On 17-Dec-18 10:45 AM, Hideyuki Yamashita wrote:
On 17-Dec-18 10:02 AM, Hideyuki Yamashita wrote:
Dear Thomas and all,
I took a look on dpdk code.
I firstly write qustions and my analisys
on the current dpdk code follows after that.
[1.Questions]
I have several questions to ask again.
Is my understanding correct about followings
Q1: "EAL:ERROR, Invalid memory" is ignorable
Q2: there is no big difference between calling
rte_eal_hotplug_remove(bus->name, dev->name)
and
rte_dev_remove(dev) because anyway it
reaches to rte_pmd_vhost_remove and encounter
the same error.
[2.snip from my code]
.....
rte_eth_dev_close(port_id);
ret = rte_dev_remove(dev);
if (ret < 0)
return ret;
rte_eth_dev_release_port(&rte_eth_devices[port_id]);
[3. My analysis on dpdk code]
static int
rte_pmd_vhost_remove(struct rte_vdev_device *dev)
{
...........
eth_dev_close(eth_dev);
rte_free(vring_states[eth_dev->data->port_id]);
vring_states[eth_dev->data->port_id] = NULL;
rte_eth_dev_release_port(eth_dev);
As you can see in rte_eth_vhost.c
It calls both eth_dev_close and rte_eth_dev_release_port.
And inside both functions, it tries to free mac_addrs.
rte_free(dev->data->mac_addrs); //in rth_dev_close
rte_free(eth_dev->data->mac_addrs); //in rte_eth_dev_release_port
I understand that is the reason why
/* Free the memory space back to heap */
void rte_free(void *addr)
{
if (addr == NULL) return;
if (malloc_heap_free(malloc_elem_from_data(addr)) < 0)
RTE_LOG(ERR, EAL, "Error: Invalid memory\n");
}
encounter the error.
As an experiment, I commented out one of them, "ERR, Invalid memory"
disappered.
Thanks and BR,
Hideyuki Yamashita
NTT TechnoCross
Adding my colleague Yasufumi and Hiroyuki as CC.
We are waiting valuable advice from you.
Thanks in advance,
Hideyuki Yamashita
NTT TechnoCross
Dear Thomas and all,
I hope you all get safely back home after DPDK summit.
(When I get back Japan, it is chilling. (start of winter))
On DPDK 18.11.0, we tried to remove vhost device by using
rte_eal_hotplug_remove().
However, following syslog message is printed.
“EAL: Error: Invalid memory”
At DPDK summit San Jose, we had chance to ask Thomas how to handle the error
message, and he gave us following advice:
Replace “rte_eal_hotplug_add()” to “rte_dev_probe(devargs)” and
“rte_eal_hotplug_remove()” to “rte_eth_dev_close() and rte_dev_remove(rte_dev)”
We tested above changes, but the result is the same (i.e., same error message
is printed).
The debug log message says:
---
[primary]
VHOST_CONFIG: vhost-user server: socket created, fd: 17
VHOST_CONFIG: bind to /tmp/sock0
EAL: Error: Invalid memory
VHOST_CONFIG: vhost-user server: socket created, fd: 17
VHOST_CONFIG: bind to /tmp/sock0
[secondary]
APP: devargs=eth_vhost0,iface=/tmp/sock0,queues=1
EAL: request: eal_dev_mp_request
EAL: msg: eal_dev_mp_request
EAL: request: bus_vdev_mp
EAL: msg: bus_vdev_mp
EAL: msg: bus_vdev_mp
EAL: reply: eal_dev_mp_request
EAL: msg: eal_dev_mp_request
rte_eth_promiscuous_disable: Function not supported
rte_eth_allmulticast_disable: Function not supported
APP: To Server: add
EAL: request: eal_dev_mp_request
EAL: msg: eal_dev_mp_request
EAL: reply: eal_dev_mp_request
EAL: msg: eal_dev_mp_request
APP: To Server: del
APP: devargs=eth_vhost0,iface=/tmp/sock0,queues=1
EAL: request: eal_dev_mp_request
EAL: msg: eal_dev_mp_request
EAL: request: bus_vdev_mp
EAL: msg: bus_vdev_mp
EAL: msg: bus_vdev_mp
EAL: reply: eal_dev_mp_request
EAL: msg: eal_dev_mp_request
rte_eth_promiscuous_disable: Function not supported
rte_eth_allmulticast_disable: Function not supported
APP: To Server: add
---
We would like to ask:
1) Is the message “EAL: Error: Invalid memory” ignorable or not? There is
no obstacle except this message to re-add the vhost device.
2) Which is the better(best?) way to add/del vhost device
“rte_eal_hotplug_add/remove()” or the way Thomas suggested?
Thanks in advance and have a nice day.
BR,
Hideyuki Yamashita
NTT TechnoCross
Hi Hideyuki,
The error you're referring to (about invalid memory) means that you're trying
to free a pointer that points to invalid memory. Meaning, either the pointer
itself is not pointing to an allocated area, or it points to memory that has
already been freed.
If dev->data->mac_addrs and eth_dev->data->mac_addrs point to the same area,
this is a bug, because this would lead to double free, and rte_malloc will rightly complain
about invalid memory. Now, malloc won't try to do anything with the invalid memory, so the
error itself is harmless *as far as malloc is concerned*, but these attempts to free the
memory twice should be fixed whereever they happen.
I'm not well-versed in dev infrastructure, so i wouldn't be able to say which
one of the rte_free calls is an extra, unneeded one. This is something e.g.
Thomas could help with, or the driver maintainer.
--Thanks,
Anatoly
Hello Anatoly,
Thanks for your reply for my newbie question.
Now I understand that this error is harmless from DPDK application(SPP)
point of view in practice. Thanks.
But anyway if there is a double free logic, it is a bug and should be
fixed.
The remaining issues are
1. If it is really a bug (or my mis-understanding)
2. If is is a bug which function should remove rte_free(mac_addrs)
From description, it looks like a bug. Correct usage of API
(rte_dev_close() followed by rte_dev_remove()) should not trigger any
errors. You might want to create a BugZilla entry describing the issue.
Thanks,
Hideyuki Yamashita
NTT TechnoCross
--
Thanks,
Anatoly
