This is a follow-up series of [1]. It tries to fix a possible UAF in the fops of cros_ec_chardev after the underlying protocol device has gone by using revocable. The 1st patch introduces the revocable which is an implementation of ideas from the talk [2]. The 2nd and 3rd patches add test cases for revocable in Kunit and selftest. The 4th patch converts existing protocol devices to resource providers of cros_ec_device. The 5th patch converts cros_ec_chardev to a resource consumer of cros_ec_device to fix the UAF. [1] https://lore.kernel.org/chrome-platform/20250721044456.2736300-6-tzungbi@xxxxxxxxxx/ [2] https://lpc.events/event/17/contributions/1627/ Cc: Laurent Pinchart <laurent.pinchart@xxxxxxxxxxxxxxxx> Cc: Bartosz Golaszewski <bartosz.golaszewski@xxxxxxxxxx> Cc: Wolfram Sang <wsa+renesas@xxxxxxxxxxxxxxxxxxxx> v2: - Rename "ref_proxy" -> "revocable". - Add test cases in Kunit and selftest. v1: https://lore.kernel.org/chrome-platform/20250814091020.1302888-1-tzungbi@xxxxxxxxxx/ Tzung-Bi Shih (5): revocable: Revocable resource management revocable: Add Kunit test cases selftests: revocable: Add kselftest cases platform/chrome: Protect cros_ec_device lifecycle with revocable platform/chrome: cros_ec_chardev: Consume cros_ec_device via revocable .../driver-api/driver-model/index.rst | 1 + .../driver-api/driver-model/revocable.rst | 151 ++++++++++++ MAINTAINERS | 9 + drivers/base/Kconfig | 8 + drivers/base/Makefile | 5 +- drivers/base/revocable.c | 229 ++++++++++++++++++ drivers/base/revocable_test.c | 110 +++++++++ drivers/platform/chrome/cros_ec_chardev.c | 124 +++++++--- drivers/platform/chrome/cros_ec_i2c.c | 5 + drivers/platform/chrome/cros_ec_ishtp.c | 5 + drivers/platform/chrome/cros_ec_lpc.c | 5 + drivers/platform/chrome/cros_ec_rpmsg.c | 5 + drivers/platform/chrome/cros_ec_spi.c | 4 + drivers/platform/chrome/cros_ec_uart.c | 5 + include/linux/platform_data/cros_ec_proto.h | 4 + include/linux/revocable.h | 37 +++ tools/testing/selftests/Makefile | 1 + .../selftests/drivers/base/revocable/Makefile | 7 + .../drivers/base/revocable/revocable_test.c | 116 +++++++++ .../drivers/base/revocable/test-revocable.sh | 39 +++ .../base/revocable/test_modules/Makefile | 10 + .../revocable/test_modules/revocable_test.c | 188 ++++++++++++++ 22 files changed, 1027 insertions(+), 41 deletions(-) create mode 100644 Documentation/driver-api/driver-model/revocable.rst create mode 100644 drivers/base/revocable.c create mode 100644 drivers/base/revocable_test.c create mode 100644 include/linux/revocable.h create mode 100644 tools/testing/selftests/drivers/base/revocable/Makefile create mode 100644 tools/testing/selftests/drivers/base/revocable/revocable_test.c create mode 100755 tools/testing/selftests/drivers/base/revocable/test-revocable.sh create mode 100644 tools/testing/selftests/drivers/base/revocable/test_modules/Makefile create mode 100644 tools/testing/selftests/drivers/base/revocable/test_modules/revocable_test.c -- 2.51.0.rc1.167.g924127e9c0-goog
