[LTP] [PATCH] kvm: Fix Nix build failure by moving -fno-stack-protector to CFLAGS

[LTP] [PATCH] kvm: Fix Nix build failure by moving -fno-stack-protector to CFLAGS

[Richard Palethorpe via ltp]

Nix (and by extension NixOS) uses a binutils wrapper of some sort to
allow switching between toolchains. This seems to be causing a problem
for the KVM tests although it may not be unique to Nix.

gcc -I/home/rich/kernel/ltp/testcases/kernel/kvm/include -DCOMPILE_PAYLOAD -ffreestanding -O2 -Wall -fno-asynchronous-unwind-tables -mno-mmx\
 -mno-sse -fno-pie -c -o lib_guest.o lib_guest.c
as  -c -o bootstrap_x86_64.o bootstrap_x86_64.S
gcc -I/home/rich/kernel/ltp/testcases/kernel/kvm/include -DCOMPILE_PAYLOAD -ffreestanding -O2 -Wall -fno-asynchronous-unwind-tables -mno-mmx\
 -mno-sse -fno-pie -c -o lib_x86.o lib_x86.c
gcc -I/home/rich/kernel/ltp/testcases/kernel/kvm/include -I../../../include -I../../../include -I../../../include/old/ -DCOMPILE_PAYLOAD -ff\
reestanding -O2 -Wall -fno-asynchronous-unwind-tables -mno-mmx -mno-sse -fno-pie -nostdlib -Wl,--build-id=none -fno-stack-protector -z noexe\
cstack -no-pie -Wl,-T/home/rich/kernel/ltp/testcases/kernel/kvm/linker/x86_64.lds -o kvm_pagefault01-payload.elf kvm_pagefault01.c lib_guest\
.o bootstrap_x86_64.o lib_x86.o
/nix/store/inq79dwl8sz1ygmfbgsmg77i5cwmdjpz-binutils-2.40/bin/ld: lib_x86.o: in function `kvm_init_guest_vmcb':
lib_x86.c:(.text+0x7b3): undefined reference to `__stack_chk_fail'
collect2: error: ld returned 1 exit status
make: *** [Makefile:58: kvm_pagefault01-payload.o] Error 1

__stack_chk_fail is added to lib_x86.o which means that
-fstack-protector somehow gets added to the compilation of lib_x86.o.

Swapping -fno-stack-protector from the LD flags to the C flags ensures
it is disabled when compiling lib_x86.o.

Signed-off-by: Richard Palethorpe <rpalethorpe@suse.com>
---
 testcases/kernel/kvm/Makefile | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/testcases/kernel/kvm/Makefile b/testcases/kernel/kvm/Makefile
index d9eb10728..ce4a5ede2 100644
--- a/testcases/kernel/kvm/Makefile
+++ b/testcases/kernel/kvm/Makefile
@@ -8,8 +8,8 @@ include $(top_srcdir)/include/mk/testcases.mk
 ASFLAGS =
 CPPFLAGS += -I$(abs_srcdir)/include
 GUEST_CPPFLAGS = $(CPPFLAGS) -DCOMPILE_PAYLOAD
-GUEST_CFLAGS = -ffreestanding -O2 -Wall -fno-asynchronous-unwind-tables -mno-mmx -mno-sse
-GUEST_LDFLAGS = -nostdlib -Wl,--build-id=none -fno-stack-protector -z noexecstack
+GUEST_CFLAGS = -ffreestanding -O2 -Wall -fno-asynchronous-unwind-tables -fno-stack-protector -mno-mmx -mno-sse
+GUEST_LDFLAGS = -nostdlib -Wl,--build-id=none -z noexecstack
 GUEST_LDLIBS =
 KVM_LD ?= $(LD)
 
-- 
2.42.0


-- 
Mailing list info: https://lists.linux.it/listinfo/ltp

Re: [LTP] [PATCH] kvm: Fix Nix build failure by moving -fno-stack-protector to CFLAGS

[Martin Doucha]

Hi,
pvorel should have a look whether it doesn't break the other systems 
where -fno-stack-protector is needed, but otherwise:

Reviewed-by: Martin Doucha <mdoucha@suse.cz>

On 19. 09. 23 10:38, Richard Palethorpe wrote:
> Nix (and by extension NixOS) uses a binutils wrapper of some sort to
> allow switching between toolchains. This seems to be causing a problem
> for the KVM tests although it may not be unique to Nix.
> 
> gcc -I/home/rich/kernel/ltp/testcases/kernel/kvm/include -DCOMPILE_PAYLOAD -ffreestanding -O2 -Wall -fno-asynchronous-unwind-tables -mno-mmx\
>   -mno-sse -fno-pie -c -o lib_guest.o lib_guest.c
> as  -c -o bootstrap_x86_64.o bootstrap_x86_64.S
> gcc -I/home/rich/kernel/ltp/testcases/kernel/kvm/include -DCOMPILE_PAYLOAD -ffreestanding -O2 -Wall -fno-asynchronous-unwind-tables -mno-mmx\
>   -mno-sse -fno-pie -c -o lib_x86.o lib_x86.c
> gcc -I/home/rich/kernel/ltp/testcases/kernel/kvm/include -I../../../include -I../../../include -I../../../include/old/ -DCOMPILE_PAYLOAD -ff\
> reestanding -O2 -Wall -fno-asynchronous-unwind-tables -mno-mmx -mno-sse -fno-pie -nostdlib -Wl,--build-id=none -fno-stack-protector -z noexe\
> cstack -no-pie -Wl,-T/home/rich/kernel/ltp/testcases/kernel/kvm/linker/x86_64.lds -o kvm_pagefault01-payload.elf kvm_pagefault01.c lib_guest\
> .o bootstrap_x86_64.o lib_x86.o
> /nix/store/inq79dwl8sz1ygmfbgsmg77i5cwmdjpz-binutils-2.40/bin/ld: lib_x86.o: in function `kvm_init_guest_vmcb':
> lib_x86.c:(.text+0x7b3): undefined reference to `__stack_chk_fail'
> collect2: error: ld returned 1 exit status
> make: *** [Makefile:58: kvm_pagefault01-payload.o] Error 1
> 
> __stack_chk_fail is added to lib_x86.o which means that
> -fstack-protector somehow gets added to the compilation of lib_x86.o.
> 
> Swapping -fno-stack-protector from the LD flags to the C flags ensures
> it is disabled when compiling lib_x86.o.
> 
> Signed-off-by: Richard Palethorpe <rpalethorpe@suse.com>
> ---
>   testcases/kernel/kvm/Makefile | 4 ++--
>   1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/testcases/kernel/kvm/Makefile b/testcases/kernel/kvm/Makefile
> index d9eb10728..ce4a5ede2 100644
> --- a/testcases/kernel/kvm/Makefile
> +++ b/testcases/kernel/kvm/Makefile
> @@ -8,8 +8,8 @@ include $(top_srcdir)/include/mk/testcases.mk
>   ASFLAGS =
>   CPPFLAGS += -I$(abs_srcdir)/include
>   GUEST_CPPFLAGS = $(CPPFLAGS) -DCOMPILE_PAYLOAD
> -GUEST_CFLAGS = -ffreestanding -O2 -Wall -fno-asynchronous-unwind-tables -mno-mmx -mno-sse
> -GUEST_LDFLAGS = -nostdlib -Wl,--build-id=none -fno-stack-protector -z noexecstack
> +GUEST_CFLAGS = -ffreestanding -O2 -Wall -fno-asynchronous-unwind-tables -fno-stack-protector -mno-mmx -mno-sse
> +GUEST_LDFLAGS = -nostdlib -Wl,--build-id=none -z noexecstack
>   GUEST_LDLIBS =
>   KVM_LD ?= $(LD)
>   

-- 
Martin Doucha   mdoucha@suse.cz
SW Quality Engineer
SUSE LINUX, s.r.o.
CORSO IIa
Krizikova 148/34
186 00 Prague 8
Czech Republic


-- 
Mailing list info: https://lists.linux.it/listinfo/ltp

Re: [LTP] [PATCH] kvm: Fix Nix build failure by moving -fno-stack-protector to CFLAGS

[Richard Palethorpe]

Hello,

Martin Doucha <mdoucha@suse.cz> writes:

> Hi,
> pvorel should have a look whether it doesn't break the other systems
> where -fno-stack-protector is needed, but otherwise:
>
> Reviewed-by: Martin Doucha <mdoucha@suse.cz>

Compilation appears to be fine:
https://github.com/richiejp/ltp/actions/runs/6232857602/job/16916865952

The tests just TCONF on my hardware, but I guess the risk of breaking
the test at runtime is low?

-- 
Thank you,
Richard.

-- 
Mailing list info: https://lists.linux.it/listinfo/ltp

Re: [LTP] [PATCH] kvm: Fix Nix build failure by moving -fno-stack-protector to CFLAGS

[Petr Vorel]

Hi Richie,

> Hello,

> Martin Doucha <mdoucha@suse.cz> writes:

> > Hi,
> > pvorel should have a look whether it doesn't break the other systems
> > where -fno-stack-protector is needed, but otherwise:

> > Reviewed-by: Martin Doucha <mdoucha@suse.cz>

> Compilation appears to be fine:
> https://github.com/richiejp/ltp/actions/runs/6232857602/job/16916865952

> The tests just TCONF on my hardware, but I guess the risk of breaking
> the test at runtime is low?

I'll test tonight Buildroot toolchains, which usually find errors which aren't
spot by our github CI.

Kind regards,
Petr

-- 
Mailing list info: https://lists.linux.it/listinfo/ltp

Re: [LTP] [PATCH] kvm: Fix Nix build failure by moving -fno-stack-protector to CFLAGS

[Petr Vorel]

Hi all,

[I Cc Fabrice and Buildroot ML]

On Tue, 19 Sept 2023 at 14:51, Martin Doucha <mdoucha@suse.cz> wrote:
>
> Hi,
> pvorel should have a look whether it doesn't break the other systems
> where -fno-stack-protector is needed, but otherwise:

Yesterday night I tested the current LTP master with ./utils/test-pkg. Some
Bootlin toolchains keep failing (bootlin-x86-64-musl, bootlin-x86-64-glibc):

CC testcases/kernel/kvm/lib_x86.o
gbr-test-pkg/bootlin-x86-64-musl/host/opt/ext-toolchain/bin/../lib/gcc/x86_64-buildroot-linux-musl/11.3.0/../../../../x86_64-buildroot-linux-musl/bin/ld:
lib_x86.o: in function `kvm_init_guest_vmcb':
lib_x86.c:(.text+0x7c8): undefined reference to `__stack_chk_fail'
collect2: error: ld returned 1 exit status

Problems are only on x86_64, other archs (aarch64, riscv64, mipsel, amv7r)
are OK.

NOTE: In Buildroot LTP is currently disabled when musl is used due  5.11
headers requirement for musl toolchain [1], but I temporarily remove this
requirement to get more testing. That's why there are also musl results.

It looks like this patch actually fixes it, thus:
Acked-by: Petr Vorel <pvorel@suse.cz>

There are even more kvm test related results [2], but I suspect they are more
related to the Buildroot toolchain than LTP itself:

CC testcases/kernel/kvm/lib_guest.o
bootstrap_x86_64.S: Assembler messages:
bootstrap_x86_64.S:16: Error: unknown pseudo-op: `.code16'
bootstrap_x86_64.S:19: Error: unknown mnemonic `cli' -- `cli'
bootstrap_x86_64.S:21: Error: unknown mnemonic `lgdt' -- `lgdt kvm_gdt32_desc'
bootstrap_x86_64.S:23: Error: operand 1 must be an integer register --
`mov $0x11,%eax'
bootstrap_x86_64.S:24: Error: operand 1 must be an integer register --
`mov %eax,%cr0'
bootstrap_x86_64.S:26: Error: unknown mnemonic `jmp' -- `jmp
$3*8,$protected_mode_entry'
bootstrap_x86_64.S:28: Error: unknown pseudo-op: `.code32'

Kind regards,
Petr

[1] https://git.busybox.net/buildroot/commit/?id=5e1c238b7202c3b04d9eab94e429c5580c77444b
[2] http://autobuild.buildroot.net/results/6fe953a989a83da67e7ec228ab1668998928ad11/build-end.log
>
> Reviewed-by: Martin Doucha <mdoucha@suse.cz>
>
> On 19. 09. 23 10:38, Richard Palethorpe wrote:
> > Nix (and by extension NixOS) uses a binutils wrapper of some sort to
> > allow switching between toolchains. This seems to be causing a problem
> > for the KVM tests although it may not be unique to Nix.
> >
> > gcc -I/home/rich/kernel/ltp/testcases/kernel/kvm/include -DCOMPILE_PAYLOAD -ffreestanding -O2 -Wall -fno-asynchronous-unwind-tables -mno-mmx\
> >   -mno-sse -fno-pie -c -o lib_guest.o lib_guest.c
> > as  -c -o bootstrap_x86_64.o bootstrap_x86_64.S
> > gcc -I/home/rich/kernel/ltp/testcases/kernel/kvm/include -DCOMPILE_PAYLOAD -ffreestanding -O2 -Wall -fno-asynchronous-unwind-tables -mno-mmx\
> >   -mno-sse -fno-pie -c -o lib_x86.o lib_x86.c
> > gcc -I/home/rich/kernel/ltp/testcases/kernel/kvm/include -I../../../include -I../../../include -I../../../include/old/ -DCOMPILE_PAYLOAD -ff\
> > reestanding -O2 -Wall -fno-asynchronous-unwind-tables -mno-mmx -mno-sse -fno-pie -nostdlib -Wl,--build-id=none -fno-stack-protector -z noexe\
> > cstack -no-pie -Wl,-T/home/rich/kernel/ltp/testcases/kernel/kvm/linker/x86_64.lds -o kvm_pagefault01-payload.elf kvm_pagefault01.c lib_guest\
> > .o bootstrap_x86_64.o lib_x86.o
> > /nix/store/inq79dwl8sz1ygmfbgsmg77i5cwmdjpz-binutils-2.40/bin/ld: lib_x86.o: in function `kvm_init_guest_vmcb':
> > lib_x86.c:(.text+0x7b3): undefined reference to `__stack_chk_fail'
> > collect2: error: ld returned 1 exit status
> > make: *** [Makefile:58: kvm_pagefault01-payload.o] Error 1
> >
> > __stack_chk_fail is added to lib_x86.o which means that
> > -fstack-protector somehow gets added to the compilation of lib_x86.o.
> >
> > Swapping -fno-stack-protector from the LD flags to the C flags ensures
> > it is disabled when compiling lib_x86.o.
> >
> > Signed-off-by: Richard Palethorpe <rpalethorpe@suse.com>
> > ---
> >   testcases/kernel/kvm/Makefile | 4 ++--
> >   1 file changed, 2 insertions(+), 2 deletions(-)
> >
> > diff --git a/testcases/kernel/kvm/Makefile b/testcases/kernel/kvm/Makefile
> > index d9eb10728..ce4a5ede2 100644
> > --- a/testcases/kernel/kvm/Makefile
> > +++ b/testcases/kernel/kvm/Makefile
> > @@ -8,8 +8,8 @@ include $(top_srcdir)/include/mk/testcases.mk
> >   ASFLAGS =
> >   CPPFLAGS += -I$(abs_srcdir)/include
> >   GUEST_CPPFLAGS = $(CPPFLAGS) -DCOMPILE_PAYLOAD
> > -GUEST_CFLAGS = -ffreestanding -O2 -Wall -fno-asynchronous-unwind-tables -mno-mmx -mno-sse
> > -GUEST_LDFLAGS = -nostdlib -Wl,--build-id=none -fno-stack-protector -z noexecstack
> > +GUEST_CFLAGS = -ffreestanding -O2 -Wall -fno-asynchronous-unwind-tables -fno-stack-protector -mno-mmx -mno-sse
> > +GUEST_LDFLAGS = -nostdlib -Wl,--build-id=none -z noexecstack
> >   GUEST_LDLIBS =
> >   KVM_LD ?= $(LD)
> >
>
> --
> Martin Doucha   mdoucha@suse.cz
> SW Quality Engineer
> SUSE LINUX, s.r.o.
> CORSO IIa
> Krizikova 148/34
> 186 00 Prague 8
> Czech Republic
>
>
> --
> Mailing list info: https://lists.linux.it/listinfo/ltp

-- 
Mailing list info: https://lists.linux.it/listinfo/ltp

Re: [LTP] [PATCH] kvm: Fix Nix build failure by moving -fno-stack-protector to CFLAGS

[Richard Palethorpe]

Hello,

Petr Vorel <petr.vorel@gmail.com> writes:

> Hi all,
>
> [I Cc Fabrice and Buildroot ML]
>
> On Tue, 19 Sept 2023 at 14:51, Martin Doucha <mdoucha@suse.cz> wrote:
>>
>> Hi,
>> pvorel should have a look whether it doesn't break the other systems
>> where -fno-stack-protector is needed, but otherwise:
>
> Yesterday night I tested the current LTP master with ./utils/test-pkg. Some
> Bootlin toolchains keep failing (bootlin-x86-64-musl, bootlin-x86-64-glibc):
>
> CC testcases/kernel/kvm/lib_x86.o
> gbr-test-pkg/bootlin-x86-64-musl/host/opt/ext-toolchain/bin/../lib/gcc/x86_64-buildroot-linux-musl/11.3.0/../../../../x86_64-buildroot-linux-musl/bin/ld:
> lib_x86.o: in function `kvm_init_guest_vmcb':
> lib_x86.c:(.text+0x7c8): undefined reference to `__stack_chk_fail'
> collect2: error: ld returned 1 exit status
>
> Problems are only on x86_64, other archs (aarch64, riscv64, mipsel, amv7r)
> are OK.

I think only x86_64 is supported.

>
> NOTE: In Buildroot LTP is currently disabled when musl is used due  5.11
> headers requirement for musl toolchain [1], but I temporarily remove this
> requirement to get more testing. That's why there are also musl results.
>
> It looks like this patch actually fixes it, thus:
> Acked-by: Petr Vorel <pvorel@suse.cz>

Right, it's not just Nix then. I will merge it.

>
> There are even more kvm test related results [2], but I suspect they are more
> related to the Buildroot toolchain than LTP itself:
>
> CC testcases/kernel/kvm/lib_guest.o
> bootstrap_x86_64.S: Assembler messages:
> bootstrap_x86_64.S:16: Error: unknown pseudo-op: `.code16'
> bootstrap_x86_64.S:19: Error: unknown mnemonic `cli' -- `cli'
> bootstrap_x86_64.S:21: Error: unknown mnemonic `lgdt' -- `lgdt kvm_gdt32_desc'
> bootstrap_x86_64.S:23: Error: operand 1 must be an integer register --
> `mov $0x11,%eax'
> bootstrap_x86_64.S:24: Error: operand 1 must be an integer register --
> `mov %eax,%cr0'
> bootstrap_x86_64.S:26: Error: unknown mnemonic `jmp' -- `jmp
> $3*8,$protected_mode_entry'
> bootstrap_x86_64.S:28: Error: unknown pseudo-op: `.code32'

For me I would at the least we need V=1 enabled or the names and
versions of the tools being used to guess what is wrong here.

mov $0x11,%eax looks like a really simple op to put 11 in EAX using
AT&T/GAS syntax. If that goes wrong then possibly the wrong syntax is
expected by the assembler or else a previous line is confusing it.

-- 
Thank you,
Richard.

-- 
Mailing list info: https://lists.linux.it/listinfo/ltp

Re: [LTP] [PATCH] kvm: Fix Nix build failure by moving -fno-stack-protector to CFLAGS

[Petr Vorel]

> Hello,

> Petr Vorel <petr.vorel@gmail.com> writes:

> > Hi all,

> > [I Cc Fabrice and Buildroot ML]

> > On Tue, 19 Sept 2023 at 14:51, Martin Doucha <mdoucha@suse.cz> wrote:

> >> Hi,
> >> pvorel should have a look whether it doesn't break the other systems
> >> where -fno-stack-protector is needed, but otherwise:

> > Yesterday night I tested the current LTP master with ./utils/test-pkg. Some
> > Bootlin toolchains keep failing (bootlin-x86-64-musl, bootlin-x86-64-glibc):

> > CC testcases/kernel/kvm/lib_x86.o
> > gbr-test-pkg/bootlin-x86-64-musl/host/opt/ext-toolchain/bin/../lib/gcc/x86_64-buildroot-linux-musl/11.3.0/../../../../x86_64-buildroot-linux-musl/bin/ld:
> > lib_x86.o: in function `kvm_init_guest_vmcb':
> > lib_x86.c:(.text+0x7c8): undefined reference to `__stack_chk_fail'
> > collect2: error: ld returned 1 exit status

> > Problems are only on x86_64, other archs (aarch64, riscv64, mipsel, amv7r)
> > are OK.

> I think only x86_64 is supported.

Yes (+ i386). Thanks, I forgot on it.


> > NOTE: In Buildroot LTP is currently disabled when musl is used due  5.11
> > headers requirement for musl toolchain [1], but I temporarily remove this
> > requirement to get more testing. That's why there are also musl results.

> > It looks like this patch actually fixes it, thus:
> > Acked-by: Petr Vorel <pvorel@suse.cz>

> Right, it's not just Nix then. I will merge it.

+1


> > There are even more kvm test related results [2], but I suspect they are more
> > related to the Buildroot toolchain than LTP itself:

> > CC testcases/kernel/kvm/lib_guest.o
> > bootstrap_x86_64.S: Assembler messages:
> > bootstrap_x86_64.S:16: Error: unknown pseudo-op: `.code16'
> > bootstrap_x86_64.S:19: Error: unknown mnemonic `cli' -- `cli'
> > bootstrap_x86_64.S:21: Error: unknown mnemonic `lgdt' -- `lgdt kvm_gdt32_desc'
> > bootstrap_x86_64.S:23: Error: operand 1 must be an integer register --
> > `mov $0x11,%eax'
> > bootstrap_x86_64.S:24: Error: operand 1 must be an integer register --
> > `mov %eax,%cr0'
> > bootstrap_x86_64.S:26: Error: unknown mnemonic `jmp' -- `jmp
> > $3*8,$protected_mode_entry'
> > bootstrap_x86_64.S:28: Error: unknown pseudo-op: `.code32'

> For me I would at the least we need V=1 enabled or the names and
> versions of the tools being used to guess what is wrong here.

I'm not sure if I find some spare time in my after-work time.
If yes, I'll post logs.

Kind regards,
Petr

> mov $0x11,%eax looks like a really simple op to put 11 in EAX using
> AT&T/GAS syntax. If that goes wrong then possibly the wrong syntax is
> expected by the assembler or else a previous line is confusing it.

-- 
Mailing list info: https://lists.linux.it/listinfo/ltp