The branch main has been updated by markj:
URL:
https://cgit.FreeBSD.org/src/commit/?id=a8aa6f1f784b91acb4ef9387a28c78311493eb66
commit a8aa6f1f784b91acb4ef9387a28c78311493eb66
Author: Mark Johnston <ma...@freebsd.org>
AuthorDate: 2021-09-07 18:51:54 +0000
Commit: Mark Johnston <ma...@freebsd.org>
CommitDate: 2021-09-07 21:12:09 +0000
socket: Avoid clearing SS_ISCONNECTING if soconnect() fails
This behaviour appears to date from the 4.4 BSD import. It has two
problems:
1. The update to so_state is not protected by the socket lock, so
concurrent updates to so_state may be lost.
2. Suppose two threads race to call connect(2) on a socket, and one
succeeds while the other fails. Then the failing thread may
incorrectly clear SS_ISCONNECTING, confusing the state machine.
Simply remove the update. It does not appear to be necessary:
pru_connect implementations which call soisconnecting() only do so after
all failure modes have been handled. For instance, tcp_connect() and
tcp6_connect() will never return an error after calling soisconnected().
However, we cannot correctly assert that SS_ISCONNECTED is not set after
an error from soconnect() since the socket lock is not held across the
pru_connect call, so a concurrent connect(2) may have set the flag.
MFC after: 1 month
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D31699
---
sys/kern/uipc_syscalls.c | 9 ++-------
1 file changed, 2 insertions(+), 7 deletions(-)
diff --git a/sys/kern/uipc_syscalls.c b/sys/kern/uipc_syscalls.c
index 3208dc0491dd..44079bae1e9b 100644
--- a/sys/kern/uipc_syscalls.c
+++ b/sys/kern/uipc_syscalls.c
@@ -484,7 +484,7 @@ kern_connectat(struct thread *td, int dirfd, int fd, struct
sockaddr *sa)
{
struct socket *so;
struct file *fp;
- int error, interrupted = 0;
+ int error;
#ifdef CAPABILITY_MODE
if (IN_CAPABILITY_MODE(td) && (dirfd == AT_FDCWD))
@@ -522,11 +522,8 @@ kern_connectat(struct thread *td, int dirfd, int fd,
struct sockaddr *sa)
while ((so->so_state & SS_ISCONNECTING) && so->so_error == 0) {
error = msleep(&so->so_timeo, &so->so_lock, PSOCK | PCATCH,
"connec", 0);
- if (error != 0) {
- if (error == EINTR || error == ERESTART)
- interrupted = 1;
+ if (error != 0)
break;
- }
}
if (error == 0) {
error = so->so_error;
@@ -534,8 +531,6 @@ kern_connectat(struct thread *td, int dirfd, int fd, struct
sockaddr *sa)
}
SOCK_UNLOCK(so);
bad:
- if (!interrupted)
- so->so_state &= ~SS_ISCONNECTING;
if (error == ERESTART)
error = EINTR;
done1:
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