* [PATCH] am65-cpsw: avoid null pointer arithmetic
@ 2021-09-27 9:37 Arnd Bergmann
2021-09-28 12:20 ` patchwork-bot+netdevbpf
0 siblings, 1 reply; 2+ messages in thread
From: Arnd Bergmann @ 2021-09-27 9:37 UTC (permalink / raw)
To: David S. Miller, Jakub Kicinski, Nathan Chancellor, Nick Desaulniers
Cc: Arnd Bergmann, netdev, linux-kernel, llvm
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
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH] am65-cpsw: avoid null pointer arithmetic
2021-09-27 9:37 [PATCH] am65-cpsw: avoid null pointer arithmetic Arnd Bergmann
@ 2021-09-28 12:20 ` patchwork-bot+netdevbpf
0 siblings, 0 replies; 2+ messages in thread
From: patchwork-bot+netdevbpf @ 2021-09-28 12:20 UTC (permalink / raw)
To: Arnd Bergmann
Cc: davem, kuba, nathan, ndesaulniers, arnd, netdev, linux-kernel, llvm
Hello:
This patch was applied to netdev/net-next.git (refs/heads/master):
On Mon, 27 Sep 2021 11:37:57 +0200 you wrote:
> 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 + \
> ^ ~~~~~~~~~~~~~~~~
>
> [...]
Here is the summary with links:
- am65-cpsw: avoid null pointer arithmetic
https://git.kernel.org/netdev/net-next/c/861f40fa0edf
You are awesome, thank you!
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2021-09-27 9:37 [PATCH] am65-cpsw: avoid null pointer arithmetic Arnd Bergmann
2021-09-28 12:20 ` patchwork-bot+netdevbpf
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