Messages in this thread Patch in this message | | | From | Amos Kong <> | Subject | [PATCH v2 4/6] hw_random: fix unregister race. | Date | Thu, 18 Sep 2014 20:37:45 +0800 |
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From: Rusty Russell <rusty@rustcorp.com.au>
The previous patch added one potential problem: we can still be reading from a hwrng when it's unregistered. Add a wait for zero in the hwrng_unregister path.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> --- drivers/char/hw_random/core.c | 2 ++ 1 file changed, 2 insertions(+)
diff --git a/drivers/char/hw_random/core.c b/drivers/char/hw_random/core.c index ee9e504..9f6f5bb 100644 --- a/drivers/char/hw_random/core.c +++ b/drivers/char/hw_random/core.c @@ -60,6 +60,7 @@ static DEFINE_MUTEX(rng_mutex); static DEFINE_MUTEX(reading_mutex); static int data_avail; static u8 *rng_buffer, *rng_fillbuf; +static DECLARE_WAIT_QUEUE_HEAD(rng_done); static unsigned short current_quality; static unsigned short default_quality; /* = 0; default to "off" */ @@ -98,6 +99,7 @@ static inline void cleanup_rng(struct kref *kref) if (rng->cleanup) rng->cleanup(rng); + wake_up_all(&rng_done); } static void set_current_rng(struct hwrng *rng) -- 1.9.3
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