2019-01-02 18:51:53

by Laura Abbott

[permalink] [raw]
Subject: compilation failure with CONFIG_VFIO_PCI_NVLINK2

Hi,

I got a compilation failure when building with CONFIG_VFIO_PCI_NVLINK2
enabled:

+ make -s 'HOSTCFLAGS=-O2 -g -pipe -Wall -Werror=format-security -Wp,-D_FORTIFY_SOURCE=2 -Wp,-D_GLIBCXX_ASSERTIONS -fexceptions -fstack-protector-strong -grecord-gcc-switches -specs=/usr/lib/rpm/redhat/redhat-hardened-cc1 -specs=/usr/lib/rpm/redhat/redhat-annobin-cc1 -m64 -mcpu=power8 -mtune=power8 -fasynchronous-unwind-tables -fstack-clash-protection' 'HOSTLDFLAGS=-Wl,-z,relro -Wl,--as-needed -Wl,-z,now -specs=/usr/lib/rpm/redhat/redhat-hardened-ld -Wl,--build-id=uuid' ARCH=powerpc -j4 modules
BUILDSTDERR: In file included from drivers/vfio/pci/trace.h:102,
BUILDSTDERR: from drivers/vfio/pci/vfio_pci_nvlink2.c:29:
BUILDSTDERR: ./include/trace/define_trace.h:89:42: fatal error: ./trace.h: No such file or directory
BUILDSTDERR: #include TRACE_INCLUDE(TRACE_INCLUDE_FILE)
BUILDSTDERR: ^
BUILDSTDERR: compilation terminated.
BUILDSTDERR: make[3]: *** [scripts/Makefile.build:277: drivers/vfio/pci/vfio_pci_nvlink2.o] Error 1
BUILDSTDERR: make[2]: *** [scripts/Makefile.build:492: drivers/vfio/pci] Error 2
BUILDSTDERR: make[1]: *** [scripts/Makefile.build:492: drivers/vfio] Error 2
BUILDSTDERR: make: *** [Makefile:1053: drivers] Error 2
BUILDSTDERR: make: *** Waiting for unfinished jobs....

I don't know enough about ftrace building to make a guess here.
Config is attacked.

Also, would it be possible to switch this option from def_bool to
bool? I can't turn it off directly when it's def_bool.

Thanks,
Laura


Attachments:
kernel-4.21.0-ppc64le.config (163.05 kB)

2019-01-03 21:00:02

by Alexey Kardashevskiy

[permalink] [raw]
Subject: Re: compilation failure with CONFIG_VFIO_PCI_NVLINK2



On 03/01/2019 03:37, Laura Abbott wrote:
> Hi,
>
> I got a compilation failure when building with CONFIG_VFIO_PCI_NVLINK2
> enabled:
>
> + make -s 'HOSTCFLAGS=-O2 -g -pipe -Wall -Werror=format-security
> -Wp,-D_FORTIFY_SOURCE=2 -Wp,-D_GLIBCXX_ASSERTIONS -fexceptions
> -fstack-protector-strong -grecord-gcc-switches
> -specs=/usr/lib/rpm/redhat/redhat-hardened-cc1
> -specs=/usr/lib/rpm/redhat/redhat-annobin-cc1 -m64 -mcpu=power8
> -mtune=power8 -fasynchronous-unwind-tables -fstack-clash-protection'
> 'HOSTLDFLAGS=-Wl,-z,relro -Wl,--as-needed  -Wl,-z,now
> -specs=/usr/lib/rpm/redhat/redhat-hardened-ld -Wl,--build-id=uuid'
> ARCH=powerpc -j4 modules
> BUILDSTDERR: In file included from drivers/vfio/pci/trace.h:102,
> BUILDSTDERR:                  from drivers/vfio/pci/vfio_pci_nvlink2.c:29:
> BUILDSTDERR: ./include/trace/define_trace.h:89:42: fatal error:
> ./trace.h: No such file or directory
> BUILDSTDERR:  #include TRACE_INCLUDE(TRACE_INCLUDE_FILE)
> BUILDSTDERR:                                           ^
> BUILDSTDERR: compilation terminated.
> BUILDSTDERR: make[3]: *** [scripts/Makefile.build:277:
> drivers/vfio/pci/vfio_pci_nvlink2.o] Error 1
> BUILDSTDERR: make[2]: *** [scripts/Makefile.build:492: drivers/vfio/pci]
> Error 2
> BUILDSTDERR: make[1]: *** [scripts/Makefile.build:492: drivers/vfio]
> Error 2
> BUILDSTDERR: make: *** [Makefile:1053: drivers] Error 2
> BUILDSTDERR: make: *** Waiting for unfinished jobs....
>
> I don't know enough about ftrace building to make a guess here.
> Config is attacked.

What gcc is this and what is the exact sha1 of the tree? gcc8 prints
other error with your config in drivers/scsi/esas2r/esas2r_ioctl.c but
not this one so I am curious.

>
> Also, would it be possible to switch this option from def_bool to
> bool? I can't turn it off directly when it's def_bool.

Why? Honestly I'd rather fix the compile error.


--
Alexey

2019-01-03 21:46:54

by Laura Abbott

[permalink] [raw]
Subject: Re: compilation failure with CONFIG_VFIO_PCI_NVLINK2

On 1/3/19 5:49 AM, Alexey Kardashevskiy wrote:
>
>
> On 03/01/2019 03:37, Laura Abbott wrote:
>> Hi,
>>
>> I got a compilation failure when building with CONFIG_VFIO_PCI_NVLINK2
>> enabled:
>>
>> + make -s 'HOSTCFLAGS=-O2 -g -pipe -Wall -Werror=format-security
>> -Wp,-D_FORTIFY_SOURCE=2 -Wp,-D_GLIBCXX_ASSERTIONS -fexceptions
>> -fstack-protector-strong -grecord-gcc-switches
>> -specs=/usr/lib/rpm/redhat/redhat-hardened-cc1
>> -specs=/usr/lib/rpm/redhat/redhat-annobin-cc1 -m64 -mcpu=power8
>> -mtune=power8 -fasynchronous-unwind-tables -fstack-clash-protection'
>> 'HOSTLDFLAGS=-Wl,-z,relro -Wl,--as-needed  -Wl,-z,now
>> -specs=/usr/lib/rpm/redhat/redhat-hardened-ld -Wl,--build-id=uuid'
>> ARCH=powerpc -j4 modules
>> BUILDSTDERR: In file included from drivers/vfio/pci/trace.h:102,
>> BUILDSTDERR:                  from drivers/vfio/pci/vfio_pci_nvlink2.c:29:
>> BUILDSTDERR: ./include/trace/define_trace.h:89:42: fatal error:
>> ./trace.h: No such file or directory
>> BUILDSTDERR:  #include TRACE_INCLUDE(TRACE_INCLUDE_FILE)
>> BUILDSTDERR:                                           ^
>> BUILDSTDERR: compilation terminated.
>> BUILDSTDERR: make[3]: *** [scripts/Makefile.build:277:
>> drivers/vfio/pci/vfio_pci_nvlink2.o] Error 1
>> BUILDSTDERR: make[2]: *** [scripts/Makefile.build:492: drivers/vfio/pci]
>> Error 2
>> BUILDSTDERR: make[1]: *** [scripts/Makefile.build:492: drivers/vfio]
>> Error 2
>> BUILDSTDERR: make: *** [Makefile:1053: drivers] Error 2
>> BUILDSTDERR: make: *** Waiting for unfinished jobs....
>>
>> I don't know enough about ftrace building to make a guess here.
>> Config is attacked.
>
> What gcc is this and what is the exact sha1 of the tree? gcc8 prints
> other error with your config in drivers/scsi/esas2r/esas2r_ioctl.c but
> not this one so I am curious.
>

gcc (GCC) 8.2.1 20181215 (Red Hat 8.2.1-6)

sha 8e143b90e4d45cca3dc53760d3cfab988bc74571

>>
>> Also, would it be possible to switch this option from def_bool to
>> bool? I can't turn it off directly when it's def_bool.
>
> Why? Honestly I'd rather fix the compile error.
>
>

It's not just about this error, there may be other situations where
it would be good to have this turned off.

Thanks,
Luara

2019-01-07 02:59:31

by Alexey Kardashevskiy

[permalink] [raw]
Subject: Re: compilation failure with CONFIG_VFIO_PCI_NVLINK2



On 04/01/2019 02:08, Laura Abbott wrote:
> On 1/3/19 5:49 AM, Alexey Kardashevskiy wrote:
>>
>>
>> On 03/01/2019 03:37, Laura Abbott wrote:
>>> Hi,
>>>
>>> I got a compilation failure when building with CONFIG_VFIO_PCI_NVLINK2
>>> enabled:
>>>
>>> + make -s 'HOSTCFLAGS=-O2 -g -pipe -Wall -Werror=format-security
>>> -Wp,-D_FORTIFY_SOURCE=2 -Wp,-D_GLIBCXX_ASSERTIONS -fexceptions
>>> -fstack-protector-strong -grecord-gcc-switches
>>> -specs=/usr/lib/rpm/redhat/redhat-hardened-cc1
>>> -specs=/usr/lib/rpm/redhat/redhat-annobin-cc1 -m64 -mcpu=power8
>>> -mtune=power8 -fasynchronous-unwind-tables -fstack-clash-protection'
>>> 'HOSTLDFLAGS=-Wl,-z,relro -Wl,--as-needed  -Wl,-z,now
>>> -specs=/usr/lib/rpm/redhat/redhat-hardened-ld -Wl,--build-id=uuid'
>>> ARCH=powerpc -j4 modules
>>> BUILDSTDERR: In file included from drivers/vfio/pci/trace.h:102,
>>> BUILDSTDERR:                  from
>>> drivers/vfio/pci/vfio_pci_nvlink2.c:29:
>>> BUILDSTDERR: ./include/trace/define_trace.h:89:42: fatal error:
>>> ./trace.h: No such file or directory
>>> BUILDSTDERR:  #include TRACE_INCLUDE(TRACE_INCLUDE_FILE)
>>> BUILDSTDERR:                                           ^
>>> BUILDSTDERR: compilation terminated.
>>> BUILDSTDERR: make[3]: *** [scripts/Makefile.build:277:
>>> drivers/vfio/pci/vfio_pci_nvlink2.o] Error 1
>>> BUILDSTDERR: make[2]: *** [scripts/Makefile.build:492: drivers/vfio/pci]
>>> Error 2
>>> BUILDSTDERR: make[1]: *** [scripts/Makefile.build:492: drivers/vfio]
>>> Error 2
>>> BUILDSTDERR: make: *** [Makefile:1053: drivers] Error 2
>>> BUILDSTDERR: make: *** Waiting for unfinished jobs....
>>>
>>> I don't know enough about ftrace building to make a guess here.
>>> Config is attacked.
>>
>> What gcc is this and what is the exact sha1 of the tree? gcc8 prints
>> other error with your config in drivers/scsi/esas2r/esas2r_ioctl.c but
>> not this one so I am curious.
>>
>
> gcc (GCC) 8.2.1 20181215 (Red Hat 8.2.1-6)
>
> sha 8e143b90e4d45cca3dc53760d3cfab988bc74571


Your config and this sha1 still make "make oldconfig" ask few questions
and then it compiles just fine, are you sure about the config?

These are questions on "make oldconfig":

Kernel Live Patching (LIVEPATCH) [N/y/?] (NEW)
Stack Protector buffer overflow detection (STACKPROTECTOR) [Y/n/?] (NEW)
Strong Stack Protector (STACKPROTECTOR_STRONG) [Y/n/?] (NEW)
Do NOT protect notrace function from kprobe events
(KPROBE_EVENTS_ON_NOTRACE) [N/y/?] (NEW)



>>>
>>> Also, would it be possible to switch this option from def_bool to
>>> bool? I can't turn it off directly when it's def_bool.
>>
>> Why? Honestly I'd rather fix the compile error.
>>
>>
>
> It's not just about this error, there may be other situations where
> it would be good to have this turned off.

Oh well I think I misunderstood what "def_bool" actually does (it does
not make much sense without "if" conditions). I'll post a patch.



--
Alexey

2019-01-07 07:27:51

by Alexey Kardashevskiy

[permalink] [raw]
Subject: Re: compilation failure with CONFIG_VFIO_PCI_NVLINK2



On 07/01/2019 13:58, Alexey Kardashevskiy wrote:
>
>
> On 04/01/2019 02:08, Laura Abbott wrote:
>> On 1/3/19 5:49 AM, Alexey Kardashevskiy wrote:
>>>
>>>
>>> On 03/01/2019 03:37, Laura Abbott wrote:
>>>> Hi,
>>>>
>>>> I got a compilation failure when building with CONFIG_VFIO_PCI_NVLINK2
>>>> enabled:
>>>>
>>>> + make -s 'HOSTCFLAGS=-O2 -g -pipe -Wall -Werror=format-security
>>>> -Wp,-D_FORTIFY_SOURCE=2 -Wp,-D_GLIBCXX_ASSERTIONS -fexceptions
>>>> -fstack-protector-strong -grecord-gcc-switches
>>>> -specs=/usr/lib/rpm/redhat/redhat-hardened-cc1
>>>> -specs=/usr/lib/rpm/redhat/redhat-annobin-cc1 -m64 -mcpu=power8
>>>> -mtune=power8 -fasynchronous-unwind-tables -fstack-clash-protection'
>>>> 'HOSTLDFLAGS=-Wl,-z,relro -Wl,--as-needed  -Wl,-z,now
>>>> -specs=/usr/lib/rpm/redhat/redhat-hardened-ld -Wl,--build-id=uuid'
>>>> ARCH=powerpc -j4 modules
>>>> BUILDSTDERR: In file included from drivers/vfio/pci/trace.h:102,
>>>> BUILDSTDERR:                  from
>>>> drivers/vfio/pci/vfio_pci_nvlink2.c:29:
>>>> BUILDSTDERR: ./include/trace/define_trace.h:89:42: fatal error:
>>>> ./trace.h: No such file or directory
>>>> BUILDSTDERR:  #include TRACE_INCLUDE(TRACE_INCLUDE_FILE)
>>>> BUILDSTDERR:                                           ^
>>>> BUILDSTDERR: compilation terminated.
>>>> BUILDSTDERR: make[3]: *** [scripts/Makefile.build:277:
>>>> drivers/vfio/pci/vfio_pci_nvlink2.o] Error 1
>>>> BUILDSTDERR: make[2]: *** [scripts/Makefile.build:492: drivers/vfio/pci]
>>>> Error 2
>>>> BUILDSTDERR: make[1]: *** [scripts/Makefile.build:492: drivers/vfio]
>>>> Error 2
>>>> BUILDSTDERR: make: *** [Makefile:1053: drivers] Error 2
>>>> BUILDSTDERR: make: *** Waiting for unfinished jobs....
>>>>
>>>> I don't know enough about ftrace building to make a guess here.
>>>> Config is attacked.
>>>
>>> What gcc is this and what is the exact sha1 of the tree? gcc8 prints
>>> other error with your config in drivers/scsi/esas2r/esas2r_ioctl.c but
>>> not this one so I am curious.
>>>
>>
>> gcc (GCC) 8.2.1 20181215 (Red Hat 8.2.1-6)
>>
>> sha 8e143b90e4d45cca3dc53760d3cfab988bc74571
>
>
> Your config and this sha1 still make "make oldconfig" ask few questions
> and then it compiles just fine, are you sure about the config?
>
> These are questions on "make oldconfig":
>
> Kernel Live Patching (LIVEPATCH) [N/y/?] (NEW)
> Stack Protector buffer overflow detection (STACKPROTECTOR) [Y/n/?] (NEW)
> Strong Stack Protector (STACKPROTECTOR_STRONG) [Y/n/?] (NEW)
> Do NOT protect notrace function from kprobe events
> (KPROBE_EVENTS_ON_NOTRACE) [N/y/?] (NEW)


Ok, I figured it out. This is because you compile in tree while I
compile out of tree (with O=builddir) and the difference is that in my
case gcc gets these additional -I$(src) statements and in your case you
need to add them manually:

yours V=1:

gcc
-Wp,-MD,drivers/vfio/pci/.vfio_pci_nvlink2.o.d
-nostdinc
-isystem /usr/lib/gcc/powerpc64le-linux-gnu/7/include
-I./arch/powerpc/include
-I./arch/powerpc/include/generated
-I./include
-I./arch/powerpc/include/uapi
-I./arch/powerpc/include/generated/uapi
-I./include/uapi
-I./include/generated/uapi
-include ./include/linux/kconfig.h
-include ./include/linux/compiler_types.h
-D__KERNEL__
...


mine V=1 (has -I/home/aik/p/kernel/drivers/vfio/pci and
-Idrivers/vfio/pci):

/opt/cross/gcc-powerpc64le-linux-8.2.1-nolibc/bin/powerpc64le-linux-gcc
-Wp,-MD,drivers/vfio/pci/.vfio_pci_nvlink2.o.d
-nostdinc
-isystem
/opt/cross/gcc-powerpc64le-linux-8.2.1-nolibc/bin/../lib/gcc/powerpc64le-linux/8.2.1/include
-I/home/aik/p/kernel/arch/powerpc/include
-I./arch/powerpc/include/generated
-I/home/aik/p/kernel/include
-I./include
-I/home/aik/p/kernel/arch/powerpc/include/uapi
-I./arch/powerpc/include/generated/uapi
-I/home/aik/p/kernel/include/uapi
-I./include/generated/uapi
-include /home/aik/p/kernel/include/linux/kconfig.h
-include /home/aik/p/kernel/include/linux/compiler_types.h
-I/home/aik/p/kernel/drivers/vfio/pci
-Idrivers/vfio/pci
-D__KERNEL__
...


This is where it happens:

https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/scripts/Makefile.lib#n143


I'd rather prefer to fix this in scripts/Makefile.lib#n143 than doing
-I$(src) but this is what everybody does already and therefore I guess
"[PATCH] vfio_pci: Add local source directory as include" from
https://patchwork.kernel.org/patch/10748803/ is correct.


>
>
>
>>>>
>>>> Also, would it be possible to switch this option from def_bool to
>>>> bool? I can't turn it off directly when it's def_bool.
>>>
>>> Why? Honestly I'd rather fix the compile error.
>>>
>>>
>>
>> It's not just about this error, there may be other situations where
>> it would be good to have this turned off.
>
> Oh well I think I misunderstood what "def_bool" actually does (it does
> not make much sense without "if" conditions). I'll post a patch.

I've had a quick discussion here, and the point is that the distros are
going to enable this anyway and it is quite hard to think of a scenario
when we want VFIO_PCI and POWERNV but not this NVLINK2 support. What
scenario do you have in mind?



--
Alexey

2019-01-07 10:22:03

by Michael Ellerman

[permalink] [raw]
Subject: Out-of-tree build works, in-tree build fails due to tracing (was Re: compilation failure with CONFIG_VFIO_PCI_NVLINK2)

[ + Masahiro & Steve ]

Alexey Kardashevskiy <[email protected]> writes:
> On 07/01/2019 13:58, Alexey Kardashevskiy wrote:
>> On 04/01/2019 02:08, Laura Abbott wrote:
>>> On 1/3/19 5:49 AM, Alexey Kardashevskiy wrote:
>>>> On 03/01/2019 03:37, Laura Abbott wrote:
>>>>> Hi,
>>>>>
>>>>> I got a compilation failure when building with CONFIG_VFIO_PCI_NVLINK2
>>>>> enabled:
>>>>>
>>>>> + make -s 'HOSTCFLAGS=-O2 -g -pipe -Wall -Werror=format-security
>>>>> -Wp,-D_FORTIFY_SOURCE=2 -Wp,-D_GLIBCXX_ASSERTIONS -fexceptions
>>>>> -fstack-protector-strong -grecord-gcc-switches
>>>>> -specs=/usr/lib/rpm/redhat/redhat-hardened-cc1
>>>>> -specs=/usr/lib/rpm/redhat/redhat-annobin-cc1 -m64 -mcpu=power8
>>>>> -mtune=power8 -fasynchronous-unwind-tables -fstack-clash-protection'
>>>>> 'HOSTLDFLAGS=-Wl,-z,relro -Wl,--as-needed  -Wl,-z,now
>>>>> -specs=/usr/lib/rpm/redhat/redhat-hardened-ld -Wl,--build-id=uuid'
>>>>> ARCH=powerpc -j4 modules
>>>>> BUILDSTDERR: In file included from drivers/vfio/pci/trace.h:102,
>>>>> BUILDSTDERR:                  from
>>>>> drivers/vfio/pci/vfio_pci_nvlink2.c:29:
>>>>> BUILDSTDERR: ./include/trace/define_trace.h:89:42: fatal error:
>>>>> ./trace.h: No such file or directory
>>>>> BUILDSTDERR:  #include TRACE_INCLUDE(TRACE_INCLUDE_FILE)
>>>>> BUILDSTDERR:                                           ^
>>>>> BUILDSTDERR: compilation terminated.
>>>>> BUILDSTDERR: make[3]: *** [scripts/Makefile.build:277:
>>>>> drivers/vfio/pci/vfio_pci_nvlink2.o] Error 1
>>>>> BUILDSTDERR: make[2]: *** [scripts/Makefile.build:492: drivers/vfio/pci]
>>>>> Error 2
>>>>> BUILDSTDERR: make[1]: *** [scripts/Makefile.build:492: drivers/vfio]
>>>>> Error 2
>>>>> BUILDSTDERR: make: *** [Makefile:1053: drivers] Error 2
>>>>> BUILDSTDERR: make: *** Waiting for unfinished jobs....
>>>>>
>>>>> I don't know enough about ftrace building to make a guess here.
>>>>> Config is attacked.
>>>>
>>>> What gcc is this and what is the exact sha1 of the tree? gcc8 prints
>>>> other error with your config in drivers/scsi/esas2r/esas2r_ioctl.c but
>>>> not this one so I am curious.
>>>>
>>>
>>> gcc (GCC) 8.2.1 20181215 (Red Hat 8.2.1-6)
>>>
>>> sha 8e143b90e4d45cca3dc53760d3cfab988bc74571
>>
>>
>> Your config and this sha1 still make "make oldconfig" ask few questions
>> and then it compiles just fine, are you sure about the config?
>>
>> These are questions on "make oldconfig":
>>
>> Kernel Live Patching (LIVEPATCH) [N/y/?] (NEW)
>> Stack Protector buffer overflow detection (STACKPROTECTOR) [Y/n/?] (NEW)
>> Strong Stack Protector (STACKPROTECTOR_STRONG) [Y/n/?] (NEW)
>> Do NOT protect notrace function from kprobe events
>> (KPROBE_EVENTS_ON_NOTRACE) [N/y/?] (NEW)
>
>
> Ok, I figured it out. This is because you compile in tree while I
> compile out of tree (with O=builddir) and the difference is that in my
> case gcc gets these additional -I$(src) statements and in your case you
> need to add them manually:
>
> yours V=1:
>
> gcc
> -Wp,-MD,drivers/vfio/pci/.vfio_pci_nvlink2.o.d
> -nostdinc
> -isystem /usr/lib/gcc/powerpc64le-linux-gnu/7/include
> -I./arch/powerpc/include
> -I./arch/powerpc/include/generated
> -I./include
> -I./arch/powerpc/include/uapi
> -I./arch/powerpc/include/generated/uapi
> -I./include/uapi
> -I./include/generated/uapi
> -include ./include/linux/kconfig.h
> -include ./include/linux/compiler_types.h
> -D__KERNEL__
> ...
>
>
> mine V=1 (has -I/home/aik/p/kernel/drivers/vfio/pci and
> -Idrivers/vfio/pci):
>
> /opt/cross/gcc-powerpc64le-linux-8.2.1-nolibc/bin/powerpc64le-linux-gcc
> -Wp,-MD,drivers/vfio/pci/.vfio_pci_nvlink2.o.d
> -nostdinc
> -isystem
> /opt/cross/gcc-powerpc64le-linux-8.2.1-nolibc/bin/../lib/gcc/powerpc64le-linux/8.2.1/include
> -I/home/aik/p/kernel/arch/powerpc/include
> -I./arch/powerpc/include/generated
> -I/home/aik/p/kernel/include
> -I./include
> -I/home/aik/p/kernel/arch/powerpc/include/uapi
> -I./arch/powerpc/include/generated/uapi
> -I/home/aik/p/kernel/include/uapi
> -I./include/generated/uapi
> -include /home/aik/p/kernel/include/linux/kconfig.h
> -include /home/aik/p/kernel/include/linux/compiler_types.h
> -I/home/aik/p/kernel/drivers/vfio/pci
> -Idrivers/vfio/pci
> -D__KERNEL__
> ...
>
>
> This is where it happens:
>
> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/scripts/Makefile.lib#n143
>
>
> I'd rather prefer to fix this in scripts/Makefile.lib#n143 than doing
> -I$(src) but this is what everybody does already and therefore I guess
> "[PATCH] vfio_pci: Add local source directory as include" from
> https://patchwork.kernel.org/patch/10748803/ is correct.

Where the patch does:
+ccflags-y += -I$(src)


This seems like a bug in the build system?

ie. depending on whether you build in-tree or out-of-tree the build can
fail, or not.

Can we fix this once and for all in Makefile.lib as Alexey suggests, or
is there some reason that doesn't work?

(As an aside, why do we even support in-tree build any more?)

cheers