From: Arnd Bergmann <arnd@kernel.org>
To: "David S. Miller" <davem@davemloft.net>,
Jakub Kicinski <kuba@kernel.org>,
Nathan Chancellor <nathan@kernel.org>,
Nick Desaulniers <ndesaulniers@google.com>
Cc: Arnd Bergmann <arnd@arndb.de>,
netdev@vger.kernel.org, linux-kernel@vger.kernel.org,
llvm@lists.linux.dev
Subject: [PATCH] am65-cpsw: avoid null pointer arithmetic
Date: Mon, 27 Sep 2021 11:37:57 +0200 [thread overview]
Message-ID: <20210927093803.474510-1-arnd@kernel.org> (raw)
From: Arnd Bergmann <arnd@arndb.de>
clang warns about arithmetic on NULL pointers:
drivers/net/ethernet/ti/am65-cpsw-ethtool.c:71:2: error: performing pointer subtraction with a null pointer has undefined behavior [-Werror,-Wnull-pointer-subtraction]
AM65_CPSW_REGDUMP_REC(AM65_CPSW_REGDUMP_MOD_NUSS, 0x0, 0x1c),
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
drivers/net/ethernet/ti/am65-cpsw-ethtool.c:64:29: note: expanded from macro 'AM65_CPSW_REGDUMP_REC'
.hdr.len = (((u32 *)(end)) - ((u32 *)(start)) + 1) * sizeof(u32) * 2 + \
^ ~~~~~~~~~~~~~~~~
The expression here is easily changed to a calculation based on integers
that is no less readable.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
drivers/net/ethernet/ti/am65-cpsw-ethtool.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/net/ethernet/ti/am65-cpsw-ethtool.c b/drivers/net/ethernet/ti/am65-cpsw-ethtool.c
index 6e4d4f9e32e0..b05de9b61ad6 100644
--- a/drivers/net/ethernet/ti/am65-cpsw-ethtool.c
+++ b/drivers/net/ethernet/ti/am65-cpsw-ethtool.c
@@ -61,7 +61,7 @@ struct am65_cpsw_regdump_item {
#define AM65_CPSW_REGDUMP_REC(mod, start, end) { \
.hdr.module_id = (mod), \
- .hdr.len = (((u32 *)(end)) - ((u32 *)(start)) + 1) * sizeof(u32) * 2 + \
+ .hdr.len = (end + 4 - start) * 2 + \
sizeof(struct am65_cpsw_regdump_hdr), \
.start_ofs = (start), \
.end_ofs = end, \
--
2.29.2
next reply other threads:[~2021-09-27 9:38 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-09-27 9:37 Arnd Bergmann [this message]
2021-09-28 12:20 ` [PATCH] am65-cpsw: avoid null pointer arithmetic patchwork-bot+netdevbpf
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