Naveen N. Rao wrote:
quoted hunk ↗ jump to hunk
+
+unsigned long ftrace_get_traced_func_if_no_stackframe(unsigned long ip, unsigned long *stack)
+{
+ if (!is_ftrace_entry(ip))
+ return 0;
+
+ if (IS_ENABLED(CONFIG_PPC32))
+ return stack[11]; /* see MCOUNT_SAVE_FRAME */
+
+ if (!IS_ENABLED(CONFIG_MPROFILE_KERNEL))
+ return 0;
+
+ return stack[(STACK_FRAME_OVERHEAD + offsetof(struct pt_regs, nip)) / sizeof(unsigned long)];
Looking at Daniel's patch to address KASAN errors with our stack walk code in show_stack() [*], I realized that I am not validating the stack pointer here for the above accesses...
[*] http://lkml.kernel.org/r/20210528074806.1311297-1-dja@axtens.net
quoted hunk ↗ jump to hunk
+}
+
+#ifdef CONFIG_STACK_TRACER
+void stack_get_trace(unsigned long traced_ip,
+ unsigned long *stack_ref __maybe_unused,
+ unsigned long stack_size __maybe_unused,
+ int *tracer_frame)
+{
+ unsigned long sp, newsp, top, ip;
+ int ftrace_call_found = 0;
+ unsigned long *stack;
+ int i = 0;
+
+ sp = current_stack_frame();
+ top = (unsigned long)task_stack_page(current) + THREAD_SIZE;
+
+ while (validate_sp(sp, current, STACK_FRAME_OVERHEAD) && i < STACK_TRACE_ENTRIES) {
+ stack = (unsigned long *) sp;
+ newsp = stack[0];
+ ip = stack[STACK_FRAME_LR_SAVE];
+
+ if (ftrace_call_found) {
+ stack_dump_trace[i] = ip;
+ stack_trace_index[i++] = top - sp;
+ }
And I need to make the above accesses bypass KASAN as well.
- Naveen