>
> From: Victor Toso <me@xxxxxxxxxxxxxx>
>
> This is a CLANG_WARNING found by covscan. It is a false positive as
> g_clear_pointer() does set vportp to NULL, meaning that the situation
> described by covscan below should not be reached. Moving away from
> g_clear_pointer() in this specific case just to make our tool happy.
>
> Covscan report:
> > spice-vdagent-0.19.0/src/vdagentd/virtio-port.c:458:9: warning: Use of
> > memory after it is freed
> > # if (wbuf->write_pos != wbuf->size) {
> > # ^
> > spice-vdagent-0.19.0/src/vdagentd/virtio-port.c:268:12: note: Assuming the
> > condition is true
> > # while (*vportp && (*vportp)->write_buf)
> > # ^~~~~~~
> > spice-vdagent-0.19.0/src/vdagentd/virtio-port.c:268:12: note: Left side of
> > '&&' is true
> > spice-vdagent-0.19.0/src/vdagentd/virtio-port.c:268:5: note: Loop
> > condition is true. Entering loop body
> > # while (*vportp && (*vportp)->write_buf)
> > # ^
> > spice-vdagent-0.19.0/src/vdagentd/virtio-port.c:269:9: note: Calling
> > 'vdagent_virtio_port_do_write'
> > # vdagent_virtio_port_do_write(vportp);
> > # ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> > spice-vdagent-0.19.0/src/vdagentd/virtio-port.c:453:5: note: Taking false
> > branch
> > # if (!wbuf) {
> > # ^
> > spice-vdagent-0.19.0/src/vdagentd/virtio-port.c:458:9: note: Assuming the
> > condition is false
> > # if (wbuf->write_pos != wbuf->size) {
> > # ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> > spice-vdagent-0.19.0/src/vdagentd/virtio-port.c:458:5: note: Taking false
> > branch
> > # if (wbuf->write_pos != wbuf->size) {
> > # ^
> > spice-vdagent-0.19.0/src/vdagentd/virtio-port.c:465:9: note: Assuming 'n'
> > is < 0
> > # if (n < 0) {
> > # ^~~~~
> > spice-vdagent-0.19.0/src/vdagentd/virtio-port.c:465:5: note: Taking true
> > branch
> > # if (n < 0) {
> > # ^
> > spice-vdagent-0.19.0/src/vdagentd/virtio-port.c:466:13: note: Assuming the
> > condition is false
> > # if (errno == EINTR)
> > # ^~~~~~~~~~~~~~
> > /usr/include/errno.h:38:16: note: expanded from macro 'errno'
> > ## define errno (*__errno_location ())
> > # ^
> > spice-vdagent-0.19.0/src/vdagentd/virtio-port.c:466:9: note: Taking false
> > branch
> > # if (errno == EINTR)
> > # ^
> > spice-vdagent-0.19.0/src/vdagentd/virtio-port.c:469:9: note: Calling
> > 'vdagent_virtio_port_destroy'
> > # vdagent_virtio_port_destroy(vportp);
> > # ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> > spice-vdagent-0.19.0/src/vdagentd/virtio-port.c:130:5: note: Taking false
> > branch
> > # if (!vport)
> > # ^
> > spice-vdagent-0.19.0/src/vdagentd/virtio-port.c:133:9: note: Assuming the
> > condition is false
> > # if (vport->disconnect_callback)
> > # ^~~~~~~~~~~~~~~~~~~~~~~~~~
> > spice-vdagent-0.19.0/src/vdagentd/virtio-port.c:133:5: note: Taking false
> > branch
> > # if (vport->disconnect_callback)
> > # ^
> > spice-vdagent-0.19.0/src/vdagentd/virtio-port.c:137:5: note: Loop
> > condition is true. Entering loop body
> > # while (wbuf) {
> > # ^
> > spice-vdagent-0.19.0/src/vdagentd/virtio-port.c:140:9: note: Memory is
> > released
> > # g_free(wbuf);
> > # ^~~~~~~~~~~~
> > spice-vdagent-0.19.0/src/vdagentd/virtio-port.c:137:5: note: Loop
> > condition is false. Execution continues on line 144
> > # while (wbuf) {
> > # ^
> > spice-vdagent-0.19.0/src/vdagentd/virtio-port.c:144:5: note: Loop
> > condition is true. Entering loop body
> > # for (i = 0; i < VDP_END_PORT; i++) {
> > # ^
> > spice-vdagent-0.19.0/src/vdagentd/virtio-port.c:144:5: note: Loop
> > condition is true. Entering loop body
> > spice-vdagent-0.19.0/src/vdagentd/virtio-port.c:144:5: note: Loop
> > condition is true. Entering loop body
> > spice-vdagent-0.19.0/src/vdagentd/virtio-port.c:144:5: note: Loop
> > condition is false. Execution continues on line 148
> > spice-vdagent-0.19.0/src/vdagentd/virtio-port.c:149:5: note: Assuming '_p'
> > is null
> > # g_clear_pointer(vportp, g_free);
> > # ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> > /usr/include/glib-2.0/glib/gmem.h:124:9: note: expanded from macro
> > 'g_clear_pointer'
> > # if (_p)
> > \
> > # ^~
> > spice-vdagent-0.19.0/src/vdagentd/virtio-port.c:149:5: note: Taking false
> > branch
> > /usr/include/glib-2.0/glib/gmem.h:124:5: note: expanded from macro
> > 'g_clear_pointer'
> > # if (_p)
> > \
> > # ^
> > spice-vdagent-0.19.0/src/vdagentd/virtio-port.c:149:5: note: Loop
> > condition is false. Exiting loop
> > /usr/include/glib-2.0/glib/gmem.h:114:3: note: expanded from macro
> > 'g_clear_pointer'
> > # G_STMT_START {
> > \
> > # ^
> > /usr/include/glib-2.0/glib/gmacros.h:346:23: note: expanded from macro
> > 'G_STMT_START'
> > ##define G_STMT_START do
> > # ^
> > spice-vdagent-0.19.0/src/vdagentd/virtio-port.c:469:9: note: Returning;
> > memory was released
> > # vdagent_virtio_port_destroy(vportp);
> > # ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> > spice-vdagent-0.19.0/src/vdagentd/virtio-port.c:269:9: note: Returning;
> > memory was released
> > # vdagent_virtio_port_do_write(vportp);
> > # ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> > spice-vdagent-0.19.0/src/vdagentd/virtio-port.c:268:12: note: Left side of
> > '&&' is true
> > # while (*vportp && (*vportp)->write_buf)
> > # ^
> > spice-vdagent-0.19.0/src/vdagentd/virtio-port.c:268:5: note: Loop
> > condition is true. Entering loop body
> > # while (*vportp && (*vportp)->write_buf)
> > # ^
> > spice-vdagent-0.19.0/src/vdagentd/virtio-port.c:269:9: note: Calling
> > 'vdagent_virtio_port_do_write'
> > # vdagent_virtio_port_do_write(vportp);
> > # ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> > spice-vdagent-0.19.0/src/vdagentd/virtio-port.c:453:5: note: Taking false
> > branch
> > # if (!wbuf) {
> > # ^
> > spice-vdagent-0.19.0/src/vdagentd/virtio-port.c:458:9: note: Use of memory
> > after it is freed
> > # if (wbuf->write_pos != wbuf->size) {
> > # ^~~~~~~~~~~~~~~
> > # 456| }
> > # 457|
> > # 458|-> if (wbuf->write_pos != wbuf->size) {
> > # 459| syslog(LOG_ERR, "do_write: buffer is incomplete!!");
> > # 460| return;
>
> Signed-off-by: Victor Toso <victortoso@xxxxxxxxxx>
> ---
> src/vdagentd/virtio-port.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/src/vdagentd/virtio-port.c b/src/vdagentd/virtio-port.c
> index b0556ce..3ae7f22 100644
> --- a/src/vdagentd/virtio-port.c
> +++ b/src/vdagentd/virtio-port.c
> @@ -146,7 +146,8 @@ void vdagent_virtio_port_destroy(struct
> vdagent_virtio_port **vportp)
> }
>
> close(vport->fd);
> - g_clear_pointer(vportp, g_free);
> + g_free(vport);
> + *vportp = NULL;
> }
>
> int vdagent_virtio_port_fill_fds(struct vdagent_virtio_port *vport,
Acked.
Probably clang is not able to understand the alias.
Frediano
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