ip4_other_query.delay_time = 0;
brmctx->ip4_querier.port_ifidx = 0;
- seqcount_init(&brmctx->ip4_querier.seq);
+ seqcount_spinlock_init(&brmctx->ip4_querier.seq,
&br->multicast_lock);
brmctx->multicast_igmp_version = 2;
#if IS_ENABLED(CONFIG_IPV6)
brmctx->multicast_mld_version = 1;
brmctx->ip6_other_query.delay_time = 0;
brmctx->ip6_querier.port_ifidx = 0;
- seqcount_init(&brmctx->ip6_querier.seq);
+ seqcount_spinlock_init(&brmctx->ip6_querier.seq,
&br->multicast_lock);
#endif
timer_setup(&brmctx->ip4_mc_router_timer,
--- a/net/bridge/br_private.h
+++ b/net/bridge/br_private.h
@@ -82,7 +82,7 @@ struct bridge_mcast_other_query {
struct bridge_mcast_querier {
struct br_ip addr;
int port_ifidx;
- seqcount_t seq;
+ seqcount_spinlock_t seq;
};
/* IGMP/MLD statistics */
Nikolay Aleksandrov
2021-Sep-28 14:41 UTC
[Bridge] [PATCH net] net: bridge: mcast: Associate the seqcount with its protecting lock.
On 28/09/2021 17:10, Sebastian Andrzej Siewior wrote:> From: Thomas Gleixner <tglx at linutronix.de> > > The sequence count bridge_mcast_querier::seq is protected by > net_bridge::multicast_lock but seqcount_init() does not associate the > seqcount with the lock. This leads to a warning on PREEMPT_RT because > preemption is still enabled. > > Let seqcount_init() associate the seqcount with lock that protects the > write section. Remove lockdep_assert_held_once() because lockdep already checks > whether the associated lock is held. > > Fixes: 67b746f94ff39 ("net: bridge: mcast: make sure querier port/address updates are consistent") > Reported-by: Mike Galbraith <efault at gmx.de> > Signed-off-by: Thomas Gleixner <tglx at linutronix.de> > Signed-off-by: Sebastian Andrzej Siewior <bigeasy at linutronix.de> > Tested-by: Mike Galbraith <efault at gmx.de> > --- > net/bridge/br_multicast.c | 6 ++---- > net/bridge/br_private.h | 2 +- > 2 files changed, 3 insertions(+), 5 deletions(-) > > --- a/net/bridge/br_multicast.c > +++ b/net/bridge/br_multicast.c > @@ -1677,8 +1677,6 @@ static void br_multicast_update_querier( > int ifindex, > struct br_ip *saddr) > { > - lockdep_assert_held_once(&brmctx->br->multicast_lock); > - > write_seqcount_begin(&querier->seq); > querier->port_ifidx = ifindex; > memcpy(&querier->addr, saddr, sizeof(*saddr)); > @@ -3867,13 +3865,13 @@ void br_multicast_ctx_init(struct net_br > > brmctx->ip4_other_query.delay_time = 0; > brmctx->ip4_querier.port_ifidx = 0; > - seqcount_init(&brmctx->ip4_querier.seq); > + seqcount_spinlock_init(&brmctx->ip4_querier.seq, &br->multicast_lock); > brmctx->multicast_igmp_version = 2; > #if IS_ENABLED(CONFIG_IPV6) > brmctx->multicast_mld_version = 1; > brmctx->ip6_other_query.delay_time = 0; > brmctx->ip6_querier.port_ifidx = 0; > - seqcount_init(&brmctx->ip6_querier.seq); > + seqcount_spinlock_init(&brmctx->ip6_querier.seq, &br->multicast_lock); > #endif > > timer_setup(&brmctx->ip4_mc_router_timer, > --- a/net/bridge/br_private.h > +++ b/net/bridge/br_private.h > @@ -82,7 +82,7 @@ struct bridge_mcast_other_query { > struct bridge_mcast_querier { > struct br_ip addr; > int port_ifidx; > - seqcount_t seq; > + seqcount_spinlock_t seq; > }; > > /* IGMP/MLD statistics */ >Thanks for fixing it, Acked-by: Nikolay Aleksandrov <nikolay at nvidia.com>
patchwork-bot+netdevbpf at kernel.org
2021-Sep-29 02:40 UTC
[Bridge] [PATCH net] net: bridge: mcast: Associate the seqcount with its protecting lock.
Hello: This patch was applied to netdev/net.git (refs/heads/master): On Tue, 28 Sep 2021 16:10:49 +0200 you wrote:> From: Thomas Gleixner <tglx at linutronix.de> > > The sequence count bridge_mcast_querier::seq is protected by > net_bridge::multicast_lock but seqcount_init() does not associate the > seqcount with the lock. This leads to a warning on PREEMPT_RT because > preemption is still enabled. > > [...]Here is the summary with links: - [net] net: bridge: mcast: Associate the seqcount with its protecting lock. https://git.kernel.org/netdev/net/c/f936bb42aeb9 You are awesome, thank you! -- Deet-doot-dot, I am a bot. https://korg.docs.kernel.org/patchwork/pwbot.html