[PATCH 2/2] rawfbt: prvname is not properly set

[eugene.loh@oracle.com]

From: Eugene Loh <eugene.loh@oracle.com>

The char array prvname[] is set for each provider.  It is used in the
file that implements the provider.  It might also be passed to
dt_sdt_populate() via a function argument.

However, dt_provider_tp.h also defines the macro GROUP_DATA in terms of
prvname.  In turn, GROUP_DATA is used not only in dt_prov_dtrace.c but
then again in dt_prov_fbt.c to define FBT_GROUP_DATA.

In commit 0b7c5a632 ("fbt, rawfbt: consolidate code to avoid duplication"),
the fbt and rawfbt providers are combined into a single file.  Thus, two
uses of prvname collide.  The in-file collisions get resolved, but the
cascade of macro definitions does not:  FBT_GROUP_DATA ends up using
"fbt" for both fbt and rawfbt providers.  As a result, it is possible
for rawfbt probes not to be seen.

Notice that GROUP_DATA is always paired with prp->desc->prb.  Therefore,
simply replace:
    -#define GROUP_DATA     getpid(), prvname
    +#define PROBE_DATA     getpid(), prp->desc->prv, prp->desc->prb
This makes the code more compact and relieves the macro definitions from
needing prvname.  It also makes the FBT_GROUP_DATA macro unnecessary.

The format (FMT) macro is similarly renamed and redefined to include the
probe info.

Add a test to check that a rawfbt probe can be found behind an fbt probe
when the probe description has a wildcard provider.

Orabug: 38842114
Signed-off-by: Eugene Loh <eugene.loh@oracle.com>
---
 libdtrace/dt_prov_dtrace.c                    | 14 ++++++-------
 libdtrace/dt_prov_fbt.c                       | 13 ++++++------
 libdtrace/dt_prov_rawtp.c                     |  4 ++--
 libdtrace/dt_prov_sdt.c                       |  4 ++--
 libdtrace/dt_provider_tp.h                    | 12 +++++------
 .../providers/rawfbt/tst.wildcard-provider.d  | 20 +++++++++++++++++++
 .../providers/rawfbt/tst.wildcard-provider.r  |  2 ++
 7 files changed, 45 insertions(+), 24 deletions(-)
 create mode 100644 test/unittest/providers/rawfbt/tst.wildcard-provider.d
 create mode 100644 test/unittest/providers/rawfbt/tst.wildcard-provider.r

diff --git a/libdtrace/dt_prov_dtrace.c b/libdtrace/dt_prov_dtrace.c
index 34b5d8e24..102afd84e 100644
--- a/libdtrace/dt_prov_dtrace.c
+++ b/libdtrace/dt_prov_dtrace.c
@@ -243,8 +243,8 @@ static int attach(dtrace_hdl_t *dtp, const dt_probe_t *prp, int bpf_fd)
 		/* add a uprobe */
 		fd = open(UPROBE_EVENTS, O_WRONLY | O_APPEND);
 		if (fd != -1) {
-			rc = dprintf(fd, "p:" GROUP_FMT "/%s %s\n",
-				     GROUP_DATA, prp->desc->prb, spec);
+			rc = dprintf(fd, "p:" PROBE_FMT " %s\n",
+				     PROBE_DATA, spec);
 			close(fd);
 		}
 		free(spec);
@@ -252,14 +252,14 @@ static int attach(dtrace_hdl_t *dtp, const dt_probe_t *prp, int bpf_fd)
 			return -ENOENT;
 
 		/* open format file */
-		len = snprintf(NULL, 0, "%s" GROUP_FMT "/%s/format",
-			       EVENTSFS, GROUP_DATA, prp->desc->prb) + 1;
+		len = snprintf(NULL, 0, "%s" PROBE_FMT "/format",
+			       EVENTSFS, PROBE_DATA) + 1;
 		fn = dt_alloc(dtp, len);
 		if (fn == NULL)
 			return -ENOENT;
 
-		snprintf(fn, len, "%s" GROUP_FMT "/%s/format",
-			 EVENTSFS, GROUP_DATA, prp->desc->prb);
+		snprintf(fn, len, "%s" PROBE_FMT "/format",
+			 EVENTSFS, PROBE_DATA);
 		f = fopen(fn, "r");
 		dt_free(dtp, fn);
 		if (f == NULL)
@@ -300,7 +300,7 @@ static void detach(dtrace_hdl_t *dtp, const dt_probe_t *prp)
 	if (fd == -1)
 		return;
 
-	dprintf(fd, "-:" GROUP_FMT "/%s\n", GROUP_DATA, prp->desc->prb);
+	dprintf(fd, "-:" PROBE_FMT "\n", PROBE_DATA);
 	close(fd);
 }
 
diff --git a/libdtrace/dt_prov_fbt.c b/libdtrace/dt_prov_fbt.c
index 3feac56ea..8dbf9740a 100644
--- a/libdtrace/dt_prov_fbt.c
+++ b/libdtrace/dt_prov_fbt.c
@@ -53,8 +53,7 @@ static const char		prvname[] = "fbt";
 
 #define KPROBE_EVENTS		TRACEFS "kprobe_events"
 
-#define FBT_GROUP_FMT		GROUP_FMT "_%s"
-#define FBT_GROUP_DATA		GROUP_DATA, prp->desc->prb
+#define FBT_PROBE_FMT		"dt_%d_%s_%s"
 
 static const dtrace_pattr_t	pattr = {
 { DTRACE_STABILITY_EVOLVING, DTRACE_STABILITY_EVOLVING, DTRACE_CLASS_COMMON },
@@ -508,16 +507,16 @@ static int kprobe_attach(dtrace_hdl_t *dtp, const dt_probe_t *prp, int bpf_fd)
 		if (fd == -1)
 			goto out;
 
-		rc = dprintf(fd, "%c:" FBT_GROUP_FMT "/%s %s\n",
+		rc = dprintf(fd, "%c:" FBT_PROBE_FMT "/%s %s\n",
 			     prp->desc->prb[0] == 'e' ? 'p' : 'r',
-			     FBT_GROUP_DATA, tpn, fun);
+			     PROBE_DATA, tpn, fun);
 		close(fd);
 		if (rc == -1)
 			goto out;
 
 		/* create format file name */
-		if (asprintf(&fn, "%s" FBT_GROUP_FMT "/%s/format", EVENTSFS,
-			     FBT_GROUP_DATA, tpn) == -1)
+		if (asprintf(&fn, "%s" FBT_PROBE_FMT "/%s/format", EVENTSFS,
+			     PROBE_DATA, tpn) == -1)
 			goto out;
 
 		/* open format file */
@@ -583,7 +582,7 @@ static void kprobe_detach(dtrace_hdl_t *dtp, const dt_probe_t *prp)
 		}
 	}
 
-	dprintf(fd, "-:" FBT_GROUP_FMT "/%s\n", FBT_GROUP_DATA, tpn);
+	dprintf(fd, "-:" FBT_PROBE_FMT "/%s\n", PROBE_DATA, tpn);
 	close(fd);
 
 	if (tpn != prp->desc->fun)
diff --git a/libdtrace/dt_prov_rawtp.c b/libdtrace/dt_prov_rawtp.c
index 709f7040f..e3269f4b3 100644
--- a/libdtrace/dt_prov_rawtp.c
+++ b/libdtrace/dt_prov_rawtp.c
@@ -56,7 +56,7 @@ static const dtrace_pattr_t	pattr = {
 /*
  * The PROBE_LIST file lists all tracepoints in a <group>:<name> format.
  * We need to ignore these groups:
- *   - GROUP_FMT (created by DTrace processes)
+ *   - PROBE_SFMT
  *   - kprobes and uprobes
  *   - syscalls (handled by a different provider)
  *   - pid and usdt probes (ditto)
@@ -89,7 +89,7 @@ static int populate(dtrace_hdl_t *dtp)
 
 			*p++ = '\0';
 
-			if (sscanf(buf, GROUP_SFMT, &dummy, &str) == 2) {
+			if (sscanf(buf, PROBE_SFMT, &dummy, &str) == 2) {
 				free(str);
 				continue;
 			}
diff --git a/libdtrace/dt_prov_sdt.c b/libdtrace/dt_prov_sdt.c
index 74555f5be..ee2cc3c27 100644
--- a/libdtrace/dt_prov_sdt.c
+++ b/libdtrace/dt_prov_sdt.c
@@ -54,7 +54,7 @@ static const dtrace_pattr_t	pattr = {
 /*
  * The PROBE_LIST file lists all tracepoints in a <group>:<name> format.
  * We need to ignore these groups:
- *   - GROUP_FMT (created by DTrace processes)
+ *   - PROBE_SFMT
  *   - kprobes and uprobes
  *   - syscalls (handled by a different provider)
  *   - pid and usdt probes (ditto)
@@ -87,7 +87,7 @@ static int populate(dtrace_hdl_t *dtp)
 
 			*p++ = '\0';
 
-			if (sscanf(buf, GROUP_SFMT, &dummy, &str) == 2) {
+			if (sscanf(buf, PROBE_SFMT, &dummy, &str) == 2) {
 				free(str);
 				continue;
 			}
diff --git a/libdtrace/dt_provider_tp.h b/libdtrace/dt_provider_tp.h
index f131b1e02..406609d1b 100644
--- a/libdtrace/dt_provider_tp.h
+++ b/libdtrace/dt_provider_tp.h
@@ -18,13 +18,13 @@ extern "C" {
  * Tracepoint group naming format for DTrace providers.  Providers may append
  * to this format string as needed.
  *
- * GROUP_DATA provides the necessary data items to populate the format string
- * (PID of the dtrace process and the provider name).  GROUP_SFMT is like
- * GROUP_FMT, but for sscanf().
+ * PROBE_DATA provides the necessary data items to populate the format string.
+ * PROBE_FMT formats that data.
+ * PROBE_SFMT is a format string for recognizing PROBE_FMT data in sscanf().
  */
-#define GROUP_FMT	"dt_%d_%s"
-#define GROUP_SFMT	"dt_%d_%ms"
-#define GROUP_DATA	getpid(), prvname
+#define PROBE_DATA	getpid(), prp->desc->prv, prp->desc->prb
+#define PROBE_FMT	"dt_%d_%s/%s"
+#define PROBE_SFMT	"dt_%d_%ms"
 
 typedef struct tp_probe tp_probe_t;
 
diff --git a/test/unittest/providers/rawfbt/tst.wildcard-provider.d b/test/unittest/providers/rawfbt/tst.wildcard-provider.d
new file mode 100644
index 000000000..ad9f4c779
--- /dev/null
+++ b/test/unittest/providers/rawfbt/tst.wildcard-provider.d
@@ -0,0 +1,20 @@
+/*
+ * Oracle Linux DTrace.
+ * Copyright (c) 2026, Oracle and/or its affiliates. All rights reserved.
+ * Licensed under the Universal Permissive License v 1.0 as shown at
+ * http://oss.oracle.com/licenses/upl.
+ */
+
+/*
+ * ASSERTION: rawfbt probes can be found even when a wildcard provider
+ * description also allows fbt probes.
+ */
+
+#pragma D option quiet
+
+BEGIN,
+*fbt:vmlinux:do_sys_open*:entry
+{
+	printf("success\n");
+	exit(0);
+}
diff --git a/test/unittest/providers/rawfbt/tst.wildcard-provider.r b/test/unittest/providers/rawfbt/tst.wildcard-provider.r
new file mode 100644
index 000000000..b34a52d2f
--- /dev/null
+++ b/test/unittest/providers/rawfbt/tst.wildcard-provider.r
@@ -0,0 +1,2 @@
+success
+
-- 
2.47.3