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kernel_optimize_test/lib/locking-selftest.c
Ingo Molnar fbb9ce9530 [PATCH] lockdep: core 
Do 'make oldconfig' and accept all the defaults for new config options -
reboot into the kernel and if everything goes well it should boot up fine and
you should have /proc/lockdep and /proc/lockdep_stats files.

Typically if the lock validator finds some problem it will print out
voluminous debug output that begins with "BUG: ..." and which syslog output
can be used by kernel developers to figure out the precise locking scenario.

What does the lock validator do?  It "observes" and maps all locking rules as
they occur dynamically (as triggered by the kernel's natural use of spinlocks,
rwlocks, mutexes and rwsems).  Whenever the lock validator subsystem detects a
new locking scenario, it validates this new rule against the existing set of
rules.  If this new rule is consistent with the existing set of rules then the
new rule is added transparently and the kernel continues as normal.  If the
new rule could create a deadlock scenario then this condition is printed out.

When determining validity of locking, all possible "deadlock scenarios" are
considered: assuming arbitrary number of CPUs, arbitrary irq context and task
context constellations, running arbitrary combinations of all the existing
locking scenarios.  In a typical system this means millions of separate
scenarios.  This is why we call it a "locking correctness" validator - for all
rules that are observed the lock validator proves it with mathematical
certainty that a deadlock could not occur (assuming that the lock validator
implementation itself is correct and its internal data structures are not
corrupted by some other kernel subsystem).  [see more details and conditionals
of this statement in include/linux/lockdep.h and
Documentation/lockdep-design.txt]

Furthermore, this "all possible scenarios" property of the validator also
enables the finding of complex, highly unlikely multi-CPU multi-context races
via single single-context rules, increasing the likelyhood of finding bugs
drastically.  In practical terms: the lock validator already found a bug in
the upstream kernel that could only occur on systems with 3 or more CPUs, and
which needed 3 very unlikely code sequences to occur at once on the 3 CPUs.
That bug was found and reported on a single-CPU system (!).  So in essence a
race will be found "piecemail-wise", triggering all the necessary components
for the race, without having to reproduce the race scenario itself!  In its
short existence the lock validator found and reported many bugs before they
actually caused a real deadlock.

To further increase the efficiency of the validator, the mapping is not per
"lock instance", but per "lock-class".  For example, all struct inode objects
in the kernel have inode->inotify_mutex.  If there are 10,000 inodes cached,
then there are 10,000 lock objects.  But ->inotify_mutex is a single "lock
type", and all locking activities that occur against ->inotify_mutex are
"unified" into this single lock-class.  The advantage of the lock-class
approach is that all historical ->inotify_mutex uses are mapped into a single
(and as narrow as possible) set of locking rules - regardless of how many
different tasks or inode structures it took to build this set of rules.  The
set of rules persist during the lifetime of the kernel.

To see the rough magnitude of checking that the lock validator does, here's a
portion of /proc/lockdep_stats, fresh after bootup:

 lock-classes:                            694 [max: 2048]
 direct dependencies:                  1598 [max: 8192]
 indirect dependencies:               17896
 all direct dependencies:             16206
 dependency chains:                    1910 [max: 8192]
 in-hardirq chains:                      17
 in-softirq chains:                     105
 in-process chains:                    1065
 stack-trace entries:                 38761 [max: 131072]
 combined max dependencies:         2033928
 hardirq-safe locks:                     24
 hardirq-unsafe locks:                  176
 softirq-safe locks:                     53
 softirq-unsafe locks:                  137
 irq-safe locks:                         59
 irq-unsafe locks:                      176

The lock validator has observed 1598 actual single-thread locking patterns,
and has validated all possible 2033928 distinct locking scenarios.

More details about the design of the lock validator can be found in
Documentation/lockdep-design.txt, which can also found at:

   http://redhat.com/~mingo/lockdep-patches/lockdep-design.txt

[bunk@stusta.de: cleanups]
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
Signed-off-by: Adrian Bunk <bunk@stusta.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-07-03 15:27:03 -07:00

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/*
* lib/locking-selftest.c
*
* Testsuite for various locking APIs: spinlocks, rwlocks,
* mutexes and rw-semaphores.
*
* It is checking both false positives and false negatives.
*
* Started by Ingo Molnar:
*
* Copyright (C) 2006 Red Hat, Inc., Ingo Molnar <mingo@redhat.com>
*/
#include <linux/rwsem.h>
#include <linux/mutex.h>
#include <linux/sched.h>
#include <linux/delay.h>
#include <linux/module.h>
#include <linux/lockdep.h>
#include <linux/spinlock.h>
#include <linux/kallsyms.h>
#include <linux/interrupt.h>
#include <linux/debug_locks.h>
#include <linux/irqflags.h>
/*
* Change this to 1 if you want to see the failure printouts:
*/
static unsigned int debug_locks_verbose;
static int __init setup_debug_locks_verbose(char *str)
{
get_option(&str, &debug_locks_verbose);
return 1;
}
__setup("debug_locks_verbose=", setup_debug_locks_verbose);
#define FAILURE 0
#define SUCCESS 1
#define LOCKTYPE_SPIN 0x1
#define LOCKTYPE_RWLOCK 0x2
#define LOCKTYPE_MUTEX 0x4
#define LOCKTYPE_RWSEM 0x8
/*
* Normal standalone locks, for the circular and irq-context
* dependency tests:
*/
static DEFINE_SPINLOCK(lock_A);
static DEFINE_SPINLOCK(lock_B);
static DEFINE_SPINLOCK(lock_C);
static DEFINE_SPINLOCK(lock_D);
static DEFINE_RWLOCK(rwlock_A);
static DEFINE_RWLOCK(rwlock_B);
static DEFINE_RWLOCK(rwlock_C);
static DEFINE_RWLOCK(rwlock_D);
static DEFINE_MUTEX(mutex_A);
static DEFINE_MUTEX(mutex_B);
static DEFINE_MUTEX(mutex_C);
static DEFINE_MUTEX(mutex_D);
static DECLARE_RWSEM(rwsem_A);
static DECLARE_RWSEM(rwsem_B);
static DECLARE_RWSEM(rwsem_C);
static DECLARE_RWSEM(rwsem_D);
/*
* Locks that we initialize dynamically as well so that
* e.g. X1 and X2 becomes two instances of the same class,
* but X* and Y* are different classes. We do this so that
* we do not trigger a real lockup:
*/
static DEFINE_SPINLOCK(lock_X1);
static DEFINE_SPINLOCK(lock_X2);
static DEFINE_SPINLOCK(lock_Y1);
static DEFINE_SPINLOCK(lock_Y2);
static DEFINE_SPINLOCK(lock_Z1);
static DEFINE_SPINLOCK(lock_Z2);
static DEFINE_RWLOCK(rwlock_X1);
static DEFINE_RWLOCK(rwlock_X2);
static DEFINE_RWLOCK(rwlock_Y1);
static DEFINE_RWLOCK(rwlock_Y2);
static DEFINE_RWLOCK(rwlock_Z1);
static DEFINE_RWLOCK(rwlock_Z2);
static DEFINE_MUTEX(mutex_X1);
static DEFINE_MUTEX(mutex_X2);
static DEFINE_MUTEX(mutex_Y1);
static DEFINE_MUTEX(mutex_Y2);
static DEFINE_MUTEX(mutex_Z1);
static DEFINE_MUTEX(mutex_Z2);
static DECLARE_RWSEM(rwsem_X1);
static DECLARE_RWSEM(rwsem_X2);
static DECLARE_RWSEM(rwsem_Y1);
static DECLARE_RWSEM(rwsem_Y2);
static DECLARE_RWSEM(rwsem_Z1);
static DECLARE_RWSEM(rwsem_Z2);
/*
* non-inlined runtime initializers, to let separate locks share
* the same lock-class:
*/
#define INIT_CLASS_FUNC(class) \
static noinline void \
init_class_##class(spinlock_t *lock, rwlock_t *rwlock, struct mutex *mutex, \
struct rw_semaphore *rwsem) \
{ \
spin_lock_init(lock); \
rwlock_init(rwlock); \
mutex_init(mutex); \
init_rwsem(rwsem); \
}
INIT_CLASS_FUNC(X)
INIT_CLASS_FUNC(Y)
INIT_CLASS_FUNC(Z)
static void init_shared_classes(void)
{
init_class_X(&lock_X1, &rwlock_X1, &mutex_X1, &rwsem_X1);
init_class_X(&lock_X2, &rwlock_X2, &mutex_X2, &rwsem_X2);
init_class_Y(&lock_Y1, &rwlock_Y1, &mutex_Y1, &rwsem_Y1);
init_class_Y(&lock_Y2, &rwlock_Y2, &mutex_Y2, &rwsem_Y2);
init_class_Z(&lock_Z1, &rwlock_Z1, &mutex_Z1, &rwsem_Z1);
init_class_Z(&lock_Z2, &rwlock_Z2, &mutex_Z2, &rwsem_Z2);
}
/*
* For spinlocks and rwlocks we also do hardirq-safe / softirq-safe tests.
* The following functions use a lock from a simulated hardirq/softirq
* context, causing the locks to be marked as hardirq-safe/softirq-safe:
*/
#define HARDIRQ_DISABLE local_irq_disable
#define HARDIRQ_ENABLE local_irq_enable
#define HARDIRQ_ENTER() \
local_irq_disable(); \
irq_enter(); \
WARN_ON(!in_irq());
#define HARDIRQ_EXIT() \
__irq_exit(); \
local_irq_enable();
#define SOFTIRQ_DISABLE local_bh_disable
#define SOFTIRQ_ENABLE local_bh_enable
#define SOFTIRQ_ENTER() \
local_bh_disable(); \
local_irq_disable(); \
trace_softirq_enter(); \
WARN_ON(!in_softirq());
#define SOFTIRQ_EXIT() \
trace_softirq_exit(); \
local_irq_enable(); \
local_bh_enable();
/*
* Shortcuts for lock/unlock API variants, to keep
* the testcases compact:
*/
#define L(x) spin_lock(&lock_##x)
#define U(x) spin_unlock(&lock_##x)
#define LU(x) L(x); U(x)
#define SI(x) spin_lock_init(&lock_##x)
#define WL(x) write_lock(&rwlock_##x)
#define WU(x) write_unlock(&rwlock_##x)
#define WLU(x) WL(x); WU(x)
#define RL(x) read_lock(&rwlock_##x)
#define RU(x) read_unlock(&rwlock_##x)
#define RLU(x) RL(x); RU(x)
#define RWI(x) rwlock_init(&rwlock_##x)
#define ML(x) mutex_lock(&mutex_##x)
#define MU(x) mutex_unlock(&mutex_##x)
#define MI(x) mutex_init(&mutex_##x)
#define WSL(x) down_write(&rwsem_##x)
#define WSU(x) up_write(&rwsem_##x)
#define RSL(x) down_read(&rwsem_##x)
#define RSU(x) up_read(&rwsem_##x)
#define RWSI(x) init_rwsem(&rwsem_##x)
#define LOCK_UNLOCK_2(x,y) LOCK(x); LOCK(y); UNLOCK(y); UNLOCK(x)
/*
* Generate different permutations of the same testcase, using
* the same basic lock-dependency/state events:
*/
#define GENERATE_TESTCASE(name) \
\
static void name(void) { E(); }
#define GENERATE_PERMUTATIONS_2_EVENTS(name) \
\
static void name##_12(void) { E1(); E2(); } \
static void name##_21(void) { E2(); E1(); }
#define GENERATE_PERMUTATIONS_3_EVENTS(name) \
\
static void name##_123(void) { E1(); E2(); E3(); } \
static void name##_132(void) { E1(); E3(); E2(); } \
static void name##_213(void) { E2(); E1(); E3(); } \
static void name##_231(void) { E2(); E3(); E1(); } \
static void name##_312(void) { E3(); E1(); E2(); } \
static void name##_321(void) { E3(); E2(); E1(); }
/*
* AA deadlock:
*/
#define E() \
\
LOCK(X1); \
LOCK(X2); /* this one should fail */
/*
* 6 testcases:
*/
#include "locking-selftest-spin.h"
GENERATE_TESTCASE(AA_spin)
#include "locking-selftest-wlock.h"
GENERATE_TESTCASE(AA_wlock)
#include "locking-selftest-rlock.h"
GENERATE_TESTCASE(AA_rlock)
#include "locking-selftest-mutex.h"
GENERATE_TESTCASE(AA_mutex)
#include "locking-selftest-wsem.h"
GENERATE_TESTCASE(AA_wsem)
#include "locking-selftest-rsem.h"
GENERATE_TESTCASE(AA_rsem)
#undef E
/*
* Special-case for read-locking, they are
* allowed to recurse on the same lock instance:
*/
static void rlock_AA1(void)
{
RL(X1);
RL(X1); // this one should NOT fail
}
static void rlock_AA1B(void)
{
RL(X1);
RL(X2); // this one should fail
}
static void rsem_AA1(void)
{
RSL(X1);
RSL(X1); // this one should fail
}
static void rsem_AA1B(void)
{
RSL(X1);
RSL(X2); // this one should fail
}
/*
* The mixing of read and write locks is not allowed:
*/
static void rlock_AA2(void)
{
RL(X1);
WL(X2); // this one should fail
}
static void rsem_AA2(void)
{
RSL(X1);
WSL(X2); // this one should fail
}
static void rlock_AA3(void)
{
WL(X1);
RL(X2); // this one should fail
}
static void rsem_AA3(void)
{
WSL(X1);
RSL(X2); // this one should fail
}
/*
* ABBA deadlock:
*/
#define E() \
\
LOCK_UNLOCK_2(A, B); \
LOCK_UNLOCK_2(B, A); /* fail */
/*
* 6 testcases:
*/
#include "locking-selftest-spin.h"
GENERATE_TESTCASE(ABBA_spin)
#include "locking-selftest-wlock.h"
GENERATE_TESTCASE(ABBA_wlock)
#include "locking-selftest-rlock.h"
GENERATE_TESTCASE(ABBA_rlock)
#include "locking-selftest-mutex.h"
GENERATE_TESTCASE(ABBA_mutex)
#include "locking-selftest-wsem.h"
GENERATE_TESTCASE(ABBA_wsem)
#include "locking-selftest-rsem.h"
GENERATE_TESTCASE(ABBA_rsem)
#undef E
/*
* AB BC CA deadlock:
*/
#define E() \
\
LOCK_UNLOCK_2(A, B); \
LOCK_UNLOCK_2(B, C); \
LOCK_UNLOCK_2(C, A); /* fail */
/*
* 6 testcases:
*/
#include "locking-selftest-spin.h"
GENERATE_TESTCASE(ABBCCA_spin)
#include "locking-selftest-wlock.h"
GENERATE_TESTCASE(ABBCCA_wlock)
#include "locking-selftest-rlock.h"
GENERATE_TESTCASE(ABBCCA_rlock)
#include "locking-selftest-mutex.h"
GENERATE_TESTCASE(ABBCCA_mutex)
#include "locking-selftest-wsem.h"
GENERATE_TESTCASE(ABBCCA_wsem)
#include "locking-selftest-rsem.h"
GENERATE_TESTCASE(ABBCCA_rsem)
#undef E
/*
* AB CA BC deadlock:
*/
#define E() \
\
LOCK_UNLOCK_2(A, B); \
LOCK_UNLOCK_2(C, A); \
LOCK_UNLOCK_2(B, C); /* fail */
/*
* 6 testcases:
*/
#include "locking-selftest-spin.h"
GENERATE_TESTCASE(ABCABC_spin)
#include "locking-selftest-wlock.h"
GENERATE_TESTCASE(ABCABC_wlock)
#include "locking-selftest-rlock.h"
GENERATE_TESTCASE(ABCABC_rlock)
#include "locking-selftest-mutex.h"
GENERATE_TESTCASE(ABCABC_mutex)
#include "locking-selftest-wsem.h"
GENERATE_TESTCASE(ABCABC_wsem)
#include "locking-selftest-rsem.h"
GENERATE_TESTCASE(ABCABC_rsem)
#undef E
/*
* AB BC CD DA deadlock:
*/
#define E() \
\
LOCK_UNLOCK_2(A, B); \
LOCK_UNLOCK_2(B, C); \
LOCK_UNLOCK_2(C, D); \
LOCK_UNLOCK_2(D, A); /* fail */
/*
* 6 testcases:
*/
#include "locking-selftest-spin.h"
GENERATE_TESTCASE(ABBCCDDA_spin)
#include "locking-selftest-wlock.h"
GENERATE_TESTCASE(ABBCCDDA_wlock)
#include "locking-selftest-rlock.h"
GENERATE_TESTCASE(ABBCCDDA_rlock)
#include "locking-selftest-mutex.h"
GENERATE_TESTCASE(ABBCCDDA_mutex)
#include "locking-selftest-wsem.h"
GENERATE_TESTCASE(ABBCCDDA_wsem)
#include "locking-selftest-rsem.h"
GENERATE_TESTCASE(ABBCCDDA_rsem)
#undef E
/*
* AB CD BD DA deadlock:
*/
#define E() \
\
LOCK_UNLOCK_2(A, B); \
LOCK_UNLOCK_2(C, D); \
LOCK_UNLOCK_2(B, D); \
LOCK_UNLOCK_2(D, A); /* fail */
/*
* 6 testcases:
*/
#include "locking-selftest-spin.h"
GENERATE_TESTCASE(ABCDBDDA_spin)
#include "locking-selftest-wlock.h"
GENERATE_TESTCASE(ABCDBDDA_wlock)
#include "locking-selftest-rlock.h"
GENERATE_TESTCASE(ABCDBDDA_rlock)
#include "locking-selftest-mutex.h"
GENERATE_TESTCASE(ABCDBDDA_mutex)
#include "locking-selftest-wsem.h"
GENERATE_TESTCASE(ABCDBDDA_wsem)
#include "locking-selftest-rsem.h"
GENERATE_TESTCASE(ABCDBDDA_rsem)
#undef E
/*
* AB CD BC DA deadlock:
*/
#define E() \
\
LOCK_UNLOCK_2(A, B); \
LOCK_UNLOCK_2(C, D); \
LOCK_UNLOCK_2(B, C); \
LOCK_UNLOCK_2(D, A); /* fail */
/*
* 6 testcases:
*/
#include "locking-selftest-spin.h"
GENERATE_TESTCASE(ABCDBCDA_spin)
#include "locking-selftest-wlock.h"
GENERATE_TESTCASE(ABCDBCDA_wlock)
#include "locking-selftest-rlock.h"
GENERATE_TESTCASE(ABCDBCDA_rlock)
#include "locking-selftest-mutex.h"
GENERATE_TESTCASE(ABCDBCDA_mutex)
#include "locking-selftest-wsem.h"
GENERATE_TESTCASE(ABCDBCDA_wsem)
#include "locking-selftest-rsem.h"
GENERATE_TESTCASE(ABCDBCDA_rsem)
#undef E
/*
* Double unlock:
*/
#define E() \
\
LOCK(A); \
UNLOCK(A); \
UNLOCK(A); /* fail */
/*
* 6 testcases:
*/
#include "locking-selftest-spin.h"
GENERATE_TESTCASE(double_unlock_spin)
#include "locking-selftest-wlock.h"
GENERATE_TESTCASE(double_unlock_wlock)
#include "locking-selftest-rlock.h"
GENERATE_TESTCASE(double_unlock_rlock)
#include "locking-selftest-mutex.h"
GENERATE_TESTCASE(double_unlock_mutex)
#include "locking-selftest-wsem.h"
GENERATE_TESTCASE(double_unlock_wsem)
#include "locking-selftest-rsem.h"
GENERATE_TESTCASE(double_unlock_rsem)
#undef E
/*
* Bad unlock ordering:
*/
#define E() \
\
LOCK(A); \
LOCK(B); \
UNLOCK(A); /* fail */ \
UNLOCK(B);
/*
* 6 testcases:
*/
#include "locking-selftest-spin.h"
GENERATE_TESTCASE(bad_unlock_order_spin)
#include "locking-selftest-wlock.h"
GENERATE_TESTCASE(bad_unlock_order_wlock)
#include "locking-selftest-rlock.h"
GENERATE_TESTCASE(bad_unlock_order_rlock)
#include "locking-selftest-mutex.h"
GENERATE_TESTCASE(bad_unlock_order_mutex)
#include "locking-selftest-wsem.h"
GENERATE_TESTCASE(bad_unlock_order_wsem)
#include "locking-selftest-rsem.h"
GENERATE_TESTCASE(bad_unlock_order_rsem)
#undef E
/*
* initializing a held lock:
*/
#define E() \
\
LOCK(A); \
INIT(A); /* fail */
/*
* 6 testcases:
*/
#include "locking-selftest-spin.h"
GENERATE_TESTCASE(init_held_spin)
#include "locking-selftest-wlock.h"
GENERATE_TESTCASE(init_held_wlock)
#include "locking-selftest-rlock.h"
GENERATE_TESTCASE(init_held_rlock)
#include "locking-selftest-mutex.h"
GENERATE_TESTCASE(init_held_mutex)
#include "locking-selftest-wsem.h"
GENERATE_TESTCASE(init_held_wsem)
#include "locking-selftest-rsem.h"
GENERATE_TESTCASE(init_held_rsem)
#undef E
/*
* locking an irq-safe lock with irqs enabled:
*/
#define E1() \
\
IRQ_ENTER(); \
LOCK(A); \
UNLOCK(A); \
IRQ_EXIT();
#define E2() \
\
LOCK(A); \
UNLOCK(A);
/*
* Generate 24 testcases:
*/
#include "locking-selftest-spin-hardirq.h"
GENERATE_PERMUTATIONS_2_EVENTS(irqsafe1_hard_spin)
#include "locking-selftest-rlock-hardirq.h"
GENERATE_PERMUTATIONS_2_EVENTS(irqsafe1_hard_rlock)
#include "locking-selftest-wlock-hardirq.h"
GENERATE_PERMUTATIONS_2_EVENTS(irqsafe1_hard_wlock)
#include "locking-selftest-spin-softirq.h"
GENERATE_PERMUTATIONS_2_EVENTS(irqsafe1_soft_spin)
#include "locking-selftest-rlock-softirq.h"
GENERATE_PERMUTATIONS_2_EVENTS(irqsafe1_soft_rlock)
#include "locking-selftest-wlock-softirq.h"
GENERATE_PERMUTATIONS_2_EVENTS(irqsafe1_soft_wlock)
#undef E1
#undef E2
/*
* Enabling hardirqs with a softirq-safe lock held:
*/
#define E1() \
\
SOFTIRQ_ENTER(); \
LOCK(A); \
UNLOCK(A); \
SOFTIRQ_EXIT();
#define E2() \
\
HARDIRQ_DISABLE(); \
LOCK(A); \
HARDIRQ_ENABLE(); \
UNLOCK(A);
/*
* Generate 12 testcases:
*/
#include "locking-selftest-spin.h"
GENERATE_PERMUTATIONS_2_EVENTS(irqsafe2A_spin)
#include "locking-selftest-wlock.h"
GENERATE_PERMUTATIONS_2_EVENTS(irqsafe2A_wlock)
#include "locking-selftest-rlock.h"
GENERATE_PERMUTATIONS_2_EVENTS(irqsafe2A_rlock)
#undef E1
#undef E2
/*
* Enabling irqs with an irq-safe lock held:
*/
#define E1() \
\
IRQ_ENTER(); \
LOCK(A); \
UNLOCK(A); \
IRQ_EXIT();
#define E2() \
\
IRQ_DISABLE(); \
LOCK(A); \
IRQ_ENABLE(); \
UNLOCK(A);
/*
* Generate 24 testcases:
*/
#include "locking-selftest-spin-hardirq.h"
GENERATE_PERMUTATIONS_2_EVENTS(irqsafe2B_hard_spin)
#include "locking-selftest-rlock-hardirq.h"
GENERATE_PERMUTATIONS_2_EVENTS(irqsafe2B_hard_rlock)
#include "locking-selftest-wlock-hardirq.h"
GENERATE_PERMUTATIONS_2_EVENTS(irqsafe2B_hard_wlock)
#include "locking-selftest-spin-softirq.h"
GENERATE_PERMUTATIONS_2_EVENTS(irqsafe2B_soft_spin)
#include "locking-selftest-rlock-softirq.h"
GENERATE_PERMUTATIONS_2_EVENTS(irqsafe2B_soft_rlock)
#include "locking-selftest-wlock-softirq.h"
GENERATE_PERMUTATIONS_2_EVENTS(irqsafe2B_soft_wlock)
#undef E1
#undef E2
/*
* Acquiring a irq-unsafe lock while holding an irq-safe-lock:
*/
#define E1() \
\
LOCK(A); \
LOCK(B); \
UNLOCK(B); \
UNLOCK(A); \
#define E2() \
\
LOCK(B); \
UNLOCK(B);
#define E3() \
\
IRQ_ENTER(); \
LOCK(A); \
UNLOCK(A); \
IRQ_EXIT();
/*
* Generate 36 testcases:
*/
#include "locking-selftest-spin-hardirq.h"
GENERATE_PERMUTATIONS_3_EVENTS(irqsafe3_hard_spin)
#include "locking-selftest-rlock-hardirq.h"
GENERATE_PERMUTATIONS_3_EVENTS(irqsafe3_hard_rlock)
#include "locking-selftest-wlock-hardirq.h"
GENERATE_PERMUTATIONS_3_EVENTS(irqsafe3_hard_wlock)
#include "locking-selftest-spin-softirq.h"
GENERATE_PERMUTATIONS_3_EVENTS(irqsafe3_soft_spin)
#include "locking-selftest-rlock-softirq.h"
GENERATE_PERMUTATIONS_3_EVENTS(irqsafe3_soft_rlock)
#include "locking-selftest-wlock-softirq.h"
GENERATE_PERMUTATIONS_3_EVENTS(irqsafe3_soft_wlock)
#undef E1
#undef E2
#undef E3
/*
* If a lock turns into softirq-safe, but earlier it took
* a softirq-unsafe lock:
*/
#define E1() \
IRQ_DISABLE(); \
LOCK(A); \
LOCK(B); \
UNLOCK(B); \
UNLOCK(A); \
IRQ_ENABLE();
#define E2() \
LOCK(B); \
UNLOCK(B);
#define E3() \
IRQ_ENTER(); \
LOCK(A); \
UNLOCK(A); \
IRQ_EXIT();
/*
* Generate 36 testcases:
*/
#include "locking-selftest-spin-hardirq.h"
GENERATE_PERMUTATIONS_3_EVENTS(irqsafe4_hard_spin)
#include "locking-selftest-rlock-hardirq.h"
GENERATE_PERMUTATIONS_3_EVENTS(irqsafe4_hard_rlock)
#include "locking-selftest-wlock-hardirq.h"
GENERATE_PERMUTATIONS_3_EVENTS(irqsafe4_hard_wlock)
#include "locking-selftest-spin-softirq.h"
GENERATE_PERMUTATIONS_3_EVENTS(irqsafe4_soft_spin)
#include "locking-selftest-rlock-softirq.h"
GENERATE_PERMUTATIONS_3_EVENTS(irqsafe4_soft_rlock)
#include "locking-selftest-wlock-softirq.h"
GENERATE_PERMUTATIONS_3_EVENTS(irqsafe4_soft_wlock)
#undef E1
#undef E2
#undef E3
/*
* read-lock / write-lock irq inversion.
*
* Deadlock scenario:
*
* CPU#1 is at #1, i.e. it has write-locked A, but has not
* taken B yet.
*
* CPU#2 is at #2, i.e. it has locked B.
*
* Hardirq hits CPU#2 at point #2 and is trying to read-lock A.
*
* The deadlock occurs because CPU#1 will spin on B, and CPU#2
* will spin on A.
*/
#define E1() \
\
IRQ_DISABLE(); \
WL(A); \
LOCK(B); \
UNLOCK(B); \
WU(A); \
IRQ_ENABLE();
#define E2() \
\
LOCK(B); \
UNLOCK(B);
#define E3() \
\
IRQ_ENTER(); \
RL(A); \
RU(A); \
IRQ_EXIT();
/*
* Generate 36 testcases:
*/
#include "locking-selftest-spin-hardirq.h"
GENERATE_PERMUTATIONS_3_EVENTS(irq_inversion_hard_spin)
#include "locking-selftest-rlock-hardirq.h"
GENERATE_PERMUTATIONS_3_EVENTS(irq_inversion_hard_rlock)
#include "locking-selftest-wlock-hardirq.h"
GENERATE_PERMUTATIONS_3_EVENTS(irq_inversion_hard_wlock)
#include "locking-selftest-spin-softirq.h"
GENERATE_PERMUTATIONS_3_EVENTS(irq_inversion_soft_spin)
#include "locking-selftest-rlock-softirq.h"
GENERATE_PERMUTATIONS_3_EVENTS(irq_inversion_soft_rlock)
#include "locking-selftest-wlock-softirq.h"
GENERATE_PERMUTATIONS_3_EVENTS(irq_inversion_soft_wlock)
#undef E1
#undef E2
#undef E3
/*
* read-lock / write-lock recursion that is actually safe.
*/
#define E1() \
\
IRQ_DISABLE(); \
WL(A); \
WU(A); \
IRQ_ENABLE();
#define E2() \
\
RL(A); \
RU(A); \
#define E3() \
\
IRQ_ENTER(); \
RL(A); \
L(B); \
U(B); \
RU(A); \
IRQ_EXIT();
/*
* Generate 12 testcases:
*/
#include "locking-selftest-hardirq.h"
GENERATE_PERMUTATIONS_3_EVENTS(irq_read_recursion_hard)
#include "locking-selftest-softirq.h"
GENERATE_PERMUTATIONS_3_EVENTS(irq_read_recursion_soft)
#undef E1
#undef E2
#undef E3
/*
* read-lock / write-lock recursion that is unsafe.
*/
#define E1() \
\
IRQ_DISABLE(); \
L(B); \
WL(A); \
WU(A); \
U(B); \
IRQ_ENABLE();
#define E2() \
\
RL(A); \
RU(A); \
#define E3() \
\
IRQ_ENTER(); \
L(B); \
U(B); \
IRQ_EXIT();
/*
* Generate 12 testcases:
*/
#include "locking-selftest-hardirq.h"
// GENERATE_PERMUTATIONS_3_EVENTS(irq_read_recursion2_hard)
#include "locking-selftest-softirq.h"
// GENERATE_PERMUTATIONS_3_EVENTS(irq_read_recursion2_soft)
#ifdef CONFIG_DEBUG_LOCK_ALLOC
# define I_SPINLOCK(x) lockdep_reset_lock(&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)
#else
# define I_SPINLOCK(x)
# define I_RWLOCK(x)
# define I_MUTEX(x)
# define I_RWSEM(x)
#endif
#define I1(x) \
do { \
I_SPINLOCK(x); \
I_RWLOCK(x); \
I_MUTEX(x); \
I_RWSEM(x); \
} while (0)
#define I2(x) \
do { \
spin_lock_init(&lock_##x); \
rwlock_init(&rwlock_##x); \
mutex_init(&mutex_##x); \
init_rwsem(&rwsem_##x); \
} while (0)
static void reset_locks(void)
{
local_irq_disable();
I1(A); I1(B); I1(C); I1(D);
I1(X1); I1(X2); I1(Y1); I1(Y2); I1(Z1); I1(Z2);
lockdep_reset();
I2(A); I2(B); I2(C); I2(D);
init_shared_classes();
local_irq_enable();
}
#undef I
static int testcase_total;
static int testcase_successes;
static int expected_testcase_failures;
static int unexpected_testcase_failures;
static void dotest(void (*testcase_fn)(void), int expected, int lockclass_mask)
{
unsigned long saved_preempt_count = preempt_count();
int expected_failure = 0;
WARN_ON(irqs_disabled());
testcase_fn();
/*
* Filter out expected failures:
*/
#ifndef CONFIG_PROVE_LOCKING
if ((lockclass_mask & LOCKTYPE_SPIN) && debug_locks != expected)
expected_failure = 1;
if ((lockclass_mask & LOCKTYPE_RWLOCK) && debug_locks != expected)
expected_failure = 1;
if ((lockclass_mask & LOCKTYPE_MUTEX) && debug_locks != expected)
expected_failure = 1;
if ((lockclass_mask & LOCKTYPE_RWSEM) && debug_locks != expected)
expected_failure = 1;
#endif
if (debug_locks != expected) {
if (expected_failure) {
expected_testcase_failures++;
printk("failed|");
} else {
unexpected_testcase_failures++;
printk("FAILED|");
}
} else {
testcase_successes++;
printk(" ok |");
}
testcase_total++;
if (debug_locks_verbose)
printk(" lockclass mask: %x, debug_locks: %d, expected: %d\n",
lockclass_mask, debug_locks, expected);
/*
* Some tests (e.g. double-unlock) might corrupt the preemption
* count, so restore it:
*/
preempt_count() = saved_preempt_count;
#ifdef CONFIG_TRACE_IRQFLAGS
if (softirq_count())
current->softirqs_enabled = 0;
else
current->softirqs_enabled = 1;
#endif
reset_locks();
}
static inline void print_testname(const char *testname)
{
printk("%33s:", testname);
}
#define DO_TESTCASE_1(desc, name, nr) \
print_testname(desc"/"#nr); \
dotest(name##_##nr, SUCCESS, LOCKTYPE_RWLOCK); \
printk("\n");
#define DO_TESTCASE_1B(desc, name, nr) \
print_testname(desc"/"#nr); \
dotest(name##_##nr, FAILURE, LOCKTYPE_RWLOCK); \
printk("\n");
#define DO_TESTCASE_3(desc, name, nr) \
print_testname(desc"/"#nr); \
dotest(name##_spin_##nr, FAILURE, LOCKTYPE_SPIN); \
dotest(name##_wlock_##nr, FAILURE, LOCKTYPE_RWLOCK); \
dotest(name##_rlock_##nr, SUCCESS, LOCKTYPE_RWLOCK); \
printk("\n");
#define DO_TESTCASE_3RW(desc, name, nr) \
print_testname(desc"/"#nr); \
dotest(name##_spin_##nr, FAILURE, LOCKTYPE_SPIN|LOCKTYPE_RWLOCK);\
dotest(name##_wlock_##nr, FAILURE, LOCKTYPE_RWLOCK); \
dotest(name##_rlock_##nr, SUCCESS, LOCKTYPE_RWLOCK); \
printk("\n");
#define DO_TESTCASE_6(desc, name) \
print_testname(desc); \
dotest(name##_spin, FAILURE, LOCKTYPE_SPIN); \
dotest(name##_wlock, FAILURE, LOCKTYPE_RWLOCK); \
dotest(name##_rlock, FAILURE, LOCKTYPE_RWLOCK); \
dotest(name##_mutex, FAILURE, LOCKTYPE_MUTEX); \
dotest(name##_wsem, FAILURE, LOCKTYPE_RWSEM); \
dotest(name##_rsem, FAILURE, LOCKTYPE_RWSEM); \
printk("\n");
#define DO_TESTCASE_6_SUCCESS(desc, name) \
print_testname(desc); \
dotest(name##_spin, SUCCESS, LOCKTYPE_SPIN); \
dotest(name##_wlock, SUCCESS, LOCKTYPE_RWLOCK); \
dotest(name##_rlock, SUCCESS, LOCKTYPE_RWLOCK); \
dotest(name##_mutex, SUCCESS, LOCKTYPE_MUTEX); \
dotest(name##_wsem, SUCCESS, LOCKTYPE_RWSEM); \
dotest(name##_rsem, SUCCESS, LOCKTYPE_RWSEM); \
printk("\n");
/*
* 'read' variant: rlocks must not trigger.
*/
#define DO_TESTCASE_6R(desc, name) \
print_testname(desc); \
dotest(name##_spin, FAILURE, LOCKTYPE_SPIN); \
dotest(name##_wlock, FAILURE, LOCKTYPE_RWLOCK); \
dotest(name##_rlock, SUCCESS, LOCKTYPE_RWLOCK); \
dotest(name##_mutex, FAILURE, LOCKTYPE_MUTEX); \
dotest(name##_wsem, FAILURE, LOCKTYPE_RWSEM); \
dotest(name##_rsem, FAILURE, LOCKTYPE_RWSEM); \
printk("\n");
#define DO_TESTCASE_2I(desc, name, nr) \
DO_TESTCASE_1("hard-"desc, name##_hard, nr); \
DO_TESTCASE_1("soft-"desc, name##_soft, nr);
#define DO_TESTCASE_2IB(desc, name, nr) \
DO_TESTCASE_1B("hard-"desc, name##_hard, nr); \
DO_TESTCASE_1B("soft-"desc, name##_soft, nr);
#define DO_TESTCASE_6I(desc, name, nr) \
DO_TESTCASE_3("hard-"desc, name##_hard, nr); \
DO_TESTCASE_3("soft-"desc, name##_soft, nr);
#define DO_TESTCASE_6IRW(desc, name, nr) \
DO_TESTCASE_3RW("hard-"desc, name##_hard, nr); \
DO_TESTCASE_3RW("soft-"desc, name##_soft, nr);
#define DO_TESTCASE_2x3(desc, name) \
DO_TESTCASE_3(desc, name, 12); \
DO_TESTCASE_3(desc, name, 21);
#define DO_TESTCASE_2x6(desc, name) \
DO_TESTCASE_6I(desc, name, 12); \
DO_TESTCASE_6I(desc, name, 21);
#define DO_TESTCASE_6x2(desc, name) \
DO_TESTCASE_2I(desc, name, 123); \
DO_TESTCASE_2I(desc, name, 132); \
DO_TESTCASE_2I(desc, name, 213); \
DO_TESTCASE_2I(desc, name, 231); \
DO_TESTCASE_2I(desc, name, 312); \
DO_TESTCASE_2I(desc, name, 321);
#define DO_TESTCASE_6x2B(desc, name) \
DO_TESTCASE_2IB(desc, name, 123); \
DO_TESTCASE_2IB(desc, name, 132); \
DO_TESTCASE_2IB(desc, name, 213); \
DO_TESTCASE_2IB(desc, name, 231); \
DO_TESTCASE_2IB(desc, name, 312); \
DO_TESTCASE_2IB(desc, name, 321);
#define DO_TESTCASE_6x6(desc, name) \
DO_TESTCASE_6I(desc, name, 123); \
DO_TESTCASE_6I(desc, name, 132); \
DO_TESTCASE_6I(desc, name, 213); \
DO_TESTCASE_6I(desc, name, 231); \
DO_TESTCASE_6I(desc, name, 312); \
DO_TESTCASE_6I(desc, name, 321);
#define DO_TESTCASE_6x6RW(desc, name) \
DO_TESTCASE_6IRW(desc, name, 123); \
DO_TESTCASE_6IRW(desc, name, 132); \
DO_TESTCASE_6IRW(desc, name, 213); \
DO_TESTCASE_6IRW(desc, name, 231); \
DO_TESTCASE_6IRW(desc, name, 312); \
DO_TESTCASE_6IRW(desc, name, 321);
void locking_selftest(void)
{
/*
* Got a locking failure before the selftest ran?
*/
if (!debug_locks) {
printk("----------------------------------\n");
printk("| Locking API testsuite disabled |\n");
printk("----------------------------------\n");
return;
}
/*
* Run the testsuite:
*/
printk("------------------------\n");
printk("| Locking API testsuite:\n");
printk("----------------------------------------------------------------------------\n");
printk(" | spin |wlock |rlock |mutex | wsem | rsem |\n");
printk(" --------------------------------------------------------------------------\n");
init_shared_classes();
debug_locks_silent = !debug_locks_verbose;
DO_TESTCASE_6("A-A deadlock", AA);
DO_TESTCASE_6R("A-B-B-A deadlock", ABBA);
DO_TESTCASE_6R("A-B-B-C-C-A deadlock", ABBCCA);
DO_TESTCASE_6R("A-B-C-A-B-C deadlock", ABCABC);
DO_TESTCASE_6R("A-B-B-C-C-D-D-A deadlock", ABBCCDDA);
DO_TESTCASE_6R("A-B-C-D-B-D-D-A deadlock", ABCDBDDA);
DO_TESTCASE_6R("A-B-C-D-B-C-D-A deadlock", ABCDBCDA);
DO_TESTCASE_6("double unlock", double_unlock);
DO_TESTCASE_6("initialize held", init_held);
DO_TESTCASE_6_SUCCESS("bad unlock order", bad_unlock_order);
printk(" --------------------------------------------------------------------------\n");
print_testname("recursive read-lock");
printk(" |");
dotest(rlock_AA1, SUCCESS, LOCKTYPE_RWLOCK);
printk(" |");
dotest(rsem_AA1, FAILURE, LOCKTYPE_RWSEM);
printk("\n");
print_testname("recursive read-lock #2");
printk(" |");
dotest(rlock_AA1B, FAILURE, LOCKTYPE_RWLOCK);
printk(" |");
dotest(rsem_AA1B, FAILURE, LOCKTYPE_RWSEM);
printk("\n");
print_testname("mixed read-write-lock");
printk(" |");
dotest(rlock_AA2, FAILURE, LOCKTYPE_RWLOCK);
printk(" |");
dotest(rsem_AA2, FAILURE, LOCKTYPE_RWSEM);
printk("\n");
print_testname("mixed write-read-lock");
printk(" |");
dotest(rlock_AA3, FAILURE, LOCKTYPE_RWLOCK);
printk(" |");
dotest(rsem_AA3, FAILURE, LOCKTYPE_RWSEM);
printk("\n");
printk(" --------------------------------------------------------------------------\n");
/*
* irq-context testcases:
*/
DO_TESTCASE_2x6("irqs-on + irq-safe-A", irqsafe1);
DO_TESTCASE_2x3("sirq-safe-A => hirqs-on", irqsafe2A);
DO_TESTCASE_2x6("safe-A + irqs-on", irqsafe2B);
DO_TESTCASE_6x6("safe-A + unsafe-B #1", irqsafe3);
DO_TESTCASE_6x6("safe-A + unsafe-B #2", irqsafe4);
DO_TESTCASE_6x6RW("irq lock-inversion", irq_inversion);
DO_TESTCASE_6x2("irq read-recursion", irq_read_recursion);
// DO_TESTCASE_6x2B("irq read-recursion #2", irq_read_recursion2);
if (unexpected_testcase_failures) {
printk("-----------------------------------------------------------------\n");
debug_locks = 0;
printk("BUG: %3d unexpected failures (out of %3d) - debugging disabled! |\n",
unexpected_testcase_failures, testcase_total);
printk("-----------------------------------------------------------------\n");
} else if (expected_testcase_failures && testcase_successes) {
printk("--------------------------------------------------------\n");
printk("%3d out of %3d testcases failed, as expected. |\n",
expected_testcase_failures, testcase_total);
printk("----------------------------------------------------\n");
debug_locks = 1;
} else if (expected_testcase_failures && !testcase_successes) {
printk("--------------------------------------------------------\n");
printk("All %3d testcases failed, as expected. |\n",
expected_testcase_failures);
printk("----------------------------------------\n");
debug_locks = 1;
} else {
printk("-------------------------------------------------------\n");
printk("Good, all %3d testcases passed! |\n",
testcase_successes);
printk("---------------------------------\n");
debug_locks = 1;
}
debug_locks_silent = 0;
}
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