Re: [PATCH] tee: optee: allocate a bitmap for all valid notification keys

[Sumit Garg <sumit.garg@kernel.org>]

On Fri, 09 Oct 2026 at 20:19:48 -0700, Amirreza Zarrabi wrote:
>Notification keys are checked against an inclusive maximum, but
>optee_notif_init() passes that maximum to bitmap_zalloc() as the number of
>bits. The bitmap is therefore one bit short. When the maximum key is a
>multiple of BITS_PER_LONG, accessing that key reads or writes beyond the
>allocated bitmap. Word rounding masks the problem.
>
>Allocate max_key + 1 bits so that the highest valid key has storage.
>
>Fixes: 787c80cc7b22 ("optee: separate notification functions")
>Signed-off-by: Amirreza Zarrabi <amirreza.zarrabi@oss.qualcomm.com>
>---
> drivers/tee/optee/notif.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)

Reviewed-by: Sumit Garg <sumit.garg@oss.qualcomm.com>

-Sumit

>
>diff --git a/drivers/tee/optee/notif.c b/drivers/tee/optee/notif.c
>index 68014222d7be..2bf5ce397233 100644
>--- a/drivers/tee/optee/notif.c
>+++ b/drivers/tee/optee/notif.c
>@@ -114,7 +114,7 @@ int optee_notif_init(struct optee *optee, u_int max_key)
> {
> 	spin_lock_init(&optee->notif.lock);
> 	INIT_LIST_HEAD(&optee->notif.db);
>-	optee->notif.bitmap = bitmap_zalloc(max_key, GFP_KERNEL);
>+	optee->notif.bitmap = bitmap_zalloc(max_key + 1, GFP_KERNEL);
> 	if (!optee->notif.bitmap)
> 		return -ENOMEM;
>
>
>---
>base-commit: becb95e45ef0dda9ffb35156d909d3da7a2789c3
>change-id: 20261009-fix-tee-max-keys-50f2db87b4e5
>
>Best regards,
>-- 
>Amirreza Zarrabi <amirreza.zarrabi@oss.qualcomm.com>
>