[PATCH RFC 0/2] kcm: Fix lockdep issue

[PATCH RFC 0/2] kcm: Fix lockdep issue

[Tom Herbert]

When sock_owned_by_user returns true in strparser. Fix is to add and
call sock_owned_by_user_nocheck since the check for owned by user is
not an error condition in this case.

Fixes: 43a0c6751a322847 ("strparser: Stream parser for messages")
Reported-by: syzbot <syzkaller@googlegroups.com>

Tom Herbert (2):
  sock: Add sock_owned_by_user_nocheck
  strparser: Call sock_owned_by_user_nocheck

 include/net/sock.h        | 5 +++++
 net/strparser/strparser.c | 2 +-
 2 files changed, 6 insertions(+), 1 deletion(-)

-- 
2.11.0

[PATCH RFC 1/2] sock: Add sock_owned_by_user_nocheck

[Tom Herbert]

This allows checking socket lock ownership with producing lockdep
warnings.

Signed-off-by: Tom Herbert <tom@quantonium.net>
---
 include/net/sock.h | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/include/net/sock.h b/include/net/sock.h
index 6c1db823f8b9..66fd3951e6f3 100644
--- a/include/net/sock.h
+++ b/include/net/sock.h
@@ -1515,6 +1515,11 @@ static inline bool sock_owned_by_user(const struct sock *sk)
 	return sk->sk_lock.owned;
 }
 
+static inline bool sock_owned_by_user_nocheck(const struct sock *sk)
+{
+	return sk->sk_lock.owned;
+}
+
 /* no reclassification while locks are held */
 static inline bool sock_allow_reclassification(const struct sock *csk)
 {
-- 
2.11.0

[PATCH RFC 2/2] strparser: Call sock_owned_by_user_nocheck

[Tom Herbert]

strparser wants to check socket ownership without producing any
warnings. As indicated by the comment in the code, it is permissible
for owned_by_user to return true.

Fixes: 43a0c6751a322847 ("strparser: Stream parser for messages")
Reported-by: syzbot <syzkaller@googlegroups.com>
Signed-off-by: Tom Herbert <tom@quantonium.net>
---
 net/strparser/strparser.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/strparser/strparser.c b/net/strparser/strparser.c
index c5fda15ba319..1fdab5c4eda8 100644
--- a/net/strparser/strparser.c
+++ b/net/strparser/strparser.c
@@ -401,7 +401,7 @@ void strp_data_ready(struct strparser *strp)
 	 * allows a thread in BH context to safely check if the process
 	 * lock is held. In this case, if the lock is held, queue work.
 	 */
-	if (sock_owned_by_user(strp->sk)) {
+	if (sock_owned_by_user_nocheck(strp->sk)) {
 		queue_work(strp_wq, &strp->work);
 		return;
 	}
-- 
2.11.0