Have dt_cg_load_scalar report runtime error if it fails

Signed-off-by: Eugene Loh <eugene.loh@oracle.com> Reviewed-by: Nick Alcock <nick.alcock@oracle.com> Reviewed-by: Kris Van Hees <kris.van.hees@oracle.com>
oracle · May 25, 2023 · 7877da7 · 7877da7
1 parent 531e492
commit 7877da7
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Showing 13 changed files with 145 additions and 2 deletions.
diff --git a/libdtrace/dt_cg.c b/libdtrace/dt_cg.c
@@ -2585,22 +2585,35 @@ dt_cg_promote(const dt_node_t *dnp, ssize_t size, dt_irlist_t *dlp,
 	}
 }
 
+/*
+ * Load a scalar from an arbitrary address.
+ */
 static void
 dt_cg_load_scalar(dt_node_t *dnp, uint_t op, ssize_t size, dt_irlist_t *dlp,
 		  dt_regset_t *drp)
 {
+	uint_t Lokay = dt_irlist_label(dlp);
+
+	/* Copy the scalar onto the stack. */
 	if (dt_regset_xalloc_args(drp) == -1)
 		longjmp(yypcb->pcb_jmpbuf, EDT_NOREG);
 	emit(dlp, BPF_MOV_REG(BPF_REG_3, dnp->dn_reg));
 	emit(dlp, BPF_LOAD(BPF_DW, BPF_REG_1, BPF_REG_FP, DT_STK_SP));
 	emit(dlp, BPF_MOV_IMM(BPF_REG_2, size));
 	dt_regset_xalloc(drp, BPF_REG_0);
 	emit(dlp, BPF_CALL_HELPER(BPF_FUNC_probe_read));
-	dt_regset_free(drp, BPF_REG_0);
 	dt_regset_free_args(drp);
+
+	/* Report a fault if the copy failed. */
+	emit(dlp,  BPF_BRANCH_IMM(BPF_JEQ, BPF_REG_0, 0, Lokay));
+	dt_regset_free(drp, BPF_REG_0);
+	dt_cg_probe_error(yypcb, DTRACEFLT_BADADDR, DT_ISREG, dnp->dn_reg);
+	emitl(dlp, Lokay,
+		   BPF_NOP());
+
+	/* Load the scalar from the stack. */
 	emit(dlp, BPF_LOAD(BPF_DW, dnp->dn_reg, BPF_REG_FP, DT_STK_SP));
 	emit(dlp, BPF_LOAD(op, dnp->dn_reg, dnp->dn_reg, 0));
-
 	dt_cg_promote(dnp, size, dlp, drp);
 }
 

diff --git a/test/unittest/codegen/err.deref_0.d b/test/unittest/codegen/err.deref_0.d
@@ -0,0 +1,23 @@
+/*
+ * Oracle Linux DTrace.
+ * Copyright (c) 2023, 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.
+ */
+
+#pragma D option quiet
+
+BEGIN
+{
+	trace(*((char*)0));
+}
+
+BEGIN
+{
+	exit(0);
+}
+
+ERROR
+{
+	exit(1);
+}
diff --git a/test/unittest/codegen/err.deref_0.r b/test/unittest/codegen/err.deref_0.r
@@ -0,0 +1,3 @@
+
+-- @@stderr --
+dtrace: error on enabled probe ID 3 (ID 1: dtrace:::BEGIN): invalid address (0) in action #1 at BPF pc NNN
diff --git a/test/unittest/codegen/err.deref_0.r.p b/test/unittest/codegen/err.deref_0.r.p
@@ -0,0 +1,6 @@
+#!/usr/bin/sed -f
+
+# runtest.sh looks for "0x" to filter out pointer values.
+# Strip the 0x so that the illegal address will not be filtered out;
+# we want the address to be checked.
+s/0x//
diff --git a/test/unittest/codegen/err.deref_1.d b/test/unittest/codegen/err.deref_1.d
@@ -0,0 +1,23 @@
+/*
+ * Oracle Linux DTrace.
+ * Copyright (c) 2023, 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.
+ */
+
+#pragma D option quiet
+
+BEGIN
+{
+	trace(*((char*)1));
+}
+
+BEGIN
+{
+	exit(0);
+}
+
+ERROR
+{
+	exit(1);
+}
diff --git a/test/unittest/codegen/err.deref_1.r b/test/unittest/codegen/err.deref_1.r
@@ -0,0 +1,3 @@
+
+-- @@stderr --
+dtrace: error on enabled probe ID 3 (ID 1: dtrace:::BEGIN): invalid address (1) in action #1 at BPF pc NNN
diff --git a/test/unittest/codegen/err.deref_1.r.p b/test/unittest/codegen/err.deref_1.r.p
@@ -0,0 +1,6 @@
+#!/usr/bin/sed -f
+
+# runtest.sh looks for "0x" to filter out pointer values.
+# Strip the 0x so that the illegal address will not be filtered out;
+# we want the address to be checked.
+s/0x//
diff --git a/test/unittest/codegen/err.deref_i0.d b/test/unittest/codegen/err.deref_i0.d
@@ -0,0 +1,24 @@
+/*
+ * Oracle Linux DTrace.
+ * Copyright (c) 2023, 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.
+ */
+
+#pragma D option quiet
+
+BEGIN
+{
+	i = 0;
+	trace(*((char*)i));
+}
+
+BEGIN
+{
+	exit(0);
+}
+
+ERROR
+{
+	exit(1);
+}
diff --git a/test/unittest/codegen/err.deref_i0.r b/test/unittest/codegen/err.deref_i0.r
@@ -0,0 +1,3 @@
+
+-- @@stderr --
+dtrace: error on enabled probe ID 3 (ID 1: dtrace:::BEGIN): invalid address (0) in action #1 at BPF pc NNN
diff --git a/test/unittest/codegen/err.deref_i0.r.p b/test/unittest/codegen/err.deref_i0.r.p
@@ -0,0 +1,6 @@
+#!/usr/bin/sed -f
+
+# runtest.sh looks for "0x" to filter out pointer values.
+# Strip the 0x so that the illegal address will not be filtered out;
+# we want the address to be checked.
+s/0x//
diff --git a/test/unittest/codegen/err.deref_i1.d b/test/unittest/codegen/err.deref_i1.d
@@ -0,0 +1,24 @@
+/*
+ * Oracle Linux DTrace.
+ * Copyright (c) 2023, 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.
+ */
+
+#pragma D option quiet
+
+BEGIN
+{
+	i = 1;
+	trace(*((char*)i));
+}
+
+BEGIN
+{
+	exit(0);
+}
+
+ERROR
+{
+	exit(1);
+}
diff --git a/test/unittest/codegen/err.deref_i1.r b/test/unittest/codegen/err.deref_i1.r
@@ -0,0 +1,3 @@
+
+-- @@stderr --
+dtrace: error on enabled probe ID 3 (ID 1: dtrace:::BEGIN): invalid address (1) in action #1 at BPF pc NNN
diff --git a/test/unittest/codegen/err.deref_i1.r.p b/test/unittest/codegen/err.deref_i1.r.p
@@ -0,0 +1,6 @@
+#!/usr/bin/sed -f
+
+# runtest.sh looks for "0x" to filter out pointer values.
+# Strip the 0x so that the illegal address will not be filtered out;
+# we want the address to be checked.
+s/0x//