The commit being backported to 3.19 and 3.13 has to contain this race fix:
commit dcc909d90ccdbb73226397ff6d298f7af35b0e11
Author: Markus Pargmann <email address hidden>
Date: Tue Oct 6 20:03:54 2015 +0200
nbd: Add locking for tasks
The timeout handling introduced in 7e2893a16d3e (nbd: Fix timeout detection)
introduces a race condition which may lead to killing of tasks that are
not in nbd context anymore. This was not observed or reproducable yet.
This patch adds locking to critical use of task_recv and task_send to
avoid killing tasks that already left the NBD thread functions. This
lock is only acquired if a timeout occures or the nbd device
starts/stops.
Reported-by: Ben Hutchings <email address hidden>
Signed-off-by: Markus Pargmann <email address hidden>
Reviewed-by: Ben Hutchings <email address hidden>
Fixes: 7e2893a16d3e ("nbd: Fix timeout detection")
Signed-off-by: Jens Axboe <email address hidden>
Note to self:
The commit being backported to 3.19 and 3.13 has to contain this race fix:
commit dcc909d90ccdbb7 3226397ff6d298f 7af35b0e11
Author: Markus Pargmann <email address hidden>
Date: Tue Oct 6 20:03:54 2015 +0200
nbd: Add locking for tasks
The timeout handling introduced in
7e2893a16d3e (nbd: Fix timeout detection)
introduces a race condition which may lead to killing of tasks that are
not in nbd context anymore. This was not observed or reproducable yet.
This patch adds locking to critical use of task_recv and task_send to
avoid killing tasks that already left the NBD thread functions. This
lock is only acquired if a timeout occures or the nbd device
starts/stops.
Reported-by: Ben Hutchings <email address hidden>
Signed-off-by: Markus Pargmann <email address hidden>
Reviewed-by: Ben Hutchings <email address hidden>
Fixes: 7e2893a16d3e ("nbd: Fix timeout detection")
Signed-off-by: Jens Axboe <email address hidden>
Also.