Author: alfred
Date: Fri Dec 7 08:25:08 2012
New Revision: 243980
URL: http://svnweb.freebsd.org/changeset/base/243980
Log:
Allow KASSERT to log instead of panic.
This is to allow debug images to be used without taking down the
system when non-fatal asserts are hit.
The following sysctls are added:
debug.kassert.warn_only: 1 = log, 0 = panic
debug.kassert.do_ktr: set to a ktr mask for logging via KTR
debug.kassert.do_log: 1 = log, 0 = quiet
debug.kassert.warnings: stats, number of kasserts hit
debug.kassert.log_panic_at:
number of kasserts before we actually panic, 0 = never
debug.kassert.log_pps_limit: pps limit for log messages
debug.kassert.log_mute_at: stop warning after N kasserts, 0 = never stop
debug.kassert.kassert: set this sysctl to trigger a kassert
Discussed with: scottl, gnn, marcel
Sponsored by: iXsystems
Modified:
head/sys/kern/kern_shutdown.c
head/sys/sys/systm.h
Modified: head/sys/kern/kern_shutdown.c
==============================================================================
--- head/sys/kern/kern_shutdown.c Fri Dec 7 07:24:15 2012
(r243979)
+++ head/sys/kern/kern_shutdown.c Fri Dec 7 08:25:08 2012
(r243980)
@@ -55,6 +55,7 @@ __FBSDID("$FreeBSD$");
#include <sys/kernel.h>
#include <sys/kerneldump.h>
#include <sys/kthread.h>
+#include <sys/ktr.h>
#include <sys/malloc.h>
#include <sys/mount.h>
#include <sys/priv.h>
@@ -150,6 +151,7 @@ static void poweroff_wait(void *, int);
static void shutdown_halt(void *junk, int howto);
static void shutdown_panic(void *junk, int howto);
static void shutdown_reset(void *junk, int howto);
+static void vpanic(const char *fmt, va_list ap) __dead2;
/* register various local shutdown events */
static void
@@ -538,6 +540,120 @@ shutdown_reset(void *junk, int howto)
/* NOTREACHED */ /* assuming reset worked */
}
+#ifdef INVARIANTS
+static int kassert_warn_only = 0;
+#ifdef KTR
+static int kassert_do_ktr = 0;
+#endif
+static int kassert_do_log = 1;
+static int kassert_log_pps_limit = 4;
+static int kassert_log_mute_at = 0;
+static int kassert_log_panic_at = 0;
+static int kassert_warnings = 0;
+
+SYSCTL_NODE(_debug, OID_AUTO, kassert, CTLFLAG_RW, NULL, "kassert options");
+
+SYSCTL_INT(_debug_kassert, OID_AUTO, warn_only, CTLFLAG_RW | CTLFLAG_TUN,
+ &kassert_warn_only, 0,
+ "KASSERT triggers a panic (1) or just a warning (0)");
+TUNABLE_INT("debug.kassert.warn_only", &kassert_warn_only);
+
+#ifdef KTR
+SYSCTL_UINT(_debug_kassert, OID_AUTO, do_ktr, CTLFLAG_RW | CTLFLAG_TUN,
+ &kassert_do_ktr, 0,
+ "KASSERT does a KTR, set this to the KTRMASK you want");
+TUNABLE_INT("debug.kassert.do_ktr", &kassert_do_ktr);
+#endif
+
+SYSCTL_INT(_debug_kassert, OID_AUTO, do_log, CTLFLAG_RW | CTLFLAG_TUN,
+ &kassert_do_log, 0, "KASSERT triggers a panic (1) or just a warning (0)");
+TUNABLE_INT("debug.kassert.do_log", &kassert_do_log);
+
+SYSCTL_INT(_debug_kassert, OID_AUTO, warnings, CTLFLAG_RW | CTLFLAG_TUN,
+ &kassert_warnings, 0, "number of KASSERTs that have been triggered");
+TUNABLE_INT("debug.kassert.warnings", &kassert_warnings);
+
+SYSCTL_INT(_debug_kassert, OID_AUTO, log_panic_at, CTLFLAG_RW | CTLFLAG_TUN,
+ &kassert_log_panic_at, 0, "max number of KASSERTS before we will panic");
+TUNABLE_INT("debug.kassert.log_panic_at", &kassert_log_panic_at);
+
+SYSCTL_INT(_debug_kassert, OID_AUTO, log_pps_limit, CTLFLAG_RW | CTLFLAG_TUN,
+ &kassert_log_pps_limit, 0, "limit number of log messages per second");
+TUNABLE_INT("debug.kassert.log_pps_limit", &kassert_log_pps_limit);
+
+SYSCTL_INT(_debug_kassert, OID_AUTO, log_mute_at, CTLFLAG_RW | CTLFLAG_TUN,
+ &kassert_log_mute_at, 0, "max number of KASSERTS to log");
+TUNABLE_INT("debug.kassert.log_mute_at", &kassert_log_mute_at);
+
+static int kassert_sysctl_kassert(SYSCTL_HANDLER_ARGS);
+
+SYSCTL_PROC(_debug_kassert, OID_AUTO, kassert,
+ CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_SECURE, NULL, 0,
+ kassert_sysctl_kassert, "I", "set to trigger a test kassert");
+
+static int
+kassert_sysctl_kassert(SYSCTL_HANDLER_ARGS)
+{
+ int error, i;
+
+ error = sysctl_wire_old_buffer(req, sizeof(int));
+ if (error == 0) {
+ i = 0;
+ error = sysctl_handle_int(oidp, &i, 0, req);
+ }
+ if (error != 0 || req->newptr == NULL)
+ return (error);
+ KASSERT(0, ("kassert_sysctl_kassert triggered kassert %d", i));
+ return (0);
+}
+
+/*
+ * Called by KASSERT, this decides if we will panic
+ * or if we will log via printf and/or ktr.
+ */
+void
+kassert_panic(const char *fmt, ...)
+{
+ static char buf[256];
+ va_list ap;
+
+ va_start(ap, fmt);
+ (void)vsnprintf(buf, sizeof(buf), fmt, ap);
+ va_end(ap);
+
+ /*
+ * panic if we're not just warning, or if we've exceeded
+ * kassert_log_panic_at warnings.
+ */
+ if (!kassert_warn_only ||
+ (kassert_log_panic_at > 0 &&
+ kassert_warnings >= kassert_log_panic_at)) {
+ va_start(ap, fmt);
+ vpanic(fmt, ap);
+ /* NORETURN */
+ }
+#ifdef KTR
+ if (kassert_do_ktr)
+ CTR0(ktr_mask, buf);
+#endif /* KTR */
+ /*
+ * log if we've not yet met the mute limit.
+ */
+ if (kassert_do_log &&
+ (kassert_log_mute_at == 0 ||
+ kassert_warnings < kassert_log_mute_at)) {
+ static struct timeval lasterr;
+ static int curerr;
+
+ if (ppsratecheck(&lasterr, &curerr, kassert_log_pps_limit)) {
+ printf("KASSERT failed: %s\n", buf);
+ kdb_backtrace();
+ }
+ }
+ atomic_add_int(&kassert_warnings, 1);
+}
+#endif
+
/*
* Panic is called on unresolvable fatal errors. It prints "panic: mesg",
* and then reboots. If we are called twice, then we avoid trying to sync
@@ -546,12 +662,20 @@ shutdown_reset(void *junk, int howto)
void
panic(const char *fmt, ...)
{
+ va_list ap;
+
+ va_start(ap, fmt);
+ vpanic(fmt, ap);
+}
+
+static void
+vpanic(const char *fmt, va_list ap)
+{
#ifdef SMP
cpuset_t other_cpus;
#endif
struct thread *td = curthread;
int bootopt, newpanic;
- va_list ap;
static char buf[256];
spinlock_enter();
@@ -587,7 +711,6 @@ panic(const char *fmt, ...)
newpanic = 1;
}
- va_start(ap, fmt);
if (newpanic) {
(void)vsnprintf(buf, sizeof(buf), fmt, ap);
panicstr = buf;
@@ -598,7 +721,6 @@ panic(const char *fmt, ...)
vprintf(fmt, ap);
printf("\n");
}
- va_end(ap);
#ifdef SMP
printf("cpuid = %d\n", PCPU_GET(cpuid));
#endif
Modified: head/sys/sys/systm.h
==============================================================================
--- head/sys/sys/systm.h Fri Dec 7 07:24:15 2012 (r243979)
+++ head/sys/sys/systm.h Fri Dec 7 08:25:08 2012 (r243980)
@@ -73,14 +73,16 @@ extern int vm_guest; /* Running as virt
enum VM_GUEST { VM_GUEST_NO = 0, VM_GUEST_VM, VM_GUEST_XEN };
#ifdef INVARIANTS /* The option is always available */
+void kassert_panic(const char *fmt, ...);
+
#define KASSERT(exp,msg) do {
\
if (__predict_false(!(exp))) \
- panic msg; \
+ kassert_panic msg;
\
} while (0)
#define VNASSERT(exp, vp, msg) do {
\
if (__predict_false(!(exp))) { \
vn_printf(vp, "VNASSERT failed\n"); \
- panic msg; \
+ kassert_panic msg;
\
} \
} while (0)
#else
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