Messages in this thread | | | Subject | Re: [PATCH] xen: unexport __init-annotated xen_xlate_map_ballooned_pages() | From | Oleksandr <> | Date | Mon, 6 Jun 2022 19:17:56 +0300 |
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On 06.06.22 07:59, Masahiro Yamada wrote:
Hello
> 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.
Good description.
> > 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>
I think the patch is correct.
Reviewed-by: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com>
> --- > > drivers/xen/xlate_mmu.c | 1 - > 1 file changed, 1 deletion(-) > > diff --git a/drivers/xen/xlate_mmu.c b/drivers/xen/xlate_mmu.c > index 34742c6e189e..f17c4c03db30 100644 > --- a/drivers/xen/xlate_mmu.c > +++ b/drivers/xen/xlate_mmu.c > @@ -261,7 +261,6 @@ int __init xen_xlate_map_ballooned_pages(xen_pfn_t **gfns, void **virt, > > return 0; > } > -EXPORT_SYMBOL_GPL(xen_xlate_map_ballooned_pages); > > struct remap_pfn { > struct mm_struct *mm;
-- Regards,
Oleksandr Tyshchenko
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