Code implementing .receive_buf() callback can potentially call serdev_device_write(), which will call serdev_device_poller(). We need to make sure that such a call is a no-op in order to prevent corrupting shared data buffer as well as breaking .receive_buf callback that most likely does not expect that to happen.
Signed-off-by: Andrey Smirnov <[email protected]> --- common/serdev.c | 6 ++++++ include/serdev.h | 2 ++ 2 files changed, 8 insertions(+) diff --git a/common/serdev.c b/common/serdev.c index 4a6dbefe6..3e0da0846 100644 --- a/common/serdev.c +++ b/common/serdev.c @@ -9,6 +9,10 @@ static void serdev_device_poller(void *context) unsigned char *buf = serdev->buf; int ret, len; + if (serdev->locked) + return; + + serdev->locked = true; /* * Since this callback is a part of poller infrastructure we * want to use _non_interruptible version of the function @@ -37,6 +41,8 @@ static void serdev_device_poller(void *context) } else { poller_async_cancel(&serdev->poller); } + + serdev->locked = false; } static int serdev_device_set_polling_interval(struct param_d *param, void *serdev) diff --git a/include/serdev.h b/include/serdev.h index f5d34f527..29030538e 100644 --- a/include/serdev.h +++ b/include/serdev.h @@ -14,6 +14,7 @@ * @poller Async poller used to poll this serdev * @polling_interval: Async poller periodicity * @polling_window: Duration of a single busy loop poll + * @locked: Lock to prevent recursive polling * @receive_buf: Function called with data received from device; * returns number of bytes accepted; */ @@ -24,6 +25,7 @@ struct serdev_device { struct poller_async poller; uint64_t polling_interval; uint64_t polling_window; + bool locked; int (*receive_buf)(struct serdev_device *, const unsigned char *, size_t); -- 2.21.0 _______________________________________________ barebox mailing list [email protected] http://lists.infradead.org/mailman/listinfo/barebox
