linux-kernel - [PATCH 7/9] infiniband: uverbs: avoid out-of-range warnings

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Date: Thu, 28 Mar 2024 15:30:45 +0100
From: Arnd Bergmann <arnd@...nel.org>
To: linux-kernel@...r.kernel.org,
	Jason Gunthorpe <jgg@...pe.ca>,
	Leon Romanovsky <leon@...nel.org>,
	Nathan Chancellor <nathan@...nel.org>
Cc: Arnd Bergmann <arnd@...db.de>,
	Nick Desaulniers <ndesaulniers@...gle.com>,
	Bill Wendling <morbo@...gle.com>,
	Justin Stitt <justinstitt@...gle.com>,
	Kees Cook <keescook@...omium.org>,
	"Gustavo A. R. Silva" <gustavoars@...nel.org>,
	linux-rdma@...r.kernel.org,
	llvm@...ts.linux.dev
Subject: [PATCH 7/9] infiniband: uverbs: avoid out-of-range warnings

From: Arnd Bergmann <arnd@...db.de>

clang warns for comparisons that are always true, which is the case
for these two page size checks on architectures with 64KB pages:

drivers/infiniband/core/uverbs_ioctl.c:90:39: error: result of comparison of constant 65536 with expression of type 'u16' (aka 'unsigned short') is always false [-Werror,-Wtautological-constant-out-of-range-compare]
        WARN_ON_ONCE(method_elm->bundle_size > PAGE_SIZE);
        ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~
include/asm-generic/bug.h:104:25: note: expanded from macro 'WARN_ON_ONCE'
        int __ret_warn_on = !!(condition);                      \
                               ^~~~~~~~~
drivers/infiniband/core/uverbs_ioctl.c:621:17: error: result of comparison of constant 65536 with expression of type '__u16' (aka 'unsigned short') is always false [-Werror,-Wtautological-constant-out-of-range-compare]
        if (hdr.length > PAGE_SIZE ||
            ~~~~~~~~~~ ^ ~~~~~~~~~

Add a cast to u32 in both cases, so it never warns about this.

Signed-off-by: Arnd Bergmann <arnd@...db.de>
---
 drivers/infiniband/core/uverbs_ioctl.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/infiniband/core/uverbs_ioctl.c b/drivers/infiniband/core/uverbs_ioctl.c
index f80da6a67e24..e0cc3ddae71b 100644
--- a/drivers/infiniband/core/uverbs_ioctl.c
+++ b/drivers/infiniband/core/uverbs_ioctl.c
@@ -90,7 +90,7 @@ void uapi_compute_bundle_size(struct uverbs_api_ioctl_method *method_elm,
 		ALIGN(bundle_size + 256, sizeof(*pbundle->internal_buffer));
 
 	/* Do not want order-2 allocations for this. */
-	WARN_ON_ONCE(method_elm->bundle_size > PAGE_SIZE);
+	WARN_ON_ONCE((u32)method_elm->bundle_size > PAGE_SIZE);
 }
 
 /**
@@ -636,7 +636,7 @@ long ib_uverbs_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
 	if (err)
 		return -EFAULT;
 
-	if (hdr.length > PAGE_SIZE ||
+	if ((u32)hdr.length > PAGE_SIZE ||
 	    hdr.length != struct_size(&hdr, attrs, hdr.num_attrs))
 		return -EINVAL;
 
-- 
2.39.2