linux-kernel - Re: [PATCH] KVM: arm64: Fix hypervisor address symbolization

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Message-ID: <CA+EHjTxXX_d8M9VGCBokoKCCuvOoR_1u4JrSNKPTdN3qp9bQog@mail.gmail.com>
Date:   Mon, 18 Jul 2022 10:08:08 +0100
From:   Fuad Tabba <tabba@...gle.com>
To:     Kalesh Singh <kaleshsingh@...gle.com>
Cc:     maz@...nel.org, mark.rutland@....com, broonie@...nel.org,
        madvenka@...ux.microsoft.com, will@...nel.org, qperret@...gle.com,
        android-mm@...gle.com, kernel-team@...roid.com,
        James Morse <james.morse@....com>,
        Alexandru Elisei <alexandru.elisei@....com>,
        Suzuki K Poulose <suzuki.poulose@....com>,
        Catalin Marinas <catalin.marinas@....com>,
        linux-arm-kernel@...ts.infradead.org, kvmarm@...ts.cs.columbia.edu,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH] KVM: arm64: Fix hypervisor address symbolization

Hi Kalesh,

On Sat, Jul 16, 2022 at 12:58 AM Kalesh Singh <kaleshsingh@...gle.com> wrote:
>
> With CONFIG_RANDOMIZE_BASE=y vmlinux addresses will resolve correctly
> from kallsyms. Fix this by adding the KASLR offset before printing the
> symbols.
>
> Based on arm64 for-next/stacktrace.
>
> Fixes: 6ccf9cb557bd ("KVM: arm64: Symbolize the nVHE HYP addresses")
> Reported-by: Fuad Tabba <tabba@...gle.com>
> Signed-off-by: Kalesh Singh <kaleshsingh@...gle.com>
> ---

Even with this patch applied I still don't get symbolization unless I
disable randomization, either by setting CONFIG_RANDOMIZE_BASE=n or
pass nokaslr as a kernel parameter. I tried both and in either case it
works.

Thanks,
/fuad


>  arch/arm64/kvm/handle_exit.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/arch/arm64/kvm/handle_exit.c b/arch/arm64/kvm/handle_exit.c
> index f66c0142b335..e43926ef2bc2 100644
> --- a/arch/arm64/kvm/handle_exit.c
> +++ b/arch/arm64/kvm/handle_exit.c
> @@ -347,10 +347,10 @@ void __noreturn __cold nvhe_hyp_panic_handler(u64 esr, u64 spsr,
>                         kvm_err("nVHE hyp BUG at: %s:%u!\n", file, line);
>                 else
>                         kvm_err("nVHE hyp BUG at: [<%016llx>] %pB!\n", panic_addr,
> -                                       (void *)panic_addr);
> +                                       (void *)(panic_addr + kaslr_offset()));
>         } else {
>                 kvm_err("nVHE hyp panic at: [<%016llx>] %pB!\n", panic_addr,
> -                               (void *)panic_addr);
> +                               (void *)(panic_addr + kaslr_offset()));
>         }
>
>         /*
>
> base-commit: 82a592c13b0aeff94d84d54183dae0b26384c95f
> --
> 2.37.0.170.g444d1eabd0-goog
>