From patchwork Thu Jun 15 11:32:02 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: David Howells X-Patchwork-Id: 13281090 X-Patchwork-Delegate: kuba@kernel.org Received: from lindbergh.monkeyblade.net (lindbergh.monkeyblade.net [23.128.96.19]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 50E7E10798 for ; Thu, 15 Jun 2023 11:32:16 +0000 (UTC) Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 2E1F1297B for ; Thu, 15 Jun 2023 04:32:11 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1686828730; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type; bh=2jLPUY6QsgU36zacDi9VUOh4wRLZuAcl8Xg9zAds7pQ=; b=aaWb458x9Gf1ojHI1+5j5M1FW507Zr64X7xeKtd3nrSehh7trh0gBu2fUCrWKL3Yp7nHw4 Byf0V5BQ4qJbF+kTnupsJOBKz680BnrY+78zMOw86CqxElZj1FTGudToodB+ZOVVYXb1hL o/SvBVDNhlUg3ratqQJFau6/e24cldA= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-517-B0uJZzaOOPCYIxFhQXYuOA-1; Thu, 15 Jun 2023 07:32:07 -0400 X-MC-Unique: B0uJZzaOOPCYIxFhQXYuOA-1 Received: from smtp.corp.redhat.com (int-mx07.intmail.prod.int.rdu2.redhat.com [10.11.54.7]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 2D21E8022EF; Thu, 15 Jun 2023 11:32:06 +0000 (UTC) Received: from warthog.procyon.org.uk (unknown [10.42.28.51]) by smtp.corp.redhat.com (Postfix) with ESMTP id 053F21415102; Thu, 15 Jun 2023 11:32:03 +0000 (UTC) Organization: Red Hat UK Ltd. Registered Address: Red Hat UK Ltd, Amberley Place, 107-111 Peascod Street, Windsor, Berkshire, SI4 1TE, United Kingdom. Registered in England and Wales under Company Registration No. 3798903 From: David Howells To: netdev@vger.kernel.org cc: dhowells@redhat.com, syzbot+dd1339599f1840e4cc65@syzkaller.appspotmail.com, Tom Herbert , Tom Herbert , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Jens Axboe , Matthew Wilcox , linux-kernel@vger.kernel.org Subject: [PATCH net-next] kcm: Fix unnecessary psock unreservation. Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-ID: <20786.1686828722.1@warthog.procyon.org.uk> Date: Thu, 15 Jun 2023 12:32:02 +0100 Message-ID: <20787.1686828722@warthog.procyon.org.uk> X-Scanned-By: MIMEDefang 3.1 on 10.11.54.7 X-Spam-Status: No, score=-2.1 required=5.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,RCVD_IN_DNSWL_NONE, SPF_HELO_NONE,SPF_NONE,T_SCC_BODY_TEXT_LINE autolearn=unavailable autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net X-Patchwork-Delegate: kuba@kernel.org kcm_write_msgs() calls unreserve_psock() to release its hold on the underlying TCP socket if it has run out of things to transmit, but if we have nothing in the write queue on entry (e.g. because someone did a zero-length sendmsg), we don't actually go into the transmission loop and as a consequence don't call reserve_psock(). Fix this by skipping the call to unreserve_psock() if we didn't reserve a psock. Fixes: c31a25e1db48 ("kcm: Send multiple frags in one sendmsg()") Reported-by: syzbot+dd1339599f1840e4cc65@syzkaller.appspotmail.com Link: https://lore.kernel.org/r/000000000000a61ffe05fe0c3d08@google.com/ Signed-off-by: David Howells Tested-by: syzbot+dd1339599f1840e4cc65@syzkaller.appspotmail.com cc: Tom Herbert cc: Tom Herbert cc: "David S. Miller" cc: Eric Dumazet cc: Jakub Kicinski cc: Paolo Abeni cc: Jens Axboe cc: Matthew Wilcox cc: netdev@vger.kernel.org --- net/kcm/kcmsock.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/net/kcm/kcmsock.c b/net/kcm/kcmsock.c index d75d775e9462..d0537c1c8cd7 100644 --- a/net/kcm/kcmsock.c +++ b/net/kcm/kcmsock.c @@ -661,6 +661,7 @@ static int kcm_write_msgs(struct kcm_sock *kcm) kcm_abort_tx_psock(psock, ret ? -ret : EPIPE, true); unreserve_psock(kcm); + psock = NULL; txm->started_tx = false; kcm_report_tx_retry(kcm); @@ -696,7 +697,8 @@ static int kcm_write_msgs(struct kcm_sock *kcm) if (!head) { /* Done with all queued messages. */ WARN_ON(!skb_queue_empty(&sk->sk_write_queue)); - unreserve_psock(kcm); + if (psock) + unreserve_psock(kcm); } /* Check if write space is available */