Messages in this thread Patch in this message | | | Date | Sat, 15 May 2021 01:01:31 +0200 | From | Marco Elver <> | Subject | Re: [PATCH] kcsan: fix debugfs initcall return type |
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On Fri, May 14, 2021 at 11:16PM +0200, Arnd Bergmann wrote: > On Fri, May 14, 2021 at 10:18 PM Paul E. McKenney <paulmck@kernel.org> wrote: > > On Fri, May 14, 2021 at 01:11:05PM -0700, Nathan Chancellor wrote: > > > > You can see my response to Marco here: > > > > > > https://lore.kernel.org/r/ad7fa126-f371-5a24-1d80-27fe8f655b05@kernel.org/ > > > > > > Maybe some improved wording might look like > > > > > > clang with CONFIG_LTO_CLANG points out that an initcall function should > > > return an 'int' due to the changes made to the initcall macros in commit > > > 3578ad11f3fb ("init: lto: fix PREL32 relocations"): > > > > OK, so the naive reading was correct, thank you! > > > > > ... > > > > > > Arnd, do you have any objections? > > > > In the meantime, here is what I have. Please let me know of any needed > > updates. > > > > Looks good to me, thanks for the improvements!
FWIW, this prompted me to see if I can convince the compiler to complain in all configs. The below is what I came up with and will send once the fix here has landed. Need to check a few other config+arch combinations (allyesconfig with gcc on x86_64 is good).
Thanks, -- Marco
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From 96c1c4e9902e96485268909d5ea8f91b9595e187 Mon Sep 17 00:00:00 2001 From: Marco Elver <elver@google.com> Date: Fri, 14 May 2021 21:08:50 +0200 Subject: [PATCH] init: verify that function is initcall_t at compile-time
In the spirit of making it hard to misuse an interface, add a compile-time assertion in the CONFIG_HAVE_ARCH_PREL32_RELOCATIONS case to verify the initcall function matches initcall_t, because the inline asm bypasses any type-checking the compiler would otherwise do. This will help developers catch incorrect API use in all configurations.
A recent example of this is: https://lkml.kernel.org/r/20210514140015.2944744-1-arnd@kernel.org
Signed-off-by: Marco Elver <elver@google.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Joe Perches <joe@perches.com> Cc: Masahiro Yamada <masahiroy@kernel.org> Cc: Miguel Ojeda <ojeda@kernel.org> Cc: Nathan Chancellor <nathan@kernel.org> Cc: "Paul E. McKenney" <paulmck@kernel.org> --- include/linux/init.h | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/include/linux/init.h b/include/linux/init.h index 045ad1650ed1..d82b4b2e1d25 100644 --- a/include/linux/init.h +++ b/include/linux/init.h @@ -242,7 +242,8 @@ extern bool initcall_debug; asm(".section \"" __sec "\", \"a\" \n" \ __stringify(__name) ": \n" \ ".long " __stringify(__stub) " - . \n" \ - ".previous \n"); + ".previous \n"); \ + static_assert(__same_type(initcall_t, &fn)); #else #define ____define_initcall(fn, __unused, __name, __sec) \ static initcall_t __name __used \ -- 2.31.1.751.gd2f1c929bd-goog
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