Module Name: src
Committed By: riastradh
Date: Wed Mar 16 23:56:55 UTC 2022
Modified Files:
src/sys/kern: kern_entropy.c
Log Message:
entropy(9): Forbid entropy_extract in hard interrupt context.
With a little additional work, this will let us reduce the global
entropy pool lock so it never blocks interrupts.
To generate a diff of this commit:
cvs rdiff -u -r1.34 -r1.35 src/sys/kern/kern_entropy.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/kern_entropy.c
diff -u src/sys/kern/kern_entropy.c:1.34 src/sys/kern/kern_entropy.c:1.35
--- src/sys/kern/kern_entropy.c:1.34 Fri Mar 4 21:12:03 2022
+++ src/sys/kern/kern_entropy.c Wed Mar 16 23:56:55 2022
@@ -1,4 +1,4 @@
-/* $NetBSD: kern_entropy.c,v 1.34 2022/03/04 21:12:03 andvar Exp $ */
+/* $NetBSD: kern_entropy.c,v 1.35 2022/03/16 23:56:55 riastradh Exp $ */
/*-
* Copyright (c) 2019 The NetBSD Foundation, Inc.
@@ -75,7 +75,7 @@
*/
#include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: kern_entropy.c,v 1.34 2022/03/04 21:12:03 andvar Exp $");
+__KERNEL_RCSID(0, "$NetBSD: kern_entropy.c,v 1.35 2022/03/16 23:56:55 riastradh Exp $");
#include <sys/param.h>
#include <sys/types.h>
@@ -211,9 +211,6 @@ EVCNT_ATTACH_STATIC(entropy_partial_evcn
static struct evcnt entropy_consolidate_evcnt =
EVCNT_INITIALIZER(EVCNT_TYPE_MISC, NULL, "entropy", "consolidate");
EVCNT_ATTACH_STATIC(entropy_consolidate_evcnt);
-static struct evcnt entropy_extract_intr_evcnt =
- EVCNT_INITIALIZER(EVCNT_TYPE_MISC, NULL, "entropy", "extract intr");
-EVCNT_ATTACH_STATIC(entropy_extract_intr_evcnt);
static struct evcnt entropy_extract_fail_evcnt =
EVCNT_INITIALIZER(EVCNT_TYPE_MISC, NULL, "entropy", "extract fail");
EVCNT_ATTACH_STATIC(entropy_extract_fail_evcnt);
@@ -1278,14 +1275,13 @@ entropy_extract(void *buf, size_t len, i
"can't wait for entropy until warm");
}
+ /* Refuse to operate in interrupt context. */
+ KASSERT(!cpu_intr_p());
+
/* Acquire the global lock to get at the global pool. */
if (E->stage >= ENTROPY_WARM)
mutex_enter(&E->lock);
- /* Count up request for entropy in interrupt context. */
- if (cpu_intr_p())
- entropy_extract_intr_evcnt.ev_count++;
-
/* Wait until there is enough entropy in the system. */
error = 0;
while (E->needed) {
