There is a bug when setting the RSS options in virtio_net that can break the whole machine, getting the kernel into an infinite loop.
Running the following command in any QEMU virtual machine with virtionet will reproduce this problem:
# ethtool -X eth0 hfunc toeplitz
This is how the problem happens:
1) ethtool_set_rxfh() calls virtnet_set_rxfh()
2) virtnet_set_rxfh() calls virtnet_commit_rss_command()
3) virtnet_commit_rss_command() populates 4 entries for the rss scatter-gather
4) Since the command above does not have a key, then the last scatter-gatter entry will be zeroed, since rss_key_size == 0. sg_buf_size = vi->rss_key_size;
5) This buffer is passed to qemu, but qemu is not happy with a buffer with zero length, and do the following in virtqueue_map_desc() (QEMU function):
if (!sz) { virtio_error(vdev, "virtio: zero sized buffers are not allowed");
6) virtio_error() (also QEMU function) set the device as broken
vdev->broken = true;
7) Qemu bails out, and do not repond this crazy kernel.
8) The kernel is waiting for the response to come back (function virtnet_send_command())
9) The kernel is waiting doing the following :
while (!virtqueue_get_buf(vi->cvq, &tmp) && !virtqueue_is_broken(vi->cvq)) cpu_relax();
10) None of the following functions above is true, thus, the kernel loops here forever. Keeping in mind that virtqueue_is_broken() does not look at the qemu `vdev->broken`, so, it never realizes that the vitio is broken at QEMU side.
Fix it by not sending the key scatter-gatter key if it is not set.
Fixes: c7114b1249fa ("drivers/net/virtio_net: Added basic RSS support.") Signed-off-by: Breno Leitao leitao@debian.org Cc: stable@vger.kernel.org Cc: qemu-devel@nongnu.org --- drivers/net/virtio_net.c | 16 +++++++++++++--- 1 file changed, 13 insertions(+), 3 deletions(-)
diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c index d7ce4a1011ea..5a7700b103f8 100644 --- a/drivers/net/virtio_net.c +++ b/drivers/net/virtio_net.c @@ -3041,11 +3041,16 @@ static int virtnet_set_ringparam(struct net_device *dev, static bool virtnet_commit_rss_command(struct virtnet_info *vi) { struct net_device *dev = vi->dev; + int has_key = vi->rss_key_size; struct scatterlist sgs[4]; unsigned int sg_buf_size; + int nents = 3; + + if (has_key) + nents += 1;
/* prepare sgs */ - sg_init_table(sgs, 4); + sg_init_table(sgs, nents);
sg_buf_size = offsetof(struct virtio_net_ctrl_rss, indirection_table); sg_set_buf(&sgs[0], &vi->ctrl->rss, sg_buf_size); @@ -3057,8 +3062,13 @@ static bool virtnet_commit_rss_command(struct virtnet_info *vi) - offsetof(struct virtio_net_ctrl_rss, max_tx_vq); sg_set_buf(&sgs[2], &vi->ctrl->rss.max_tx_vq, sg_buf_size);
- sg_buf_size = vi->rss_key_size; - sg_set_buf(&sgs[3], vi->ctrl->rss.key, sg_buf_size); + if (has_key) { + /* Only populate if key is available, otherwise + * populating a buffer with zero size breaks virtio + */ + sg_buf_size = vi->rss_key_size; + sg_set_buf(&sgs[3], vi->ctrl->rss.key, sg_buf_size); + }
if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_MQ, vi->has_rss ? VIRTIO_NET_CTRL_MQ_RSS_CONFIG
On Thu, 21 Mar 2024 09:54:30 -0700, Breno Leitao leitao@debian.org wrote:
There is a bug when setting the RSS options in virtio_net that can break the whole machine, getting the kernel into an infinite loop.
Running the following command in any QEMU virtual machine with virtionet will reproduce this problem:
# ethtool -X eth0 hfunc toeplitz
This is how the problem happens:
ethtool_set_rxfh() calls virtnet_set_rxfh()
virtnet_set_rxfh() calls virtnet_commit_rss_command()
virtnet_commit_rss_command() populates 4 entries for the rss scatter-gather
Since the command above does not have a key, then the last scatter-gatter entry will be zeroed, since rss_key_size == 0. sg_buf_size = vi->rss_key_size;
if (vi->has_rss || vi->has_rss_hash_report) { vi->rss_indir_table_size = virtio_cread16(vdev, offsetof(struct virtio_net_config, rss_max_indirection_table_length)); vi->rss_key_size = virtio_cread8(vdev, offsetof(struct virtio_net_config, rss_max_key_size));
vi->rss_hash_types_supported = virtio_cread32(vdev, offsetof(struct virtio_net_config, supported_hash_types)); vi->rss_hash_types_supported &= ~(VIRTIO_NET_RSS_HASH_TYPE_IP_EX | VIRTIO_NET_RSS_HASH_TYPE_TCP_EX | VIRTIO_NET_RSS_HASH_TYPE_UDP_EX);
dev->hw_features |= NETIF_F_RXHASH; }
vi->rss_key_size is initiated here, I wonder if there is something wrong?
Thanks.
This buffer is passed to qemu, but qemu is not happy with a buffer with zero length, and do the following in virtqueue_map_desc() (QEMU function):
if (!sz) { virtio_error(vdev, "virtio: zero sized buffers are not allowed");
virtio_error() (also QEMU function) set the device as broken
vdev->broken = true;
Qemu bails out, and do not repond this crazy kernel.
The kernel is waiting for the response to come back (function virtnet_send_command())
The kernel is waiting doing the following :
while (!virtqueue_get_buf(vi->cvq, &tmp) && !virtqueue_is_broken(vi->cvq)) cpu_relax();None of the following functions above is true, thus, the kernel loops here forever. Keeping in mind that virtqueue_is_broken() does not look at the qemu `vdev->broken`, so, it never realizes that the vitio is broken at QEMU side.
Fix it by not sending the key scatter-gatter key if it is not set.
Fixes: c7114b1249fa ("drivers/net/virtio_net: Added basic RSS support.") Signed-off-by: Breno Leitao leitao@debian.org Cc: stable@vger.kernel.org Cc: qemu-devel@nongnu.org
drivers/net/virtio_net.c | 16 +++++++++++++--- 1 file changed, 13 insertions(+), 3 deletions(-)
diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c index d7ce4a1011ea..5a7700b103f8 100644 --- a/drivers/net/virtio_net.c +++ b/drivers/net/virtio_net.c @@ -3041,11 +3041,16 @@ static int virtnet_set_ringparam(struct net_device *dev, static bool virtnet_commit_rss_command(struct virtnet_info *vi) { struct net_device *dev = vi->dev;
int has_key = vi->rss_key_size; struct scatterlist sgs[4]; unsigned int sg_buf_size;
int nents = 3;
if (has_key)
nents += 1;/* prepare sgs */
- sg_init_table(sgs, 4);
sg_init_table(sgs, nents);
sg_buf_size = offsetof(struct virtio_net_ctrl_rss, indirection_table); sg_set_buf(&sgs[0], &vi->ctrl->rss, sg_buf_size);
@@ -3057,8 +3062,13 @@ static bool virtnet_commit_rss_command(struct virtnet_info *vi) - offsetof(struct virtio_net_ctrl_rss, max_tx_vq); sg_set_buf(&sgs[2], &vi->ctrl->rss.max_tx_vq, sg_buf_size);
- sg_buf_size = vi->rss_key_size;
- sg_set_buf(&sgs[3], vi->ctrl->rss.key, sg_buf_size);
if (has_key) {
/* Only populate if key is available, otherwise* populating a buffer with zero size breaks virtio*/sg_buf_size = vi->rss_key_size;sg_set_buf(&sgs[3], vi->ctrl->rss.key, sg_buf_size);}
if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_MQ, vi->has_rss ? VIRTIO_NET_CTRL_MQ_RSS_CONFIG
-- 2.43.0
Hello Xuan,
On Fri, Mar 22, 2024 at 10:00:22AM +0800, Xuan Zhuo wrote:
On Thu, 21 Mar 2024 09:54:30 -0700, Breno Leitao leitao@debian.org wrote:
- Since the command above does not have a key, then the last scatter-gatter entry will be zeroed, since rss_key_size == 0. sg_buf_size = vi->rss_key_size;
if (vi->has_rss || vi->has_rss_hash_report) { vi->rss_indir_table_size = virtio_cread16(vdev, offsetof(struct virtio_net_config, rss_max_indirection_table_length)); vi->rss_key_size = virtio_cread8(vdev, offsetof(struct virtio_net_config, rss_max_key_size));
vi->rss_hash_types_supported = virtio_cread32(vdev, offsetof(struct virtio_net_config, supported_hash_types)); vi->rss_hash_types_supported &= ~(VIRTIO_NET_RSS_HASH_TYPE_IP_EX | VIRTIO_NET_RSS_HASH_TYPE_TCP_EX | VIRTIO_NET_RSS_HASH_TYPE_UDP_EX); dev->hw_features |= NETIF_F_RXHASH;}
vi->rss_key_size is initiated here, I wonder if there is something wrong?
Not really, the code above is never executed (in my machines). This is because `vi->has_rss` and `vi->has_rss_hash_report` are both unset.
Looking further, vdev does not have the VIRTIO_NET_F_RSS and VIRTIO_NET_F_HASH_REPORT features.
Also, when I run `ethtool -x`, I got:
# ethtool -x eth0 RX flow hash indirection table for eth0 with 1 RX ring(s): Operation not supported RSS hash key: Operation not supported RSS hash function: toeplitz: on xor: off crc32: off
On Fri, 22 Mar 2024 03:21:21 -0700, Breno Leitao leitao@debian.org wrote:
Hello Xuan,
On Fri, Mar 22, 2024 at 10:00:22AM +0800, Xuan Zhuo wrote:
On Thu, 21 Mar 2024 09:54:30 -0700, Breno Leitao leitao@debian.org wrote:
- Since the command above does not have a key, then the last scatter-gatter entry will be zeroed, since rss_key_size == 0. sg_buf_size = vi->rss_key_size;
if (vi->has_rss || vi->has_rss_hash_report) { vi->rss_indir_table_size = virtio_cread16(vdev, offsetof(struct virtio_net_config, rss_max_indirection_table_length)); vi->rss_key_size = virtio_cread8(vdev, offsetof(struct virtio_net_config, rss_max_key_size));
vi->rss_hash_types_supported = virtio_cread32(vdev, offsetof(struct virtio_net_config, supported_hash_types)); vi->rss_hash_types_supported &= ~(VIRTIO_NET_RSS_HASH_TYPE_IP_EX | VIRTIO_NET_RSS_HASH_TYPE_TCP_EX | VIRTIO_NET_RSS_HASH_TYPE_UDP_EX); dev->hw_features |= NETIF_F_RXHASH;}
vi->rss_key_size is initiated here, I wonder if there is something wrong?
Not really, the code above is never executed (in my machines). This is because `vi->has_rss` and `vi->has_rss_hash_report` are both unset.
Looking further, vdev does not have the VIRTIO_NET_F_RSS and VIRTIO_NET_F_HASH_REPORT features.
Also, when I run `ethtool -x`, I got:
# ethtool -x eth0 RX flow hash indirection table for eth0 with 1 RX ring(s): Operation not supported RSS hash key: Operation not supported RSS hash function: toeplitz: on xor: off crc32: off
The spec saies: Note that if the device offers VIRTIO_NET_F_HASH_REPORT, even if it supports only one pair of virtqueues, it MUST support at least one of commands of VIRTIO_NET_CTRL_MQ class to configure reported hash parameters:
If the device offers VIRTIO_NET_F_RSS, it MUST support VIRTIO_NET_CTRL_MQ_RSS_CONFIG command per 5.1.6.5.7.1.
Otherwise the device MUST support VIRTIO_NET_CTRL_MQ_HASH_CONFIG command per 5.1.6.5.6.4.
So if we have not anyone of `vi->has_rss` and `vi->has_rss_hash_report`, we should return from virtnet_set_rxfh directly.
Thanks.
Hello Xuan,
On Mon, Mar 25, 2024 at 01:57:53PM +0800, Xuan Zhuo wrote:
On Fri, 22 Mar 2024 03:21:21 -0700, Breno Leitao leitao@debian.org wrote:
Hello Xuan,
On Fri, Mar 22, 2024 at 10:00:22AM +0800, Xuan Zhuo wrote:
On Thu, 21 Mar 2024 09:54:30 -0700, Breno Leitao leitao@debian.org wrote:
- Since the command above does not have a key, then the last scatter-gatter entry will be zeroed, since rss_key_size == 0. sg_buf_size = vi->rss_key_size;
if (vi->has_rss || vi->has_rss_hash_report) { vi->rss_indir_table_size = virtio_cread16(vdev, offsetof(struct virtio_net_config, rss_max_indirection_table_length)); vi->rss_key_size = virtio_cread8(vdev, offsetof(struct virtio_net_config, rss_max_key_size));
vi->rss_hash_types_supported = virtio_cread32(vdev, offsetof(struct virtio_net_config, supported_hash_types)); vi->rss_hash_types_supported &= ~(VIRTIO_NET_RSS_HASH_TYPE_IP_EX | VIRTIO_NET_RSS_HASH_TYPE_TCP_EX | VIRTIO_NET_RSS_HASH_TYPE_UDP_EX); dev->hw_features |= NETIF_F_RXHASH;}
vi->rss_key_size is initiated here, I wonder if there is something wrong?
Not really, the code above is never executed (in my machines). This is because `vi->has_rss` and `vi->has_rss_hash_report` are both unset.
Looking further, vdev does not have the VIRTIO_NET_F_RSS and VIRTIO_NET_F_HASH_REPORT features.
Also, when I run `ethtool -x`, I got:
# ethtool -x eth0 RX flow hash indirection table for eth0 with 1 RX ring(s): Operation not supported RSS hash key: Operation not supported RSS hash function: toeplitz: on xor: off crc32: off
The spec saies: Note that if the device offers VIRTIO_NET_F_HASH_REPORT, even if it supports only one pair of virtqueues, it MUST support at least one of commands of VIRTIO_NET_CTRL_MQ class to configure reported hash parameters:
If the device offers VIRTIO_NET_F_RSS, it MUST support VIRTIO_NET_CTRL_MQ_RSS_CONFIG command per 5.1.6.5.7.1.
Otherwise the device MUST support VIRTIO_NET_CTRL_MQ_HASH_CONFIG command per 5.1.6.5.6.4.
So if we have not anyone of `vi->has_rss` and `vi->has_rss_hash_report`, we should return from virtnet_set_rxfh directly.
Makes sense. Although it is not clear to me how vi->has_rss_hash_report is related here, but, I am convinced that we shouldn't do any RSS operation if the device doesn't have the RSS feature, i.e, vi->has_rss is false.
That said, I am thinking about something like this. How does it sound?
diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c index 5a7700b103f8..8c1ad7361cf2 100644 --- a/drivers/net/virtio_net.c +++ b/drivers/net/virtio_net.c @@ -3780,6 +3780,9 @@ static int virtnet_set_rxfh(struct net_device *dev, struct virtnet_info *vi = netdev_priv(dev); int i; + if (!vi->has_rss) + return -EOPNOTSUPP; + if (rxfh->hfunc != ETH_RSS_HASH_NO_CHANGE && rxfh->hfunc != ETH_RSS_HASH_TOP) return -EOPNOTSUPP;
Thanks!
On Mon, 25 Mar 2024 04:26:08 -0700, Breno Leitao leitao@debian.org wrote:
Hello Xuan,
On Mon, Mar 25, 2024 at 01:57:53PM +0800, Xuan Zhuo wrote:
On Fri, 22 Mar 2024 03:21:21 -0700, Breno Leitao leitao@debian.org wrote:
Hello Xuan,
On Fri, Mar 22, 2024 at 10:00:22AM +0800, Xuan Zhuo wrote:
On Thu, 21 Mar 2024 09:54:30 -0700, Breno Leitao leitao@debian.org wrote:
- Since the command above does not have a key, then the last scatter-gatter entry will be zeroed, since rss_key_size == 0. sg_buf_size = vi->rss_key_size;
if (vi->has_rss || vi->has_rss_hash_report) { vi->rss_indir_table_size = virtio_cread16(vdev, offsetof(struct virtio_net_config, rss_max_indirection_table_length)); vi->rss_key_size = virtio_cread8(vdev, offsetof(struct virtio_net_config, rss_max_key_size));
vi->rss_hash_types_supported = virtio_cread32(vdev, offsetof(struct virtio_net_config, supported_hash_types)); vi->rss_hash_types_supported &= ~(VIRTIO_NET_RSS_HASH_TYPE_IP_EX | VIRTIO_NET_RSS_HASH_TYPE_TCP_EX | VIRTIO_NET_RSS_HASH_TYPE_UDP_EX); dev->hw_features |= NETIF_F_RXHASH;}
vi->rss_key_size is initiated here, I wonder if there is something wrong?
Not really, the code above is never executed (in my machines). This is because `vi->has_rss` and `vi->has_rss_hash_report` are both unset.
Looking further, vdev does not have the VIRTIO_NET_F_RSS and VIRTIO_NET_F_HASH_REPORT features.
Also, when I run `ethtool -x`, I got:
# ethtool -x eth0 RX flow hash indirection table for eth0 with 1 RX ring(s): Operation not supported RSS hash key: Operation not supported RSS hash function: toeplitz: on xor: off crc32: off
The spec saies: Note that if the device offers VIRTIO_NET_F_HASH_REPORT, even if it supports only one pair of virtqueues, it MUST support at least one of commands of VIRTIO_NET_CTRL_MQ class to configure reported hash parameters:
If the device offers VIRTIO_NET_F_RSS, it MUST support VIRTIO_NET_CTRL_MQ_RSS_CONFIG command per 5.1.6.5.7.1.
Otherwise the device MUST support VIRTIO_NET_CTRL_MQ_HASH_CONFIG command per 5.1.6.5.6.4.
So if we have not anyone of `vi->has_rss` and `vi->has_rss_hash_report`, we should return from virtnet_set_rxfh directly.
Makes sense. Although it is not clear to me how vi->has_rss_hash_report is related here, but, I am convinced that we shouldn't do any RSS operation if the device doesn't have the RSS feature, i.e, vi->has_rss is false.
That said, I am thinking about something like this. How does it sound?
diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c index 5a7700b103f8..8c1ad7361cf2 100644 --- a/drivers/net/virtio_net.c +++ b/drivers/net/virtio_net.c @@ -3780,6 +3780,9 @@ static int virtnet_set_rxfh(struct net_device *dev, struct virtnet_info *vi = netdev_priv(dev); int i;
- if (!vi->has_rss)
return -EOPNOTSUPP;
Should we check has_rss_hash_report?
@Heng Qi
Could you help us?
Thanks.
if (rxfh->hfunc != ETH_RSS_HASH_NO_CHANGE && rxfh->hfunc != ETH_RSS_HASH_TOP) return -EOPNOTSUPP;Thanks!
在 2024/3/25 下午7:35, Xuan Zhuo 写道:
On Mon, 25 Mar 2024 04:26:08 -0700, Breno Leitao leitao@debian.org wrote:
Hello Xuan,
On Mon, Mar 25, 2024 at 01:57:53PM +0800, Xuan Zhuo wrote:
On Fri, 22 Mar 2024 03:21:21 -0700, Breno Leitao leitao@debian.org wrote:
Hello Xuan,
On Fri, Mar 22, 2024 at 10:00:22AM +0800, Xuan Zhuo wrote:
On Thu, 21 Mar 2024 09:54:30 -0700, Breno Leitao leitao@debian.org wrote:
- Since the command above does not have a key, then the last scatter-gatter entry will be zeroed, since rss_key_size == 0. sg_buf_size = vi->rss_key_size;
if (vi->has_rss || vi->has_rss_hash_report) { vi->rss_indir_table_size = virtio_cread16(vdev, offsetof(struct virtio_net_config, rss_max_indirection_table_length)); vi->rss_key_size = virtio_cread8(vdev, offsetof(struct virtio_net_config, rss_max_key_size));
vi->rss_hash_types_supported = virtio_cread32(vdev, offsetof(struct virtio_net_config, supported_hash_types)); vi->rss_hash_types_supported &= ~(VIRTIO_NET_RSS_HASH_TYPE_IP_EX | VIRTIO_NET_RSS_HASH_TYPE_TCP_EX | VIRTIO_NET_RSS_HASH_TYPE_UDP_EX); dev->hw_features |= NETIF_F_RXHASH;}
vi->rss_key_size is initiated here, I wonder if there is something wrong?
Not really, the code above is never executed (in my machines). This is because `vi->has_rss` and `vi->has_rss_hash_report` are both unset.
Looking further, vdev does not have the VIRTIO_NET_F_RSS and VIRTIO_NET_F_HASH_REPORT features.
Also, when I run `ethtool -x`, I got:
# ethtool -x eth0 RX flow hash indirection table for eth0 with 1 RX ring(s): Operation not supported RSS hash key: Operation not supported RSS hash function: toeplitz: on xor: off crc32: off
The spec saies: Note that if the device offers VIRTIO_NET_F_HASH_REPORT, even if it supports only one pair of virtqueues, it MUST support at least one of commands of VIRTIO_NET_CTRL_MQ class to configure reported hash parameters:
If the device offers VIRTIO_NET_F_RSS, it MUST support VIRTIO_NET_CTRL_MQ_RSS_CONFIG command per 5.1.6.5.7.1.
Otherwise the device MUST support VIRTIO_NET_CTRL_MQ_HASH_CONFIG command per 5.1.6.5.6.4.
So if we have not anyone of `vi->has_rss` and `vi->has_rss_hash_report`, we should return from virtnet_set_rxfh directly.
Makes sense. Although it is not clear to me how vi->has_rss_hash_report is related here, but, I am convinced that we shouldn't do any RSS operation if the device doesn't have the RSS feature, i.e, vi->has_rss is false.
That said, I am thinking about something like this. How does it sound?
diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c index 5a7700b103f8..8c1ad7361cf2 100644 --- a/drivers/net/virtio_net.c +++ b/drivers/net/virtio_net.c @@ -3780,6 +3780,9 @@ static int virtnet_set_rxfh(struct net_device *dev, struct virtnet_info *vi = netdev_priv(dev); int i;
- if (!vi->has_rss)
return -EOPNOTSUPP;Should we check has_rss_hash_report?
Hi, Breno.
You can refer to the following modification. It is worth noting that \field{rss_max_indirection_table_length} should only be accessed if VIRTIO_NET_F_RSS is negotiated, which I have modified below:
diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c index 727c874..fb4c438 100644 --- a/drivers/net/virtio_net.c +++ b/drivers/net/virtio_net.c @@ -3836,10 +3836,16 @@ static int virtnet_set_rxfh(struct net_device *dev, struct virtnet_info *vi = netdev_priv(dev); int i;
+ if (!vi->has_rss && !vi->has_rss_hash_report) + return -EOPNOTSUPP; + if (rxfh->hfunc != ETH_RSS_HASH_NO_CHANGE && rxfh->hfunc != ETH_RSS_HASH_TOP) return -EOPNOTSUPP;
+ if (rxfh->indir && !vi->has_rss) + return -EINVAL; + if (rxfh->indir) { for (i = 0; i < vi->rss_indir_table_size; ++i) vi->ctrl->rss.indirection_table[i] = rxfh->indir[i]; @@ -4757,13 +4763,14 @@ static int virtnet_probe(struct virtio_device *vdev) if (virtio_has_feature(vdev, VIRTIO_NET_F_HASH_REPORT)) vi->has_rss_hash_report = true;
- if (virtio_has_feature(vdev, VIRTIO_NET_F_RSS)) + if (virtio_has_feature(vdev, VIRTIO_NET_F_RSS)) { vi->has_rss = true; - - if (vi->has_rss || vi->has_rss_hash_report) { vi->rss_indir_table_size = virtio_cread16(vdev, offsetof(struct virtio_net_config, rss_max_indirection_table_length)); + } + + if (vi->has_rss || vi->has_rss_hash_report) { vi->rss_key_size = virtio_cread8(vdev, offsetof(struct virtio_net_config, rss_max_key_size));
Regards, Heng
@Heng Qi
Could you help us?
Thanks.
if (rxfh->hfunc != ETH_RSS_HASH_NO_CHANGE && rxfh->hfunc != ETH_RSS_HASH_TOP) return -EOPNOTSUPP;Thanks!
linux-stable-mirror@lists.linaro.org
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Breno Leitao -
Heng Qi -
Xuan Zhuo