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Subjectrandom: Wake up all getrandom(2) callers when pool is ready
On Thu, May 21, 2015 at 09:55:17AM +0200, Stephan Mueller wrote:
>
> So, I will create a 2nd wait queue in random.c for uninterruptible waits,
> change the get_blocking_random_bytes back to void and use wait_event to wait
> for the initialization.

Hold your horses. You don't need a second queue, you just need to
change wake_up_interruptible to wake_up.

Hmm, in fact shouldn't this be wake_up_all? Otherwise what are the
other getrandom(2) callers going to do? Ted?

---8<---
If more than one application invokes getrandom(2) before the pool
is ready, then all bar one will be stuck forever because we use
wake_up_interruptible which wakes up a single task.

This patch replaces it with wake_up_all.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

diff --git a/drivers/char/random.c b/drivers/char/random.c
index 9cd6968..8b8c46b 100644
--- a/drivers/char/random.c
+++ b/drivers/char/random.c
@@ -660,7 +660,7 @@ retry:
r->entropy_total = 0;
if (r == &nonblocking_pool) {
prandom_reseed_late();
- wake_up_interruptible(&urandom_init_wait);
+ wake_up_all(&urandom_init_wait);
pr_notice("random: %s pool is initialized\n", r->name);
}
}
Cheers,
--
Email: Herbert Xu <herbert@gondor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt


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