git: 6f8ef4d6e44e - stable/14 - kasan: Add corresponding sysctl knob for loader tunable

The branch stable/14 has been updated by zlei:

URL: https://cgit.FreeBSD.org/src/commit/?id=6f8ef4d6e44ee27a08c14ab6a892ffccf332bcf7

commit 6f8ef4d6e44ee27a08c14ab6a892ffccf332bcf7
Author:     Zhenlei Huang <zlei@FreeBSD.org>
AuthorDate: 2023-10-12 10:14:48 +0000
Commit:     Zhenlei Huang <zlei@FreeBSD.org>
CommitDate: 2023-10-19 14:00:56 +0000

    kasan: Add corresponding sysctl knob for loader tunable
    
    The loader tunable 'debug.kasan.disabled' does not have corresponding
    sysctl MIB entry. Add it so that it can be retrieved, and `sysctl -T`
    will also report it correctly.
    
    Reviewed by:    markj
    MFC after:      1 week
    Differential Revision:  https://reviews.freebsd.org/D42138
    
    (cherry picked from commit db5d0bc868be669ed6588ebeccf8c02e76aabc41)
---
 sys/kern/subr_asan.c | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/sys/kern/subr_asan.c b/sys/kern/subr_asan.c
index 44c96435a499..c3664d9cf6c2 100644
--- a/sys/kern/subr_asan.c
+++ b/sys/kern/subr_asan.c
@@ -92,7 +92,10 @@ SYSCTL_INT(_debug_kasan, OID_AUTO, panic_on_violation, CTLFLAG_RDTUN,
     &panic_on_violation, 0,
     "Panic if an invalid access is detected");
 
-static bool kasan_enabled __read_mostly = false;
+#define kasan_enabled (!kasan_disabled)
+static bool kasan_disabled __read_mostly = true;
+SYSCTL_BOOL(_debug_kasan, OID_AUTO, disabled, CTLFLAG_RDTUN | CTLFLAG_NOFETCH,
+    &kasan_disabled, 0, "KASAN is disabled");
 
 /* -------------------------------------------------------------------------- */
 
@@ -136,7 +139,7 @@ kasan_init(void)
 	kasan_md_init();
 
 	/* Now officially enabled. */
-	kasan_enabled = true;
+	kasan_disabled = false;
 }
 
 void
@@ -180,7 +183,7 @@ kasan_code_name(uint8_t code)
 
 #define	REPORT(f, ...) do {				\
 	if (panic_on_violation) {			\
-		kasan_enabled = false;			\
+		kasan_disabled = true;			\
 		panic(f, __VA_ARGS__);			\
 	} else {					\
 		struct stack st;			\