When the currently in-use hw rng is being removed from the system, explicitly drop it before using enable_best_rng as enable_best_rng will not do anything if the list of avaialble RNGs is empty.
Without this, the last RNG removed from the system will never get cleaned up and hwrng_unregister will hang. Signed-off-by: Keith Packard <kei...@keithp.com> --- drivers/char/hw_random/core.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/drivers/char/hw_random/core.c b/drivers/char/hw_random/core.c index 657b8770b6b9..8df3f9f147e2 100644 --- a/drivers/char/hw_random/core.c +++ b/drivers/char/hw_random/core.c @@ -515,8 +515,10 @@ void hwrng_unregister(struct hwrng *rng) mutex_lock(&rng_mutex); list_del(&rng->list); - if (current_rng == rng) + if (current_rng == rng) { + drop_current_rng(); enable_best_rng(); + } if (list_empty(&rng_list)) { mutex_unlock(&rng_mutex); -- 2.15.1