| Message ID | 20240730104425.607083-1-patrykd@google.com (mailing list archive) |
|---|---|
| State | Accepted |
| Commit | df615907f1bf907260af01ccb904d0e9304b5278 |
| Headers | show |
| Series | [v3] platform/chrome: cros_ec_proto: Lock device when updating MKBP version | expand |
On Tue, Jul 30, 2024 at 10:44:25AM +0000, Patryk Duda wrote: > The cros_ec_get_host_command_version_mask() function requires that the > caller must have ec_dev->lock mutex before calling it. This requirement > was not met and as a result it was possible that two commands were sent > to the device at the same time. > > [...] Applied to https://git.kernel.org/pub/scm/linux/kernel/git/chrome-platform/linux.git chrome-platform-6.11 Thanks! [1/1] platform/chrome: cros_ec_proto: Lock device when updating MKBP version commit: df615907f1bf907260af01ccb904d0e9304b5278
diff --git a/drivers/platform/chrome/cros_ec_proto.c b/drivers/platform/chrome/cros_ec_proto.c index f776fd42244f..73f75958e15c 100644 --- a/drivers/platform/chrome/cros_ec_proto.c +++ b/drivers/platform/chrome/cros_ec_proto.c @@ -813,9 +813,11 @@ int cros_ec_get_next_event(struct cros_ec_device *ec_dev, if (ret == -ENOPROTOOPT) { dev_dbg(ec_dev->dev, "GET_NEXT_EVENT returned invalid version error.\n"); + mutex_lock(&ec_dev->lock); ret = cros_ec_get_host_command_version_mask(ec_dev, EC_CMD_GET_NEXT_EVENT, &ver_mask); + mutex_unlock(&ec_dev->lock); if (ret < 0 || ver_mask == 0) /* * Do not change the MKBP supported version if we can't
The cros_ec_get_host_command_version_mask() function requires that the caller must have ec_dev->lock mutex before calling it. This requirement was not met and as a result it was possible that two commands were sent to the device at the same time. The problem was observed while using UART backend which doesn't use any additional locks, unlike SPI backend which locks the controller until response is received. Fixes: f74c7557ed0d ("platform/chrome: cros_ec_proto: Update version on GET_NEXT_EVENT failure") Cc: stable@vger.kernel.org Signed-off-by: Patryk Duda <patrykd@google.com> --- The f74c7557ed0d patch was tested with Fingerprint MCU (FPMCU) that uses SPI to communicate with chipset. At that time, UART FPMCU had the same version of GET_NEXT_EVENT command in RO and RW, so the MKBP version was never updated in this case. Version 3 of GET_NEXT_EVENT command was recently added to CrosEC. As a result MKBP version is also updated when UART FPMCU is used which exposed this problem. Best regards, Patryk V1 -> V2 - Added missing mutex_unlock() on cros_ec_get_host_command_version_mask() failure. V2 -> V3 - Moved call to mutex_unlock() below call to cros_ec_get_host_command_version_mask(). drivers/platform/chrome/cros_ec_proto.c | 2 ++ 1 file changed, 2 insertions(+)