From 384900542dc85f3aac7918fea8e7ef62141e3ea6 Mon Sep 17 00:00:00 2001 From: Kuniyuki Iwashima Date: Sat, 15 Nov 2025 02:08:35 +0000 Subject: af_unix: Don't call wait_for_unix_gc() on every sendmsg(). We have been calling wait_for_unix_gc() on every sendmsg() in case there are too many inflight AF_UNIX sockets. This is also because the old GC implementation had poor knowledge of the inflight sockets and had to suspect every sendmsg(). This was improved by commit d9f21b361333 ("af_unix: Try to run GC async."), but we do not even need to call wait_for_unix_gc() if the process is not sending AF_UNIX sockets. The wait_for_unix_gc() call only helps when a malicious process continues to create cyclic references, and we can detect that in a better place and slow it down. Let's move wait_for_unix_gc() to unix_prepare_fpl() that is called only when AF_UNIX socket fd is passed via SCM_RIGHTS. Signed-off-by: Kuniyuki Iwashima Link: https://patch.msgid.link/20251115020935.2643121-5-kuniyu@google.com Signed-off-by: Jakub Kicinski --- net/unix/af_unix.c | 4 ---- 1 file changed, 4 deletions(-) (limited to 'net/unix/af_unix.c') diff --git a/net/unix/af_unix.c b/net/unix/af_unix.c index 4a80dac56bbd..34952242bd81 100644 --- a/net/unix/af_unix.c +++ b/net/unix/af_unix.c @@ -2098,8 +2098,6 @@ static int unix_dgram_sendmsg(struct socket *sock, struct msghdr *msg, if (err < 0) return err; - wait_for_unix_gc(scm.fp); - if (msg->msg_flags & MSG_OOB) { err = -EOPNOTSUPP; goto out; @@ -2393,8 +2391,6 @@ static int unix_stream_sendmsg(struct socket *sock, struct msghdr *msg, if (err < 0) return err; - wait_for_unix_gc(scm.fp); - if (msg->msg_flags & MSG_OOB) { err = -EOPNOTSUPP; #if IS_ENABLED(CONFIG_AF_UNIX_OOB) -- cgit v1.2.3