The branch main has been updated by markj:
URL:
https://cgit.FreeBSD.org/src/commit/?id=e6c19aa94da4a799472f8b82f196ffc42d0dbdaf
commit e6c19aa94da4a799472f8b82f196ffc42d0dbdaf
Author: Mark Johnston <ma...@freebsd.org>
AuthorDate: 2021-09-14 13:02:05 +0000
Commit: Mark Johnston <ma...@freebsd.org>
CommitDate: 2021-09-14 13:02:05 +0000
sctp: Allow blocking on I/O locks even with non-blocking sockets
There are two flags to request a non-blocking receive on a socket:
MSG_NBIO and MSG_DONTWAIT. They are handled a bit differently in that
soreceive_generic() and soreceive_stream() will block on the socket I/O
lock when MSG_NBIO is set, but not if MSG_DONTWAIT is set. In general,
MSG_NBIO seems to mean, "don't block if there is no data to receive" and
MSG_DONTWAIT means "don't go to sleep for any reason".
SCTP's soreceive implementation did not allow blocking on the I/O lock
if either flag is set, but this violates an assumption in
aio_process_sb(), which specifies MSG_NBIO but nonetheless
expects to make progress if data is available to read. Change
sctp_sorecvmsg() to block on the I/O lock only if MSG_DONTWAIT
is not set.
Reported by: syzbot+c7d22dbbb9aef5094...@syzkaller.appspotmail.com
Reviewed by: tuexen
MFC after: 1 week
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D31915
---
sys/netinet/sctputil.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/sys/netinet/sctputil.c b/sys/netinet/sctputil.c
index 09d486038b65..c6cdd3315704 100644
--- a/sys/netinet/sctputil.c
+++ b/sys/netinet/sctputil.c
@@ -5585,7 +5585,7 @@ sctp_sorecvmsg(struct socket *so,
rwnd_req, block_allowed, so->so_rcv.sb_cc,
(uint32_t)uio->uio_resid);
}
- error = SOCK_IO_RECV_LOCK(so, (block_allowed ? SBL_WAIT : 0));
+ error = SOCK_IO_RECV_LOCK(so, SBLOCKWAIT(in_flags));
if (error) {
goto release_unlocked;
}
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