From 1dacb395d68a14825ee48c0843335e3181aea675 Mon Sep 17 00:00:00 2001 From: Amos Kong Date: Mon, 8 Dec 2014 16:50:36 +0800 Subject: [PATCH] hwrng: move some code out mutex_lock for avoiding underlying deadlock In next patch, we use reference counting for each struct hwrng, changing reference count also needs to take mutex_lock. Before releasing the lock, if we try to stop a kthread that waits to take the lock to reduce the referencing count, deadlock will occur. Signed-off-by: Amos Kong Signed-off-by: Herbert Xu --- drivers/char/hw_random/core.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/drivers/char/hw_random/core.c b/drivers/char/hw_random/core.c index 2dd3144..b4c0e87 100644 --- a/drivers/char/hw_random/core.c +++ b/drivers/char/hw_random/core.c @@ -470,12 +470,12 @@ void hwrng_unregister(struct hwrng *rng) } } if (list_empty(&rng_list)) { + mutex_unlock(&rng_mutex); unregister_miscdev(); if (hwrng_fill) kthread_stop(hwrng_fill); - } - - mutex_unlock(&rng_mutex); + } else + mutex_unlock(&rng_mutex); } EXPORT_SYMBOL_GPL(hwrng_unregister); -- 2.7.4