From acafd7d8a6297fe40960d12dd86a974a53072cfb Mon Sep 17 00:00:00 2001 From: Luca Boccassi Date: Fri, 19 Jul 2019 11:54:15 +0100 Subject: [PATCH] core: add KExecWatchdogSec option Rather than always enabling the shutdown WD on kexec, which might be dangerous in case the kernel driver and/or the hardware implementation does not reset the wd on kexec, add a new timer, disabled by default, to let users optionally enable the shutdown WD on kexec separately from the runtime and reboot ones. Advise in the documentation to also use the runtime WD in conjunction with it. Fixes: a637d0f9ecbe ("core: set shutdown watchdog on kexec too") --- man/systemd-system.conf.xml | 9 ++++++++- src/core/dbus-manager.c | 1 + src/core/main.c | 21 +++++++++++++++------ src/core/manager.h | 1 + src/core/system.conf.in | 1 + test/fuzz/fuzz-unit-file/directives.service | 1 + 6 files changed, 27 insertions(+), 7 deletions(-) diff --git a/man/systemd-system.conf.xml b/man/systemd-system.conf.xml index 5b80479a0a..4dd4bf0ca8 100644 --- a/man/systemd-system.conf.xml +++ b/man/systemd-system.conf.xml @@ -128,6 +128,7 @@ RuntimeWatchdogSec= ShutdownWatchdogSec= + KExecWatchdogSec= Configure the hardware watchdog at runtime and at reboot. Takes a timeout value in seconds (or in other time units if suffixed with ms, min, h, @@ -149,7 +150,13 @@ phase of system shutdown, configure JobTimeoutSec= and JobTimeoutAction= in the [Unit] section of the shutdown.target unit. By default RuntimeWatchdogSec= defaults to 0 (off), and ShutdownWatchdogSec= to - 10min. These settings have no effect if a hardware watchdog is not available. + 10min. KExecWatchdogSec= may be used to additionally enable the watchdog when kexec + is being executed rather than when rebooting. Note that if the kernel does not reset the watchdog on kexec (depending + on the specific hardware and/or driver), in this case the watchdog might not get disabled after kexec succeeds + and thus the system might get rebooted, unless RuntimeWatchdogSec= is also enabled at the same time. + For this reason it is recommended to enable KExecWatchdogSec= only if + RuntimeWatchdogSec= is also enabled. + These settings have no effect if a hardware watchdog is not available. diff --git a/src/core/dbus-manager.c b/src/core/dbus-manager.c index 9fb3ed516a..e70c1e132a 100644 --- a/src/core/dbus-manager.c +++ b/src/core/dbus-manager.c @@ -2410,6 +2410,7 @@ const sd_bus_vtable bus_manager_vtable[] = { SD_BUS_PROPERTY("DefaultStandardError", "s", bus_property_get_exec_output, offsetof(Manager, default_std_output), SD_BUS_VTABLE_PROPERTY_CONST), SD_BUS_WRITABLE_PROPERTY("RuntimeWatchdogUSec", "t", bus_property_get_usec, property_set_runtime_watchdog, offsetof(Manager, runtime_watchdog), 0), SD_BUS_WRITABLE_PROPERTY("ShutdownWatchdogUSec", "t", bus_property_get_usec, bus_property_set_usec, offsetof(Manager, shutdown_watchdog), 0), + SD_BUS_WRITABLE_PROPERTY("KExecWatchdogUSec", "t", bus_property_get_usec, bus_property_set_usec, offsetof(Manager, kexec_watchdog), 0), SD_BUS_WRITABLE_PROPERTY("ServiceWatchdogs", "b", bus_property_get_bool, bus_property_set_bool, offsetof(Manager, service_watchdogs), 0), SD_BUS_PROPERTY("ControlGroup", "s", NULL, offsetof(Manager, cgroup_root), 0), SD_BUS_PROPERTY("SystemState", "s", property_get_system_state, 0, 0), diff --git a/src/core/main.c b/src/core/main.c index 8de3d4753d..ccfa22c814 100644 --- a/src/core/main.c +++ b/src/core/main.c @@ -122,6 +122,7 @@ static usec_t arg_default_start_limit_interval; static unsigned arg_default_start_limit_burst; static usec_t arg_runtime_watchdog; static usec_t arg_shutdown_watchdog; +static usec_t arg_kexec_watchdog; static char *arg_early_core_pattern; static char *arg_watchdog_device; static char **arg_default_environment; @@ -555,6 +556,7 @@ static int parse_config_file(void) { { "Manager", "JoinControllers", config_parse_warn_compat, DISABLED_CONFIGURATION, NULL }, { "Manager", "RuntimeWatchdogSec", config_parse_sec, 0, &arg_runtime_watchdog }, { "Manager", "ShutdownWatchdogSec", config_parse_sec, 0, &arg_shutdown_watchdog }, + { "Manager", "KExecWatchdogSec", config_parse_sec, 0, &arg_kexec_watchdog }, { "Manager", "WatchdogDevice", config_parse_path, 0, &arg_watchdog_device }, { "Manager", "CapabilityBoundingSet", config_parse_capability_set, 0, &arg_capability_bounding_set }, { "Manager", "NoNewPrivileges", config_parse_bool, 0, &arg_no_new_privs }, @@ -674,6 +676,7 @@ static void set_manager_settings(Manager *m) { m->service_watchdogs = arg_service_watchdogs; m->runtime_watchdog = arg_runtime_watchdog; m->shutdown_watchdog = arg_shutdown_watchdog; + m->kexec_watchdog = arg_kexec_watchdog; m->cad_burst_action = arg_cad_burst_action; manager_set_show_status(m, arg_show_status); @@ -1356,6 +1359,7 @@ static int become_shutdown( _cleanup_strv_free_ char **env_block = NULL; size_t pos = 7; int r; + usec_t watchdog_timer = 0; assert(shutdown_verb); assert(!command_line[pos]); @@ -1396,20 +1400,23 @@ static int become_shutdown( assert(pos < ELEMENTSOF(command_line)); - if (STR_IN_SET(shutdown_verb, "reboot", "kexec") && - arg_shutdown_watchdog > 0 && - arg_shutdown_watchdog != USEC_INFINITY) { + if (streq(shutdown_verb, "reboot")) + watchdog_timer = arg_shutdown_watchdog; + else if (streq(shutdown_verb, "kexec")) + watchdog_timer = arg_kexec_watchdog; + + if (watchdog_timer > 0 && watchdog_timer != USEC_INFINITY) { char *e; - /* If we reboot let's set the shutdown + /* If we reboot or kexec let's set the shutdown * watchdog and tell the shutdown binary to * repeatedly ping it */ - r = watchdog_set_timeout(&arg_shutdown_watchdog); + r = watchdog_set_timeout(&watchdog_timer); watchdog_close(r < 0); /* Tell the binary how often to ping, ignore failure */ - if (asprintf(&e, "WATCHDOG_USEC="USEC_FMT, arg_shutdown_watchdog) > 0) + if (asprintf(&e, "WATCHDOG_USEC="USEC_FMT, watchdog_timer) > 0) (void) strv_consume(&env_block, e); if (arg_watchdog_device && @@ -2100,6 +2107,7 @@ static void reset_arguments(void) { arg_default_start_limit_burst = DEFAULT_START_LIMIT_BURST; arg_runtime_watchdog = 0; arg_shutdown_watchdog = 10 * USEC_PER_MINUTE; + arg_kexec_watchdog = 0; arg_early_core_pattern = NULL; arg_watchdog_device = NULL; @@ -2639,6 +2647,7 @@ finish: if (m) { arg_shutdown_watchdog = m->shutdown_watchdog; + arg_kexec_watchdog = m->kexec_watchdog; m = manager_free(m); } diff --git a/src/core/manager.h b/src/core/manager.h index 9f2b5a0eb0..9600ab5144 100644 --- a/src/core/manager.h +++ b/src/core/manager.h @@ -229,6 +229,7 @@ struct Manager { usec_t runtime_watchdog; usec_t shutdown_watchdog; + usec_t kexec_watchdog; dual_timestamp timestamps[_MANAGER_TIMESTAMP_MAX]; diff --git a/src/core/system.conf.in b/src/core/system.conf.in index 8617ec20aa..af6e5d9f62 100644 --- a/src/core/system.conf.in +++ b/src/core/system.conf.in @@ -27,6 +27,7 @@ #NUMAMask= #RuntimeWatchdogSec=0 #ShutdownWatchdogSec=10min +#KExecWatchdogSec=0 #WatchdogDevice= #CapabilityBoundingSet= #NoNewPrivileges=no diff --git a/test/fuzz/fuzz-unit-file/directives.service b/test/fuzz/fuzz-unit-file/directives.service index 2f59585671..d19610fc55 100644 --- a/test/fuzz/fuzz-unit-file/directives.service +++ b/test/fuzz/fuzz-unit-file/directives.service @@ -703,6 +703,7 @@ LogTarget= RuntimeWatchdogSec= ShowStatus= ShutdownWatchdogSec= +KExecWatchdogSec= SuspendMode= SuspendState= SystemCallArchitectures=