From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail333.us4.mandrillapp.com ([205.201.137.77]:58947 "EHLO mail333.us4.mandrillapp.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754057AbcCAVm4 (ORCPT ); Tue, 1 Mar 2016 16:42:56 -0500 Received: from pmta03.dal05.mailchimp.com (127.0.0.1) by mail333.us4.mandrillapp.com id hqo6e0174nom for ; Tue, 1 Mar 2016 21:42:44 +0000 (envelope-from ) From: Subject: Patch "libceph: don't bail early from try_read() when skipping a message" has been added to the 4.4-stable tree To: , , , Cc: , Message-Id: <145686856285173@kroah.com> Date: Tue, 01 Mar 2016 21:42:44 +0000 MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Sender: stable-owner@vger.kernel.org List-ID: This is a note to let you know that I've just added the patch titled libceph: don't bail early from try_read() when skipping a message to the 4.4-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: libceph-don-t-bail-early-from-try_read-when-skipping-a-message.patch and it can be found in the queue-4.4 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let know about it. >>From e7a88e82fe380459b864e05b372638aeacb0f52d Mon Sep 17 00:00:00 2001 From: Ilya Dryomov Date: Wed, 17 Feb 2016 20:04:08 +0100 Subject: libceph: don't bail early from try_read() when skipping a message From: Ilya Dryomov commit e7a88e82fe380459b864e05b372638aeacb0f52d upstream. The contract between try_read() and try_write() is that when called each processes as much data as possible. When instructed by osd_client to skip a message, try_read() is violating this contract by returning after receiving and discarding a single message instead of checking for more. try_write() then gets a chance to write out more requests, generating more replies/skips for try_read() to handle, forcing the messenger into a starvation loop. Reported-by: Varada Kari Signed-off-by: Ilya Dryomov Tested-by: Varada Kari Reviewed-by: Alex Elder Signed-off-by: Greg Kroah-Hartman --- net/ceph/messenger.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) --- a/net/ceph/messenger.c +++ b/net/ceph/messenger.c @@ -2340,7 +2340,7 @@ static int read_partial_message(struct c con->in_base_pos = -front_len - middle_len - data_len - sizeof(m->footer); con->in_tag = CEPH_MSGR_TAG_READY; - return 0; + return 1; } else if ((s64)seq - (s64)con->in_seq > 1) { pr_err("read_partial_message bad seq %lld expected %lld\n", seq, con->in_seq + 1); @@ -2366,7 +2366,7 @@ static int read_partial_message(struct c sizeof(m->footer); con->in_tag = CEPH_MSGR_TAG_READY; con->in_seq++; - return 0; + return 1; } BUG_ON(!con->in_msg); Patches currently in stable-queue which might be from idryomov@gmail.com are queue-4.4/libceph-fix-ceph_msg_revoke.patch queue-4.4/tcp-dccp-fix-another-race-at-listener-dismantle.patch queue-4.4/libceph-don-t-spam-dmesg-with-stray-reply-warnings.patch queue-4.4/libceph-don-t-bail-early-from-try_read-when-skipping-a-message.patch queue-4.4/libceph-use-the-right-footer-size-when-skipping-a-message.patch