From: "Jason A. Donenfeld" <Jason@xxxxxxxxx>
commit a3f9e8910e1584d7725ef7d5ac870920d42d0bb4 upstream.
The only time that we need to wake up /dev/random writers on
RNDCLEARPOOL/RNDZAPPOOL is when we're changing from a value that is
greater than or equal to POOL_MIN_BITS to zero, because if we're
changing from below POOL_MIN_BITS to zero, the writers are already
unblocked.
Cc: Theodore Ts'o <tytso@xxxxxxx>
Reviewed-by: Dominik Brodowski <linux@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Jason A. Donenfeld <Jason@xxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/char/random.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
--- a/drivers/char/random.c
+++ b/drivers/char/random.c
@@ -1577,7 +1577,7 @@ static long random_ioctl(struct file *f,
*/
if (!capable(CAP_SYS_ADMIN))
return -EPERM;
- if (xchg(&input_pool.entropy_count, 0)) {
+ if (xchg(&input_pool.entropy_count, 0) >= POOL_MIN_BITS) {
wake_up_interruptible(&random_write_wait);
kill_fasync(&fasync, SIGIO, POLL_OUT);
}
