Attachment 180352 Details for Bug 217408 – This patch makes it more likely we will hit the race condition on bootup. It can be used for seeing the bug and testing fixes.

[patch] This patch makes it more likely we will hit the race condition on bootup. It can be used for seeing the bug and testing fixes.

ncd-3560-repro.diff (text/plain), 5.69 KB, created by Jonathan T. Looney on 2017-02-28 00:09:24 UTC

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Creator: Jonathan T. Looney

Created: 2017-02-28 00:09:24 UTC

Size: 5.69 KB

patch

obsolete

>Index: sys/dev/vt/vt_core.c
>===================================================================
>--- sys/dev/vt/vt_core.c	(revision 313561)
>+++ sys/dev/vt/vt_core.c	(working copy)
>@@ -36,9 +36,12 @@
> #include "opt_compat.h"
> 
> #include <sys/param.h>
>+#include <sys/systm.h>
>+#include <sys/bus.h>
> #include <sys/consio.h>
> #include <sys/eventhandler.h>
> #include <sys/fbio.h>
>+#include <sys/interrupt.h>
> #include <sys/kbio.h>
> #include <sys/kdb.h>
> #include <sys/kernel.h>
>@@ -50,7 +53,8 @@
> #include <sys/proc.h>
> #include <sys/random.h>
> #include <sys/reboot.h>
>-#include <sys/systm.h>
>+#include <sys/sched.h>
>+#include <sys/smp.h>
> #include <sys/terminal.h>
> 
> #include <dev/kbd/kbdreg.h>
>@@ -281,7 +285,7 @@
> 		/* Default to initial value. */
> 		ms = 1000 / VT_TIMERFREQ;
> 
>-	callout_schedule(&vd->vd_timer, hz / (1000 / ms));
>+	callout_schedule_delay(&vd->vd_timer, hz / (1000 / ms));
> }
> 
> void
>@@ -1565,6 +1569,46 @@
> 	return (0);
> }
> 
>+static void *mycookie;
>+static bool vt_intr_init = false;
>+volatile int in_change_font = 0;
>+static int change_font_cpu;
>+
>+
>+static void
>+vt_dummy_intr(void *arg __unused)
>+{
>+	int count = 1000;
>+
>+	while (count-- && in_change_font && curcpu != change_font_cpu)
>+		printf("testing.\n");
>+	if (curcpu == change_font_cpu)
>+		printf("exiting early due to same CPU\n");
>+}
>+
>+static void
>+do_vt_intr_init(void)
>+{
>+	struct intr_event *ie;
>+	char name[16];
>+	int cpu;
>+
>+	if (vt_intr_init)
>+		return;
>+	vt_intr_init = true;
>+	CPU_FOREACH(cpu) {
>+		if (cpu == curcpu)
>+			continue;
>+		snprintf(name, sizeof(name), "test (%d)", cpu);
>+		ie = NULL;
>+		if (!swi_add(&ie, name, vt_dummy_intr, NULL, SWI_TTY,
>+		    INTR_MPSAFE, &mycookie)) {
>+			intr_event_bind(ie, cpu);
>+			break;
>+		}
>+	}
>+}
>+
> static int
> vt_change_font(struct vt_window *vw, struct vt_font *vf)
> {
>@@ -2605,6 +2649,7 @@
> 		}
> 
> 	}
>+	do_vt_intr_init();
> 	VT_LOCK(vd);
> 	if (vd->vd_curwindow == NULL)
> 		vd->vd_curwindow = vd->vd_windows[VT_CONSWINDOW];
>@@ -2614,14 +2659,20 @@
> 		/* Attach keyboard. */
> 		vt_allocate_keyboard(vd);
> 
>+		change_font_cpu = curcpu;
>+		atomic_add_acq_int(&in_change_font, 1);
>+		swi_sched(mycookie, 0);
>+
> 		/* Init 25 Hz timer. */
> 		callout_init_mtx(&vd->vd_timer, &vd->vd_lock, 0);
> 
> 		/* Start timer when everything ready. */
> 		vd->vd_flags |= VDF_ASYNC;
>-		callout_reset(&vd->vd_timer, hz / VT_TIMERFREQ, vt_timer, vd);
>+		callout_reset_delay(&vd->vd_timer, hz / VT_TIMERFREQ, vt_timer, vd);
> 		vd->vd_timer_armed = 1;
> 		register_handlers = 1;
>+
>+		atomic_store_rel_int(&in_change_font, 0);
> 	}
> 
> 	VT_UNLOCK(vd);
>Index: sys/kern/kern_timeout.c
>===================================================================
>--- sys/kern/kern_timeout.c	(revision 313561)
>+++ sys/kern/kern_timeout.c	(working copy)
>@@ -1014,8 +1014,8 @@
>  * callout_deactivate() - marks the callout as having been serviced
>  */
> int
>-callout_reset_sbt_on(struct callout *c, sbintime_t sbt, sbintime_t prec,
>-    void (*ftn)(void *), void *arg, int cpu, int flags)
>+callout_reset_sbt_on_(struct callout *c, sbintime_t sbt, sbintime_t prec,
>+    void (*ftn)(void *), void *arg, int cpu, int flags, bool delay)
> {
> 	sbintime_t to_sbt, precision;
> 	struct callout_cpu *cc;
>@@ -1149,6 +1149,8 @@
> 	}
> #endif
> 
>+	if (delay)
>+		DELAY(10000);
> 	callout_cc_add(c, cc, to_sbt, precision, ftn, arg, cpu, flags);
> 	CTR6(KTR_CALLOUT, "%sscheduled %p func %p arg %p in %d.%08x",
> 	    cancelled ? "re" : "", c, c->c_func, c->c_arg, (int)(to_sbt >> 32),
>@@ -1174,6 +1176,12 @@
> }
> 
> int
>+callout_schedule_delay(struct callout *c, int to_ticks)
>+{
>+	return callout_reset_on_delay(c, to_ticks, c->c_func, c->c_arg, c->c_cpu);
>+}
>+
>+int
> _callout_stop_safe(struct callout *c, int flags, void (*drain)(void *))
> {
> 	struct callout_cpu *cc, *old_cc;
>Index: sys/sys/callout.h
>===================================================================
>--- sys/sys/callout.h	(revision 313561)
>+++ sys/sys/callout.h	(working copy)
>@@ -100,8 +100,11 @@
> 	_callout_init_lock((c), ((rw) != NULL) ? &(rw)->lock_object :	\
> 	   NULL, (flags))
> #define	callout_pending(c)	((c)->c_iflags & CALLOUT_PENDING)
>-int	callout_reset_sbt_on(struct callout *, sbintime_t, sbintime_t,
>-	    void (*)(void *), void *, int, int);
>+int	callout_reset_sbt_on_(struct callout *, sbintime_t, sbintime_t,
>+	    void (*)(void *), void *, int, int, bool);
>+#define	callout_reset_sbt_on(c, sbt, pr, fn, arg, cpu, flags)		\
>+    callout_reset_sbt_on_((c), (sbt), (pr), (fn), (arg), (cpu), (flags),\
>+        false)
> #define	callout_reset_sbt(c, sbt, pr, fn, arg, flags)			\
>     callout_reset_sbt_on((c), (sbt), (pr), (fn), (arg), -1, (flags))
> #define	callout_reset_sbt_curcpu(c, sbt, pr, fn, arg, flags)		\
>@@ -110,8 +113,13 @@
> #define	callout_reset_on(c, to_ticks, fn, arg, cpu)			\
>     callout_reset_sbt_on((c), tick_sbt * (to_ticks), 0, (fn), (arg),	\
>         (cpu), C_HARDCLOCK)
>+#define	callout_reset_on_delay(c, to_ticks, fn, arg, cpu)		\
>+    callout_reset_sbt_on_((c), tick_sbt * (to_ticks), 0, (fn), (arg),	\
>+        (cpu), C_HARDCLOCK, true)
> #define	callout_reset(c, on_tick, fn, arg)				\
>     callout_reset_on((c), (on_tick), (fn), (arg), -1)
>+#define callout_reset_delay(c, on_tick, fn, arg)			\
>+    callout_reset_on_delay((c), (on_tick), (fn), (arg), -1)
> #define	callout_reset_curcpu(c, on_tick, fn, arg)			\
>     callout_reset_on((c), (on_tick), (fn), (arg), PCPU_GET(cpuid))
> #define	callout_schedule_sbt_on(c, sbt, pr, cpu, flags)			\
>@@ -122,6 +130,7 @@
> #define	callout_schedule_sbt_curcpu(c, sbt, pr, flags)			\
>     callout_schedule_sbt_on((c), (sbt), (pr), PCPU_GET(cpuid), (flags))
> int	callout_schedule(struct callout *, int);
>+int	callout_schedule_delay(struct callout *, int);
> int	callout_schedule_on(struct callout *, int, int);
> #define	callout_schedule_curcpu(c, on_tick)				\
>     callout_schedule_on((c), (on_tick), PCPU_GET(cpuid))

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Attachments on bug 217408: 180352