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>
This commit is contained in:
Lars Ellenberg 2014-07-09 21:18:32 +02:00 committed by Jens Axboe
parent d45b3279a5
commit bbc1c5e8ad
1 changed files with 6 additions and 0 deletions

View File

@ -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");