svn commit: r365453 - stable/12/sys/cddl/dev/dtrace/amd64

[Mark Johnston]

Author: markj
Date: Tue Sep  8 12:37:46 2020
New Revision: 365453
URL: https://svnweb.freebsd.org/changeset/base/365453

Log:
  MFC r365048:
  Tighten frame pointer checking in DTrace's amd64 stack unwinder.

Modified:
  stable/12/sys/cddl/dev/dtrace/amd64/dtrace_isa.c
Directory Properties:
  stable/12/   (props changed)

Modified: stable/12/sys/cddl/dev/dtrace/amd64/dtrace_isa.c
==============================================================================
--- stable/12/sys/cddl/dev/dtrace/amd64/dtrace_isa.c	Tue Sep  8 12:37:18 2020	(r365452)
+++ stable/12/sys/cddl/dev/dtrace/amd64/dtrace_isa.c	Tue Sep  8 12:37:46 2020	(r365453)
@@ -56,6 +56,7 @@ void
 dtrace_getpcstack(pc_t *pcstack, int pcstack_limit, int aframes,
     uint32_t *intrpc)
 {
+	struct thread *td;
 	int depth = 0;
 	register_t rbp;
 	struct amd64_frame *frame;
@@ -70,10 +71,16 @@ dtrace_getpcstack(pc_t *pcstack, int pcstack_limit, in
 	__asm __volatile("movq %%rbp,%0" : "=r" (rbp));
 
 	frame = (struct amd64_frame *)rbp;
+	td = curthread;
 	while (depth < pcstack_limit) {
 		if (!INKERNEL((long) frame))
 			break;
 
+		if ((vm_offset_t)frame >=
+		    td->td_kstack + ptoa(td->td_kstack_pages) ||
+		    (vm_offset_t)frame < td->td_kstack)
+			break;
+
 		callpc = frame->f_retaddr;
 
 		if (!INKERNEL(callpc))
@@ -84,14 +91,11 @@ dtrace_getpcstack(pc_t *pcstack, int pcstack_limit, in
 			if ((aframes == 0) && (caller != 0)) {
 				pcstack[depth++] = caller;
 			}
-		}
-		else {
+		} else {
 			pcstack[depth++] = callpc;
 		}
 
-		if (frame->f_frame <= frame ||
-		    (vm_offset_t)frame->f_frame >= curthread->td_kstack +
-		    curthread->td_kstack_pages * PAGE_SIZE)
+		if ((vm_offset_t)frame->f_frame <= (vm_offset_t)frame)
 			break;
 		frame = frame->f_frame;
 	}