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authorLinus Torvalds <torvalds@linux-foundation.org>2019-05-26 08:30:16 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2019-05-26 08:30:16 -0700
commit128f2bfafcf2e65504013934202f460a3b2e378c (patch)
treeea2eb2449397f4f60c5cc77e3bbd346a55ad8749
parent35efb51eee2241a970dcf70ed950f9db7e5351f7 (diff)
parent58be0106c5306b939b07b4b8bf00669a20593f4b (diff)
downloadlinux-128f2bfafcf2e65504013934202f460a3b2e378c.tar.gz
Merge tag 'random_for_linus_stable' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/random
Pull /dev/random fix from Ted Ts'o: "Fix a soft lockup regression when reading from /dev/random in early boot" * tag 'random_for_linus_stable' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/random: random: fix soft lockup when trying to read from an uninitialized blocking pool
-rw-r--r--drivers/char/random.c16
1 files changed, 13 insertions, 3 deletions
diff --git a/drivers/char/random.c b/drivers/char/random.c
index a42b3d764da8..5d5ea4ce1442 100644
--- a/drivers/char/random.c
+++ b/drivers/char/random.c
@@ -772,8 +772,11 @@ retry:
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_);
@@ -789,6 +792,13 @@ retry:
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)) {
@@ -1936,8 +1946,8 @@ _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;
}