Re: [LTP] [PATCH 2/2] kvm: Fix undefined reference to __stack_chk_fail()

Joerg Vehlow
2022-06-10T07:56:57Z

Hi,

Am 6/9/2022 um 10:26 AM schrieb Martin Doucha:
> On 06. 06. 22 20:43, Petr Vorel wrote:
>> Some x86_64 buildroot toolchains (bootlin-x86-64-glibc,
>> bootlin-x86-64-musl) try to link to __stack_chk_fail().
>> -nostdlib is not enough, it requires also -fstack-protector.
>>
>> x86_64-buildroot-linux-gnu/bin/ld: /tmp/ccgBXEoR.o: in function `handle_page_fault':
>> kvm_pagefault01.c:(.text+0x5d): undefined reference to `__stack_chk_fail'
>> collect2: error: ld returned 1 exit status
>>
>> Signed-off-by: Petr Vorel <petr.vorel@gmail.com>
>> ---
>> testcases/kernel/kvm/Makefile | 2 +-
>> 1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/testcases/kernel/kvm/Makefile b/testcases/kernel/kvm/Makefile
>> index 8d5193d8e..bce1a4eb5 100644
>> --- a/testcases/kernel/kvm/Makefile
>> +++ b/testcases/kernel/kvm/Makefile
>> @@ -9,7 +9,7 @@ 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
>> +GUEST_LDFLAGS = -nostdlib -Wl,--build-id=none -fstack-protector
>
> We should use -fno-stack-protector here instead. Your patch probably
> enables linking of libssp despite -nostdlib which we don't want. The GCC
> stack protector may also break tests because bootstrap initializes stack
> manually instead of letting GCC handle it.
I can confirm, that adding -fno-stack-protector to GUEST_LDFLAGS fixes
the linker error.

>
>> GUEST_LDLIBS =
>>
>> FILTER_OUT_MAKE_TARGETS := lib_guest lib_host lib_x86
>
>

Joerg