Module Name: src
Committed By: riastradh
Date: Tue Aug 30 22:38:27 UTC 2022
Modified Files:
src/sys/kern: kern_crashme.c
Log Message:
crashme(9): New debug.crashme.mutex_recursion method.
Takes a lock twice. Set it to 1 for adaptive lock, 2 for spin lock.
To generate a diff of this commit:
cvs rdiff -u -r1.6 -r1.7 src/sys/kern/kern_crashme.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_crashme.c
diff -u src/sys/kern/kern_crashme.c:1.6 src/sys/kern/kern_crashme.c:1.7
--- src/sys/kern/kern_crashme.c:1.6 Tue Aug 16 10:24:17 2022
+++ src/sys/kern/kern_crashme.c Tue Aug 30 22:38:26 2022
@@ -1,4 +1,4 @@
-/* $NetBSD: kern_crashme.c,v 1.6 2022/08/16 10:24:17 riastradh Exp $ */
+/* $NetBSD: kern_crashme.c,v 1.7 2022/08/30 22:38:26 riastradh Exp $ */
/*
* Copyright (c) 2018, 2019 Matthew R. Green
@@ -66,6 +66,7 @@ static int crashme_ddb(int);
#ifdef LOCKDEBUG
static int crashme_kernel_lock_spinout(int);
#endif
+static int crashme_mutex_recursion(int);
#define CMNODE(name, lname, func) \
{ \
@@ -85,6 +86,8 @@ static crashme_node nodes[] = {
CMNODE("kernel_lock_spinout", "infinite kernel lock",
crashme_kernel_lock_spinout),
#endif
+ CMNODE("mutex_recursion", "enter the same mutex twice",
+ crashme_mutex_recursion),
};
static crashme_node *first_node;
static kmutex_t crashme_lock;
@@ -290,3 +293,36 @@ crashme_kernel_lock_spinout(int flags)
return 0;
}
#endif
+
+static int
+crashme_mutex_recursion(int flags)
+{
+ kmutex_t crashme_spinlock;
+
+ switch (flags) {
+ case 0:
+ return 0;
+ case 1:
+ default:
+ /*
+ * printf makes the return address of the first
+ * mutex_enter call a little more obvious, so the line
+ * number of the _return address_ for the first
+ * mutex_enter doesn't confusingly point at the second
+ * mutex_enter.
+ */
+ mutex_enter(&crashme_lock);
+ printf("%s: locked once\n", __func__);
+ mutex_enter(&crashme_lock);
+ printf("%s: locked twice\n", __func__);
+ return -1;
+ case 2:
+ mutex_init(&crashme_spinlock, MUTEX_DEFAULT, IPL_VM);
+ printf("%s: initialized\n", __func__);
+ mutex_enter(&crashme_spinlock);
+ printf("%s: locked once\n", __func__);
+ mutex_enter(&crashme_spinlock);
+ printf("%s: locked twice\n", __func__);
+ return -1;
+ }
+}
