Boot failure when using NFS on OMAP based evms

DISCUSSION Franklin S Cooper Jr. 3 participants 5 messages Apr 6, 2016 – Apr 7, 2016

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Networking Network drivers NFS client NFS server +1 more subsystems

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Franklin S Cooper Jr.

author

2016-04-06 23:12 UTC #0 lore raw

Hi All,

Currently linux-next is failing to boot via NFS on my AM335x GP evm, AM437x GP evm and Beagle X15. I bisected the problem down to the commit "udp: remove headers from UDP packets before queueing".

I had to revert the following three commits to get things working again:

e6afc8ace6dd5cef5e812f26c72579da8806f5ac
udp: remove headers from UDP packets before queueing

627d2d6b550094d88f9e518e15967e7bf906ebbf
udp: enable MSG_PEEK at non-zero offset

b9bb53f3836f4eb2bdeb3447be11042bd29c2408
sock: convert sk_peek_offset functions to WRITE_ONCE

I'm using omap2plus_defconfig for my config.

Below bootlogs are from my AM335x GP evm:

Working
http://pastebin.ubuntu.com/15661989/ (Linux-next 3 patches reverted)

Failing
http://pastebin.ubuntu.com/15661318/ (Linux-next)

Willem de Bruijn

2016-04-07 02:22 UTC #1 lore raw

Quoted 8 lines · Franklin S Cooper Jr.

Hi All,
Currently linux-next is failing to boot via NFS on my AM335x GP evm, AM437x GP evm and Beagle X15. I bisected the problem down to the commit "udp: remove headers from UDP packets before queueing".
I had to revert the following three commits to get things working again:

Quoted 9 lines

e6afc8ace6dd5cef5e812f26c72579da8806f5ac
udp: remove headers from UDP packets before queueing
627d2d6b550094d88f9e518e15967e7bf906ebbf
udp: enable MSG_PEEK at non-zero offset
b9bb53f3836f4eb2bdeb3447be11042bd29c2408
sock: convert sk_peek_offset functions to WRITE_ONCE

Thanks for the report, and apologies for breaking your configuration. I had missed that sunrpc can dequeue skbs from a udp receive queue and makes assumptions about the layout of those packets. rxrpc does the same. From what I can tell so far, those are the only two protocols that do this. I have verified that the following fixes rxrpc for me

net/rxrpc/ar-input.c +0 -0

@@ -612,9 +612,9 @@ int rxrpc_extract_header(struct rxrpc_skb_priv

*sp, struct sk_buff *skb)

        struct rxrpc_wire_header whdr;

        /* dig out the RxRPC connection details */
-       if (skb_copy_bits(skb, sizeof(struct udphdr), &whdr, sizeof(whdr)) < 0)
+       if (skb_copy_bits(skb, 0, &whdr, sizeof(whdr)) < 0)
                return -EBADMSG;
-       if (!pskb_pull(skb, sizeof(struct udphdr) + sizeof(whdr)))
+       if (!pskb_pull(skb, sizeof(whdr)))
                BUG();

I have not yet been able to reproduce the sunrpc/nfs issue, but I suspect that the following might fix it. I will try to create an NFS setup.

net/sunrpc/socklib.c +0 -0

index 2df87f7..8ab40ba 100644
@@ -155,7 +155,7 @@ int csum_partial_copy_to_xdr(struct xdr_buf *xdr,

struct sk_buff *skb)

        struct xdr_skb_reader   desc;

        desc.skb = skb;
-       desc.offset = sizeof(struct udphdr);
+       desc.offset = 0;
        desc.count = skb->len - desc.offset;

        if (skb_csum_unnecessary(skb))

net/sunrpc/svcsock.c +0 -0

index 1413cdc..71d6072 100644
@@ -617,7 +617,7 @@ static int svc_udp_recvfrom(struct svc_rqst *rqstp)
        svsk->sk_sk->sk_stamp = skb->tstamp;
        set_bit(XPT_DATA, &svsk->sk_xprt.xpt_flags); /* there may be

more data... */

-       len  = skb->len - sizeof(struct udphdr);
+       len  = skb->len;
        rqstp->rq_arg.len = len;

        rqstp->rq_prot = IPPROTO_UDP;
@@ -641,8 +641,7 @@ static int svc_udp_recvfrom(struct svc_rqst *rqstp)
                skb_free_datagram_locked(svsk->sk_sk, skb);
        } else {
                /* we can use it in-place */
-               rqstp->rq_arg.head[0].iov_base = skb->data +
-                       sizeof(struct udphdr);
+               rqstp->rq_arg.head[0].iov_base = skb->data;
                rqstp->rq_arg.head[0].iov_len = len;
                if (skb_checksum_complete(skb))
                        goto out_free;

net/sunrpc/xprtsock.c +2 -3

index 65e7595..c1fc7b2 100644
@@ -995,15 +995,14 @@ static void xs_udp_data_read_skb(struct rpc_xprt *xprt,
        u32 _xid;
        __be32 *xp;
 
-       repsize = skb->len - sizeof(struct udphdr);
+       repsize = skb->len;
        if (repsize < 4) {
                dprintk("RPC:       impossible RPC reply size %d!\n", repsize);
                return;
        }
 
 
 
        /* Copy the XID from the skb... */
-       xp = skb_header_pointer(skb, sizeof(struct udphdr),
-                               sizeof(_xid), &_xid);
+       xp = skb_header_pointer(skb, 0, sizeof(_xid), &_xid);
        if (xp == NULL)

                return;

Franklin S Cooper Jr.

author

2016-04-07 14:36 UTC #2 lore raw

Quoted 103 lines · Willem de Bruijn

Quoted 8 lines · Franklin S Cooper Jr.

Hi All,
Currently linux-next is failing to boot via NFS on my AM335x GP evm, AM437x GP evm and Beagle X15. I bisected the problem down to the commit "udp: remove headers from UDP packets before queueing".
I had to revert the following three commits to get things working again:

Quoted 9 lines

e6afc8ace6dd5cef5e812f26c72579da8806f5ac
udp: remove headers from UDP packets before queueing
627d2d6b550094d88f9e518e15967e7bf906ebbf
udp: enable MSG_PEEK at non-zero offset
b9bb53f3836f4eb2bdeb3447be11042bd29c2408
sock: convert sk_peek_offset functions to WRITE_ONCE

net/rxrpc/ar-input.c +2 -2

@@ -612,9 +612,9 @@ int rxrpc_extract_header(struct rxrpc_skb_priv
 *sp, struct sk_buff *skb)
        struct rxrpc_wire_header whdr;
 
        /* dig out the RxRPC connection details */
-       if (skb_copy_bits(skb, sizeof(struct udphdr), &whdr, sizeof(whdr)) < 0)
+       if (skb_copy_bits(skb, 0, &whdr, sizeof(whdr)) < 0)
                return -EBADMSG;
-       if (!pskb_pull(skb, sizeof(struct udphdr) + sizeof(whdr)))
+       if (!pskb_pull(skb, sizeof(whdr)))
                BUG();

I have not yet been able to reproduce the sunrpc/nfs issue, but I suspect that the following might fix it. I will try to create an NFS setup.

net/sunrpc/socklib.c +1 -1

index 2df87f7..8ab40ba 100644
@@ -155,7 +155,7 @@ int csum_partial_copy_to_xdr(struct xdr_buf *xdr,
 struct sk_buff *skb)
        struct xdr_skb_reader   desc;
 
        desc.skb = skb;
-       desc.offset = sizeof(struct udphdr);
+       desc.offset = 0;
        desc.count = skb->len - desc.offset;

if (skb_csum_unnecessary(skb))

net/sunrpc/svcsock.c +0 -0

index 1413cdc..71d6072 100644
@@ -617,7 +617,7 @@ static int svc_udp_recvfrom(struct svc_rqst *rqstp)
        svsk->sk_sk->sk_stamp = skb->tstamp;
        set_bit(XPT_DATA, &svsk->sk_xprt.xpt_flags); /* there may be

more data... */

net/sunrpc/svcsock.c +2 -3

-       len  = skb->len - sizeof(struct udphdr);
+       len  = skb->len;
        rqstp->rq_arg.len = len;
 
        rqstp->rq_prot = IPPROTO_UDP;

@@ -641,8 +641,7 @@ static int svc_udp_recvfrom(struct svc_rqst *rqstp)
                skb_free_datagram_locked(svsk->sk_sk, skb);
        } else {
                /* we can use it in-place */
-               rqstp->rq_arg.head[0].iov_base = skb->data +
-                       sizeof(struct udphdr);
+               rqstp->rq_arg.head[0].iov_base = skb->data;
                rqstp->rq_arg.head[0].iov_len = len;
                if (skb_checksum_complete(skb))
                        goto out_free;

net/sunrpc/xprtsock.c +2 -3

index 65e7595..c1fc7b2 100644
@@ -995,15 +995,14 @@ static void xs_udp_data_read_skb(struct rpc_xprt *xprt,
        u32 _xid;
        __be32 *xp;
 
-       repsize = skb->len - sizeof(struct udphdr);
+       repsize = skb->len;
        if (repsize < 4) {
                dprintk("RPC:       impossible RPC reply size %d!\n", repsize);
                return;
        }
 
 
 
        /* Copy the XID from the skb... */
-       xp = skb_header_pointer(skb, sizeof(struct udphdr),
-                               sizeof(_xid), &_xid);
+       xp = skb_header_pointer(skb, 0, sizeof(_xid), &_xid);
        if (xp == NULL)

Quoted 2 lines

                return;

Thank you for your quick response. I verified with all of the above suggested changes that NFS works again on my 3 evms.

Willem de Bruijn

2016-04-07 14:39 UTC #3 lore raw

Quoted 101 lines · Franklin S Cooper Jr.

Quoted 98 lines · Willem de Bruijn

Quoted 8 lines · Franklin S Cooper Jr.

Hi All,
Currently linux-next is failing to boot via NFS on my AM335x GP evm, AM437x GP evm and Beagle X15. I bisected the problem down to the commit "udp: remove headers from UDP packets before queueing".
I had to revert the following three commits to get things working again:

Quoted 9 lines

e6afc8ace6dd5cef5e812f26c72579da8806f5ac
udp: remove headers from UDP packets before queueing
627d2d6b550094d88f9e518e15967e7bf906ebbf
udp: enable MSG_PEEK at non-zero offset
b9bb53f3836f4eb2bdeb3447be11042bd29c2408
sock: convert sk_peek_offset functions to WRITE_ONCE

net/rxrpc/ar-input.c +2 -2

@@ -612,9 +612,9 @@ int rxrpc_extract_header(struct rxrpc_skb_priv
 *sp, struct sk_buff *skb)
        struct rxrpc_wire_header whdr;
 
        /* dig out the RxRPC connection details */
-       if (skb_copy_bits(skb, sizeof(struct udphdr), &whdr, sizeof(whdr)) < 0)
+       if (skb_copy_bits(skb, 0, &whdr, sizeof(whdr)) < 0)
                return -EBADMSG;
-       if (!pskb_pull(skb, sizeof(struct udphdr) + sizeof(whdr)))
+       if (!pskb_pull(skb, sizeof(whdr)))
                BUG();

I have not yet been able to reproduce the sunrpc/nfs issue, but I suspect that the following might fix it. I will try to create an NFS setup.

net/sunrpc/socklib.c +1 -1

index 2df87f7..8ab40ba 100644
@@ -155,7 +155,7 @@ int csum_partial_copy_to_xdr(struct xdr_buf *xdr,
 struct sk_buff *skb)
        struct xdr_skb_reader   desc;
 
        desc.skb = skb;
-       desc.offset = sizeof(struct udphdr);
+       desc.offset = 0;
        desc.count = skb->len - desc.offset;

if (skb_csum_unnecessary(skb))

net/sunrpc/svcsock.c +0 -0

index 1413cdc..71d6072 100644
@@ -617,7 +617,7 @@ static int svc_udp_recvfrom(struct svc_rqst *rqstp)
        svsk->sk_sk->sk_stamp = skb->tstamp;
        set_bit(XPT_DATA, &svsk->sk_xprt.xpt_flags); /* there may be

more data... */

net/sunrpc/svcsock.c +2 -3

-       len  = skb->len - sizeof(struct udphdr);
+       len  = skb->len;
        rqstp->rq_arg.len = len;
 
        rqstp->rq_prot = IPPROTO_UDP;

@@ -641,8 +641,7 @@ static int svc_udp_recvfrom(struct svc_rqst *rqstp)
                skb_free_datagram_locked(svsk->sk_sk, skb);
        } else {
                /* we can use it in-place */
-               rqstp->rq_arg.head[0].iov_base = skb->data +
-                       sizeof(struct udphdr);
+               rqstp->rq_arg.head[0].iov_base = skb->data;
                rqstp->rq_arg.head[0].iov_len = len;
                if (skb_checksum_complete(skb))
                        goto out_free;

net/sunrpc/xprtsock.c +1 -1

index 65e7595..c1fc7b2 100644
@@ -995,15 +995,14 @@ static void xs_udp_data_read_skb(struct rpc_xprt *xprt,
        u32 _xid;
        __be32 *xp;
 
-       repsize = skb->len - sizeof(struct udphdr);
+       repsize = skb->len;
        if (repsize < 4) {
                dprintk("RPC:       impossible RPC reply size %d!\n", repsize);
                return;
        }

Quoted 11 lines

Quoted 7 lines

net/sunrpc/xprtsock.c +1 -2

        /* Copy the XID from the skb... */
-       xp = skb_header_pointer(skb, sizeof(struct udphdr),
-                               sizeof(_xid), &_xid);
+       xp = skb_header_pointer(skb, 0, sizeof(_xid), &_xid);
        if (xp == NULL)

                return;

Thank you for your quick response. I verified with all of the above suggested changes that NFS works again on my 3 evms.

Thanks a lot for testing, Franklin. I will send out the two patches.

Willem de Bruijn

2016-04-07 15:52 UTC #4 lore raw

Quoted 11 lines

Quoted 11 lines
Quoted 10 lines
Quoted 3 lines
Currently linux-next is failing to boot via NFS on my AM335x GP evm, AM437x GP evm and Beagle X15. I bisected the problem down to the commit "udp: remove headers from UDP packets before queueing".
Thanks for the report, and apologies for breaking your configuration. I had missed that sunrpc can dequeue skbs from a udp receive queue and makes assumptions about the layout of those packets. rxrpc does the same. From what I can tell so far, those are the only two protocols that do this. I have verified that the following fixes rxrpc for me

Quoted 4 lines

Quoted 2 lines
Thank you for your quick response. I verified with all of the above suggested changes that NFS works again on my 3 evms.
Thanks a lot for testing, Franklin. I will send out the two patches.

Patches sent to netdev. I'll do another scan to verify that there are no additional protocols that dequeue skbs from udp receive queues and expect udp headers present.