linux-kernel - [PATCH 3.13 092/105] um: ubd: Fix for processes stuck in D state forever

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <1414436240-13879-93-git-send-email-kamal@canonical.com>
Date:	Mon, 27 Oct 2014 11:57:07 -0700
From:	Kamal Mostafa <kamal@...onical.com>
To:	linux-kernel@...r.kernel.org, stable@...r.kernel.org,
	kernel-team@...ts.ubuntu.com
Cc:	Thorsten Knabe <linux@...rsten-knabe.de>,
	Richard Weinberger <richard@....at>,
	Kamal Mostafa <kamal@...onical.com>
Subject: [PATCH 3.13 092/105] um: ubd: Fix for processes stuck in D state forever

3.13.11.10 -stable review patch.  If anyone has any objections, please let me know.

------------------

From: Thorsten Knabe <linux@...rsten-knabe.de>

commit 2a2361228c5e6d8c1733f00653481de918598e50 upstream.

Starting with Linux 3.12 processes get stuck in D state forever in
UserModeLinux under sync heavy workloads. This bug was introduced by
commit 805f11a0d5 (um: ubd: Add REQ_FLUSH suppport).
Fix bug by adding a check if FLUSH request was successfully submitted to
the I/O thread and keeping the FLUSH request on the request queue on
submission failures.

Fixes: 805f11a0d5 (um: ubd: Add REQ_FLUSH suppport)
Signed-off-by: Thorsten Knabe <linux@...rsten-knabe.de>
Signed-off-by: Richard Weinberger <richard@....at>
Signed-off-by: Kamal Mostafa <kamal@...onical.com>
---
 arch/um/drivers/ubd_kern.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/arch/um/drivers/ubd_kern.c b/arch/um/drivers/ubd_kern.c
index 3716e69..e8ab93c 100644
--- a/arch/um/drivers/ubd_kern.c
+++ b/arch/um/drivers/ubd_kern.c
@@ -1277,7 +1277,7 @@ static void do_ubd_request(struct request_queue *q)
 
 	while(1){
 		struct ubd *dev = q->queuedata;
-		if(dev->end_sg == 0){
+		if(dev->request == NULL){
 			struct request *req = blk_fetch_request(q);
 			if(req == NULL)
 				return;
@@ -1299,7 +1299,8 @@ static void do_ubd_request(struct request_queue *q)
 				return;
 			}
 			prepare_flush_request(req, io_req);
-			submit_request(io_req, dev);
+			if (submit_request(io_req, dev) == false)
+				return;
 		}
 
 		while(dev->start_sg < dev->end_sg){
-- 
1.9.1

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/