[PATCH 1/2] afs: Read of file returns EBADMSG

[PATCH 1/2] afs: Read of file returns EBADMSG

[David Howells]

From: Anton Blanchard <anton@samba.org>

A read of a large file on an afs mount failed:

# cat junk.file > /dev/null
cat: junk.file: Bad message

Looking at the trace, call->offset wrapped since it is only an
unsigned short. In afs_extract_data:


        _enter("{%u},{%zu},%d,,%zu", call->offset, len, last, count);
...

        if (call->offset < count) {
                if (last) {
                        _leave(" = -EBADMSG [%d < %zu]", call->offset, count);
                        return -EBADMSG;
                }


Which matches the trace:

[cat   ] ==> afs_extract_data({65132},{524},1,,65536)
[cat   ] <== afs_extract_data() = -EBADMSG [0 < 65536]

call->offset went from 65132 to 0. Fix this by making call->offset an
unsigned int.

Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: David Howells <dhowells@redhat.com>
Cc: <stable@kernel.org>
---

 fs/afs/internal.h |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/fs/afs/internal.h b/fs/afs/internal.h
index d2b0888..a306bb6 100644
--- a/fs/afs/internal.h
+++ b/fs/afs/internal.h
@@ -109,7 +109,7 @@ struct afs_call {
 	unsigned		reply_size;	/* current size of reply */
 	unsigned		first_offset;	/* offset into mapping[first] */
 	unsigned		last_to;	/* amount of mapping[last] */
-	unsigned short		offset;		/* offset into received data store */
+	unsigned		offset;		/* offset into received data store */
 	unsigned char		unmarshall;	/* unmarshalling phase */
 	bool			incoming;	/* T if incoming call */
 	bool			send_pages;	/* T if data from mapping should be sent */

[PATCH 2/2] afs: Remote abort can cause BUG in rxrpc code

[David Howells]

From: Anton Blanchard <anton@samba.org>

When writing files to afs I sometimes hit a BUG:

kernel BUG at fs/afs/rxrpc.c:179!

With a backtrace of:

	afs_free_call
	afs_make_call
	afs_fs_store_data
	afs_vnode_store_data
	afs_write_back_from_locked_page
	afs_writepages_region
	afs_writepages

The cause is:

	ASSERT(skb_queue_empty(&call->rx_queue));

Looking at a tcpdump of the session the abort happens because we
are exceeding our disk quota:

	rx abort fs reply store-data error diskquota exceeded (32)

So the abort error is valid. We hit the BUG because we haven't
freed all the resources for the call.

By freeing any skbs in call->rx_queue before calling afs_free_call
we avoid hitting leaking memory and avoid hitting the BUG.

Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: David Howells <dhowells@redhat.com>
Cc: <stable@kernel.org>
---

 fs/afs/rxrpc.c |    3 +++
 1 files changed, 3 insertions(+), 0 deletions(-)

diff --git a/fs/afs/rxrpc.c b/fs/afs/rxrpc.c
index e45a323..8ad8c2a 100644
--- a/fs/afs/rxrpc.c
+++ b/fs/afs/rxrpc.c
@@ -314,6 +314,7 @@ int afs_make_call(struct in_addr *addr, struct afs_call *call, gfp_t gfp,
 	struct msghdr msg;
 	struct kvec iov[1];
 	int ret;
+	struct sk_buff *skb;
 
 	_enter("%x,{%d},", addr->s_addr, ntohs(call->port));
 
@@ -380,6 +381,8 @@ int afs_make_call(struct in_addr *addr, struct afs_call *call, gfp_t gfp,
 
 error_do_abort:
 	rxrpc_kernel_abort_call(rxcall, RX_USER_ABORT);
+	while ((skb = skb_dequeue(&call->rx_queue)))
+		afs_free_skb(skb);
 	rxrpc_kernel_end_call(rxcall);
 	call->rxcall = NULL;
 error_kill_call: