Attachment 204233 Details for Bug 237758 – Patch for panic on kldunload dcons

[patch] Patch for panic on kldunload dcons

dcons_deferred_free.diff (text/plain), 1.67 KB, created by Ian Lepore on 2019-05-06 04:37:05 UTC

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Creator: Ian Lepore

Created: 2019-05-06 04:37:05 UTC

Size: 1.67 KB

patch

obsolete

>Index: sys/dev/dcons/dcons_os.c
>===================================================================
>--- sys/dev/dcons/dcons_os.c	(revision 347133)
>+++ sys/dev/dcons/dcons_os.c	(working copy)
>@@ -52,6 +52,7 @@
> #include <sys/proc.h>
> #include <sys/ucred.h>
> 
>+#include <machine/atomic.h>
> #include <machine/bus.h>
> 
> #include <dev/dcons/dcons.h>
>@@ -135,12 +136,16 @@ extern struct gdb_dbgport *gdb_cur;
> #endif
> 
> static tsw_outwakeup_t dcons_outwakeup;
>+static tsw_free_t      dcons_free;
> 
> static struct ttydevsw dcons_ttydevsw = {
> 	.tsw_flags      = TF_NOPREFIX,
> 	.tsw_outwakeup  = dcons_outwakeup,
>+	.tsw_free       = dcons_free,
> };
> 
>+static int dcons_close_refs;
>+
> #if (defined(GDB) || defined(DDB))
> static int
> dcons_check_break(struct dcons_softc *dc, int c)
>@@ -198,6 +203,14 @@ dcons_os_putc(struct dcons_softc *dc, int c)
> }
> 
> static void
>+dcons_free(void *xsc __unused)
>+{
>+
>+	/* Our deferred free has arrived, now we're waiting for one fewer. */
>+	atomic_subtract_rel_int(&dcons_close_refs, 1);
>+}
>+
>+static void
> dcons_outwakeup(struct tty *tp)
> {
> 	struct dcons_softc *dc;
>@@ -396,6 +409,8 @@ dcons_detach(int port)
> 	dc = &sc[port];
> 	tp = dc->tty;
> 
>+	/* tty_rel_gone() schedules a deferred free callback, count it. */
>+	atomic_add_int(&dcons_close_refs, 1);
> 	tty_lock(tp);
> 	tty_rel_gone(tp);
> 
>@@ -430,6 +445,9 @@ dcons_modevent(module_t mode, int type, void *data
> 			contigfree(dg.buf, DCONS_BUF_SIZE, M_DEVBUF);
> 		}
> 
>+		/* Wait for tty deferred free callbacks to complete. */
>+		while (atomic_load_acq_int(&dcons_close_refs) > 0)
>+                        pause_sbt("dcunld", mstosbt(50), mstosbt(10), 0);
> 		break;
> 	case MOD_SHUTDOWN:
> #if 0		/* Keep connection after halt */

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Attachments on bug 237758: 204230 | 204233