2020-02-21 15:17:56

by Amol Grover

Subject: [PATCH] tcp, ulp: Pass lockdep expression to RCU lists

tcp_ulp_list is traversed using list_for_each_entry_rcu
outside an RCU read-side critical section but under the protection
of tcp_ulp_list_lock.

Hence, add corresponding lockdep expression to silence false-positive
warnings, and harden RCU lists.t

Signed-off-by: Amol Grover <[email protected]>
---
net/ipv4/tcp_ulp.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/net/ipv4/tcp_ulp.c b/net/ipv4/tcp_ulp.c
index 38d3ad141161..b9e55759054e 100644
--- a/net/ipv4/tcp_ulp.c
+++ b/net/ipv4/tcp_ulp.c
@@ -22,7 +22,8 @@ static struct tcp_ulp_ops *tcp_ulp_find(const char *name)
{
struct tcp_ulp_ops *e;

- list_for_each_entry_rcu(e, &tcp_ulp_list, list) {
+ list_for_each_entry_rcu(e, &tcp_ulp_list, list,
+ lockdep_is_held(&tcp_ulp_list_lock)) {
if (strcmp(e->name, name) == 0)
return e;
}
--
2.24.1

2020-02-24 21:02:54

by David Miller

Subject: Re: [PATCH] tcp, ulp: Pass lockdep expression to RCU lists

From: Amol Grover <[email protected]>
Date: Fri, 21 Feb 2020 20:45:38 +0530

> tcp_ulp_list is traversed using list_for_each_entry_rcu
> outside an RCU read-side critical section but under the protection
> of tcp_ulp_list_lock.
>
> Hence, add corresponding lockdep expression to silence false-positive
> warnings, and harden RCU lists.t
>
> Signed-off-by: Amol Grover <[email protected]>

Applied.