[PATCH 6.12 035/139] selftests: drv-net: fix RPS mask handling for high CPU numbers

[Greg Kroah-Hartman <gregkh@linuxfoundation.org>]

6.12-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Gal Pressman <gal@nvidia.com>

[ Upstream commit cf055f8c000445aa688c53a706ef4f580818eedb ]

The RPS bitmask bounds check uses ~(RPS_MAX_CPUS - 1) which equals ~15 =
0xfff0, only allowing CPUs 0-3.

Change the mask to ~((1UL << RPS_MAX_CPUS) - 1) = ~0xffff to allow CPUs
0-15.

Fixes: 5ebfb4cc3048 ("selftests/net: toeplitz test")
Reviewed-by: Nimrod Oren <noren@nvidia.com>
Signed-off-by: Gal Pressman <gal@nvidia.com>
Reviewed-by: Willem de Bruijn <willemb@google.com>
Link: https://patch.msgid.link/20260112173715.384843-3-gal@nvidia.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 tools/testing/selftests/net/toeplitz.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/tools/testing/selftests/net/toeplitz.c b/tools/testing/selftests/net/toeplitz.c
index 9ba03164d73a6..5099157f01b9a 100644
--- a/tools/testing/selftests/net/toeplitz.c
+++ b/tools/testing/selftests/net/toeplitz.c
@@ -473,8 +473,8 @@ static void parse_rps_bitmap(const char *arg)
 
 	bitmap = strtoul(arg, NULL, 0);
 
-	if (bitmap & ~(RPS_MAX_CPUS - 1))
-		error(1, 0, "rps bitmap 0x%lx out of bounds 0..%lu",
+	if (bitmap & ~((1UL << RPS_MAX_CPUS) - 1))
+		error(1, 0, "rps bitmap 0x%lx out of bounds, max cpu %lu",
 		      bitmap, RPS_MAX_CPUS - 1);
 
 	for (i = 0; i < RPS_MAX_CPUS; i++)
-- 
2.51.0