[DTrace-devel] [PATCH v2 3/4] probe: do not try to reify probes from uncooked providers

[Nick Alcock]

If there is a syntax error in the middle of a .d script processed
by -h, we will be left with a provider in question in an uncooked
state (where dt_provider_create() has been called on it with a NULL
provider by dt_node_provider(), but it has not had its provider
set yet by dt_cook_provider()).

In this case, the attempt to pop the parser stack on error will
fail because probe iteration is attempting to reify probes out
of providers without making sure they're cooked first:

    at libdtrace/dt_probe.c:1006
    argv=0x535830, fp=0x21e4630, s=0x0) at libdtrace/dt_cc.c:789
    fp=0x21e4630, s=0x0) at libdtrace/dt_cc.c:1419
    at libdtrace/dt_cc.c:1441

The fix is simple: treat providers with no provimpl just like we do
providers with no provide() method in their provimpl: they cannot provide
probes, so don't try. (Test coming in a later commit in this series.)

Signed-off-by: Nick Alcock <nick.alcock at oracle.com>
---
 libdtrace/dt_probe.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/libdtrace/dt_probe.c b/libdtrace/dt_probe.c
index 189bf7928e145..ccaa3081c5b23 100644
--- a/libdtrace/dt_probe.c
+++ b/libdtrace/dt_probe.c
@@ -1007,7 +1007,8 @@ dt_probe_iter(dtrace_hdl_t *dtp, const dtrace_probedesc_t *pdp,
 	 * Loop over providers, allowing them to provide these probes.
 	 */
 	while ((pvp = dt_htab_next(dtp->dt_provs, &it)) != NULL) {
-		if (pvp->impl->provide == NULL ||
+		if (pvp->impl == NULL ||
+		    pvp->impl->provide == NULL ||
 		    !dt_gmatch(pvp->desc.dtvd_name, pdp->prv))
 			continue;
 		memcpy(&desc, pdp, sizeof(desc));
-- 
2.46.0.278.g36e3a12567