From: Alice Ryhl <aliceryhl@google.com>
Date: Tue, 18 Nov 2025 17:32:50 +0000 (+0000)
Subject: uaccess: gate _copy_[to|from]_user on !INLINE_COPY_FROM_USER
X-Git-Tag: v6.19-rc1~70^2~63
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=9031b852c97f1db52180878aed66ca08946eca93;p=thirdparty%2Fkernel%2Flinux.git

uaccess: gate _copy_[to|from]_user on !INLINE_COPY_FROM_USER

These methods only exist when INLINE_COPY_FROM_USER is disabled, so update
the header file to reflect that.

This fixes the following error on builds that enable both RUST and
INLINE_COPY_FROM_USER.

ERROR: modpost: "_copy_from_user" [samples/rust/rust_misc_device.ko] undefined!
ERROR: modpost: "_copy_to_user" [samples/rust/rust_misc_device.ko] undefined!

This error is triggered because when a method is available both as a
rust_helper_* and normal method, Rust will call the normal method.

[akpm@linux-foundation.org: s/INLINE_COPY_FROM_USER/INLINE_COPY_TO_USER/, per Alice]
Link: https://lkml.kernel.org/r/20251118173250.2821388-1-aliceryhl@google.com
Fixes: d99dc586ca7c ("uaccess: decouple INLINE_COPY_FROM_USER and CONFIG_RUST")
Signed-off-by: Alice Ryhl <aliceryhl@google.com>
Cc: Alex Gaynor <alex.gaynor@gmail.com>
Cc: Andreas Hindborg <a.hindborg@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Björn Roy Baron <bjorn3_gh@protonmail.com>
Cc: Boqun Feng <boqun.feng@gmail.com>
Cc: Danilo Krummrich <dakr@kernel.org>
Cc: Gary Guo <gary@garyguo.net>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Miguel Ojeda <ojeda@kernel.org>
Cc: Trevor Gross <tmgross@umich.edu>
Cc: Yury Norov (NVIDIA) <yury.norov@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

diff --git a/include/linux/uaccess.h b/include/linux/uaccess.h
index 01cbd7dd0ba3a..5594012160da2 100644
--- a/include/linux/uaccess.h
+++ b/include/linux/uaccess.h
@@ -181,8 +181,10 @@ fail:
 	memset(to + (n - res), 0, res);
 	return res;
 }
+#ifndef INLINE_COPY_FROM_USER
 extern __must_check unsigned long
 _copy_from_user(void *, const void __user *, unsigned long);
+#endif
 
 static inline __must_check unsigned long
 _inline_copy_to_user(void __user *to, const void *from, unsigned long n)
@@ -196,8 +198,10 @@ _inline_copy_to_user(void __user *to, const void *from, unsigned long n)
 	}
 	return n;
 }
+#ifndef INLINE_COPY_TO_USER
 extern __must_check unsigned long
 _copy_to_user(void __user *, const void *, unsigned long);
+#endif
 
 static __always_inline unsigned long __must_check
 copy_from_user(void *to, const void __user *from, unsigned long n)