Messages in this thread Patch in this message | | | From | Greg Kroah-Hartman <> | Subject | [PATCH 4.14 32/35] xen: unexport __init-annotated xen_xlate_map_ballooned_pages() | Date | Thu, 30 Jun 2022 15:46:43 +0200 |
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From: Masahiro Yamada <masahiroy@kernel.org>
commit dbac14a5a05ff8e1ce7c0da0e1f520ce39ec62ea upstream.
EXPORT_SYMBOL and __init is a bad combination because the .init.text section is freed up after the initialization. Hence, modules cannot use symbols annotated __init. The access to a freed symbol may end up with kernel panic.
modpost used to detect it, but it has been broken for a decade.
Recently, I fixed modpost so it started to warn it again, then this showed up in linux-next builds.
There are two ways to fix it:
- Remove __init - Remove EXPORT_SYMBOL
I chose the latter for this case because none of the in-tree call-sites (arch/arm/xen/enlighten.c, arch/x86/xen/grant-table.c) is compiled as modular.
Fixes: 243848fc018c ("xen/grant-table: Move xlated_setup_gnttab_pages to common place") Reported-by: Stephen Rothwell <sfr@canb.auug.org.au> Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Reviewed-by: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com> Acked-by: Stefano Stabellini <sstabellini@kernel.org> Link: https://lore.kernel.org/r/20220606045920.4161881-1-masahiroy@kernel.org Signed-off-by: Juergen Gross <jgross@suse.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> --- drivers/xen/xlate_mmu.c | 1 - 1 file changed, 1 deletion(-)
--- a/drivers/xen/xlate_mmu.c +++ b/drivers/xen/xlate_mmu.c @@ -262,4 +262,3 @@ int __init xen_xlate_map_ballooned_pages return 0; } -EXPORT_SYMBOL_GPL(xen_xlate_map_ballooned_pages);
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