This is a note to let you know that I've just added the patch titled
xen: unexport __init-annotated xen_xlate_map_ballooned_pages()
to the 4.19-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
xen-unexport-__init-annotated-xen_xlate_map_ballooned_pages.patch
and it can be found in the queue-4.19 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From dbac14a5a05ff8e1ce7c0da0e1f520ce39ec62ea Mon Sep 17 00:00:00 2001
From: Masahiro Yamada <masahiroy@xxxxxxxxxx>
Date: Mon, 6 Jun 2022 13:59:20 +0900
Subject: xen: unexport __init-annotated xen_xlate_map_ballooned_pages()
From: Masahiro Yamada <masahiroy@xxxxxxxxxx>
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@xxxxxxxxxxxxxxxx>
Signed-off-by: Masahiro Yamada <masahiroy@xxxxxxxxxx>
Reviewed-by: Oleksandr Tyshchenko <oleksandr_tyshchenko@xxxxxxxx>
Acked-by: Stefano Stabellini <sstabellini@xxxxxxxxxx>
Link: https://lore.kernel.org/r/20220606045920.4161881-1-masahiroy@xxxxxxxxxx
Signed-off-by: Juergen Gross <jgross@xxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
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);
Patches currently in stable-queue which might be from masahiroy@xxxxxxxxxx are
queue-4.19/kbuild-link-vmlinux-only-once-for-config_trim_unused_ksyms-2nd-attempt.patch
queue-4.19/xen-unexport-__init-annotated-xen_xlate_map_ballooned_pages.patch
queue-4.19/modpost-fix-section-mismatch-check-for-exported-init-exit-sections.patch
