From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:37822) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1gX9ft-0005gl-CX for qemu-devel@nongnu.org; Wed, 12 Dec 2018 13:56:02 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1gX9fq-0000yz-Lo for qemu-devel@nongnu.org; Wed, 12 Dec 2018 13:56:01 -0500 Received: from userp2120.oracle.com ([156.151.31.85]:43858) by eggs.gnu.org with esmtps (TLS1.0:RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1gX9fq-0000yM-CB for qemu-devel@nongnu.org; Wed, 12 Dec 2018 13:55:58 -0500 Date: Wed, 12 Dec 2018 20:55:34 +0200 From: Yuval Shaia Message-ID: <20181212185533.GG5747@lap1> References: <20181212114726.24060-1-ppandit@redhat.com> <20181212114726.24060-6-ppandit@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20181212114726.24060-6-ppandit@redhat.com> Subject: Re: [Qemu-devel] [PATCH v1 5/6] pvrdma: check return value from pvrdma_idx_ring_has_ routines List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: P J P Cc: Qemu Developers , Marcel Apfelbaum , Saar Amar , Li Qiang , Prasad J Pandit , yuval.shaia@oracle.com On Wed, Dec 12, 2018 at 05:17:25PM +0530, P J P wrote: > From: Prasad J Pandit > > pvrdma_idx_ring_has_[data/space] routines also return invalid > index PVRDMA_INVALID_IDX[=-1], if ring has no data/space. Check > return value from these routines to avoid plausible infinite loops. > > Reported-by: Li Qiang > Signed-off-by: Prasad J Pandit > --- > hw/rdma/vmw/pvrdma_dev_ring.c | 37 +++++++++++++++++------------------ > 1 file changed, 18 insertions(+), 19 deletions(-) > > Update v1: receive error code in idx variable, remove comments > -> https://lists.gnu.org/archive/html/qemu-devel/2018-12/msg02342.html > > diff --git a/hw/rdma/vmw/pvrdma_dev_ring.c b/hw/rdma/vmw/pvrdma_dev_ring.c > index 01247fc041..2dccac8442 100644 > --- a/hw/rdma/vmw/pvrdma_dev_ring.c > +++ b/hw/rdma/vmw/pvrdma_dev_ring.c > @@ -73,23 +73,22 @@ out: > > void *pvrdma_ring_next_elem_read(PvrdmaRing *ring) > { > - unsigned int idx = 0, offset; > + int idx; > + unsigned int offset, head; > > - /* > - pr_dbg("%s: t=%d, h=%d\n", ring->name, ring->ring_state->prod_tail, > - ring->ring_state->cons_head); > - */ > - > - if (!pvrdma_idx_ring_has_data(ring->ring_state, ring->max_elems, &idx)) { > + idx = pvrdma_idx_ring_has_data(ring->ring_state, ring->max_elems, &head); > + if (idx <= 0) { > pr_dbg("No more data in ring\n"); > return NULL; > } > > + idx = pvrdma_idx(&ring->ring_state->cons_head, ring->max_elems); > + if (idx < 0 || head != idx) { > + pr_dbg("invalid idx\n"); > + return NULL; > + } > + Sorry, i mislead you here, idx was already populated by pvrdma_idx_ring_has_data so call to pvrdma_idx just to retrieve the index is waste. Please revert back to using another variable to check the return value from pvrdma_idx_ring_has_data and drop this call to pvrdma_idx. > offset = idx * ring->elem_sz; > - /* > - pr_dbg("idx=%d\n", idx); > - pr_dbg("offset=%d\n", offset); > - */ > return ring->pages[offset / TARGET_PAGE_SIZE] + (offset % TARGET_PAGE_SIZE); > } > > @@ -105,20 +104,20 @@ void pvrdma_ring_read_inc(PvrdmaRing *ring) > > void *pvrdma_ring_next_elem_write(PvrdmaRing *ring) > { > - unsigned int idx, offset, tail; > + int idx; > + unsigned int offset, tail; > > - /* > - pr_dbg("%s: t=%d, h=%d\n", ring->name, ring->ring_state->prod_tail, > - ring->ring_state->cons_head); > - */ > - > - if (!pvrdma_idx_ring_has_space(ring->ring_state, ring->max_elems, &tail)) { > + idx = pvrdma_idx_ring_has_space(ring->ring_state, ring->max_elems, &tail); > + if (idx <= 0) { > pr_dbg("CQ is full\n"); > return NULL; > } > > idx = pvrdma_idx(&ring->ring_state->prod_tail, ring->max_elems); > - /* TODO: tail == idx */ > + if (idx < 0 || tail != idx) { > + pr_dbg("invalid idx\n"); > + return NULL; > + } > > offset = idx * ring->elem_sz; > return ring->pages[offset / TARGET_PAGE_SIZE] + (offset % TARGET_PAGE_SIZE); > -- > 2.19.2 >