Re: [PATCH 5.4 and earlier only] mm: Fix '.data.once' orphan section warning

Greg Kroah-Hartman
2022-12-03T13:34:29Z

On Mon, Nov 28, 2022 at 03:53:46PM -0700, Nathan Chancellor wrote:
> Portions of upstream commit a4055888629b ("mm/memcg: warning on !memcg
> after readahead page charged") were backported as commit cfe575954ddd
> ("mm: add VM_WARN_ON_ONCE_PAGE() macro"). Unfortunately, the backport
> did not account for the lack of commit 33def8498fdd ("treewide: Convert
> macro and uses of __section(foo) to __section("foo")") in kernels prior
> to 5.10, resulting in the following orphan section warnings on PowerPC
> clang builds with CONFIG_DEBUG_VM=y:
>
> powerpc64le-linux-gnu-ld: warning: orphan section `".data.once"' from `mm/huge_memory.o' being placed in section `".data.once"'
> powerpc64le-linux-gnu-ld: warning: orphan section `".data.once"' from `mm/huge_memory.o' being placed in section `".data.once"'
> powerpc64le-linux-gnu-ld: warning: orphan section `".data.once"' from `mm/huge_memory.o' being placed in section `".data.once"'
>
> This is a difference between how clang and gcc handle macro
> stringification, which was resolved for the kernel by not stringifying
> the argument to the __section() macro. Since that change was deemed not
> suitable for the stable kernels by commit 59f89518f510 ("once: fix
> section mismatch on clang builds"), do that same thing as that change
> and remove the quotes from the argument to __section().
>
> Fixes: cfe575954ddd ("mm: add VM_WARN_ON_ONCE_PAGE() macro")
> Signed-off-by: Nathan Chancellor <nathan@kernel.org>
> ---
>
> As far as I can tell, this should be applied to 5.4 and earlier. It
> should apply cleanly but let me know if not.

Queued up everywhere, thanks.

greg k-h