On Thu, Nov 10, 2016 at 09:16:01PM +0100, Thomas Huth wrote: > When using the serial console in the GTK interface of QEMU (and > QEMU has been compiled with CONFIG_VTE), it is possible to trigger > the assert() statement in vty_receive() in spapr_vty.c by pasting > a chunk of text with length > 16 into the QEMU window. > Most of the other serial backends seem to simply drop characters > that they can not handle, so I think we should also do the same in > spapr-vty to fix this issue. > > Buglink: https://bugs.launchpad.net/qemu/+bug/1639322 > Signed-off-by: Thomas Huth <th...@redhat.com> > --- > v2: > - Do not increase the buffer size since this breaks migration. > (We should figure out a better solution for the size of the > buffer once 2.8 is released)
Applied to ppc-for-2.8. since actually hitting the assert is clearly
bad. I still think this smells like a bug on the other side of the
chardev, feeding in more characters than the can_receive() hook says
can be supplied.
>
> hw/char/spapr_vty.c | 11 ++++++++++-
> 1 file changed, 10 insertions(+), 1 deletion(-)
>
> diff --git a/hw/char/spapr_vty.c b/hw/char/spapr_vty.c
> index 31822fe..06b9b39 100644
> --- a/hw/char/spapr_vty.c
> +++ b/hw/char/spapr_vty.c
> @@ -1,4 +1,5 @@
> #include "qemu/osdep.h"
> +#include "qemu/error-report.h"
> #include "qapi/error.h"
> #include "qemu-common.h"
> #include "cpu.h"
> @@ -37,7 +38,15 @@ static void vty_receive(void *opaque, const uint8_t *buf,
> int size)
> qemu_irq_pulse(spapr_vio_qirq(&dev->sdev));
> }
> for (i = 0; i < size; i++) {
> - assert((dev->in - dev->out) < VTERM_BUFSIZE);
> + if (dev->in - dev->out >= VTERM_BUFSIZE) {
> + static bool reported;
> + if (!reported) {
> + error_report("VTY input buffer exhausted - characters
> dropped."
> + " (input size = %i)", size);
> + reported = true;
> + }
> + break;
> + }
> dev->buf[dev->in++ % VTERM_BUFSIZE] = buf[i];
> }
> }
--
David Gibson | I'll have my music baroque, and my code
david AT gibson.dropbear.id.au | minimalist, thank you. NOT _the_ _other_
| _way_ _around_!
http://www.ozlabs.org/~dgibson
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