One should never allocate 4-kilobyte structs and such on the interrupt

stack.  It's bad for your machine's health.

Make the two huge structs in reseed() static to prevent crashes.  This
is the bug that people have been running into and panic()ing on for the
past few days.

Reviewed by:	phk

2 files changed, 12 insertions, 4 deletions

diff --git a/sys/dev/random/yarrow.c b/sys/dev/random/yarrow.c
index 2ad981b..75bcf6c 100644
--- a/sys/dev/random/yarrow.c
+++ b/sys/dev/random/yarrow.c
@@ -101,9 +101,13 @@ random_deinit(void)
 static void
 reseed(int fastslow)
 {
-	unsigned char v[TIMEBIN][KEYSIZE];	/* v[i] */
+	/*
+	 * Allocate the huge variables statically.  They _will_ run you
+	 * out of interrupt-context stack otherwise!
+	 */
+	static BF_KEY hashkey;
+	static unsigned char v[TIMEBIN][KEYSIZE];	/* v[i] */
 	unsigned char hash[KEYSIZE];		/* h' */
-	BF_KEY hashkey;
 	unsigned char ivec[8];
 	unsigned char temp[KEYSIZE];
 	struct entropy *bucket;
diff --git a/sys/dev/randomdev/yarrow.c b/sys/dev/randomdev/yarrow.c
index 2ad981b..75bcf6c 100644
--- a/sys/dev/randomdev/yarrow.c
+++ b/sys/dev/randomdev/yarrow.c
@@ -101,9 +101,13 @@ random_deinit(void)
 static void
 reseed(int fastslow)
 {
-	unsigned char v[TIMEBIN][KEYSIZE];	/* v[i] */
+	/*
+	 * Allocate the huge variables statically.  They _will_ run you
+	 * out of interrupt-context stack otherwise!
+	 */
+	static BF_KEY hashkey;
+	static unsigned char v[TIMEBIN][KEYSIZE];	/* v[i] */
 	unsigned char hash[KEYSIZE];		/* h' */
-	BF_KEY hashkey;
 	unsigned char ivec[8];
 	unsigned char temp[KEYSIZE];
 	struct entropy *bucket;