Module Name: src
Committed By: tls
Date: Tue Apr 10 15:12:40 UTC 2012
Modified Files:
src/sys/kern: subr_cprng.c
Log Message:
Fix LOCKDEBUG problems pointed out by drochner@
1) Lock ordering in cprng_strong_destroy had us take a spin mutex then
an adaptive mutex. Can't do that. Reordering this requires changing
cprng_strong_reseed to tryenter the cprng's own mutex and skip the
reseed on failure, or we could deadlock.
2) Can't free memory with a valid mutex in it.
To generate a diff of this commit:
cvs rdiff -u -r1.6 -r1.7 src/sys/kern/subr_cprng.c
Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.
Modified files:
Index: src/sys/kern/subr_cprng.c
diff -u src/sys/kern/subr_cprng.c:1.6 src/sys/kern/subr_cprng.c:1.7
--- src/sys/kern/subr_cprng.c:1.6 Tue Apr 10 14:02:28 2012
+++ src/sys/kern/subr_cprng.c Tue Apr 10 15:12:40 2012
@@ -1,4 +1,4 @@
-/* $NetBSD: subr_cprng.c,v 1.6 2012/04/10 14:02:28 tls Exp $ */
+/* $NetBSD: subr_cprng.c,v 1.7 2012/04/10 15:12:40 tls Exp $ */
/*-
* Copyright (c) 2011 The NetBSD Foundation, Inc.
@@ -46,7 +46,7 @@
#include <sys/cprng.h>
-__KERNEL_RCSID(0, "$NetBSD: subr_cprng.c,v 1.6 2012/04/10 14:02:28 tls Exp $");
+__KERNEL_RCSID(0, "$NetBSD: subr_cprng.c,v 1.7 2012/04/10 15:12:40 tls Exp $");
void
cprng_init(void)
@@ -90,7 +90,10 @@ cprng_strong_reseed(void *const arg)
uint8_t key[NIST_BLOCK_KEYLEN_BYTES];
uint32_t cc = cprng_counter();
- mutex_enter(&c->mtx);
+ if (!mutex_tryenter(&c->mtx)) {
+ return;
+ }
+
if (c->reseed.len != sizeof(key)) {
panic("cprng_strong_reseed: bad entropy length %d "
" (expected %d)", (int)c->reseed.len, (int)sizeof(key));
@@ -268,8 +271,8 @@ cprng_strong(cprng_strong_t *const c, vo
void
cprng_strong_destroy(cprng_strong_t *c)
{
- mutex_spin_enter(&c->reseed.mtx);
mutex_enter(&c->mtx);
+ mutex_spin_enter(&c->reseed.mtx);
if (c->flags & CPRNG_USE_CV) {
KASSERT(!cv_has_waiters(&c->cv));
@@ -281,6 +284,7 @@ cprng_strong_destroy(cprng_strong_t *c)
rndsink_detach(&c->reseed);
}
mutex_spin_exit(&c->reseed.mtx);
+ mutex_destroy(&c->reseed.mtx);
nist_ctr_drbg_destroy(&c->drbg);
