[DTrace-devel] [PATCH v2 03/04] rawtp: report lockmem issues when determining rawtp argument count

[Kris Van Hees]

No test is added for this condition because any such test would have to
be removed again in the next patch, where a better way to retrieve rawtp
argument info will be introduced.  This code will remain as a fallback,
but we do not have any way to programmatically force it to be used.

Signed-off-by: Kris Van Hees <kris.van.hees at oracle.com>
---
 libdtrace/dt_bpf.c        | 2 +-
 libdtrace/dt_bpf.h        | 2 ++
 libdtrace/dt_cc.c         | 3 +++
 libdtrace/dt_prov_rawtp.c | 4 +++-
 4 files changed, 9 insertions(+), 2 deletions(-)

diff --git a/libdtrace/dt_bpf.c b/libdtrace/dt_bpf.c
index 8034af48..730f8d8e 100644
--- a/libdtrace/dt_bpf.c
+++ b/libdtrace/dt_bpf.c
@@ -62,7 +62,7 @@ dt_bpf_error(dtrace_hdl_t *dtp, const char *fmt, ...)
 	return dt_set_errno(dtp, EDT_BPF);
 }
 
-static int
+int
 dt_bpf_lockmem_error(dtrace_hdl_t *dtp, const char *msg)
 {
 	return dt_bpf_error(dtp, "%s:\n"
diff --git a/libdtrace/dt_bpf.h b/libdtrace/dt_bpf.h
index 125a250d..9a8e9492 100644
--- a/libdtrace/dt_bpf.h
+++ b/libdtrace/dt_bpf.h
@@ -50,6 +50,8 @@ extern int perf_event_open(struct perf_event_attr *attr, pid_t pid, int cpu,
 extern int bpf(enum bpf_cmd cmd, union bpf_attr *attr);
 
 extern int dt_bpf_gmap_create(struct dtrace_hdl *);
+extern int dt_bpf_lockmem_error(struct dtrace_hdl *dtp, const char *msg);
+
 extern int dt_bpf_map_lookup(int fd, const void *key, void *val);
 extern int dt_bpf_map_next_key(int fd, const void *key, void *nxt);
 extern int dt_bpf_map_update(int fd, const void *key, const void *val);
diff --git a/libdtrace/dt_cc.c b/libdtrace/dt_cc.c
index a42109f1..887e0be1 100644
--- a/libdtrace/dt_cc.c
+++ b/libdtrace/dt_cc.c
@@ -307,6 +307,9 @@ dt_setcontext(dtrace_hdl_t *dtp, const dtrace_probedesc_t *pdp)
 			pdp->prb);
 	}
 
+	if (err == EDT_BPF)
+		(yypcb->pcb_jmpbuf, err);
+
 	if (err != EDT_NOPROBE && err != EDT_UNSTABLE && err != 0)
 		xyerror(D_PDESC_INVAL, "%s\n", dtrace_errmsg(dtp, err));
 
diff --git a/libdtrace/dt_prov_rawtp.c b/libdtrace/dt_prov_rawtp.c
index 24104dd5..93a30bb7 100644
--- a/libdtrace/dt_prov_rawtp.c
+++ b/libdtrace/dt_prov_rawtp.c
@@ -181,7 +181,9 @@ static int probe_info(dtrace_hdl_t *dtp, const dt_probe_t *prp,
 		dif.dtdo_len = 2;
 
 		bpf_fd = dt_bpf_prog_load(dt_rawtp.prog_type, &dif, 0, NULL, 0);
-		if (bpf_fd < 0)
+		if (bpf_fd == -EPERM)
+			return dt_bpf_lockmem_error(dtp, "Cannot retrieve argument count");
+		else if (bpf_fd < 0)
 			continue;
 		rtp_fd = dt_bpf_raw_tracepoint_open(prp->desc->prb, bpf_fd);
 		close(bpf_fd);
-- 
2.42.0