Allow DOF sections with excessively long probe function components.

Without this change, DTrace will refuse to load a DOF section if the
function component of any of its probes exceeds DTRACE_FUNCNAMELEN (128).
Probes in C++ programs can have very long function components. Rather than
rejecting all probes if a single probe exceeds the limit, simply skip the
invalid probe and emit a warning. This ensures that valid probes are
instantiated.

PR:		207735
MFC after:	2 weeks

1 files changed, 11 insertions, 1 deletions

diff --git a/sys/cddl/contrib/opensolaris/uts/common/dtrace/dtrace.c b/sys/cddl/contrib/opensolaris/uts/common/dtrace/dtrace.c
index 0012975..086d778 100644
--- a/sys/cddl/contrib/opensolaris/uts/common/dtrace/dtrace.c
+++ b/sys/cddl/contrib/opensolaris/uts/common/dtrace/dtrace.c
@@ -9355,6 +9355,10 @@ dtrace_helper_provide_one(dof_helper_t *dhp, dof_sec_t *sec, pid_t pid)
 		probe = (dof_probe_t *)(uintptr_t)(daddr +
 		    prb_sec->dofs_offset + i * prb_sec->dofs_entsize);
 
+		/* See the check in dtrace_helper_provider_validate(). */
+		if (strlen(strtab + probe->dofpr_func) >= DTRACE_FUNCNAMELEN)
+			continue;
+
 		dhpb.dthpb_mod = dhp->dofhp_mod;
 		dhpb.dthpb_func = strtab + probe->dofpr_func;
 		dhpb.dthpb_name = strtab + probe->dofpr_name;
@@ -16042,7 +16046,13 @@ dtrace_helper_provider_validate(dof_hdr_t *dof, dof_sec_t *sec)
 
 		if (strlen(strtab + probe->dofpr_func) >= DTRACE_FUNCNAMELEN) {
 			dtrace_dof_error(dof, "function name too long");
-			return (-1);
+			/*
+			 * Keep going if the function name is too long.
+			 * Unlike provider and probe names, we cannot reasonably
+			 * impose restrictions on function names, since they're
+			 * a property of the code being instrumented. We will
+			 * skip this probe in dtrace_helper_provide_one().
+			 */
 		}
 
 		if (probe->dofpr_name >= str_sec->dofs_size ||