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authorLinus Torvalds <torvalds@linux-foundation.org>2021-02-21 21:12:01 +0100
committerLinus Torvalds <torvalds@linux-foundation.org>2021-02-21 21:12:01 +0100
commit9eef02334505411667a7b51a8f349f8c6c4f3b66 (patch)
tree3a0c8fb85d76595b2f9468d3e31f41147a43ed55 /lib
parentMerge tag 'core-rcu-2021-02-17' of git://git.kernel.org/pub/scm/linux/kernel/... (diff)
parentMerge branch 'for-mingo-lkmm' of git://git.kernel.org/pub/scm/linux/kernel/gi... (diff)
downloadlinux-9eef02334505411667a7b51a8f349f8c6c4f3b66.tar.xz
linux-9eef02334505411667a7b51a8f349f8c6c4f3b66.zip
Merge tag 'locking-core-2021-02-17' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull locking updates from Ingo Molnar: "Core locking primitives updates: - Remove mutex_trylock_recursive() from the API - no users left - Simplify + constify the futex code a bit Lockdep updates: - Teach lockdep about local_lock_t - Add CONFIG_DEBUG_IRQFLAGS=y debug config option to check for potentially unsafe IRQ mask restoration patterns. (I.e. calling raw_local_irq_restore() with IRQs enabled.) - Add wait context self-tests - Fix graph lock corner case corrupting internal data structures - Fix noinstr annotations LKMM updates: - Simplify the litmus tests - Documentation fixes KCSAN updates: - Re-enable KCSAN instrumentation in lib/random32.c Misc fixes: - Don't branch-trace static label APIs - DocBook fix - Remove stale leftover empty file" * tag 'locking-core-2021-02-17' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (24 commits) checkpatch: Don't check for mutex_trylock_recursive() locking/mutex: Kill mutex_trylock_recursive() s390: Use arch_local_irq_{save,restore}() in early boot code lockdep: Noinstr annotate warn_bogus_irq_restore() locking/lockdep: Avoid unmatched unlock locking/rwsem: Remove empty rwsem.h locking/rtmutex: Add missing kernel-doc markup futex: Remove unneeded gotos futex: Change utime parameter to be 'const ... *' lockdep: report broken irq restoration jump_label: Do not profile branch annotations locking: Add Reviewers locking/selftests: Add local_lock inversion tests locking/lockdep: Exclude local_lock_t from IRQ inversions locking/lockdep: Clean up check_redundant() a bit locking/lockdep: Add a skip() function to __bfs() locking/lockdep: Mark local_lock_t locking/selftests: More granular debug_locks_verbose lockdep/selftest: Add wait context selftests tools/memory-model: Fix typo in klitmus7 compatibility table ...
Diffstat (limited to 'lib')
-rw-r--r--lib/Kconfig.debug8
-rw-r--r--lib/Makefile3
-rw-r--r--lib/locking-selftest.c334
3 files changed, 340 insertions, 5 deletions
diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index 7937265ef879..5ea0c1773b0a 100644
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -1335,6 +1335,7 @@ config LOCKDEP_SMALL
config DEBUG_LOCKDEP
bool "Lock dependency engine debugging"
depends on DEBUG_KERNEL && LOCKDEP
+ select DEBUG_IRQFLAGS
help
If you say Y here, the lock dependency engine will do
additional runtime checks to debug itself, at the price
@@ -1423,6 +1424,13 @@ config TRACE_IRQFLAGS_NMI
depends on TRACE_IRQFLAGS
depends on TRACE_IRQFLAGS_NMI_SUPPORT
+config DEBUG_IRQFLAGS
+ bool "Debug IRQ flag manipulation"
+ help
+ Enables checks for potentially unsafe enabling or disabling of
+ interrupts, such as calling raw_local_irq_restore() when interrupts
+ are enabled.
+
config STACKTRACE
bool "Stack backtrace support"
depends on STACKTRACE_SUPPORT
diff --git a/lib/Makefile b/lib/Makefile
index a6b160c3a4fa..fb7d946bb8c3 100644
--- a/lib/Makefile
+++ b/lib/Makefile
@@ -27,9 +27,6 @@ KASAN_SANITIZE_string.o := n
CFLAGS_string.o += -fno-stack-protector
endif
-# Used by KCSAN while enabled, avoid recursion.
-KCSAN_SANITIZE_random32.o := n
-
lib-y := ctype.o string.o vsprintf.o cmdline.o \
rbtree.o radix-tree.o timerqueue.o xarray.o \
idr.o extable.o sha1.o irq_regs.o argv_split.o \
diff --git a/lib/locking-selftest.c b/lib/locking-selftest.c
index 9959ea23529e..2d85abac1744 100644
--- a/lib/locking-selftest.c
+++ b/lib/locking-selftest.c
@@ -24,6 +24,7 @@
#include <linux/debug_locks.h>
#include <linux/irqflags.h>
#include <linux/rtmutex.h>
+#include <linux/local_lock.h>
/*
* Change this to 1 if you want to see the failure printouts:
@@ -51,6 +52,7 @@ __setup("debug_locks_verbose=", setup_debug_locks_verbose);
#define LOCKTYPE_RWSEM 0x8
#define LOCKTYPE_WW 0x10
#define LOCKTYPE_RTMUTEX 0x20
+#define LOCKTYPE_LL 0x40
static struct ww_acquire_ctx t, t2;
static struct ww_mutex o, o2, o3;
@@ -64,6 +66,9 @@ static DEFINE_SPINLOCK(lock_B);
static DEFINE_SPINLOCK(lock_C);
static DEFINE_SPINLOCK(lock_D);
+static DEFINE_RAW_SPINLOCK(raw_lock_A);
+static DEFINE_RAW_SPINLOCK(raw_lock_B);
+
static DEFINE_RWLOCK(rwlock_A);
static DEFINE_RWLOCK(rwlock_B);
static DEFINE_RWLOCK(rwlock_C);
@@ -133,6 +138,8 @@ static DEFINE_RT_MUTEX(rtmutex_Z2);
#endif
+static local_lock_t local_A = INIT_LOCAL_LOCK(local_A);
+
/*
* non-inlined runtime initializers, to let separate locks share
* the same lock-class:
@@ -1306,19 +1313,23 @@ GENERATE_PERMUTATIONS_3_EVENTS(irq_read_recursion3_soft_wlock)
#ifdef CONFIG_DEBUG_LOCK_ALLOC
# define I_SPINLOCK(x) lockdep_reset_lock(&lock_##x.dep_map)
+# define I_RAW_SPINLOCK(x) lockdep_reset_lock(&raw_lock_##x.dep_map)
# define I_RWLOCK(x) lockdep_reset_lock(&rwlock_##x.dep_map)
# define I_MUTEX(x) lockdep_reset_lock(&mutex_##x.dep_map)
# define I_RWSEM(x) lockdep_reset_lock(&rwsem_##x.dep_map)
# define I_WW(x) lockdep_reset_lock(&x.dep_map)
+# define I_LOCAL_LOCK(x) lockdep_reset_lock(&local_##x.dep_map)
#ifdef CONFIG_RT_MUTEXES
# define I_RTMUTEX(x) lockdep_reset_lock(&rtmutex_##x.dep_map)
#endif
#else
# define I_SPINLOCK(x)
+# define I_RAW_SPINLOCK(x)
# define I_RWLOCK(x)
# define I_MUTEX(x)
# define I_RWSEM(x)
# define I_WW(x)
+# define I_LOCAL_LOCK(x)
#endif
#ifndef I_RTMUTEX
@@ -1358,9 +1369,16 @@ static void reset_locks(void)
I1(A); I1(B); I1(C); I1(D);
I1(X1); I1(X2); I1(Y1); I1(Y2); I1(Z1); I1(Z2);
I_WW(t); I_WW(t2); I_WW(o.base); I_WW(o2.base); I_WW(o3.base);
+ I_RAW_SPINLOCK(A); I_RAW_SPINLOCK(B);
+ I_LOCAL_LOCK(A);
+
lockdep_reset();
+
I2(A); I2(B); I2(C); I2(D);
init_shared_classes();
+ raw_spin_lock_init(&raw_lock_A);
+ raw_spin_lock_init(&raw_lock_B);
+ local_lock_init(&local_A);
ww_mutex_init(&o, &ww_lockdep); ww_mutex_init(&o2, &ww_lockdep); ww_mutex_init(&o3, &ww_lockdep);
memset(&t, 0, sizeof(t)); memset(&t2, 0, sizeof(t2));
@@ -1382,6 +1400,8 @@ static void dotest(void (*testcase_fn)(void), int expected, int lockclass_mask)
WARN_ON(irqs_disabled());
+ debug_locks_silent = !(debug_locks_verbose & lockclass_mask);
+
testcase_fn();
/*
* Filter out expected failures:
@@ -1402,7 +1422,7 @@ static void dotest(void (*testcase_fn)(void), int expected, int lockclass_mask)
}
testcase_total++;
- if (debug_locks_verbose)
+ if (debug_locks_verbose & lockclass_mask)
pr_cont(" lockclass mask: %x, debug_locks: %d, expected: %d\n",
lockclass_mask, debug_locks, expected);
/*
@@ -2419,6 +2439,311 @@ static void fs_reclaim_tests(void)
pr_cont("\n");
}
+#define __guard(cleanup) __maybe_unused __attribute__((__cleanup__(cleanup)))
+
+static void hardirq_exit(int *_)
+{
+ HARDIRQ_EXIT();
+}
+
+#define HARDIRQ_CONTEXT(name, ...) \
+ int hardirq_guard_##name __guard(hardirq_exit); \
+ HARDIRQ_ENTER();
+
+#define NOTTHREADED_HARDIRQ_CONTEXT(name, ...) \
+ int notthreaded_hardirq_guard_##name __guard(hardirq_exit); \
+ local_irq_disable(); \
+ __irq_enter(); \
+ WARN_ON(!in_irq());
+
+static void softirq_exit(int *_)
+{
+ SOFTIRQ_EXIT();
+}
+
+#define SOFTIRQ_CONTEXT(name, ...) \
+ int softirq_guard_##name __guard(softirq_exit); \
+ SOFTIRQ_ENTER();
+
+static void rcu_exit(int *_)
+{
+ rcu_read_unlock();
+}
+
+#define RCU_CONTEXT(name, ...) \
+ int rcu_guard_##name __guard(rcu_exit); \
+ rcu_read_lock();
+
+static void rcu_bh_exit(int *_)
+{
+ rcu_read_unlock_bh();
+}
+
+#define RCU_BH_CONTEXT(name, ...) \
+ int rcu_bh_guard_##name __guard(rcu_bh_exit); \
+ rcu_read_lock_bh();
+
+static void rcu_sched_exit(int *_)
+{
+ rcu_read_unlock_sched();
+}
+
+#define RCU_SCHED_CONTEXT(name, ...) \
+ int rcu_sched_guard_##name __guard(rcu_sched_exit); \
+ rcu_read_lock_sched();
+
+static void rcu_callback_exit(int *_)
+{
+ rcu_lock_release(&rcu_callback_map);
+}
+
+#define RCU_CALLBACK_CONTEXT(name, ...) \
+ int rcu_callback_guard_##name __guard(rcu_callback_exit); \
+ rcu_lock_acquire(&rcu_callback_map);
+
+
+static void raw_spinlock_exit(raw_spinlock_t **lock)
+{
+ raw_spin_unlock(*lock);
+}
+
+#define RAW_SPINLOCK_CONTEXT(name, lock) \
+ raw_spinlock_t *raw_spinlock_guard_##name __guard(raw_spinlock_exit) = &(lock); \
+ raw_spin_lock(&(lock));
+
+static void spinlock_exit(spinlock_t **lock)
+{
+ spin_unlock(*lock);
+}
+
+#define SPINLOCK_CONTEXT(name, lock) \
+ spinlock_t *spinlock_guard_##name __guard(spinlock_exit) = &(lock); \
+ spin_lock(&(lock));
+
+static void mutex_exit(struct mutex **lock)
+{
+ mutex_unlock(*lock);
+}
+
+#define MUTEX_CONTEXT(name, lock) \
+ struct mutex *mutex_guard_##name __guard(mutex_exit) = &(lock); \
+ mutex_lock(&(lock));
+
+#define GENERATE_2_CONTEXT_TESTCASE(outer, outer_lock, inner, inner_lock) \
+ \
+static void __maybe_unused inner##_in_##outer(void) \
+{ \
+ outer##_CONTEXT(_, outer_lock); \
+ { \
+ inner##_CONTEXT(_, inner_lock); \
+ } \
+}
+
+/*
+ * wait contexts (considering PREEMPT_RT)
+ *
+ * o: inner is allowed in outer
+ * x: inner is disallowed in outer
+ *
+ * \ inner | RCU | RAW_SPIN | SPIN | MUTEX
+ * outer \ | | | |
+ * ---------------+-------+----------+------+-------
+ * HARDIRQ | o | o | o | x
+ * ---------------+-------+----------+------+-------
+ * NOTTHREADED_IRQ| o | o | x | x
+ * ---------------+-------+----------+------+-------
+ * SOFTIRQ | o | o | o | x
+ * ---------------+-------+----------+------+-------
+ * RCU | o | o | o | x
+ * ---------------+-------+----------+------+-------
+ * RCU_BH | o | o | o | x
+ * ---------------+-------+----------+------+-------
+ * RCU_CALLBACK | o | o | o | x
+ * ---------------+-------+----------+------+-------
+ * RCU_SCHED | o | o | x | x
+ * ---------------+-------+----------+------+-------
+ * RAW_SPIN | o | o | x | x
+ * ---------------+-------+----------+------+-------
+ * SPIN | o | o | o | x
+ * ---------------+-------+----------+------+-------
+ * MUTEX | o | o | o | o
+ * ---------------+-------+----------+------+-------
+ */
+
+#define GENERATE_2_CONTEXT_TESTCASE_FOR_ALL_OUTER(inner, inner_lock) \
+GENERATE_2_CONTEXT_TESTCASE(HARDIRQ, , inner, inner_lock) \
+GENERATE_2_CONTEXT_TESTCASE(NOTTHREADED_HARDIRQ, , inner, inner_lock) \
+GENERATE_2_CONTEXT_TESTCASE(SOFTIRQ, , inner, inner_lock) \
+GENERATE_2_CONTEXT_TESTCASE(RCU, , inner, inner_lock) \
+GENERATE_2_CONTEXT_TESTCASE(RCU_BH, , inner, inner_lock) \
+GENERATE_2_CONTEXT_TESTCASE(RCU_CALLBACK, , inner, inner_lock) \
+GENERATE_2_CONTEXT_TESTCASE(RCU_SCHED, , inner, inner_lock) \
+GENERATE_2_CONTEXT_TESTCASE(RAW_SPINLOCK, raw_lock_A, inner, inner_lock) \
+GENERATE_2_CONTEXT_TESTCASE(SPINLOCK, lock_A, inner, inner_lock) \
+GENERATE_2_CONTEXT_TESTCASE(MUTEX, mutex_A, inner, inner_lock)
+
+GENERATE_2_CONTEXT_TESTCASE_FOR_ALL_OUTER(RCU, )
+GENERATE_2_CONTEXT_TESTCASE_FOR_ALL_OUTER(RAW_SPINLOCK, raw_lock_B)
+GENERATE_2_CONTEXT_TESTCASE_FOR_ALL_OUTER(SPINLOCK, lock_B)
+GENERATE_2_CONTEXT_TESTCASE_FOR_ALL_OUTER(MUTEX, mutex_B)
+
+/* the outer context allows all kinds of preemption */
+#define DO_CONTEXT_TESTCASE_OUTER_PREEMPTIBLE(outer) \
+ dotest(RCU_in_##outer, SUCCESS, LOCKTYPE_RWLOCK); \
+ dotest(RAW_SPINLOCK_in_##outer, SUCCESS, LOCKTYPE_SPIN); \
+ dotest(SPINLOCK_in_##outer, SUCCESS, LOCKTYPE_SPIN); \
+ dotest(MUTEX_in_##outer, SUCCESS, LOCKTYPE_MUTEX); \
+
+/*
+ * the outer context only allows the preemption introduced by spinlock_t (which
+ * is a sleepable lock for PREEMPT_RT)
+ */
+#define DO_CONTEXT_TESTCASE_OUTER_LIMITED_PREEMPTIBLE(outer) \
+ dotest(RCU_in_##outer, SUCCESS, LOCKTYPE_RWLOCK); \
+ dotest(RAW_SPINLOCK_in_##outer, SUCCESS, LOCKTYPE_SPIN); \
+ dotest(SPINLOCK_in_##outer, SUCCESS, LOCKTYPE_SPIN); \
+ dotest(MUTEX_in_##outer, FAILURE, LOCKTYPE_MUTEX); \
+
+/* the outer doesn't allows any kind of preemption */
+#define DO_CONTEXT_TESTCASE_OUTER_NOT_PREEMPTIBLE(outer) \
+ dotest(RCU_in_##outer, SUCCESS, LOCKTYPE_RWLOCK); \
+ dotest(RAW_SPINLOCK_in_##outer, SUCCESS, LOCKTYPE_SPIN); \
+ dotest(SPINLOCK_in_##outer, FAILURE, LOCKTYPE_SPIN); \
+ dotest(MUTEX_in_##outer, FAILURE, LOCKTYPE_MUTEX); \
+
+static void wait_context_tests(void)
+{
+ printk(" --------------------------------------------------------------------------\n");
+ printk(" | wait context tests |\n");
+ printk(" --------------------------------------------------------------------------\n");
+ printk(" | rcu | raw | spin |mutex |\n");
+ printk(" --------------------------------------------------------------------------\n");
+ print_testname("in hardirq context");
+ DO_CONTEXT_TESTCASE_OUTER_LIMITED_PREEMPTIBLE(HARDIRQ);
+ pr_cont("\n");
+
+ print_testname("in hardirq context (not threaded)");
+ DO_CONTEXT_TESTCASE_OUTER_NOT_PREEMPTIBLE(NOTTHREADED_HARDIRQ);
+ pr_cont("\n");
+
+ print_testname("in softirq context");
+ DO_CONTEXT_TESTCASE_OUTER_LIMITED_PREEMPTIBLE(SOFTIRQ);
+ pr_cont("\n");
+
+ print_testname("in RCU context");
+ DO_CONTEXT_TESTCASE_OUTER_LIMITED_PREEMPTIBLE(RCU);
+ pr_cont("\n");
+
+ print_testname("in RCU-bh context");
+ DO_CONTEXT_TESTCASE_OUTER_LIMITED_PREEMPTIBLE(RCU_BH);
+ pr_cont("\n");
+
+ print_testname("in RCU callback context");
+ DO_CONTEXT_TESTCASE_OUTER_LIMITED_PREEMPTIBLE(RCU_CALLBACK);
+ pr_cont("\n");
+
+ print_testname("in RCU-sched context");
+ DO_CONTEXT_TESTCASE_OUTER_NOT_PREEMPTIBLE(RCU_SCHED);
+ pr_cont("\n");
+
+ print_testname("in RAW_SPINLOCK context");
+ DO_CONTEXT_TESTCASE_OUTER_NOT_PREEMPTIBLE(RAW_SPINLOCK);
+ pr_cont("\n");
+
+ print_testname("in SPINLOCK context");
+ DO_CONTEXT_TESTCASE_OUTER_LIMITED_PREEMPTIBLE(SPINLOCK);
+ pr_cont("\n");
+
+ print_testname("in MUTEX context");
+ DO_CONTEXT_TESTCASE_OUTER_PREEMPTIBLE(MUTEX);
+ pr_cont("\n");
+}
+
+static void local_lock_2(void)
+{
+ local_lock_acquire(&local_A); /* IRQ-ON */
+ local_lock_release(&local_A);
+
+ HARDIRQ_ENTER();
+ spin_lock(&lock_A); /* IN-IRQ */
+ spin_unlock(&lock_A);
+ HARDIRQ_EXIT()
+
+ HARDIRQ_DISABLE();
+ spin_lock(&lock_A);
+ local_lock_acquire(&local_A); /* IN-IRQ <-> IRQ-ON cycle, false */
+ local_lock_release(&local_A);
+ spin_unlock(&lock_A);
+ HARDIRQ_ENABLE();
+}
+
+static void local_lock_3A(void)
+{
+ local_lock_acquire(&local_A); /* IRQ-ON */
+ spin_lock(&lock_B); /* IRQ-ON */
+ spin_unlock(&lock_B);
+ local_lock_release(&local_A);
+
+ HARDIRQ_ENTER();
+ spin_lock(&lock_A); /* IN-IRQ */
+ spin_unlock(&lock_A);
+ HARDIRQ_EXIT()
+
+ HARDIRQ_DISABLE();
+ spin_lock(&lock_A);
+ local_lock_acquire(&local_A); /* IN-IRQ <-> IRQ-ON cycle only if we count local_lock(), false */
+ local_lock_release(&local_A);
+ spin_unlock(&lock_A);
+ HARDIRQ_ENABLE();
+}
+
+static void local_lock_3B(void)
+{
+ local_lock_acquire(&local_A); /* IRQ-ON */
+ spin_lock(&lock_B); /* IRQ-ON */
+ spin_unlock(&lock_B);
+ local_lock_release(&local_A);
+
+ HARDIRQ_ENTER();
+ spin_lock(&lock_A); /* IN-IRQ */
+ spin_unlock(&lock_A);
+ HARDIRQ_EXIT()
+
+ HARDIRQ_DISABLE();
+ spin_lock(&lock_A);
+ local_lock_acquire(&local_A); /* IN-IRQ <-> IRQ-ON cycle only if we count local_lock(), false */
+ local_lock_release(&local_A);
+ spin_unlock(&lock_A);
+ HARDIRQ_ENABLE();
+
+ HARDIRQ_DISABLE();
+ spin_lock(&lock_A);
+ spin_lock(&lock_B); /* IN-IRQ <-> IRQ-ON cycle, true */
+ spin_unlock(&lock_B);
+ spin_unlock(&lock_A);
+ HARDIRQ_DISABLE();
+
+}
+
+static void local_lock_tests(void)
+{
+ printk(" --------------------------------------------------------------------------\n");
+ printk(" | local_lock tests |\n");
+ printk(" ---------------------\n");
+
+ print_testname("local_lock inversion 2");
+ dotest(local_lock_2, SUCCESS, LOCKTYPE_LL);
+ pr_cont("\n");
+
+ print_testname("local_lock inversion 3A");
+ dotest(local_lock_3A, SUCCESS, LOCKTYPE_LL);
+ pr_cont("\n");
+
+ print_testname("local_lock inversion 3B");
+ dotest(local_lock_3B, FAILURE, LOCKTYPE_LL);
+ pr_cont("\n");
+}
+
void locking_selftest(void)
{
/*
@@ -2446,7 +2771,6 @@ void locking_selftest(void)
printk(" --------------------------------------------------------------------------\n");
init_shared_classes();
- debug_locks_silent = !debug_locks_verbose;
lockdep_set_selftest_task(current);
DO_TESTCASE_6R("A-A deadlock", AA);
@@ -2542,6 +2866,12 @@ void locking_selftest(void)
fs_reclaim_tests();
+ /* Wait context test cases that are specific for RAW_LOCK_NESTING */
+ if (IS_ENABLED(CONFIG_PROVE_RAW_LOCK_NESTING))
+ wait_context_tests();
+
+ local_lock_tests();
+
if (unexpected_testcase_failures) {
printk("-----------------------------------------------------------------\n");
debug_locks = 0;