2022-06-23 19:42:51

by Masahiro Yamada

Subject: [PATCH] kbuild: link vmlinux only once for CONFIG_TRIM_UNUSED_KSYMS (2nd attempt)

If CONFIG_TRIM_UNUSED_KSYMS is enabled and the kernel is built from
a pristine state, the vmlinux is linked twice.

Commit 3fdc7d3fe4c0 ("kbuild: link vmlinux only once for
CONFIG_TRIM_UNUSED_KSYMS") explains why this happens, but it did not fix
the issue at all.

Now I realized I had applied a wrong patch.

In v1 patch [1], the autoksyms_recursive target correctly recurses to
"$(MAKE) -f $(srctree)/Makefile autoksyms_recursive".

In v2 patch [2], I accidentally dropped the diff line, and it recurses to
"$(MAKE) -f $(srctree)/Makefile vmlinux".

Restore the code I intended in v1.

[1]: https://lore.kernel.org/linux-kbuild/[email protected]/
[2]: https://lore.kernel.org/linux-kbuild/[email protected]/

Fixes: 3fdc7d3fe4c0 ("kbuild: link vmlinux only once for CONFIG_TRIM_UNUSED_KSYMS")
Signed-off-by: Masahiro Yamada <[email protected]>
---

Makefile | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/Makefile b/Makefile
index 513c1fbf7888..a3ff166c5035 100644
--- a/Makefile
+++ b/Makefile
@@ -1141,7 +1141,7 @@ KBUILD_MODULES := 1

autoksyms_recursive: descend modules.order
$(Q)$(CONFIG_SHELL) $(srctree)/scripts/adjust_autoksyms.sh \
- "$(MAKE) -f $(srctree)/Makefile vmlinux"
+ "$(MAKE) -f $(srctree)/Makefile autoksyms_recursive"
endif

autoksyms_h := $(if $(CONFIG_TRIM_UNUSED_KSYMS), include/generated/autoksyms.h)
--
2.34.1

2022-06-23 20:03:54

by Sami Tolvanen

Subject: Re: [PATCH] kbuild: link vmlinux only once for CONFIG_TRIM_UNUSED_KSYMS (2nd attempt)

On Thu, Jun 23, 2022 at 12:12 PM Masahiro Yamada <[email protected]> wrote:
>
> If CONFIG_TRIM_UNUSED_KSYMS is enabled and the kernel is built from
> a pristine state, the vmlinux is linked twice.
>
> Commit 3fdc7d3fe4c0 ("kbuild: link vmlinux only once for
> CONFIG_TRIM_UNUSED_KSYMS") explains why this happens, but it did not fix
> the issue at all.
>
> Now I realized I had applied a wrong patch.
>
> In v1 patch [1], the autoksyms_recursive target correctly recurses to
> "$(MAKE) -f $(srctree)/Makefile autoksyms_recursive".
>
> In v2 patch [2], I accidentally dropped the diff line, and it recurses to
> "$(MAKE) -f $(srctree)/Makefile vmlinux".
>
> Restore the code I intended in v1.
>
> [1]: https://lore.kernel.org/linux-kbuild/[email protected]/
> [2]: https://lore.kernel.org/linux-kbuild/[email protected]/
>
> Fixes: 3fdc7d3fe4c0 ("kbuild: link vmlinux only once for CONFIG_TRIM_UNUSED_KSYMS")
> Signed-off-by: Masahiro Yamada <[email protected]>
> ---
>
> Makefile | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/Makefile b/Makefile
> index 513c1fbf7888..a3ff166c5035 100644
> --- a/Makefile
> +++ b/Makefile
> @@ -1141,7 +1141,7 @@ KBUILD_MODULES := 1
>
> autoksyms_recursive: descend modules.order
> $(Q)$(CONFIG_SHELL) $(srctree)/scripts/adjust_autoksyms.sh \
> - "$(MAKE) -f $(srctree)/Makefile vmlinux"
> + "$(MAKE) -f $(srctree)/Makefile autoksyms_recursive"
> endif
>
> autoksyms_h := $(if $(CONFIG_TRIM_UNUSED_KSYMS), include/generated/autoksyms.h)

Thanks for looking into this, Masahiro! I can confirm that this patch
fixes the issue with vmlinux getting linked twice in our use case.

Tested-by: Sami Tolvanen <[email protected]>

Sami

2022-06-23 20:17:18

by Nick Desaulniers

Subject: Re: [PATCH] kbuild: link vmlinux only once for CONFIG_TRIM_UNUSED_KSYMS (2nd attempt)

On Thu, Jun 23, 2022 at 12:12 PM Masahiro Yamada <[email protected]> wrote:
>
> If CONFIG_TRIM_UNUSED_KSYMS is enabled and the kernel is built from
> a pristine state, the vmlinux is linked twice.
>
> Commit 3fdc7d3fe4c0 ("kbuild: link vmlinux only once for
> CONFIG_TRIM_UNUSED_KSYMS") explains why this happens, but it did not fix
> the issue at all.
>
> Now I realized I had applied a wrong patch.
>
> In v1 patch [1], the autoksyms_recursive target correctly recurses to
> "$(MAKE) -f $(srctree)/Makefile autoksyms_recursive".
>
> In v2 patch [2], I accidentally dropped the diff line, and it recurses to
> "$(MAKE) -f $(srctree)/Makefile vmlinux".
>
> Restore the code I intended in v1.
>
> [1]: https://lore.kernel.org/linux-kbuild/[email protected]/
> [2]: https://lore.kernel.org/linux-kbuild/[email protected]/
>
> Fixes: 3fdc7d3fe4c0 ("kbuild: link vmlinux only once for CONFIG_TRIM_UNUSED_KSYMS")
> Signed-off-by: Masahiro Yamada <[email protected]>

Thanks for digging into this more!
Reviewed-by: Nick Desaulniers <[email protected]>

> ---
>
> Makefile | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/Makefile b/Makefile
> index 513c1fbf7888..a3ff166c5035 100644
> --- a/Makefile
> +++ b/Makefile
> @@ -1141,7 +1141,7 @@ KBUILD_MODULES := 1
>
> autoksyms_recursive: descend modules.order
> $(Q)$(CONFIG_SHELL) $(srctree)/scripts/adjust_autoksyms.sh \
> - "$(MAKE) -f $(srctree)/Makefile vmlinux"
> + "$(MAKE) -f $(srctree)/Makefile autoksyms_recursive"
> endif
>
> autoksyms_h := $(if $(CONFIG_TRIM_UNUSED_KSYMS), include/generated/autoksyms.h)
> --
> 2.34.1
>


--
Thanks,
~Nick Desaulniers