From: Christophe Leroy
> Sent: 11 February 2022 10:16
...
> copy_overflow() is a non conditional warning called by
> check_copy_size() on an error path.
>
> check_copy_size() have to remain inlined in order to benefit
> from constant folding, but copy_overflow() is not worth inlining.
>
> Uninline it.
>
> This reduces the size of vmlinux by almost 4kbytes.
>
> Signed-off-by: Christophe Leroy <christophe.leroy@xxxxxxxxxx>
> ---
> v2: Added missing EXPORT_SYMBOL() and enhanced commit message
> ---
> include/linux/thread_info.h | 5 +----
> mm/maccess.c | 6 ++++++
> 2 files changed, 7 insertions(+), 4 deletions(-)
>
> diff --git a/include/linux/thread_info.h b/include/linux/thread_info.h
> index 73a6f34b3847..1087d1e2be5c 100644
> --- a/include/linux/thread_info.h
> +++ b/include/linux/thread_info.h
> @@ -209,10 +209,7 @@ __bad_copy_from(void);
> extern void __compiletime_error("copy destination size is too small")
> __bad_copy_to(void);
>
> -static inline void copy_overflow(int size, unsigned long count)
> -{
> - WARN(1, "Buffer overflow detected (%d < %lu)!\n", size, count);
> -}
> +void copy_overflow(int size, unsigned long count);
>
> static __always_inline __must_check bool
> check_copy_size(const void *addr, size_t bytes, bool is_source)
> diff --git a/mm/maccess.c b/mm/maccess.c
> index d3f1a1f0b1c1..6b11a22f4b01 100644
> --- a/mm/maccess.c
> +++ b/mm/maccess.c
> @@ -335,3 +335,9 @@ long strnlen_user_nofault(const void __user *unsafe_addr, long count)
>
> return ret;
> }
> +
> +void copy_overflow(int size, unsigned long count)
> +{
> + WARN(1, "Buffer overflow detected (%d < %lu)!\n", size, count);
> +}
> +EXPORT_SYMBOL_GPL(copy_overflow)
Can you remove the _GPL ????
I think that basically stops you compiling any non-gpl code if the
copy_protection is enabled in the kernel build.
I'm guessing that most of the inline wrappers calling this are non-FPL
functions.
David
-
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