Messages in this thread | | | Date | Mon, 25 Oct 2021 11:34:27 +0900 | From | Masami Hiramatsu <> | Subject | Re: [PATCH v3 2/9] kprobes: Add a test case for stacktrace from kretprobe handler |
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On Fri, 22 Oct 2021 12:15:37 -0400 Steven Rostedt <rostedt@goodmis.org> wrote:
> On Thu, 21 Oct 2021 09:54:32 +0900 > Masami Hiramatsu <mhiramat@kernel.org> wrote: > > > Add a test case for stacktrace from kretprobe handler and > > nested kretprobe handlers. > > > > This test checks both of stack trace inside kretprobe handler > > and stack trace from pt_regs. Those stack trace must include > > actual function return address instead of kretprobe trampoline. > > The nested kretprobe stacktrace test checks whether the unwinder > > can correctly unwind the call frame on the stack which has been > > modified by the kretprobe. > > > > Since the stacktrace on kretprobe is correctly fixed only on x86, > > this introduces a meta kconfig ARCH_CORRECT_STACKTRACE_ON_KRETPROBE > > which tells user that the stacktrace on kretprobe is correct or not. > > > > The test results will be shown like below; > > > > TAP version 14 > > 1..1 > > # Subtest: kprobes_test > > 1..6 > > ok 1 - test_kprobe > > ok 2 - test_kprobes > > ok 3 - test_kretprobe > > ok 4 - test_kretprobes > > ok 5 - test_stacktrace_on_kretprobe > > ok 6 - test_stacktrace_on_nested_kretprobe > > # kprobes_test: pass:6 fail:0 skip:0 total:6 > > # Totals: pass:6 fail:0 skip:0 total:6 > > ok 1 - kprobes_test > > So my allmodconfig test failed on this: > > ERROR: modpost: "stack_trace_save_regs" [kernel/test_kprobes.ko] undefined!
Oops.
> > + /* > > + * Test stacktrace from pt_regs at the return address. Thus the stack > > + * trace must start from the target return address. > > + */ > > + ret = stack_trace_save_regs(regs, stack_buf, STACK_BUF_SIZE, 0); > > + KUNIT_EXPECT_NE(current_test, ret, 0); > > + KUNIT_EXPECT_EQ(current_test, stack_buf[0], target_return_address[1]); > > + > > + return 0; > > +} > > It appears that that "stack_trace_save_regs" is not exported. And this code > can be compiled as a module.
Yes, if the selftest is compiled as a module, it has to remove the stack_trace_save_regs().
> > I'm going to continue testing my code, as I have over 40 patches that need > to go into next. I'll just rebase removing this commit only (hopefully > nothing else breaks), and if everything then passes, I'll push to next.
OK, let me fix that.
Thank you,
> > -- Steve
-- Masami Hiramatsu <mhiramat@kernel.org>
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