From 50b16d1ddb28fd72581e1a4467e4d444b6d4cf68 Mon Sep 17 00:00:00 2001 Message-Id: <50b16d1ddb28fd72581e1a4467e4d444b6d4cf68.1601675152.git.zanussi@kernel.org> In-Reply-To: <5b5a156f9808b1acf1205606e03da117214549ea.1601675151.git.zanussi@kernel.org> References: <5b5a156f9808b1acf1205606e03da117214549ea.1601675151.git.zanussi@kernel.org> From: Thomas Gleixner Date: Sun, 28 Oct 2012 11:18:08 +0100 Subject: [PATCH 234/333] net: netfilter: Serialize xt_write_recseq sections on RT Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/4.19/older/patches-4.19.148-rt64.tar.xz The netfilter code relies only on the implicit semantics of local_bh_disable() for serializing wt_write_recseq sections. RT breaks that and needs explicit serialization here. Reported-by: Peter LaDow Signed-off-by: Thomas Gleixner --- include/linux/netfilter/x_tables.h | 7 +++++++ net/netfilter/core.c | 6 ++++++ 2 files changed, 13 insertions(+) diff --git a/include/linux/netfilter/x_tables.h b/include/linux/netfilter/x_tables.h index 9077b3ebea08..1710f2aff350 100644 --- a/include/linux/netfilter/x_tables.h +++ b/include/linux/netfilter/x_tables.h @@ -6,6 +6,7 @@ #include #include #include +#include #include /* Test a struct->invflags and a boolean for inequality */ @@ -345,6 +346,8 @@ void xt_free_table_info(struct xt_table_info *info); */ DECLARE_PER_CPU(seqcount_t, xt_recseq); +DECLARE_LOCAL_IRQ_LOCK(xt_write_lock); + /* xt_tee_enabled - true if x_tables needs to handle reentrancy * * Enabled if current ip(6)tables ruleset has at least one -j TEE rule. @@ -365,6 +368,9 @@ static inline unsigned int xt_write_recseq_begin(void) { unsigned int addend; + /* RT protection */ + local_lock(xt_write_lock); + /* * Low order bit of sequence is set if we already * called xt_write_recseq_begin(). @@ -395,6 +401,7 @@ static inline void xt_write_recseq_end(unsigned int addend) /* this is kind of a write_seqcount_end(), but addend is 0 or 1 */ smp_wmb(); __this_cpu_add(xt_recseq.sequence, addend); + local_unlock(xt_write_lock); } /* diff --git a/net/netfilter/core.c b/net/netfilter/core.c index 93aaec3a54ec..b364cf8e5776 100644 --- a/net/netfilter/core.c +++ b/net/netfilter/core.c @@ -20,6 +20,7 @@ #include #include #include +#include #include #include #include @@ -27,6 +28,11 @@ #include "nf_internals.h" +#ifdef CONFIG_PREEMPT_RT_BASE +DEFINE_LOCAL_IRQ_LOCK(xt_write_lock); +EXPORT_PER_CPU_SYMBOL(xt_write_lock); +#endif + const struct nf_ipv6_ops __rcu *nf_ipv6_ops __read_mostly; EXPORT_SYMBOL_GPL(nf_ipv6_ops); -- 2.17.1