2022-07-16 00:00:11

by Kalesh Singh

Subject: [PATCH] KVM: arm64: Fix hypervisor address symbolization

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 <[email protected]>
Signed-off-by: Kalesh Singh <[email protected]>
---
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

2022-07-17 10:53:30

by Marc Zyngier

Subject: Re: [PATCH] KVM: arm64: Fix hypervisor address symbolization

On Sat, 16 Jul 2022 00:58:24 +0100,
Kalesh Singh <[email protected]> wrote:
>
> With CONFIG_RANDOMIZE_BASE=y vmlinux addresses will resolve correctly

I guess you mean *incorrectly* here, right?

> from kallsyms. Fix this by adding the KASLR offset before printing the
> symbols.
>
> Based on arm64 for-next/stacktrace.

In general, place these remarks after the '---' line, as they don't
really make sense in the commit itself (which is likely to be merged
on a different base anyway).

>
> Fixes: 6ccf9cb557bd ("KVM: arm64: Symbolize the nVHE HYP addresses")
> Reported-by: Fuad Tabba <[email protected]>
> Signed-off-by: Kalesh Singh <[email protected]>
> ---
> 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()));
> }
>
> /*
>

I'll fix the above as I apply the patch, no need to respin.

Thanks,

M.

--
Without deviation from the norm, progress is not possible.

2022-07-17 11:16:46

by Marc Zyngier

Subject: Re: [PATCH] KVM: arm64: Fix hypervisor address symbolization

On Fri, 15 Jul 2022 16:58:24 -0700, Kalesh Singh 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.

Applied to next, thanks!

[1/1] KVM: arm64: Fix hypervisor address symbolization
commit: ed6313a93fd11d2015ad17046f3c418bf6a8dab1

Cheers,

M.
--
Marc Zyngier <[email protected]>

2022-07-17 19:24:07

by Kalesh Singh

Subject: Re: [PATCH] KVM: arm64: Fix hypervisor address symbolization

On Sun, Jul 17, 2022 at 3:43 AM Marc Zyngier <[email protected]> wrote:
>
> On Sat, 16 Jul 2022 00:58:24 +0100,
> Kalesh Singh <[email protected]> wrote:
> >
> > With CONFIG_RANDOMIZE_BASE=y vmlinux addresses will resolve correctly
>
> I guess you mean *incorrectly* here, right?

Yes, sorry. "INcorrectly" I meant to say.

>
> > from kallsyms. Fix this by adding the KASLR offset before printing the
> > symbols.
> >
> > Based on arm64 for-next/stacktrace.
>
> In general, place these remarks after the '---' line, as they don't
> really make sense in the commit itself (which is likely to be merged
> on a different base anyway).
>
> >
> > Fixes: 6ccf9cb557bd ("KVM: arm64: Symbolize the nVHE HYP addresses")
> > Reported-by: Fuad Tabba <[email protected]>
> > Signed-off-by: Kalesh Singh <[email protected]>
> > ---
> > 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()));
> > }
> >
> > /*
> >
>
> I'll fix the above as I apply the patch, no need to respin.

Thanks Marc.

-- Kalesh

>
> Thanks,
>
> M.
>
> --
> Without deviation from the norm, progress is not possible.

2022-07-18 09:34:27

by Fuad Tabba

Subject: Re: [PATCH] KVM: arm64: Fix hypervisor address symbolization

Hi Kalesh,

On Sat, Jul 16, 2022 at 12:58 AM Kalesh Singh <[email protected]> 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 <[email protected]>
> Signed-off-by: Kalesh Singh <[email protected]>
> ---

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
>

2022-07-18 17:26:57

by Kalesh Singh

Subject: Re: [PATCH] KVM: arm64: Fix hypervisor address symbolization

On Mon, Jul 18, 2022 at 2:08 AM Fuad Tabba <[email protected]> wrote:
>
> Hi Kalesh,
>
> On Sat, Jul 16, 2022 at 12:58 AM Kalesh Singh <[email protected]> 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 <[email protected]>
> > Signed-off-by: Kalesh Singh <[email protected]>
> > ---
>
> 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.

Hi Fuad,

Thanks for testing it. The fix only addressed the symbolization for
the hyp panic address. I plan to fix the symbolization of stacktrace
in the next version of this series.

--Kalesh

>
> 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
> >