From: Theodore Ts'o <tytso@mit.edu> mainline inclusion from mainline-v5.2-rc2 commit 58be0106c5306b939b07b4b8bf00669a20593f4b category: bugfix bugzilla: NA CVE: NA https://gitee.com/openeuler/kernel/issues/I1CVQ4?from=project-issue ------------------------------------------------- Fixes: eb9d1bf079bb: "random: only read from /dev/random after its pool has received 128 bits" Reported-by: kernel test robot <lkp@intel.com> Signed-off-by: Theodore Ts'o <tytso@mit.edu> Signed-off-by: Yang Yingliang <yangyingliang@huawei.com> Reviewed-by: Xie XiuQi <xiexiuqi@huawei.com> Signed-off-by: Yang Yingliang <yangyingliang@huawei.com> --- drivers/char/random.c | 16 +++++++++++++--- 1 file changed, 13 insertions(+), 3 deletions(-) diff --git a/drivers/char/random.c b/drivers/char/random.c index 28aa79743e3d2..05daadfbf1ed5 100644 --- a/drivers/char/random.c +++ b/drivers/char/random.c @@ -704,8 +704,11 @@ static void credit_entropy_bits(struct entropy_store *r, int nbits) if (cmpxchg(&r->entropy_count, orig, entropy_count) != orig) goto retry; - if (has_initialized) + if (has_initialized) { r->initialized = 1; + wake_up_interruptible(&random_read_wait); + kill_fasync(&fasync, SIGIO, POLL_IN); + } trace_credit_entropy_bits(r->name, nbits, entropy_count >> ENTROPY_SHIFT, _RET_IP_); @@ -721,6 +724,13 @@ static void credit_entropy_bits(struct entropy_store *r, int nbits) entropy_bits = r->entropy_count >> ENTROPY_SHIFT; } + /* initialize the blocking pool if necessary */ + if (entropy_bits >= random_read_wakeup_bits && + !other->initialized) { + schedule_work(&other->push_work); + return; + } + /* should we wake readers? */ if (entropy_bits >= random_read_wakeup_bits && wq_has_sleeper(&random_read_wait)) { @@ -1870,8 +1880,8 @@ _random_read(int nonblock, char __user *buf, size_t nbytes) return -EAGAIN; wait_event_interruptible(random_read_wait, - ENTROPY_BITS(&input_pool) >= - random_read_wakeup_bits); + blocking_pool.initialized && + (ENTROPY_BITS(&input_pool) >= random_read_wakeup_bits)); if (signal_pending(current)) return -ERESTARTSYS; } -- 2.25.1