Commit 3b83f60d authored by Ilya Dryomov's avatar Ilya Dryomov
Browse files

libceph: enable fallback to ceph_msg_new() in ceph_msgpool_get() 



ceph_msgpool_get() can fall back to ceph_msg_new() when it is asked for
a message whose front portion is larger than pool->front_len.  However
the caller always passes 0, effectively disabling that code path.  The
allocation goes to the message pool and returns a message with a front
that is smaller than requested, setting us up for a crash.

One example of this is a directory with a large number of snapshots.
If its snap context doesn't fit, we oops in encode_request_partial().

Signed-off-by: default avatarIlya Dryomov <idryomov@gmail.com>
parent 61d2f855

net/ceph/msgpool.c

+1 −1
Original line number Diff line number Diff line
@@ -61,7 +61,7 @@ struct ceph_msg *ceph_msgpool_get(struct ceph_msgpool *pool, 
	if (front_len > pool->front_len) {

		dout("msgpool_get %s need front %d, pool size is %d\n",

		       pool->name, front_len, pool->front_len);

		WARN_ON(1);

		WARN_ON_ONCE(1);



		/* try to alloc a fresh message */

		return ceph_msg_new(pool->type, front_len, GFP_NOFS, false);

net/ceph/osd_client.c

+2 −2
Original line number Diff line number Diff line
@@ -641,7 +641,7 @@ int ceph_osdc_alloc_messages(struct ceph_osd_request *req, gfp_t gfp) 
	msg_size += 4 + 8; /* retry_attempt, features */



	if (req->r_mempool)

		msg = ceph_msgpool_get(&osdc->msgpool_op, 0);

		msg = ceph_msgpool_get(&osdc->msgpool_op, msg_size);

	else

		msg = ceph_msg_new(CEPH_MSG_OSD_OP, msg_size, gfp, true);

	if (!msg)
@@ -656,7 +656,7 @@ int ceph_osdc_alloc_messages(struct ceph_osd_request *req, gfp_t gfp) 
	msg_size += req->r_num_ops * sizeof(struct ceph_osd_op);



	if (req->r_mempool)

		msg = ceph_msgpool_get(&osdc->msgpool_op_reply, 0);

		msg = ceph_msgpool_get(&osdc->msgpool_op_reply, msg_size);

	else

		msg = ceph_msg_new(CEPH_MSG_OSD_OPREPLY, msg_size, gfp, true);

	if (!msg)

CRA Git | Maintained and supported by SUSTech CRA and CCSE