Commit bbc1c5e8 authored Jul 09, 2014 by Lars Ellenberg Committed by Jens Axboe Jul 10, 2014

drbd: fix regression 'out of mem, failed to invoke fence-peer helper'



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@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
Signed-off-by: Jens Axboe <axboe@fb.com>

parent d45b3279

drivers/block/drbd/drbd_nl.c

+6 −0

Original line number	Diff line number	Diff line
		@@ -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");