[Buildroot] [PATCH 0/2] Fix Rock 5B build, broken by gcc 12 warnings

[Buildroot] [PATCH 0/2] Fix Rock 5B build, broken by gcc 12 warnings

[Kilian Zinnecker via buildroot]

Building the image for the Radxa Rock 5B currently breaks: The gcc
version was recently changed to version 12 and gcc 12 seems to stop
compiling, if certain warnings occur. See the broken build here:

https://gitlab.com/buildroot.org/buildroot/-/jobs/4795673759

This patch series adds two patches from the mainline Linux kernel,
which fix two of the warnings. However, also custom code parts of the
used custom kernel break due to warnings from gcc 12. The best
solution would be to fix those issues as well. However, until they are
fixed, the version of gcc used for the Rock 5B is set to the previous
version, gcc 11.

Kilian Zinnecker (2):
  configs/rock5b: Freeze gcc to version 11
  board/radxa/rock5b: Add patches for gcc12 warnings

 ...st-ether_addr-prototypes-to-silence-.patch | 62 +++++++++++++++++++
 ...x-building-error-on-Werror-array-com.patch | 45 ++++++++++++++
 configs/rock5b_defconfig                      |  2 +
 3 files changed, 109 insertions(+)
 create mode 100644 board/radxa/rock5b/0001-etherdevice-Adjust-ether_addr-prototypes-to-silence-.patch
 create mode 100644 board/radxa/rock5b/0002-mm-page_alloc-fix-building-error-on-Werror-array-com.patch

-- 
2.34.1

_______________________________________________
buildroot mailing list
buildroot@buildroot.org
https://lists.buildroot.org/mailman/listinfo/buildroot

[Buildroot] [PATCH 1/2] configs/rock5b: Freeze gcc to version 11

[Kilian Zinnecker via buildroot]

This patch sets the gcc version to use for the Radxa Rock 5B to
version 11. Recently the gcc default version in buildroot was
changed to gcc 12. However, the used kernel for the Rock 5B is a
custom kernel, provided by Radxa, with specific changes. It is
derived from a 5.10 version of the mainline kernel. When compiled
with gcc 12 some kernel code parts break, due to warnings. Some of
those parts are fixed in later versions of the mainline kernel.
Others are parts customized, non-mainline code, for which no fix
seems to exist currently.

Signed-off-by: Kilian Zinnecker <kilian.zinnecker@mail.de>
---
 configs/rock5b_defconfig | 1 +
 1 file changed, 1 insertion(+)

diff --git a/configs/rock5b_defconfig b/configs/rock5b_defconfig
index 6e525d9676..93d34f8cf3 100644
--- a/configs/rock5b_defconfig
+++ b/configs/rock5b_defconfig
@@ -6,6 +6,7 @@ BR2_ROOTFS_POST_SCRIPT_ARGS=""
 BR2_TARGET_GENERIC_HOSTNAME="rock5b"
 BR2_TARGET_GENERIC_ISSUE="Welcome to the rock5b board"
 BR2_SYSTEM_DHCP="eth0"
+BR2_GCC_VERSION_11_X=y
 BR2_LINUX_KERNEL=y
 BR2_LINUX_KERNEL_CUSTOM_GIT=y
 BR2_LINUX_KERNEL_CUSTOM_REPO_URL="https://github.com/radxa/kernel.git"
-- 
2.34.1

_______________________________________________
buildroot mailing list
buildroot@buildroot.org
https://lists.buildroot.org/mailman/listinfo/buildroot

[Buildroot] [PATCH 2/2] board/radxa/rock5b: Add patches for gcc12 warnings

[Kilian Zinnecker via buildroot]

This patch introduces patches for the custom kernel, as it is
currently used for the Radxa Rock 5B. The patches fix two gcc
compiler warnings, which result in a build error, if the kernel
is used with gcc version 12.

Signed-off-by: Kilian Zinnecker <kilian.zinnecker@mail.de>
---
 ...st-ether_addr-prototypes-to-silence-.patch | 62 +++++++++++++++++++
 ...x-building-error-on-Werror-array-com.patch | 45 ++++++++++++++
 configs/rock5b_defconfig                      |  1 +
 3 files changed, 108 insertions(+)
 create mode 100644 board/radxa/rock5b/0001-etherdevice-Adjust-ether_addr-prototypes-to-silence-.patch
 create mode 100644 board/radxa/rock5b/0002-mm-page_alloc-fix-building-error-on-Werror-array-com.patch

diff --git a/board/radxa/rock5b/0001-etherdevice-Adjust-ether_addr-prototypes-to-silence-.patch b/board/radxa/rock5b/0001-etherdevice-Adjust-ether_addr-prototypes-to-silence-.patch
new file mode 100644
index 0000000000..8c1cec2f47
--- /dev/null
+++ b/board/radxa/rock5b/0001-etherdevice-Adjust-ether_addr-prototypes-to-silence-.patch
@@ -0,0 +1,62 @@
+From 2618a0dae09ef37728dab89ff60418cbe25ae6bd Mon Sep 17 00:00:00 2001
+From: Kees Cook <keescook@chromium.org>
+Date: Sat, 12 Feb 2022 09:14:49 -0800
+Subject: [PATCH] etherdevice: Adjust ether_addr* prototypes to silence
+ -Wstringop-overead
+MIME-Version: 1.0
+Content-Type: text/plain; charset=UTF-8
+Content-Transfer-Encoding: 8bit
+
+With GCC 12, -Wstringop-overread was warning about an implicit cast from
+char[6] to char[8]. However, the extra 2 bytes are always thrown away,
+alignment doesn't matter, and the risk of hitting the edge of unallocated
+memory has been accepted, so this prototype can just be converted to a
+regular char *. Silences:
+
+net/core/dev.c: In function ‘bpf_prog_run_generic_xdp’: net/core/dev.c:4618:21: warning: ‘ether_addr_equal_64bits’ reading 8 bytes from a region of size 6 [-Wstringop-overread]
+ 4618 |         orig_host = ether_addr_equal_64bits(eth->h_dest, > skb->dev->dev_addr);
+      |                     ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+net/core/dev.c:4618:21: note: referencing argument 1 of type ‘const u8[8]’ {aka ‘const unsigned char[8]’}
+net/core/dev.c:4618:21: note: referencing argument 2 of type ‘const u8[8]’ {aka ‘const unsigned char[8]’}
+In file included from net/core/dev.c:91: include/linux/etherdevice.h:375:20: note: in a call to function ‘ether_addr_equal_64bits’
+  375 | static inline bool ether_addr_equal_64bits(const u8 addr1[6+2],
+      |                    ^~~~~~~~~~~~~~~~~~~~~~~
+
+Reported-by: Marc Kleine-Budde <mkl@pengutronix.de>
+Tested-by: Marc Kleine-Budde <mkl@pengutronix.de>
+Link: https://lore.kernel.org/netdev/20220212090811.uuzk6d76agw2vv73@pengutronix.de
+Cc: Jakub Kicinski <kuba@kernel.org>
+Cc: "David S. Miller" <davem@davemloft.net>
+Cc: netdev@vger.kernel.org
+Signed-off-by: Kees Cook <keescook@chromium.org>
+Signed-off-by: David S. Miller <davem@davemloft.net>
+---
+ include/linux/etherdevice.h | 5 ++---
+ 1 file changed, 2 insertions(+), 3 deletions(-)
+
+diff --git a/include/linux/etherdevice.h b/include/linux/etherdevice.h
+index 2ad71cc90b37..92b10e67d5f8 100644
+--- a/include/linux/etherdevice.h
++++ b/include/linux/etherdevice.h
+@@ -134,7 +134,7 @@ static inline bool is_multicast_ether_addr(const u8 *addr)
+ #endif
+ }
+ 
+-static inline bool is_multicast_ether_addr_64bits(const u8 addr[6+2])
++static inline bool is_multicast_ether_addr_64bits(const u8 *addr)
+ {
+ #if defined(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS) && BITS_PER_LONG == 64
+ #ifdef __BIG_ENDIAN
+@@ -372,8 +372,7 @@ static inline bool ether_addr_equal(const u8 *addr1, const u8 *addr2)
+  * Please note that alignment of addr1 & addr2 are only guaranteed to be 16 bits.
+  */
+ 
+-static inline bool ether_addr_equal_64bits(const u8 addr1[6+2],
+-					   const u8 addr2[6+2])
++static inline bool ether_addr_equal_64bits(const u8 *addr1, const u8 *addr2)
+ {
+ #if defined(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS) && BITS_PER_LONG == 64
+ 	u64 fold = (*(const u64 *)addr1) ^ (*(const u64 *)addr2);
+-- 
+2.34.1
+
diff --git a/board/radxa/rock5b/0002-mm-page_alloc-fix-building-error-on-Werror-array-com.patch b/board/radxa/rock5b/0002-mm-page_alloc-fix-building-error-on-Werror-array-com.patch
new file mode 100644
index 0000000000..34eae9c158
--- /dev/null
+++ b/board/radxa/rock5b/0002-mm-page_alloc-fix-building-error-on-Werror-array-com.patch
@@ -0,0 +1,45 @@
+From 69848f9488bc1088bcd9a73987dff8d2cb47a060 Mon Sep 17 00:00:00 2001
+From: Xiongwei Song <sxwjean@gmail.com>
+Date: Fri, 14 Jan 2022 14:07:24 -0800
+Subject: [PATCH] mm: page_alloc: fix building error on -Werror=array-compare
+
+commit ca831f29f8f25c97182e726429b38c0802200c8f upstream.
+
+Arthur Marsh reported we would hit the error below when building kernel
+with gcc-12:
+
+  CC      mm/page_alloc.o
+  mm/page_alloc.c: In function `mem_init_print_info':
+  mm/page_alloc.c:8173:27: error: comparison between two arrays [-Werror=array-compare]
+   8173 |                 if (start <= pos && pos < end && size > adj) \
+        |
+
+In C++20, the comparision between arrays should be warned.
+
+Link: https://lkml.kernel.org/r/20211125130928.32465-1-sxwjean@me.com
+Signed-off-by: Xiongwei Song <sxwjean@gmail.com>
+Reported-by: Arthur Marsh <arthur.marsh@internode.on.net>
+Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
+Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
+Cc: Khem Raj <raj.khem@gmail.com>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+---
+ mm/page_alloc.c | 2 +-
+ 1 file changed, 1 insertion(+), 1 deletion(-)
+
+diff --git a/mm/page_alloc.c b/mm/page_alloc.c
+index f022e0024e8d..f3418edb136b 100644
+--- a/mm/page_alloc.c
++++ b/mm/page_alloc.c
+@@ -7678,7 +7678,7 @@ void __init mem_init_print_info(const char *str)
+ 	 */
+ #define adj_init_size(start, end, size, pos, adj) \
+ 	do { \
+-		if (start <= pos && pos < end && size > adj) \
++		if (&start[0] <= &pos[0] && &pos[0] < &end[0] && size > adj) \
+ 			size -= adj; \
+ 	} while (0)
+ 
+-- 
+2.34.1
+
diff --git a/configs/rock5b_defconfig b/configs/rock5b_defconfig
index 93d34f8cf3..b8c7347288 100644
--- a/configs/rock5b_defconfig
+++ b/configs/rock5b_defconfig
@@ -11,6 +11,7 @@ BR2_LINUX_KERNEL=y
 BR2_LINUX_KERNEL_CUSTOM_GIT=y
 BR2_LINUX_KERNEL_CUSTOM_REPO_URL="https://github.com/radxa/kernel.git"
 BR2_LINUX_KERNEL_CUSTOM_REPO_VERSION="52f51a2b5ba178f331af62260d2da86d7472c14b"
+BR2_LINUX_KERNEL_PATCH="board/radxa/rock5b/0001-etherdevice-Adjust-ether_addr-prototypes-to-silence-.patch board/radxa/rock5b/0002-mm-page_alloc-fix-building-error-on-Werror-array-com.patch"
 BR2_LINUX_KERNEL_DEFCONFIG="rockchip_linux"
 BR2_LINUX_KERNEL_DTS_SUPPORT=y
 BR2_LINUX_KERNEL_INTREE_DTS_NAME="rockchip/rk3588-rock-5b"
-- 
2.34.1

_______________________________________________
buildroot mailing list
buildroot@buildroot.org
https://lists.buildroot.org/mailman/listinfo/buildroot

Re: [Buildroot] [PATCH 0/2] Fix Rock 5B build, broken by gcc 12 warnings

[Thomas Petazzoni via buildroot]

Hello Kilian,

Thanks for your work. See below some comments/questions.

On Tue,  8 Aug 2023 07:01:20 +0200
Kilian Zinnecker via buildroot <buildroot@buildroot.org> wrote:

> Building the image for the Radxa Rock 5B currently breaks: The gcc
> version was recently changed to version 12 and gcc 12 seems to stop
> compiling, if certain warnings occur. See the broken build here:
> 
> https://gitlab.com/buildroot.org/buildroot/-/jobs/4795673759
> 
> This patch series adds two patches from the mainline Linux kernel,
> which fix two of the warnings. However, also custom code parts of the
> used custom kernel break due to warnings from gcc 12. The best
> solution would be to fix those issues as well. However, until they are
> fixed, the version of gcc used for the Rock 5B is set to the previous
> version, gcc 11.
> 
> Kilian Zinnecker (2):
>   configs/rock5b: Freeze gcc to version 11
>   board/radxa/rock5b: Add patches for gcc12 warnings

I'm not sure to understand the reasoning for the second patch. Does it
fix all gcc 12.x issues or not? If not, what is the motivation for this
second patch?

Also: gcc 11.x is currently the oldest version supported by Buildroot,
it means that as soon as gcc 14.x is released, we will drop support for
gcc 11.x. So clearly, the solution of sticking to gcc 11.x is not going
to work for a very long time.

Best regards,

Thomas
-- 
Thomas Petazzoni, co-owner and CEO, Bootlin
Embedded Linux and Kernel engineering and training
https://bootlin.com
_______________________________________________
buildroot mailing list
buildroot@buildroot.org
https://lists.buildroot.org/mailman/listinfo/buildroot

Re: [Buildroot] [PATCH 0/2] Fix Rock 5B build, broken by gcc 12 warnings

[Kilian Zinnecker via buildroot]

Hello Thomas, all,

> > Building the image for the Radxa Rock 5B currently breaks: The gcc
> > version was recently changed to version 12 and gcc 12 seems to stop
> > compiling, if certain warnings occur. See the broken build here:
> > 
> > https://gitlab.com/buildroot.org/buildroot/-/jobs/4795673759
> > 
> > This patch series adds two patches from the mainline Linux kernel,
> > which fix two of the warnings. However, also custom code parts of the
> > used custom kernel break due to warnings from gcc 12. The best
> > solution would be to fix those issues as well. However, until they are
> > fixed, the version of gcc used for the Rock 5B is set to the previous
> > version, gcc 11.
> > 
> > Kilian Zinnecker (2):
> >   configs/rock5b: Freeze gcc to version 11
> >   board/radxa/rock5b: Add patches for gcc12 warnings
> 
> I'm not sure to understand the reasoning for the second patch. Does it
> fix all gcc 12.x issues or not? If not, what is the motivation for this
> second patch?

No, the second patch does not fix all gcc 12.x issues. It only fixes two of 
them. I think that fixing two of the warnings for now still is a plus.

> Also: gcc 11.x is currently the oldest version supported by Buildroot,
> it means that as soon as gcc 14.x is released, we will drop support for
> gcc 11.x. So clearly, the solution of sticking to gcc 11.x is not going
> to work for a very long time.

Thanks for the info, I actually would not have known this! I think that the 
best way is to ask the maintainers of the Radxa custom kernel whether they may 
fix the remaining issues, so that the custom kernel compiles with gcc 12.x. I 
intend to do so.

I think both patches should be applied. However, the first patch alone should 
already cause to fix the build itself. (Tbh. I did not test it though.)

Best regards,
Kilian


_______________________________________________
buildroot mailing list
buildroot@buildroot.org
https://lists.buildroot.org/mailman/listinfo/buildroot

Re: [Buildroot] [PATCH 0/2] Fix Rock 5B build, broken by gcc 12 warnings

[Thomas Petazzoni via buildroot]

On Tue, 08 Aug 2023 22:44:04 +0200
Kilian Zinnecker <kilian.zinnecker@mail.de> wrote:

> > I'm not sure to understand the reasoning for the second patch. Does it
> > fix all gcc 12.x issues or not? If not, what is the motivation for this
> > second patch?  
> 
> No, the second patch does not fix all gcc 12.x issues. It only fixes two of 
> them. I think that fixing two of the warnings for now still is a plus.

Nah, it doesn't make sense to fix them because if there are remaining
issues, we can't switch to gcc 12.x anyway, and those those two patches
are basically useless dead code.

> Thanks for the info, I actually would not have known this! I think that the 
> best way is to ask the maintainers of the Radxa custom kernel whether they may 
> fix the remaining issues, so that the custom kernel compiles with gcc 12.x. I 
> intend to do so.

ACK.

> I think both patches should be applied. However, the first patch alone should 
> already cause to fix the build itself. (Tbh. I did not test it though.)

Would be good to test before sending patches :-)

Thanks!

Thomas
-- 
Thomas Petazzoni, co-owner and CEO, Bootlin
Embedded Linux and Kernel engineering and training
https://bootlin.com
_______________________________________________
buildroot mailing list
buildroot@buildroot.org
https://lists.buildroot.org/mailman/listinfo/buildroot

Re: [Buildroot] [PATCH 0/2] Fix Rock 5B build, broken by gcc 12 warnings

[Kilian Zinnecker via buildroot]

Hello Thomas,

[--SNIP--]

> > I think both patches should be applied. However, the first patch alone
> > should already cause to fix the build itself. (Tbh. I did not test it
> > though.)
> Would be good to test before sending patches :-)

I actually did test the patches, but only both patches together. But yes, now 
thinking about it, it makes sense to me to also test them incrementally 
applied. After all a single patch should probably contain one sound change, 
which should not break anything, if applied alone.

I now tested patch 1/2 alone (i.e., without patch 2/2) and building as well as 
booting the image works.

Best regards,
Kilian


_______________________________________________
buildroot mailing list
buildroot@buildroot.org
https://lists.buildroot.org/mailman/listinfo/buildroot

Re: [Buildroot] [PATCH 0/2] Fix Rock 5B build, broken by gcc 12 warnings

[Kilian Zinnecker via buildroot]

Hello Thomas,

[--SNIP--]

> > Thanks for the info, I actually would not have known this! I think that
> > the
> > best way is to ask the maintainers of the Radxa custom kernel whether they
> > may fix the remaining issues, so that the custom kernel compiles with gcc
> > 12.x. I intend to do so.
> 
> ACK.

I opened up an issue in their git about this. However, I must admit, I really 
doubt, that the Radxa people fix the warnings in their kernel in time for the 
next buildroot release, or even at all: They seem to have issues, reported 
last december, in their git, which they yet did not reply to. Now, I could 
give it a try and try to fix the warnigs of their custom code, but at the 
moment, I don't have the time, and I would rather like to focus on the 
BeagleV-Ahead board support :)

So I would argue to simply fix the gcc version to 11x for now:

1. I think this is legit in such cases - why else would the option even exist 
in buildroot.

2. Even if version 11 of gcc will be removed in the near future, we would then 
at least have one release version of buildroot, which features the Rock 5B. I 
think that would be a plus for makers, hobbyists and professionals, e.g., who 
use the Rock 5B to evaluate the RK3588 (I actually know one person who used 
the Rock 5B for such purposes). Also, maybe in the future I find time to 
prepare some patches, or maybe the Radxa people also fix it till then.

[--SNIP--]

Best regards,
Kilian




_______________________________________________
buildroot mailing list
buildroot@buildroot.org
https://lists.buildroot.org/mailman/listinfo/buildroot

Re: [Buildroot] [PATCH 0/2] Fix Rock 5B build, broken by gcc 12 warnings

[Kilian Zinnecker via buildroot]

Hello Thomas,

[--SNIP--]

> Also: gcc 11.x is currently the oldest version supported by Buildroot,
> it means that as soon as gcc 14.x is released, we will drop support for
> gcc 11.x. So clearly, the solution of sticking to gcc 11.x is not going
> to work for a very long time.

I was thinking about this again, and I personally think the most cleanest 
solution would be to simply disable the custom code parts, which throw 
warnings not accepted by gcc 12. In this particular case this basically means 
disabling WiFi support for the Rock5b. This is not nice, but I think it is the 
cleanest way untill the issues are fixed. I did send a v2 of the patches.

Best regards,
Kilian


_______________________________________________
buildroot mailing list
buildroot@buildroot.org
https://lists.buildroot.org/mailman/listinfo/buildroot