[DTrace-devel] [PATCH] Avoid out-of-memory error report when linking BPF code without relocs

[Kris Van Hees]

When there are no BPF relocation records, an allocation of size 0 was
being attempted.  Since that resulted in a NULL return value, it was
assumed that the allocation failure indicated an out-of-memory
condition.

We now simply do not try to allocate a BPF relocation table when there
are no BPF relocation records to be copied into it.

Signed-off-by: Kris Van Hees <kris.van.hees at oracle.com>
---
 libdtrace/dt_cc.c | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/libdtrace/dt_cc.c b/libdtrace/dt_cc.c
index 67834790..d6a78166 100644
--- a/libdtrace/dt_cc.c
+++ b/libdtrace/dt_cc.c
@@ -2365,9 +2365,12 @@ dt_link_stmt(dtrace_hdl_t *dtp, dtrace_prog_t *pgp, dtrace_stmtdesc_t *sdp,
 	if (fdp->dtdo_buf == NULL)
 		goto nomem;
 	fdp->dtdo_len = insc;
-	fdp->dtdo_breltab = dt_calloc(dtp, relc, sizeof(dof_relodesc_t));
-	if (fdp->dtdo_breltab == NULL)
-		goto nomem;
+	if (relc) {
+		fdp->dtdo_breltab = dt_calloc(dtp, relc,
+					      sizeof(dof_relodesc_t));
+		if (fdp->dtdo_breltab == NULL)
+			goto nomem;
+	}
 	fdp->dtdo_brelen = relc;
 
 	/*
-- 
2.26.0