From dac95906003fec1b4801115830cc14ec61c74960 Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Wed, 4 Oct 2017 11:23:10 -0700 Subject: torture: Suppress CPU stall warnings during shutdown ftrace dump The torture_shutdown() function directly invokes ftrace_dump(), which can result in RCU CPU stall warnings when the ftrace buffer is large, which it usually is. This commit therefore invoks rcu_ftrace_dump() in place of ftrace_dump(), suppressing RCU CPU stall warnings during this time. Signed-off-by: Paul E. McKenney --- kernel/torture.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'kernel/torture.c') diff --git a/kernel/torture.c b/kernel/torture.c index 637e172835d8..52781e838541 100644 --- a/kernel/torture.c +++ b/kernel/torture.c @@ -47,6 +47,7 @@ #include #include #include +#include "rcu/rcu.h" MODULE_LICENSE("GPL"); MODULE_AUTHOR("Paul E. McKenney "); @@ -500,7 +501,7 @@ static int torture_shutdown(void *arg) torture_shutdown_hook(); else VERBOSE_TOROUT_STRING("No torture_shutdown_hook(), skipping."); - ftrace_dump(DUMP_ALL); + rcu_ftrace_dump(DUMP_ALL); kernel_power_off(); /* Shut down the system. */ return 0; } -- cgit v1.2.3 From 4ced3314fd3a73dabac4e8a41747883eff36c3e8 Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Tue, 21 Nov 2017 15:01:02 -0800 Subject: torture: Make stutter less vulnerable to compilers and races The stutter_wait() function repeatedly fetched stutter_pause_test, and should really just fetch it once on each pass. The races should be harmless, but why have the races? Also, the whole point of the value "2" for stutter_pause_test is to get everyone to start at very nearly the same time, but the value "2" was the first jiffy of the stutter rather than the last jiffy of the stutter. This commit rearranges the code to be more sensible. Signed-off-by: Paul E. McKenney --- kernel/torture.c | 33 +++++++++++++++++---------------- 1 file changed, 17 insertions(+), 16 deletions(-) (limited to 'kernel/torture.c') diff --git a/kernel/torture.c b/kernel/torture.c index 52781e838541..3bcbd4fbfe18 100644 --- a/kernel/torture.c +++ b/kernel/torture.c @@ -573,18 +573,21 @@ static int stutter; */ void stutter_wait(const char *title) { + int spt; + cond_resched_rcu_qs(); - while (READ_ONCE(stutter_pause_test) || - (torture_runnable && !READ_ONCE(*torture_runnable))) { - if (stutter_pause_test) - if (READ_ONCE(stutter_pause_test) == 1) - schedule_timeout_interruptible(1); - else - while (READ_ONCE(stutter_pause_test)) - cond_resched(); - else + spt = READ_ONCE(stutter_pause_test); + while (spt || (torture_runnable && !READ_ONCE(*torture_runnable))) { + if (spt == 1) { + schedule_timeout_interruptible(1); + } else if (spt == 2) { + while (READ_ONCE(stutter_pause_test)) + cond_resched(); + } else { schedule_timeout_interruptible(round_jiffies_relative(HZ)); + } torture_shutdown_absorb(title); + spt = READ_ONCE(stutter_pause_test); } } EXPORT_SYMBOL_GPL(stutter_wait); @@ -597,17 +600,15 @@ static int torture_stutter(void *arg) { VERBOSE_TOROUT_STRING("torture_stutter task started"); do { - if (!torture_must_stop()) { - if (stutter > 1) { - schedule_timeout_interruptible(stutter - 1); - WRITE_ONCE(stutter_pause_test, 2); - } - schedule_timeout_interruptible(1); + if (!torture_must_stop() && stutter > 1) { WRITE_ONCE(stutter_pause_test, 1); + schedule_timeout_interruptible(stutter - 1); + WRITE_ONCE(stutter_pause_test, 2); + schedule_timeout_interruptible(1); } + WRITE_ONCE(stutter_pause_test, 0); if (!torture_must_stop()) schedule_timeout_interruptible(stutter); - WRITE_ONCE(stutter_pause_test, 0); torture_shutdown_absorb("torture_stutter"); } while (!torture_must_stop()); torture_kthread_stopping("torture_stutter"); -- cgit v1.2.3 From a2f2577d96ad060b65eb909dd39b57d676754119 Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Tue, 21 Nov 2017 20:19:17 -0800 Subject: torture: Eliminate torture_runnable and perf_runnable The purpose of torture_runnable is to allow rcutorture and locktorture to be started and stopped via sysfs when they are built into the kernel (as in not compiled as loadable modules). However, the 0444 permissions for both instances of torture_runnable prevent this use case from ever being put into practice. Given that there have been no complaints about this deficiency, it is reasonable to conclude that no one actually makes use of this sysfs capability. The perf_runnable module parameter for rcuperf is in the same situation. This commit therefore removes both torture_runnable instances as well as perf_runnable. Reported-by: Thomas Gleixner Signed-off-by: Paul E. McKenney --- Documentation/admin-guide/kernel-parameters.txt | 9 --------- Documentation/locking/locktorture.txt | 5 ----- include/linux/torture.h | 2 +- kernel/locking/locktorture.c | 6 +----- kernel/rcu/rcuperf.c | 6 +----- kernel/rcu/rcutorture.c | 6 +----- kernel/torture.c | 6 ++---- tools/testing/selftests/rcutorture/configs/lock/ver_functions.sh | 1 - tools/testing/selftests/rcutorture/configs/rcu/ver_functions.sh | 1 - .../selftests/rcutorture/configs/rcuperf/ver_functions.sh | 1 - 10 files changed, 6 insertions(+), 37 deletions(-) (limited to 'kernel/torture.c') diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt index 6571fbfdb2a1..66d471f0b92e 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -2049,9 +2049,6 @@ This tests the locking primitive's ability to transition abruptly to and from idle. - locktorture.torture_runnable= [BOOT] - Start locktorture running at boot time. - locktorture.torture_type= [KNL] Specify the locking implementation to test. @@ -3459,9 +3456,6 @@ the same as for rcuperf.nreaders. N, where N is the number of CPUs - rcuperf.perf_runnable= [BOOT] - Start rcuperf running at boot time. - rcuperf.perf_type= [KNL] Specify the RCU implementation to test. @@ -3595,9 +3589,6 @@ Test RCU's dyntick-idle handling. See also the rcutorture.shuffle_interval parameter. - rcutorture.torture_runnable= [BOOT] - Start rcutorture running at boot time. - rcutorture.torture_type= [KNL] Specify the RCU implementation to test. diff --git a/Documentation/locking/locktorture.txt b/Documentation/locking/locktorture.txt index a2ef3a929bf1..6a8df4cd19bf 100644 --- a/Documentation/locking/locktorture.txt +++ b/Documentation/locking/locktorture.txt @@ -57,11 +57,6 @@ torture_type Type of lock to torture. By default, only spinlocks will o "rwsem_lock": read/write down() and up() semaphore pairs. -torture_runnable Start locktorture at boot time in the case where the - module is built into the kernel, otherwise wait for - torture_runnable to be set via sysfs before starting. - By default it will begin once the module is loaded. - ** Torture-framework (RCU + locking) ** diff --git a/include/linux/torture.h b/include/linux/torture.h index 907d266aaddc..66272862070b 100644 --- a/include/linux/torture.h +++ b/include/linux/torture.h @@ -79,7 +79,7 @@ void stutter_wait(const char *title); int torture_stutter_init(int s); /* Initialization and cleanup. */ -bool torture_init_begin(char *ttype, bool v, int *runnable); +bool torture_init_begin(char *ttype, bool v); void torture_init_end(void); bool torture_cleanup_begin(void); void torture_cleanup_end(void); diff --git a/kernel/locking/locktorture.c b/kernel/locking/locktorture.c index 2a1fc2a58910..6850ffd69125 100644 --- a/kernel/locking/locktorture.c +++ b/kernel/locking/locktorture.c @@ -77,10 +77,6 @@ struct lock_stress_stats { long n_lock_acquired; }; -int torture_runnable = IS_ENABLED(MODULE); -module_param(torture_runnable, int, 0444); -MODULE_PARM_DESC(torture_runnable, "Start locktorture at module init"); - /* Forward reference. */ static void lock_torture_cleanup(void); @@ -866,7 +862,7 @@ static int __init lock_torture_init(void) &percpu_rwsem_lock_ops, }; - if (!torture_init_begin(torture_type, verbose, &torture_runnable)) + if (!torture_init_begin(torture_type, verbose)) return -EBUSY; /* Process args and tell the world that the torturer is on the job. */ diff --git a/kernel/rcu/rcuperf.c b/kernel/rcu/rcuperf.c index 1f87a02c3399..d1ebdf9868bb 100644 --- a/kernel/rcu/rcuperf.c +++ b/kernel/rcu/rcuperf.c @@ -106,10 +106,6 @@ static int rcu_perf_writer_state; #define MAX_MEAS 10000 #define MIN_MEAS 100 -static int perf_runnable = IS_ENABLED(MODULE); -module_param(perf_runnable, int, 0444); -MODULE_PARM_DESC(perf_runnable, "Start rcuperf at boot"); - /* * Operations vector for selecting different types of tests. */ @@ -646,7 +642,7 @@ rcu_perf_init(void) &tasks_ops, }; - if (!torture_init_begin(perf_type, verbose, &perf_runnable)) + if (!torture_init_begin(perf_type, verbose)) return -EBUSY; /* Process args and tell the world that the perf'er is on the job. */ diff --git a/kernel/rcu/rcutorture.c b/kernel/rcu/rcutorture.c index 1074ecc3f72f..308e6fdbced8 100644 --- a/kernel/rcu/rcutorture.c +++ b/kernel/rcu/rcutorture.c @@ -187,10 +187,6 @@ static const char *rcu_torture_writer_state_getname(void) return rcu_torture_writer_state_names[i]; } -static int torture_runnable = IS_ENABLED(MODULE); -module_param(torture_runnable, int, 0444); -MODULE_PARM_DESC(torture_runnable, "Start rcutorture at boot"); - #if defined(CONFIG_RCU_BOOST) && !defined(CONFIG_HOTPLUG_CPU) #define rcu_can_boost() 1 #else /* #if defined(CONFIG_RCU_BOOST) && !defined(CONFIG_HOTPLUG_CPU) */ @@ -1729,7 +1725,7 @@ rcu_torture_init(void) &sched_ops, &tasks_ops, }; - if (!torture_init_begin(torture_type, verbose, &torture_runnable)) + if (!torture_init_begin(torture_type, verbose)) return -EBUSY; /* Process args and tell the world that the torturer is on the job. */ diff --git a/kernel/torture.c b/kernel/torture.c index 3bcbd4fbfe18..572576ad9f58 100644 --- a/kernel/torture.c +++ b/kernel/torture.c @@ -61,7 +61,6 @@ static bool verbose; #define FULLSTOP_RMMOD 2 /* Normal rmmod of torture. */ static int fullstop = FULLSTOP_RMMOD; static DEFINE_MUTEX(fullstop_mutex); -static int *torture_runnable; #ifdef CONFIG_HOTPLUG_CPU @@ -577,7 +576,7 @@ void stutter_wait(const char *title) cond_resched_rcu_qs(); spt = READ_ONCE(stutter_pause_test); - while (spt || (torture_runnable && !READ_ONCE(*torture_runnable))) { + while (spt) { if (spt == 1) { schedule_timeout_interruptible(1); } else if (spt == 2) { @@ -649,7 +648,7 @@ static void torture_stutter_cleanup(void) * The runnable parameter points to a flag that controls whether or not * the test is currently runnable. If there is no such flag, pass in NULL. */ -bool torture_init_begin(char *ttype, bool v, int *runnable) +bool torture_init_begin(char *ttype, bool v) { mutex_lock(&fullstop_mutex); if (torture_type != NULL) { @@ -661,7 +660,6 @@ bool torture_init_begin(char *ttype, bool v, int *runnable) } torture_type = ttype; verbose = v; - torture_runnable = runnable; fullstop = FULLSTOP_DONTSTOP; return true; } diff --git a/tools/testing/selftests/rcutorture/configs/lock/ver_functions.sh b/tools/testing/selftests/rcutorture/configs/lock/ver_functions.sh index 252aae618984..80eb646e1319 100644 --- a/tools/testing/selftests/rcutorture/configs/lock/ver_functions.sh +++ b/tools/testing/selftests/rcutorture/configs/lock/ver_functions.sh @@ -38,6 +38,5 @@ per_version_boot_params () { echo $1 `locktorture_param_onoff "$1" "$2"` \ locktorture.stat_interval=15 \ locktorture.shutdown_secs=$3 \ - locktorture.torture_runnable=1 \ locktorture.verbose=1 } diff --git a/tools/testing/selftests/rcutorture/configs/rcu/ver_functions.sh b/tools/testing/selftests/rcutorture/configs/rcu/ver_functions.sh index ffb85ed786fa..24ec91041957 100644 --- a/tools/testing/selftests/rcutorture/configs/rcu/ver_functions.sh +++ b/tools/testing/selftests/rcutorture/configs/rcu/ver_functions.sh @@ -51,7 +51,6 @@ per_version_boot_params () { `rcutorture_param_n_barrier_cbs "$1"` \ rcutorture.stat_interval=15 \ rcutorture.shutdown_secs=$3 \ - rcutorture.torture_runnable=1 \ rcutorture.test_no_idle_hz=1 \ rcutorture.verbose=1 } diff --git a/tools/testing/selftests/rcutorture/configs/rcuperf/ver_functions.sh b/tools/testing/selftests/rcutorture/configs/rcuperf/ver_functions.sh index 34f2a1b35ee5..b9603115d7c7 100644 --- a/tools/testing/selftests/rcutorture/configs/rcuperf/ver_functions.sh +++ b/tools/testing/selftests/rcutorture/configs/rcuperf/ver_functions.sh @@ -46,7 +46,6 @@ rcuperf_param_nwriters () { per_version_boot_params () { echo $1 `rcuperf_param_nreaders "$1"` \ `rcuperf_param_nwriters "$1"` \ - rcuperf.perf_runnable=1 \ rcuperf.shutdown=1 \ rcuperf.verbose=1 } -- cgit v1.2.3 From 29d3939084583b26a5487be64b9523e61468f1be Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Tue, 21 Nov 2017 22:07:59 -0800 Subject: torture: Save a line in stutter_wait(): while -> for Signed-off-by: Paul E. McKenney --- kernel/torture.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) (limited to 'kernel/torture.c') diff --git a/kernel/torture.c b/kernel/torture.c index 572576ad9f58..37b94012a3f8 100644 --- a/kernel/torture.c +++ b/kernel/torture.c @@ -576,7 +576,7 @@ void stutter_wait(const char *title) cond_resched_rcu_qs(); spt = READ_ONCE(stutter_pause_test); - while (spt) { + for (; spt; spt = READ_ONCE(stutter_pause_test)) { if (spt == 1) { schedule_timeout_interruptible(1); } else if (spt == 2) { @@ -586,7 +586,6 @@ void stutter_wait(const char *title) schedule_timeout_interruptible(round_jiffies_relative(HZ)); } torture_shutdown_absorb(title); - spt = READ_ONCE(stutter_pause_test); } } EXPORT_SYMBOL_GPL(stutter_wait); -- cgit v1.2.3