This is a note to let you know that I've just added the patch titled
um: ubd: Fix for processes stuck in D state forever
to the 3.14-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:
um-ubd-fix-for-processes-stuck-in-d-state-forever.patch
and it can be found in the queue-3.14 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 2a2361228c5e6d8c1733f00653481de918598e50 Mon Sep 17 00:00:00 2001
From: Thorsten Knabe <linux@xxxxxxxxxxxxxxxxx>
Date: Sat, 23 Aug 2014 15:47:38 +0200
Subject: um: ubd: Fix for processes stuck in D state forever
From: Thorsten Knabe <linux@xxxxxxxxxxxxxxxxx>
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@xxxxxxxxxxxxxxxxx>
Signed-off-by: Richard Weinberger <richard@xxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
arch/um/drivers/ubd_kern.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
--- a/arch/um/drivers/ubd_kern.c
+++ b/arch/um/drivers/ubd_kern.c
@@ -1277,7 +1277,7 @@ static void do_ubd_request(struct reques
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 reques
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){
Patches currently in stable-queue which might be from linux@xxxxxxxxxxxxxxxxx are
queue-3.14/um-ubd-fix-for-processes-stuck-in-d-state-forever.patch
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