9db2541d4c
This adds a specific unwind plan for AArch64 Linux sigreturn frames. Previously we assumed that the fp would be valid here but it is not. https://github.com/torvalds/linux/blob/master/arch/arm64/kernel/vdso/sigreturn.S On Ubuntu Bionic it happened to point to an old frame info which meant you got what looked like a correct backtrace. On Focal, the info is completely invalid. (probably due to some code shuffling in libc) This adds an UnwindPlan that knows that the sp in a sigreturn frame points to an rt_sigframe from which we can offset to get saved sp and pc values to backtrace correctly. Based on LibUnwind's change: https://reviews.llvm.org/D90898 A new test is added that sets all compares the frames from the initial signal catch to the handler break. Ensuring that the stack/frame pointer, function name and register values match. (this test is AArch64 Linux specific because it's the only one with a specific unwind plan for this situation) Fixes https://bugs.llvm.org/show_bug.cgi?id=52165 Reviewed By: omjavaid, labath Differential Revision: https://reviews.llvm.org/D112069
81 lines
3.2 KiB
Python
81 lines
3.2 KiB
Python
"""Test that we can unwind out of a signal handler.
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Which for AArch64 Linux requires a specific unwind plan."""
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import lldb
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from lldbsuite.test.decorators import *
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from lldbsuite.test.lldbtest import *
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from lldbsuite.test import lldbutil
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class UnwindSignalTestCase(TestBase):
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mydir = TestBase.compute_mydir(__file__)
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NO_DEBUG_INFO_TESTCASE = True
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@skipUnlessArch("aarch64")
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@skipUnlessPlatform(["linux"])
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def test_unwind_signal(self):
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"""Inferior calls sigill() and handles the resultant SIGILL.
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Stopped at a breakpoint in the handler, check that we can unwind
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back to sigill() and get the expected register contents there."""
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self.build()
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exe = self.getBuildArtifact("a.out")
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target = self.dbg.CreateTarget(exe)
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self.assertTrue(target, VALID_TARGET)
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process = target.LaunchSimple(
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None, None, self.get_process_working_directory())
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self.assertTrue(process, PROCESS_IS_VALID)
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self.assertEqual(process.GetState(), lldb.eStateStopped)
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signo = process.GetUnixSignals().GetSignalNumberFromName("SIGILL")
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thread = lldbutil.get_stopped_thread(process, lldb.eStopReasonSignal)
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self.assertTrue(
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thread and thread.IsValid(),
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"Thread should be stopped due to a signal")
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self.assertTrue(
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thread.GetStopReasonDataCount() >= 1,
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"There should be data in the event.")
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self.assertEqual(thread.GetStopReasonDataAtIndex(0),
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signo, "The stop signal should be SIGILL")
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# Continue to breakpoint in sigill handler
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bkpt = target.FindBreakpointByID(
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lldbutil.run_break_set_by_source_regexp(self, "Set a breakpoint here"))
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threads = lldbutil.continue_to_breakpoint(process, bkpt)
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self.assertEqual(len(threads), 1, "Expected single thread")
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thread = threads[0]
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# Expect breakpoint in 'handler'
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frame = thread.GetFrameAtIndex(0)
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self.assertEqual(frame.GetDisplayFunctionName(), "handler", "Unexpected break?")
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# Expect that unwinding should find 'sigill'
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found_caller = False
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for frame in thread.get_thread_frames():
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if frame.GetDisplayFunctionName() == "sigill":
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# We should have ascending values in the x registers
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regs = frame.GetRegisters().GetValueAtIndex(0)
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err = lldb.SBError()
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for i in range(31):
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name = 'x{}'.format(i)
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value = regs.GetChildMemberWithName(name).GetValueAsUnsigned(err)
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self.assertTrue(err.Success(), "Failed to get register {}: {}".format(
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name, err))
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self.assertEqual(value, i, "Unexpected value for register {}".format(
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name))
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found_caller = True
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break
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self.assertTrue(found_caller, "Unwinding did not find func that caused the SIGILL")
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# Continue until we exit.
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process.Continue()
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self.assertEqual(process.GetState(), lldb.eStateExited)
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self.assertEqual(process.GetExitStatus(), 0)
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