From: Philipp Reisner <philipp.reisner@linbit.com>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Kees Cook <keescook@chromium.org>,
Luc Van Oostenryck <luc.vanoostenryck@gmail.com>,
linux-sparse@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: [PATCH] compiler.h: Fix undefined BUILD_BUG_ON_ZERO()
Date: Fri, 15 Nov 2024 21:46:02 +0100 [thread overview]
Message-ID: <20241115204602.249590-1-philipp.reisner@linbit.com> (raw)
In-Reply-To: <CAHk-=wiPZmd1hrsUoP+9vPg2=E0Jj6Li77_BZcV9GocbJg8fag@mail.gmail.com>
<linux/compiler.h> defines __must_be_array() and __must_be_cstr() and
both expand to BUILD_BUG_ON_ZERO(), but <linux/build_bug.h> defines
BUILD_BUG_ON_ZERO(). Including <linux/build_bug.h> in
<linux/compiler.h> would create a cyclic dependency as
<linux/build_bug.h> already includes <linux/compiler.h>.
Fix that by defining __BUILD_BUG_ON_ZERO_MSG() in <linux/compiler.h>
and using that for __must_be_array() and __must_be_cstr().
Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
---
include/linux/compiler.h | 11 +++++++++--
1 file changed, 9 insertions(+), 2 deletions(-)
diff --git a/include/linux/compiler.h b/include/linux/compiler.h
index 4d4e23b6e3e7..469a64dd6495 100644
--- a/include/linux/compiler.h
+++ b/include/linux/compiler.h
@@ -239,11 +239,18 @@ static inline void *offset_to_ptr(const int *off)
#endif /* __ASSEMBLY__ */
+#ifdef __CHECKER__
+#define __BUILD_BUG_ON_ZERO_MSG(e, msg) (0)
+#else /* __CHECKER__ */
+#define __BUILD_BUG_ON_ZERO_MSG(e, msg) ((int)sizeof(struct {_Static_assert(!(e), msg);}))
+#endif /* __CHECKER__ */
+
/* &a[0] degrades to a pointer: a different type from an array */
-#define __must_be_array(a) BUILD_BUG_ON_ZERO(__same_type((a), &(a)[0]))
+#define __must_be_array(a) __BUILD_BUG_ON_ZERO_MSG(__same_type((a), &(a)[0]), "must be array")
/* Require C Strings (i.e. NUL-terminated) lack the "nonstring" attribute. */
-#define __must_be_cstr(p) BUILD_BUG_ON_ZERO(__annotated(p, nonstring))
+#define __must_be_cstr(p) \
+ __BUILD_BUG_ON_ZERO_MSG(__annotated(p, nonstring), "must be cstr (NUL-terminated)")
/*
* This returns a constant expression while determining if an argument is
--
2.47.0
next prev parent reply other threads:[~2024-11-15 20:46 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-11-14 10:14 [PATCH 0/1] Add missing include in compiler.h Philipp Reisner
2024-11-14 10:14 ` [PATCH 1/1] compiler.h: Add missing include statement for build_bug.h Philipp Reisner
2024-11-14 10:40 ` Dan Carpenter
2024-11-14 11:01 ` Philipp Reisner
2024-11-14 11:05 ` Dan Carpenter
2024-11-14 17:42 ` Linus Torvalds
2024-11-14 18:28 ` Linus Torvalds
2024-11-14 18:40 ` Linus Torvalds
2024-11-15 20:46 ` Philipp Reisner [this message]
2024-11-15 20:48 ` [PATCH] compiler.h: Fix undefined BUILD_BUG_ON_ZERO() Kees Cook
2024-11-15 21:58 ` Linus Torvalds
2024-11-15 21:57 ` Linus Torvalds
2024-11-17 5:26 ` Kees Cook
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