Module Name: src
Committed By: riastradh
Date: Fri Jan 7 01:10:58 UTC 2022
Modified Files:
src/sys/dev/acpi: acpi_bat.c
Log Message:
acpibat(4): Fix race in detach with AcpiOsExecute deferred call.
To generate a diff of this commit:
cvs rdiff -u -r1.120 -r1.121 src/sys/dev/acpi/acpi_bat.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/dev/acpi/acpi_bat.c
diff -u src/sys/dev/acpi/acpi_bat.c:1.120 src/sys/dev/acpi/acpi_bat.c:1.121
--- src/sys/dev/acpi/acpi_bat.c:1.120 Fri Dec 31 14:20:56 2021
+++ src/sys/dev/acpi/acpi_bat.c Fri Jan 7 01:10:57 2022
@@ -1,4 +1,4 @@
-/* $NetBSD: acpi_bat.c,v 1.120 2021/12/31 14:20:56 riastradh Exp $ */
+/* $NetBSD: acpi_bat.c,v 1.121 2022/01/07 01:10:57 riastradh Exp $ */
/*-
* Copyright (c) 2003 The NetBSD Foundation, Inc.
@@ -75,7 +75,7 @@
*/
#include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: acpi_bat.c,v 1.120 2021/12/31 14:20:56 riastradh Exp $");
+__KERNEL_RCSID(0, "$NetBSD: acpi_bat.c,v 1.121 2022/01/07 01:10:57 riastradh Exp $");
#include <sys/param.h>
#include <sys/condvar.h>
@@ -157,6 +157,7 @@ struct acpibat_softc {
int32_t sc_lcapacity;
int32_t sc_wcapacity;
int sc_present;
+ bool sc_dying;
};
static const struct device_compatible_entry compat_data[] = {
@@ -262,12 +263,29 @@ acpibat_detach(device_t self, int flags)
{
struct acpibat_softc *sc = device_private(self);
+ /* Prevent further use of sc->sc_sme in acpibat_update_info. */
+ mutex_enter(&sc->sc_mutex);
+ sc->sc_dying = true;
+ mutex_exit(&sc->sc_mutex);
+
+ /* Prevent further calls to acpibat_resume. */
pmf_device_deregister(self);
+
+ /* Prevent further calls to acpibat_notify_handler. */
acpi_deregister_notify(sc->sc_node);
+ /* Detach sensors and prevent further calls to acpibat_refresh. */
if (sc->sc_sme != NULL)
sysmon_envsys_unregister(sc->sc_sme);
+ /*
+ * Wait for calls to acpibat_update_info/status in case sysmon
+ * envsys refreshed the sensors and queued them but they didn't
+ * run before sysmon_envsys_unregister. After this point, no
+ * asynchronous access to the softc is possible.
+ */
+ AcpiOsWaitEventsComplete();
+
if (sc->sc_sensor != NULL)
kmem_free(sc->sc_sensor, ACPIBAT_COUNT *
sizeof(*sc->sc_sensor));
@@ -599,6 +617,10 @@ acpibat_update_info(void *arg)
mutex_enter(&sc->sc_mutex);
+ /* Don't touch sc_sme if we're detaching. */
+ if (sc->sc_dying)
+ goto out;
+
rv = acpibat_get_sta(dv);
if (rv > 0) {
acpibat_get_info(dv);
@@ -619,7 +641,7 @@ acpibat_update_info(void *arg)
}
sc->sc_present = rv;
-
+out:
mutex_exit(&sc->sc_mutex);
}
