rcutorture: Add SRCU deadlock scenarios
In order to test the new SRCU-lockdep functionality, this commit adds an rcutorture.test_srcu_lockdep module parameter that, when non-zero, selects an SRCU deadlock scenario to execute. This parameter is a five-digit number formatted as DNNL, where "D" is 1 to force a deadlock and 0 to avoid doing so; "NN" is the test number, 0 for SRCU-based, 1 for SRCU/mutex-based, and 2 for SRCU/rwsem-based; and "L" is the number of steps in the deadlock cycle. Note that rcutorture.test_srcu_lockdep=1 will also force a hard hang. If a non-zero value of rcutorture.test_srcu_lockdep does not select a deadlock scenario, a console message is printed and testing continues. [ paulmck: Apply kernel test robot feedback, add rwsem support. ] [ paulmck: Apply Dan Carpenter feedback. ] Signed-off-by: Paul E. McKenney <paulmck@kernel.org> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Boqun Feng <boqun.feng@gmail.com>
This commit is contained in:
Paul E. McKenney
Boqun Feng
parent
0471db447c
commit
d94f12e8a4
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@ -120,6 +120,7 @@ torture_param(int, test_boost, 1, "Test RCU prio boost: 0=no, 1=maybe, 2=yes.");
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torture_param(int, test_boost_duration, 4, "Duration of each boost test, seconds.");
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torture_param(int, test_boost_interval, 7, "Interval between boost tests, seconds.");
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torture_param(bool, test_no_idle_hz, true, "Test support for tickless idle CPUs");
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torture_param(int, test_srcu_lockdep, 0, "Test specified SRCU deadlock scenario.");
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torture_param(int, verbose, 1, "Enable verbose debugging printk()s");
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static char *torture_type = "rcu";
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@ -3463,6 +3464,154 @@ static void rcutorture_sync(void)
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cur_ops->sync();
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}
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static DEFINE_MUTEX(mut0);
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static DEFINE_MUTEX(mut1);
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static DEFINE_MUTEX(mut2);
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static DEFINE_MUTEX(mut3);
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static DEFINE_MUTEX(mut4);
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static DEFINE_MUTEX(mut5);
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static DEFINE_MUTEX(mut6);
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static DEFINE_MUTEX(mut7);
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static DEFINE_MUTEX(mut8);
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static DEFINE_MUTEX(mut9);
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static DECLARE_RWSEM(rwsem0);
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static DECLARE_RWSEM(rwsem1);
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static DECLARE_RWSEM(rwsem2);
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static DECLARE_RWSEM(rwsem3);
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static DECLARE_RWSEM(rwsem4);
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static DECLARE_RWSEM(rwsem5);
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static DECLARE_RWSEM(rwsem6);
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static DECLARE_RWSEM(rwsem7);
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static DECLARE_RWSEM(rwsem8);
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static DECLARE_RWSEM(rwsem9);
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DEFINE_STATIC_SRCU(srcu0);
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DEFINE_STATIC_SRCU(srcu1);
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DEFINE_STATIC_SRCU(srcu2);
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DEFINE_STATIC_SRCU(srcu3);
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DEFINE_STATIC_SRCU(srcu4);
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DEFINE_STATIC_SRCU(srcu5);
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DEFINE_STATIC_SRCU(srcu6);
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DEFINE_STATIC_SRCU(srcu7);
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DEFINE_STATIC_SRCU(srcu8);
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DEFINE_STATIC_SRCU(srcu9);
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static int srcu_lockdep_next(const char *f, const char *fl, const char *fs, const char *fu, int i,
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int cyclelen, int deadlock)
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{
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int j = i + 1;
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if (j >= cyclelen)
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j = deadlock ? 0 : -1;
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if (j >= 0)
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pr_info("%s: %s(%d), %s(%d), %s(%d)\n", f, fl, i, fs, j, fu, i);
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else
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pr_info("%s: %s(%d), %s(%d)\n", f, fl, i, fu, i);
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return j;
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}
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// Test lockdep on SRCU-based deadlock scenarios.
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static void rcu_torture_init_srcu_lockdep(void)
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{
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int cyclelen;
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int deadlock;
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bool err = false;
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int i;
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int j;
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int idx;
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struct mutex *muts[] = { &mut0, &mut1, &mut2, &mut3, &mut4,
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&mut5, &mut6, &mut7, &mut8, &mut9 };
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struct rw_semaphore *rwsems[] = { &rwsem0, &rwsem1, &rwsem2, &rwsem3, &rwsem4,
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&rwsem5, &rwsem6, &rwsem7, &rwsem8, &rwsem9 };
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struct srcu_struct *srcus[] = { &srcu0, &srcu1, &srcu2, &srcu3, &srcu4,
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&srcu5, &srcu6, &srcu7, &srcu8, &srcu9 };
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int testtype;
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if (!test_srcu_lockdep)
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return;
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deadlock = test_srcu_lockdep / 1000;
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testtype = (test_srcu_lockdep / 10) % 100;
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cyclelen = test_srcu_lockdep % 10;
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WARN_ON_ONCE(ARRAY_SIZE(muts) != ARRAY_SIZE(srcus));
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if (WARN_ONCE(deadlock != !!deadlock,
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"%s: test_srcu_lockdep=%d and deadlock digit %d must be zero or one.\n",
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__func__, test_srcu_lockdep, deadlock))
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err = true;
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if (WARN_ONCE(cyclelen <= 0,
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"%s: test_srcu_lockdep=%d and cycle-length digit %d must be greater than zero.\n",
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__func__, test_srcu_lockdep, cyclelen))
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err = true;
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if (err)
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goto err_out;
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if (testtype == 0) {
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pr_info("%s: test_srcu_lockdep = %05d: SRCU %d-way %sdeadlock.\n",
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__func__, test_srcu_lockdep, cyclelen, deadlock ? "" : "non-");
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if (deadlock && cyclelen == 1)
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pr_info("%s: Expect hang.\n", __func__);
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for (i = 0; i < cyclelen; i++) {
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j = srcu_lockdep_next(__func__, "srcu_read_lock", "synchronize_srcu",
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"srcu_read_unlock", i, cyclelen, deadlock);
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idx = srcu_read_lock(srcus[i]);
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if (j >= 0)
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synchronize_srcu(srcus[j]);
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srcu_read_unlock(srcus[i], idx);
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}
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return;
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}
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if (testtype == 1) {
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pr_info("%s: test_srcu_lockdep = %05d: SRCU/mutex %d-way %sdeadlock.\n",
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__func__, test_srcu_lockdep, cyclelen, deadlock ? "" : "non-");
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for (i = 0; i < cyclelen; i++) {
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pr_info("%s: srcu_read_lock(%d), mutex_lock(%d), mutex_unlock(%d), srcu_read_unlock(%d)\n",
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__func__, i, i, i, i);
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idx = srcu_read_lock(srcus[i]);
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mutex_lock(muts[i]);
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mutex_unlock(muts[i]);
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srcu_read_unlock(srcus[i], idx);
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j = srcu_lockdep_next(__func__, "mutex_lock", "synchronize_srcu",
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"mutex_unlock", i, cyclelen, deadlock);
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mutex_lock(muts[i]);
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if (j >= 0)
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synchronize_srcu(srcus[j]);
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mutex_unlock(muts[i]);
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}
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return;
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}
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if (testtype == 2) {
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pr_info("%s: test_srcu_lockdep = %05d: SRCU/rwsem %d-way %sdeadlock.\n",
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__func__, test_srcu_lockdep, cyclelen, deadlock ? "" : "non-");
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for (i = 0; i < cyclelen; i++) {
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pr_info("%s: srcu_read_lock(%d), down_read(%d), up_read(%d), srcu_read_unlock(%d)\n",
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__func__, i, i, i, i);
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idx = srcu_read_lock(srcus[i]);
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down_read(rwsems[i]);
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up_read(rwsems[i]);
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srcu_read_unlock(srcus[i], idx);
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j = srcu_lockdep_next(__func__, "down_write", "synchronize_srcu",
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"up_write", i, cyclelen, deadlock);
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down_write(rwsems[i]);
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if (j >= 0)
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synchronize_srcu(srcus[j]);
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up_write(rwsems[i]);
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}
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return;
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}
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err_out:
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pr_info("%s: test_srcu_lockdep = %05d does nothing.\n", __func__, test_srcu_lockdep);
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pr_info("%s: test_srcu_lockdep = DNNL.\n", __func__);
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pr_info("%s: D: Deadlock if nonzero.\n", __func__);
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pr_info("%s: NN: Test number, 0=SRCU, 1=SRCU/mutex, 2=SRCU/rwsem.\n", __func__);
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pr_info("%s: L: Cycle length.\n", __func__);
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}
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static int __init
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rcu_torture_init(void)
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{
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@ -3504,6 +3653,8 @@ rcu_torture_init(void)
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if (cur_ops->init)
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cur_ops->init();
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rcu_torture_init_srcu_lockdep();
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if (nreaders >= 0) {
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nrealreaders = nreaders;
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} else {
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