Am 26.09.22 um 12:55 schrieb Christian Borntraeger:
Am 26.09.22 um 10:06 schrieb Christian Borntraeger:
Am 23.09.22 um 09:53 schrieb Christian Borntraeger:
Am 23.09.22 um 09:21 schrieb Christian Borntraeger:
Peter,
as a heads-up. This commit (bisected and verified) triggers a
regression in our KVM on s390x CI. The symptom is that a specific
testcase (start a guest with next kernel and a poky ramdisk,
then ssh via vsock into the guest and run the reboot command) now
takes much longer (300 instead of 20 seconds). From a first look
it seems that the sshd takes very long to end during shutdown
but I have not looked into that yet.
Any quick idea?
Christian
the sshd seems to hang in virtio-serial (not vsock).
FWIW, sshd does not seem to hang, instead it seems to busy loop in
wait_port_writable calling into the scheduler over and over again.
-#define TASK_FREEZABLE 0x00002000
+#define TASK_FREEZABLE 0x00000000
"Fixes" the issue. Just have to find out which of users is responsible.
So it seems that my initial test was not good enough.
diff --git a/drivers/char/virtio_console.c b/drivers/char/virtio_console.c
index 9fa3c76a267f..e93df4f735fe 100644
--- a/drivers/char/virtio_console.c
+++ b/drivers/char/virtio_console.c
@@ -790,7 +790,7 @@ static int wait_port_writable(struct port *port, bool nonblock)
if (nonblock)
return -EAGAIN;
- ret = wait_event_freezable(port->waitqueue,
+ ret = wait_event_interruptible(port->waitqueue,
!will_write_block(port));
if (ret < 0)
return ret;
Does fix the problem.
My initial test was the following
--- a/drivers/char/virtio_console.c
+++ b/drivers/char/virtio_console.c
@@ -790,10 +790,8 @@ static int wait_port_writable(struct port *port, bool nonblock)
if (nonblock)
return -EAGAIN;
- ret = wait_event_freezable(port->waitqueue,
+ wait_event(port->waitqueue,
!will_write_block(port));
- if (ret < 0)
- return ret;
}
/* Port got hot-unplugged. */
if (!port->guest_connected)
and obviously it did not provide an exit path.
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