Messages in this thread | | | Date | Wed, 27 Apr 2022 10:42:20 +0200 | From | Greg Kroah-Hartman <> | Subject | Re: [PATCH] export: fix string handling of namespace in EXPORT_SYMBOL_NS |
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On Wed, Jan 12, 2022 at 04:14:00AM +0900, Masahiro Yamada wrote: > On Sat, Jan 8, 2022 at 11:04 PM Greg Kroah-Hartman > <gregkh@linuxfoundation.org> wrote: > > > > Commit c3a6cf19e695 ("export: avoid code duplication in > > include/linux/export.h") broke the ability for a defined string to be > > used as a namespace value. Fix this up by adding another layer of > > indirection to preserve the previous functionality. > > > > Fixes: c3a6cf19e695 ("export: avoid code duplication in include/linux/export.h") > > Cc: Miroslav Benes <mbenes@suse.cz> > > Cc: Emil Velikov <emil.l.velikov@gmail.com> > > Cc: Jessica Yu <jeyu@kernel.org> > > Cc: Quentin Perret <qperret@google.com> > > Cc: Masahiro Yamada <yamada.masahiro@socionext.com> > > Cc: Matthias Maennich <maennich@google.com> > > Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> > > --- > > Note, I found this while forward porting an out-of-tree Android kernel > > patch from 5.4 to 5.10 that used module namespaces to help wall-off vfs > > symbols from being used by non-filesystem modules. This issue does not > > affect any in-kernel code, so I am not so sure if it really is needed > > here, but it does restore the previous functionality that was being used > > in older kernels so it might be good to put back in case others want to > > do much the same thing. > > > > include/linux/export.h | 6 ++++-- > > 1 file changed, 4 insertions(+), 2 deletions(-) > > > > diff --git a/include/linux/export.h b/include/linux/export.h > > index 27d848712b90..9a992809f57d 100644 > > --- a/include/linux/export.h > > +++ b/include/linux/export.h > > @@ -162,8 +162,10 @@ struct kernel_symbol { > > > > #define EXPORT_SYMBOL(sym) _EXPORT_SYMBOL(sym, "") > > #define EXPORT_SYMBOL_GPL(sym) _EXPORT_SYMBOL(sym, "_gpl") > > -#define EXPORT_SYMBOL_NS(sym, ns) __EXPORT_SYMBOL(sym, "", #ns) > > -#define EXPORT_SYMBOL_NS_GPL(sym, ns) __EXPORT_SYMBOL(sym, "_gpl", #ns) > > +#define _EXPORT_SYMBOL_NS(sym, ns) __EXPORT_SYMBOL(sym, "", #ns) > > +#define _EXPORT_SYMBOL_NS_GPL(sym, ns) __EXPORT_SYMBOL(sym, "_gpl", #ns) > > +#define EXPORT_SYMBOL_NS(sym, ns) _EXPORT_SYMBOL_NS(sym, ns) > > +#define EXPORT_SYMBOL_NS_GPL(sym, ns) _EXPORT_SYMBOL_NS_GPL(sym, ns) > > > > #endif /* !__ASSEMBLY__ */ > > > > -- > > 2.34.1 > > > > I see __stringify() a few files above. > So, you can use it here as well. > > > Does the following code work? (untested) > > > > > > diff --git a/include/linux/export.h b/include/linux/export.h > index 27d848712b90..5910ccb66ca2 100644 > --- a/include/linux/export.h > +++ b/include/linux/export.h > @@ -2,6 +2,8 @@ > #ifndef _LINUX_EXPORT_H > #define _LINUX_EXPORT_H > > +#include <linux/stringify.h> > + > /* > * Export symbols from the kernel to modules. Forked from module.h > * to reduce the amount of pointless cruft we feed to gcc when only > @@ -154,7 +156,6 @@ struct kernel_symbol { > #endif /* CONFIG_MODULES */ > > #ifdef DEFAULT_SYMBOL_NAMESPACE > -#include <linux/stringify.h> > #define _EXPORT_SYMBOL(sym, sec) __EXPORT_SYMBOL(sym, sec, > __stringify(DEFAULT_SYMBOL_NAMESPACE)) > #else > #define _EXPORT_SYMBOL(sym, sec) __EXPORT_SYMBOL(sym, sec, "") > @@ -162,8 +163,8 @@ struct kernel_symbol { > > #define EXPORT_SYMBOL(sym) _EXPORT_SYMBOL(sym, "") > #define EXPORT_SYMBOL_GPL(sym) _EXPORT_SYMBOL(sym, "_gpl") > -#define EXPORT_SYMBOL_NS(sym, ns) __EXPORT_SYMBOL(sym, "", #ns) > -#define EXPORT_SYMBOL_NS_GPL(sym, ns) __EXPORT_SYMBOL(sym, "_gpl", #ns) > +#define EXPORT_SYMBOL_NS(sym, ns) __EXPORT_SYMBOL(sym, "", > __stringify(ns)) > +#define EXPORT_SYMBOL_NS_GPL(sym, ns) __EXPORT_SYMBOL(sym, "_gpl", > __stringify(ns)) > > #endif /* !__ASSEMBLY__ */
Sorry for the long delay, but yes, this does seem to resolve the issue for me. I'll respin this and resend, thanks!
greg k-h
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