| Message ID | 1469447015-2276-1-git-send-email-shmulik.ladkani@oracle.com |
|---|---|
| State | New |
| Headers | show |
On Mon, Jul 25, 2016 at 02:43:35PM +0300, Shmulik Ladkani wrote: > From: Shmulik Ladkani <shmulik.ladkani@ravellosystems.com> > > In cases where iov_copy() is passed with zero 'bytes' argument and a > non-zero 'offset' argument, nothing gets copied - as expected. > > However since no copy iterations are performed, 'offset' is left > unaltered, leading to the final assert(offset == 0) to fail. > > Relax the assertion: if j (number of dst elements assigned) is zero, no > need to err. > > Only if j!=0 (some dst elements assigned) AND offset!=0 we should err. > > Signed-off-by: Shmulik Ladkani <shmulik.ladkani@ravellosystems.com> Reviewed-by: Michael S. Tsirkin <mst@redhat.com> > --- > util/iov.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > Flow that led to the assertion was: > net_tx_pkt_rebuild_payload() > iov_copy(... , pkt->payload_len) > > where pkt->payload_len was correctly calculated to be 0 (a packet > carrying just ipv4 header, without any payload). > > An alternative is to place the below code, early in iov_copy(): > if (!bytes) > return 0; > > diff --git a/util/iov.c b/util/iov.c > index 003fcce..17de52d 100644 > --- a/util/iov.c > +++ b/util/iov.c > @@ -260,7 +260,7 @@ unsigned iov_copy(struct iovec *dst_iov, unsigned int dst_iov_cnt, > bytes -= len; > offset = 0; > } > - assert(offset == 0); > + assert(j == 0 || offset == 0); > return j; > } > > -- > 1.9.1 >
diff --git a/util/iov.c b/util/iov.c index 003fcce..17de52d 100644 --- a/util/iov.c +++ b/util/iov.c @@ -260,7 +260,7 @@ unsigned iov_copy(struct iovec *dst_iov, unsigned int dst_iov_cnt, bytes -= len; offset = 0; } - assert(offset == 0); + assert(j == 0 || offset == 0); return j; }