On Wed, Sep 28, 2022 at 03:45:38PM +0900, Junichi Uekawa wrote:
When copying a large file over sftp over vsock, data size is usually 32kB,
and kmalloc seems to fail to try to allocate 32 32kB regions.
Call Trace:
[<ffffffffb6a0df64>] dump_stack+0x97/0xdb
[<ffffffffb68d6aed>] warn_alloc_failed+0x10f/0x138
[<ffffffffb68d868a>] ? __alloc_pages_direct_compact+0x38/0xc8
[<ffffffffb664619f>] __alloc_pages_nodemask+0x84c/0x90d
[<ffffffffb6646e56>] alloc_kmem_pages+0x17/0x19
[<ffffffffb6653a26>] kmalloc_order_trace+0x2b/0xdb
[<ffffffffb66682f3>] __kmalloc+0x177/0x1f7
[<ffffffffb66e0d94>] ? copy_from_iter+0x8d/0x31d
[<ffffffffc0689ab7>] vhost_vsock_handle_tx_kick+0x1fa/0x301 [vhost_vsock]
[<ffffffffc06828d9>] vhost_worker+0xf7/0x157 [vhost]
[<ffffffffb683ddce>] kthread+0xfd/0x105
[<ffffffffc06827e2>] ? vhost_dev_set_owner+0x22e/0x22e [vhost]
[<ffffffffb683dcd1>] ? flush_kthread_worker+0xf3/0xf3
[<ffffffffb6eb332e>] ret_from_fork+0x4e/0x80
[<ffffffffb683dcd1>] ? flush_kthread_worker+0xf3/0xf3
Work around by doing kvmalloc instead.
Signed-off-by: Junichi Uekawa <uekawa@xxxxxxxxxxxx>
---
drivers/vhost/vsock.c | 2 +-
net/vmw_vsock/virtio_transport_common.c | 2 +-
2 files changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/vhost/vsock.c b/drivers/vhost/vsock.c
index 368330417bde..5703775af129 100644
--- a/drivers/vhost/vsock.c
+++ b/drivers/vhost/vsock.c
@@ -393,7 +393,7 @@ vhost_vsock_alloc_pkt(struct vhost_virtqueue *vq,
return NULL;
}
- pkt->buf = kmalloc(pkt->len, GFP_KERNEL);
+ pkt->buf = kvmalloc(pkt->len, GFP_KERNEL);
if (!pkt->buf) {
kfree(pkt);
return NULL;
diff --git a/net/vmw_vsock/virtio_transport_common.c b/net/vmw_vsock/virtio_transport_common.c
index ec2c2afbf0d0..3a12aee33e92 100644
--- a/net/vmw_vsock/virtio_transport_common.c
+++ b/net/vmw_vsock/virtio_transport_common.c
@@ -1342,7 +1342,7 @@ EXPORT_SYMBOL_GPL(virtio_transport_recv_pkt);
void virtio_transport_free_pkt(struct virtio_vsock_pkt *pkt)
{
- kfree(pkt->buf);
+ kvfree(pkt->buf);
virtio_transport_free_pkt() is used also in virtio_transport.c and
vsock_loopback.c where pkt->buf is allocated with kmalloc(), but IIUC
kvfree() can be used with that memory, so this should be fine.
kfree(pkt);
}
EXPORT_SYMBOL_GPL(virtio_transport_free_pkt);
--
2.37.3.998.g577e59143f-goog
This issue should go away with the Bobby's work about introducing
sk_buff [1], but we can queue this for now.
I'm not sure if we should do the same also in the virtio-vsock driver
(virtio_transport.c). Here in vhost-vsock the buf allocated is only used
in the host, while in the virtio-vsock driver the buffer is exposed to
the device emulated in the host, so it should be physically contiguous
(if not, maybe we need to adjust virtio_vsock_rx_fill()).
So for now I think is fine to use kvmalloc only on vhost-vsock
(eventually we can use it also in vsock_loopback), since the Bobby's
patch should rework this code:
Reviewed-by: Stefano Garzarella <sgarzare@xxxxxxxxxx>
[1]
https://lore.kernel.org/lkml/65d117ddc530d12a6d47fcc45b38891465a90d9f.1660362668.git.bobby.eshleman@xxxxxxxxxxxxx/
Thanks,
Stefano
