On Sat, 2020-10-10 at 17:07 +1100, David Gibson wrote:
> On Fri, Oct 09, 2020 at 07:02:56AM -0700, Elena Afanasova wrote:
> > > From 09905773a00e417d3a37c12350d9e55466fdce8a Mon Sep 17 00:00:00
> > > 2001
> > From: Elena Afanasova <eafanas...@gmail.com>
> > Date: Fri, 9 Oct 2020 06:41:36 -0700
> > Subject: [PATCH] hw/net: move allocation to the heap due to very
> > large stack
> > frame
>
> Patch looks fine, but some more details of the motivation would be
> nice. I wouldn't have thought that the size of a network packet
> counted as a "very large" stack frame by userspace standards.
>
gcc with wstack-usage warns that stack frame size may be ~65Kbytes
> > Signed-off-by: Elena Afanasova <eafanas...@gmail.com>
> > ---
> > hw/net/spapr_llan.c | 5 +++--
> > 1 file changed, 3 insertions(+), 2 deletions(-)
> >
> > diff --git a/hw/net/spapr_llan.c b/hw/net/spapr_llan.c
> > index 2093f1bad0..581320a0e7 100644
> > --- a/hw/net/spapr_llan.c
> > +++ b/hw/net/spapr_llan.c
> > @@ -688,7 +688,8 @@ static target_ulong
> > h_send_logical_lan(PowerPCCPU *cpu,
> > SpaprVioDevice *sdev = spapr_vio_find_by_reg(spapr->vio_bus,
> > reg);
> > SpaprVioVlan *dev = VIO_SPAPR_VLAN_DEVICE(sdev);
> > unsigned total_len;
> > - uint8_t *lbuf, *p;
> > + uint8_t *p;
> > + g_autofree uint8_t *lbuf = NULL;
> > int i, nbufs;
> > int ret;
> >
> > @@ -729,7 +730,7 @@ static target_ulong
> > h_send_logical_lan(PowerPCCPU *cpu,
> > return H_RESOURCE;
> > }
> >
> > - lbuf = alloca(total_len);
> > + lbuf = g_malloc(total_len);
> > p = lbuf;
> > for (i = 0; i < nbufs; i++) {
> > ret = spapr_vio_dma_read(sdev, VLAN_BD_ADDR(bufs[i]),
