[tip: perf/core] perf/x86/rapl: Annotate 'struct rapl_pmus' with __counted_by

[tip-bot2 for Kees Cook]

The following commit has been merged into the perf/core branch of tip:

Commit-ID:     a56d5551e1993ca84dd0c69df5a3d8223d13fb5f
Gitweb:        https://git.kernel.org/tip/a56d5551e1993ca84dd0c69df5a3d8223d13fb5f
Author:        Kees Cook <keescook@xxxxxxxxxxxx>
AuthorDate:    Fri, 06 Oct 2023 13:17:54 -07:00
Committer:     Ingo Molnar <mingo@xxxxxxxxxx>
CommitterDate: Sun, 08 Oct 2023 12:18:17 +02:00

perf/x86/rapl: Annotate 'struct rapl_pmus' with __counted_by

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 via CONFIG_UBSAN_BOUNDS=y (for
array indexing) and CONFIG_FORTIFY_SOURCE=y (for strcpy/memcpy-family
functions).

Found with Coccinelle:

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

Add __counted_by for 'struct rapl_pmus'.

No change in functionality intended.

Signed-off-by: Kees Cook <keescook@xxxxxxxxxxxx>
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
Reviewed-by: Gustavo A. R. Silva <gustavoars@xxxxxxxxxx>
Link: https://lore.kernel.org/r/20231006201754.work.473-kees@xxxxxxxxxx
---
 arch/x86/events/rapl.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/events/rapl.c b/arch/x86/events/rapl.c
index c2c37fb..8d98d46 100644
--- a/arch/x86/events/rapl.c
+++ b/arch/x86/events/rapl.c
@@ -115,7 +115,7 @@ struct rapl_pmu {
 struct rapl_pmus {
 	struct pmu		pmu;
 	unsigned int		maxdie;
-	struct rapl_pmu		*pmus[];
+	struct rapl_pmu		*pmus[] __counted_by(maxdie);
 };
 
 enum rapl_unit_quirk {