--- /dev/null
+From 980618fd33732ebfbe97daf10e8ebc13400aee3e Mon Sep 17 00:00:00 2001
+From: YingChi Long <me@inclyc.cn>
+Date: Fri, 18 Nov 2022 08:55:35 +0800
+Subject: x86/fpu: Use _Alignof to avoid undefined behavior in TYPE_ALIGN
+
+From: YingChi Long <me@inclyc.cn>
+
+commit 55228db2697c09abddcb9487c3d9fa5854a932cd upstream.
+
+WG14 N2350 specifies that it is an undefined behavior to have type
+definitions within offsetof", see
+
+ https://www.open-std.org/jtc1/sc22/wg14/www/docs/n2350.htm
+
+This specification is also part of C23.
+
+Therefore, replace the TYPE_ALIGN macro with the _Alignof builtin to
+avoid undefined behavior. (_Alignof itself is C11 and the kernel is
+built with -gnu11).
+
+ISO C11 _Alignof is subtly different from the GNU C extension
+__alignof__. Latter is the preferred alignment and _Alignof the
+minimal alignment. For long long on x86 these are 8 and 4
+respectively.
+
+The macro TYPE_ALIGN's behavior matches _Alignof rather than
+__alignof__.
+
+ [ bp: Massage commit message. ]
+
+Signed-off-by: YingChi Long <me@inclyc.cn>
+Signed-off-by: Borislav Petkov <bp@suse.de>
+Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
+Link: https://lore.kernel.org/r/20220925153151.2467884-1-me@inclyc.cn
+Signed-off-by: Nathan Chancellor <nathan@kernel.org>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+---
+ arch/x86/kernel/fpu/init.c | 7 ++-----
+ 1 file changed, 2 insertions(+), 5 deletions(-)
+
+--- a/arch/x86/kernel/fpu/init.c
++++ b/arch/x86/kernel/fpu/init.c
+@@ -138,9 +138,6 @@ static void __init fpu__init_system_gene
+ unsigned int fpu_kernel_xstate_size;
+ EXPORT_SYMBOL_GPL(fpu_kernel_xstate_size);
+
+-/* Get alignment of the TYPE. */
+-#define TYPE_ALIGN(TYPE) offsetof(struct { char x; TYPE test; }, test)
+-
+ /*
+ * Enforce that 'MEMBER' is the last field of 'TYPE'.
+ *
+@@ -148,8 +145,8 @@ EXPORT_SYMBOL_GPL(fpu_kernel_xstate_size
+ * because that's how C aligns structs.
+ */
+ #define CHECK_MEMBER_AT_END_OF(TYPE, MEMBER) \
+- BUILD_BUG_ON(sizeof(TYPE) != ALIGN(offsetofend(TYPE, MEMBER), \
+- TYPE_ALIGN(TYPE)))
++ BUILD_BUG_ON(sizeof(TYPE) != \
++ ALIGN(offsetofend(TYPE, MEMBER), _Alignof(TYPE)))
+
+ /*
+ * We append the 'struct fpu' to the task_struct: