Re: [PATCH] netfilter: ipt_CLUSTERIP: Pass lockdep expression to RCU lists
From: Pablo Neira Ayuso <pablo@netfilter.org>
Date: 2020-03-02 12:37:07
Also in:
linux-kernel-mentees, lkml, netfilter-devel
On Wed, Feb 19, 2020 at 03:46:27PM +0530, Amol Grover wrote:
quoted hunk ↗ jump to hunk
cn->configs is traversed using list_for_each_entry_rcu outside an RCU read-side critical section but under the protection of cn->lock. Hence, add corresponding lockdep expression to silence false-positive warnings, and harden RCU lists. Signed-off-by: Amol Grover <redacted> --- net/ipv4/netfilter/ipt_CLUSTERIP.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-)diff --git a/net/ipv4/netfilter/ipt_CLUSTERIP.c b/net/ipv4/netfilter/ipt_CLUSTERIP.c index 6bdb1ab8af61..df856ff835b7 100644 --- a/net/ipv4/netfilter/ipt_CLUSTERIP.c +++ b/net/ipv4/netfilter/ipt_CLUSTERIP.c@@ -139,7 +139,8 @@ __clusterip_config_find(struct net *net, __be32 clusterip) struct clusterip_config *c; struct clusterip_net *cn = clusterip_pernet(net); - list_for_each_entry_rcu(c, &cn->configs, list) { + list_for_each_entry_rcu(c, &cn->configs, list, + lockdep_is_held(&cn->lock)) {
bh is disabled before calling __clusterip_config_find(), then rcu_read_lock_any_held() evaluates true. Are you sure this really results in a WARN_ON splat?