Messages in this thread Patch in this message | | | From | Amos Kong <> | Subject | [PATCH v5 REPOST 2/6] hw_random: move some code out mutex_lock for avoiding underlying deadlock | Date | Mon, 8 Dec 2014 16:50:36 +0800 |
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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 <akong@redhat.com> --- 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 b1b6042..a0905c8 100644 --- a/drivers/char/hw_random/core.c +++ b/drivers/char/hw_random/core.c @@ -474,12 +474,12 @@ 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); -- 1.9.3
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