[src/netbsd-6]: src/sys Apply patch (requested by riastradh in ticket #1512):

[snj <snj%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/f41d2e7885d2
branches:  netbsd-6
changeset: 777290:f41d2e7885d2
user:      snj <snj%NetBSD.org@localhost>
date:      Sat Mar 03 20:44:38 2018 +0000

description:
Apply patch (requested by riastradh in ticket #1512):
Fix panic when waiting with kqueue/kevent for a read from
/dev/random.

diffstat:

 sys/dev/rndpseudo.c   |  24 ++++++++++++++++++------
 sys/kern/subr_cprng.c |   8 ++++----
 sys/sys/cprng.h       |   7 +++----
 3 files changed, 25 insertions(+), 14 deletions(-)

diffs (121 lines):

diff -r 6b92c34940b6 -r f41d2e7885d2 sys/dev/rndpseudo.c
--- a/sys/dev/rndpseudo.c       Mon Feb 19 20:56:37 2018 +0000
+++ b/sys/dev/rndpseudo.c       Sat Mar 03 20:44:38 2018 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: rndpseudo.c,v 1.6.2.3 2012/05/21 16:49:54 jdc Exp $    */
+/*     $NetBSD: rndpseudo.c,v 1.6.2.4 2018/03/03 20:44:38 snj Exp $    */
 
 /*-
  * Copyright (c) 1997-2011 The NetBSD Foundation, Inc.
@@ -30,7 +30,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: rndpseudo.c,v 1.6.2.3 2012/05/21 16:49:54 jdc Exp $");
+__KERNEL_RCSID(0, "$NetBSD: rndpseudo.c,v 1.6.2.4 2018/03/03 20:44:38 snj Exp $");
 
 #if defined(_KERNEL_OPT)
 #include "opt_compat_netbsd.h"
@@ -673,13 +673,13 @@
                }       
        }
 
+       mutex_enter(&ctx->cprng->mtx);
        if (cprng_strong_ready(ctx->cprng)) {
                revents |= events & (POLLIN | POLLRDNORM);
        } else {
-               mutex_enter(&ctx->cprng->mtx);
                selrecord(curlwp, &ctx->cprng->selq);
-               mutex_exit(&ctx->cprng->mtx);
        }
+       mutex_exit(&ctx->cprng->mtx);
 
        return (revents);
 }
@@ -731,12 +731,24 @@
 filt_rndread(struct knote *kn, long hint)
 {
        cprng_strong_t *c = kn->kn_hook;
+       int ret;
 
+       if (hint & NOTE_SUBMIT)
+               KASSERT(mutex_owned(&c->mtx));
+       else
+               mutex_enter(&c->mtx);
        if (cprng_strong_ready(c)) {
                kn->kn_data = RND_TEMP_BUFFER_SIZE;
-               return 1;
+               ret = 1;
+       } else {
+               ret = 0;
        }
-       return 0;
+       if (hint & NOTE_SUBMIT)
+               KASSERT(mutex_owned(&c->mtx));
+       else
+               mutex_exit(&c->mtx);
+
+       return ret;
 }
 
 static const struct filterops rnd_seltrue_filtops =
diff -r 6b92c34940b6 -r f41d2e7885d2 sys/kern/subr_cprng.c
--- a/sys/kern/subr_cprng.c     Mon Feb 19 20:56:37 2018 +0000
+++ b/sys/kern/subr_cprng.c     Sat Mar 03 20:44:38 2018 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: subr_cprng.c,v 1.5.2.8 2013/03/29 00:44:28 msaitoh Exp $ */
+/*     $NetBSD: subr_cprng.c,v 1.5.2.9 2018/03/03 20:44:38 snj Exp $ */
 
 /*-
  * Copyright (c) 2011 The NetBSD Foundation, Inc.
@@ -46,7 +46,7 @@
 
 #include <sys/cprng.h>
 
-__KERNEL_RCSID(0, "$NetBSD: subr_cprng.c,v 1.5.2.8 2013/03/29 00:44:28 msaitoh Exp $");
+__KERNEL_RCSID(0, "$NetBSD: subr_cprng.c,v 1.5.2.9 2018/03/03 20:44:38 snj Exp $");
 
 void
 cprng_init(void)
@@ -95,7 +95,7 @@
        if (c->flags & CPRNG_USE_CV) {
                cv_broadcast(&c->cv);
        }
-       selnotify(&c->selq, 0, 0);
+       selnotify(&c->selq, 0, NOTE_SUBMIT);
 }
 
 static void
@@ -397,7 +397,7 @@
                        if (c->flags & CPRNG_USE_CV) {
                                cv_broadcast(&c->cv);
                        }
-                       selnotify(&c->selq, 0, 0);
+                       selnotify(&c->selq, 0, NOTE_SUBMIT);
                }
        }
        c->flags = flags;
diff -r 6b92c34940b6 -r f41d2e7885d2 sys/sys/cprng.h
--- a/sys/sys/cprng.h   Mon Feb 19 20:56:37 2018 +0000
+++ b/sys/sys/cprng.h   Sat Mar 03 20:44:38 2018 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: cprng.h,v 1.4.2.1 2012/04/20 23:35:20 riz Exp $ */
+/*     $NetBSD: cprng.h,v 1.4.2.2 2018/03/03 20:44:39 snj Exp $ */
 
 /*-
  * Copyright (c) 2011 The NetBSD Foundation, Inc.
@@ -121,12 +121,11 @@
 cprng_strong_ready(cprng_strong_t *c)
 {
        int ret = 0;
-       
-       mutex_enter(&c->mtx);
+
+       KASSERT(mutex_owned(&c->mtx));
        if (c->drbg.reseed_counter < NIST_CTR_DRBG_RESEED_INTERVAL) {
                ret = 1;
        }
-       mutex_exit(&c->mtx);
        return ret;
 }