Re: [PATCH] x86/platform/uv: Annotate struct uv_rtc_timer_head with __counted_by

From: Gustavo A. R. Silva
Date: Sat Sep 23 2023 - 13:41:56 EST




On 9/22/23 11:51, Kees Cook wrote:
Prepare for the coming implementation by GCC and Clang of the __counted_by
attribute. Flexible array members annotated with __counted_by can have
their accesses bounds-checked at run-time checking via CONFIG_UBSAN_BOUNDS
(for array indexing) and CONFIG_FORTIFY_SOURCE (for strcpy/memcpy-family
functions).

As found with Coccinelle[1], add __counted_by for struct uv_rtc_timer_head.

[1] https://github.com/kees/kernel-tools/blob/trunk/coccinelle/examples/counted_by.cocci

Cc: Steve Wahl <steve.wahl@xxxxxxx>
Cc: Mike Travis <mike.travis@xxxxxxx>
Cc: Dimitri Sivanich <dimitri.sivanich@xxxxxxx>
Cc: Russ Anderson <russ.anderson@xxxxxxx>
Cc: Darren Hart <dvhart@xxxxxxxxxxxxx>
Cc: Andy Shevchenko <andy@xxxxxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: Borislav Petkov <bp@xxxxxxxxx>
Cc: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx>
Cc: x86@xxxxxxxxxx
Cc: "H. Peter Anvin" <hpa@xxxxxxxxx>
Cc: platform-driver-x86@xxxxxxxxxxxxxxx
Signed-off-by: Kees Cook <keescook@xxxxxxxxxxxx>

Reviewed-by: Gustavo A. R. Silva <gustavoars@xxxxxxxxxx>

Thanks
--
Gustavo

---
arch/x86/platform/uv/uv_time.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/platform/uv/uv_time.c b/arch/x86/platform/uv/uv_time.c
index 54663f3e00cb..ff5afc8a5a41 100644
--- a/arch/x86/platform/uv/uv_time.c
+++ b/arch/x86/platform/uv/uv_time.c
@@ -53,7 +53,7 @@ struct uv_rtc_timer_head {
struct {
int lcpu; /* systemwide logical cpu number */
u64 expires; /* next timer expiration for this cpu */
- } cpu[];
+ } cpu[] __counted_by(ncpus);
};
/*