Hi,
On Thu, May 12, 2016 at 10:51:02PM +0200, Fabiano Fidêncio wrote:
> On Thu, May 12, 2016 at 10:42 PM, Victor Toso <victortoso@xxxxxxxxxx> wrote:
> > As one can see by the backtrace, the reason for the segfault is that
> > g_task_return_now() is called under coroutine context and in
> > spice_file_transfer_task_completed() we access memory that the
> > coroutine context has no access.
> >
> > With GTask integration its callback must respect the coroutine context
> > or return-in-idle so the callback can be called in the main context.
> >
> > In this specific case the memory access can be fixed also due the
> > error that is present which is agent being disconnected during a
> > file-xfer. In that situation, we should not try to send a message to
> > the agent.
> >
> > Program received signal SIGSEGV, Segmentation fault.
> > spice_file_transfer_task_completed (self=self@entry=0x7fffd0006f00, error=0x0) at channel-main.c:2963
> > 2963 VDAgentFileXferStatusMessage msg = {
> > (gdb) bt
> > #0 spice_file_transfer_task_completed (self=self@entry=0x7fffd0006f00, error=0x0) at channel-main.c:2963
> > #1 in file_xfer_data_flushed_cb (source_object=0x7cc1d0, res=0x953390, user_data=user_data@entry=0x7fffd0006f00) at channel-main.c:1857
> > #2 in g_task_return_now (task=0x953390) at gtask.c:1108
> > #3 in g_task_return (task=0x953390, type=<optimized out>) at gtask.c:1166
> > #4 in flush_foreach_remove (key=<optimized out>, value=<optimized out>, user_data=<optimized out>) at channel-main.c:928
> > #5 in g_hash_table_foreach_remove_or_steal (hash_table=0x70cea0, func=func@entry=0x7ffff5616f10 <flush_foreach_remove>, user_data=user_data@entry=0x0, notify=notify@entry=1) at ghash.c:1492
> > #6 in g_hash_table_foreach_remove (hash_table=<optimized out>, func=func@entry=0x7ffff5616f10 <flush_foreach_remove>, user_data=user_data@entry=0x0) at ghash.c:1538
> > #7 in file_xfer_flushed (success=0, channel=0x7cc1d0) at channel-main.c:936
> > #8 _reset_agent (channel=0x7cc1d0) at channel-main.c:466
> > #9 d (channel=0x7cc1d0, connected=connected@entry=0) at channel-main.c:1572
> > #10 in spice_main_channel_reset (channel=0x7cc1d0, migrating=0) at channel-main.c:485
> > #11 in spice_channel_coroutine (data=0x7cc1d0) at spice-channel.c:2564
> > #12 in coroutine_trampoline (cc=0x7cb860) at coroutine_ucontext.c:63
> > #13 in continuation_trampoline (i0=<optimized out>, i1=<optimized out>) at continuation.c:55
> > #14 in ?? () from /lib64/libc.so.6
> > #15 in ?? ()
> > #16 in ?? ()
> > Backtrace stopped: Cannot access memory at address
> > ---
> > src/channel-main.c | 4 +++-
> > 1 file changed, 3 insertions(+), 1 deletion(-)
> >
> > diff --git a/src/channel-main.c b/src/channel-main.c
> > index f7789dd..fb0630e 100644
> > --- a/src/channel-main.c
> > +++ b/src/channel-main.c
> > @@ -2950,6 +2950,8 @@ void spice_main_set_display_enabled(SpiceMainChannel *channel, int id, gboolean
> > static void spice_file_transfer_task_completed(SpiceFileTransferTask *self,
> > GError *error)
> > {
> > + SpiceMainChannelPrivate *main_priv = self->priv->channel->priv;
>
> Ouch, quite ugly :-\.
> IMO would be better to introduce a
> spice_main_channel_get_agent_connected() function or something like
> that.
> Do you think it would make sense?.
I do! I'll send a new one tomorrow.
Cheers,
toso
>
> > +
> > /* In case of multiple errors we only report the first error */
> > if (self->priv->error)
> > g_clear_error(&error);
> > @@ -2959,7 +2961,7 @@ static void spice_file_transfer_task_completed(SpiceFileTransferTask *self,
> > self->priv->error = error;
> > }
> >
> > - if (self->priv->error) {
> > + if (self->priv->error && main_priv->agent_connected) {
> > VDAgentFileXferStatusMessage msg = {
> > .id = self->priv->id,
> > .result = error->code == G_IO_ERROR_CANCELLED ?
> > --
> > 2.5.5
> >
> > _______________________________________________
> > Spice-devel mailing list
> > Spice-devel@xxxxxxxxxxxxxxxxxxxxx
> > https://lists.freedesktop.org/mailman/listinfo/spice-devel
>
>
> Reviewed-by: Fabiano Fidêncio <fidencio@xxxxxxxxxx>
> --
> Fabiano Fidêncio
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