On Sun, Oct 05, 2014 at 04:47:01PM -0700, Greg KH wrote:
> On Wed, Oct 01, 2014 at 11:32:29AM +0200, Philipp Reisner wrote:
> > From: Lars Ellenberg <lars.ellenberg@xxxxxxxxxx>
> >
> > Stable info:
> > This patch landed in upstream with v3.16 as commit
> > bbc1c5e8ad6dfebf9d13b8a4ccdf66c92913eac9
> > it should go into v3.14+
> >
> > Since linux kernel 3.13, kthread_run() internally uses
> > wait_for_completion_killable(). We sometimes may use kthread_run()
> > while we still have a signal pending, which we used to kick our threads
> > out of potentially blocking network functions, causing kthread_run() to
> > mistake that as a new fatal signal and fail.
> >
> > Fix: flush_signals() before kthread_run().
> >
> > Signed-off-by: Philipp Reisner <philipp.reisner@xxxxxxxxxx>
> > Signed-off-by: Lars Ellenberg <lars.ellenberg@xxxxxxxxxx>
> > Signed-off-by: Jens Axboe <axboe@xxxxxx>
> > ---
> > drivers/block/drbd/drbd_nl.c | 6 ++++++
> > 1 file changed, 6 insertions(+)
> >
> > diff --git a/drivers/block/drbd/drbd_nl.c b/drivers/block/drbd/drbd_nl.c
> > index 1b35c45..3f2e167 100644
> > --- a/drivers/block/drbd/drbd_nl.c
> > +++ b/drivers/block/drbd/drbd_nl.c
> > @@ -544,6 +544,12 @@ void conn_try_outdate_peer_async(struct drbd_connection *connection)
> > struct task_struct *opa;
> >
> > kref_get(&connection->kref);
> > + /* We may just have force_sig()'ed this thread
> > + * to get it out of some blocking network function.
> > + * Clear signals; otherwise kthread_run(), which internally uses
> > + * wait_on_completion_killable(), will mistake our pending signal
> > + * for a new fatal signal and fail. */
> > + flush_signals(current);
> > opa = kthread_run(_try_outdate_peer_async, connection, "drbd_async_h");
> > if (IS_ERR(opa)) {
> > drbd_err(connection, "out of mem, failed to invoke fence-peer helper\n");
>
> This doesn't apply to 3.16-stable or 3.14-stable, can you please provide
> a working backport?
There was a rename of "tconn" to "connection" between 3.14 and .15.
Other than that, this has not changed.
Below applies to 3.13 and 3.14 stable as of today.
Lars
8<----
>From a82efa2adeb992b5ded798b01b4567bc07b6ab1b Mon Sep 17 00:00:00 2001
From: Lars Ellenberg <lars.ellenberg@xxxxxxxxxx>
Date: Tue, 7 Oct 2014 17:20:27 +0200
Subject: [PATCH] drbd: fix regression 'out of mem, failed to invoke fence-peer
helper'
Stable info:
This patch landed in upstream with v3.16 as commit
bbc1c5e8ad6dfebf9d13b8a4ccdf66c92913eac9
it should go into v3.13+
Since linux kernel 3.13, kthread_run() internally uses
wait_for_completion_killable(). We sometimes may use kthread_run()
while we still have a signal pending, which we used to kick our threads
out of potentially blocking network functions, causing kthread_run() to
mistake that as a new fatal signal and fail.
Fix: flush_signals() before kthread_run().
Signed-off-by: Philipp Reisner <philipp.reisner@xxxxxxxxxx>
Signed-off-by: Lars Ellenberg <lars.ellenberg@xxxxxxxxxx>
Signed-off-by: Jens Axboe <axboe@xxxxxx>
---
drivers/block/drbd/drbd_nl.c | 6 ++++++
1 file changed, 6 insertions(+)
diff --git a/drivers/block/drbd/drbd_nl.c b/drivers/block/drbd/drbd_nl.c
index c706d50..8c16c2f 100644
--- a/drivers/block/drbd/drbd_nl.c
+++ b/drivers/block/drbd/drbd_nl.c
@@ -525,6 +525,12 @@ void conn_try_outdate_peer_async(struct drbd_tconn *tconn)
struct task_struct *opa;
kref_get(&tconn->kref);
+ /* We may just have force_sig()'ed this thread
+ * to get it out of some blocking network function.
+ * Clear signals; otherwise kthread_run(), which internally uses
+ * wait_on_completion_killable(), will mistake our pending signal
+ * for a new fatal signal and fail. */
+ flush_signals(current);
opa = kthread_run(_try_outdate_peer_async, tconn, "drbd_async_h");
if (IS_ERR(opa)) {
conn_err(tconn, "out of mem, failed to invoke fence-peer helper\n");
--
1.9.1
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