Messages in this thread | | | Date | Wed, 25 Jan 2023 09:18:30 +0000 | Subject | Re: [PATCH v5 0/2] arm64: Fix pending single-step debugging issues | From | Luis Machado <> |
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Hi,
Is this expected to change single-stepping operation in usespace for debuggers (gdb/lldb)? If so, it would be nice to at least test it a little to make sure it works.
On 1/24/23 18:04, Daniel Thompson wrote: > On Thu, Jan 12, 2023 at 02:52:49PM +0530, Sumit Garg wrote: >> Hi Will, Catalin, >> >> On Mon, 19 Dec 2022 at 15:55, Sumit Garg <sumit.garg@linaro.org> wrote: >>> >>> This patch-set reworks pending fixes from Wei's series [1] to make >>> single-step debugging via kgdb/kdb on arm64 work as expected. There was >>> a prior discussion on ML [2] regarding if we should keep the interrupts >>> enabled during single-stepping. So patch #1 follows suggestion from Will >>> [3] to not disable interrupts during single stepping but rather skip >>> single stepping within interrupt handler. >>> >>> [1] https://lore.kernel.org/all/20200509214159.19680-1-liwei391@huawei.com/ >>> [2] https://lore.kernel.org/all/CAD=FV=Voyfq3Qz0T3RY+aYWYJ0utdH=P_AweB=13rcV8GDBeyQ@mail.gmail.com/ >>> [3] https://lore.kernel.org/all/20200626095551.GA9312@willie-the-truck/ >>> >>> Changes in v5: >>> - Incorporated misc. comments from Mark. >>> >> >> Since patch #1 has already been reviewed/acked by Mark and the >> complete patchset has been tested by Doug, would it be fine for you to >> pick up this patchset? It fixes a real single stepping problem for >> kgdb on arm64. > > Sorry to be quiet for so long. > > Testing this patch set has proven to be a little difficult. > > It certainly fixes the single step tests in the kgdbtest suite. > That's a good start. > > Unfortunately when testing using qemu/KVM (hosted on NXP > 2k/Solidrun Honeycomb) the patch set is resulting in instability > running the built-in self tests (specifically this one: > https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/drivers/misc/kgdbts.c#n74 ). Running this test using the kgdbtest harness > results in the test failing roughly a third of the time. > > The error reported is that the trap handler tried to unlock a spinlock > that isn't currently locked. To be honest I suspect this is a generic > problem that the new feature happens to tickle (this test has > historically been unreliable on x86 too... and x86 is noteworthy for > being the only other platform I test using KVM rather than pure qemu). > Of course the only way to prove that would be to find and fix the > problem in the trap handler (which probably involves rewriting it) and I > haven't managed to do that yet. > > In short, I think the debugger is more useful with this patchset than > without so, although it is caveated by the above, I'd call this: > > Acked-by: Daniel Thompson <daniel.thompson@linaro.org> > Tested-by: Daniel Thompson <daniel.thompson@linaro.org> > > > Daniel. > > _______________________________________________ > linux-arm-kernel mailing list > linux-arm-kernel@lists.infradead.org > http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
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