D39166.id119078.diff
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D39166.id119078.diff
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	diff --git a/sys/cddl/dev/kinst/amd64/kinst_isa.c b/sys/cddl/dev/kinst/amd64/kinst_isa.c
	--- a/sys/cddl/dev/kinst/amd64/kinst_isa.c
	+++ b/sys/cddl/dev/kinst/amd64/kinst_isa.c
	@@ -507,8 +507,8 @@
	struct kinst_probe *kp;
	dtrace_kinst_probedesc_t *pd;
	const char *func;
	- int error, instrsize, n, off;
	- uint8_t instr, limit;
	+ uint8_t instr, limit, *p;
	+ int error, instrsize, n, off, found;

	pd = opaque;
	func = symval->name;
	@@ -521,12 +521,24 @@
	return (0);

	/*
	- * Ignore functions not beginning with the usual function prologue.
	- * These might correspond to exception handlers with which we should not
	- * meddle. This does however exclude functions which can be safely
	+ * Instead of ignoring functions that do not `push %rbp` in their first
	+ * instruction right away, we check if there's a `push %rbp` anywhere
	+ * in the function. Functions that do not push the frame pointer might
	+ * correspond to exception handlers with which we should not meddle.
	+ *
	+ * FIXME: This does however exclude functions which can be safely
	* traced, such as cpu_switch().
	*/
	- if (*instr != KINST_PUSHL_RBP)
	+ p = instr;
	+ found = 0;
	+ while (p < limit) {
	+ if (*p == KINST_PUSHL_RBP) {
	+ found = 1;
	+ break;
	+ }
	+ p += dtrace_instr_size(p);
	+ }
	+ if (!found)
	return (0);

	n = 0;