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These are the v5.12 updates for the locking subsystem: 

- 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
 
 Signed-off-by: Ingo Molnar <mingo@kernel.org>
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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
  ...
This commit is contained in:
Linus Torvalds 2021-02-21 12:12:01 -08:00
parent d089f48fba 3765d01bab
commit 9eef023345
57 changed files with 617 additions and 294 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

11
Documentation/admin-guide/kernel-parameters.txt
View File

@ -802,13 +802,14 @@
insecure, please do not use on production kernels.
debug_locks_verbose=
[KNL] verbose self-tests
Format=<0|1>
[KNL] verbose locking self-tests
Format: <int>
Print debugging info while doing the locking API
self-tests.
We default to 0 (no extra messages), setting it to
1 will print _a lot_ more information - normally
only useful to kernel developers.
Bitmask for the various LOCKTYPE_ tests. Defaults to 0
(no extra messages), setting it to -1 (all bits set)
will print _a_lot_ more information - normally only
useful to lockdep developers.
debug_objects [KNL] Enable object debugging

2
MAINTAINERS
View File

@ -10342,6 +10342,8 @@ LOCKING PRIMITIVES
M: Peter Zijlstra <peterz@infradead.org>
M: Ingo Molnar <mingo@redhat.com>
M: Will Deacon <will@kernel.org>
R: Waiman Long <longman@redhat.com>
R: Boqun Feng <boqun.feng@gmail.com> (LOCKDEP)
L: linux-kernel@vger.kernel.org
S: Maintained
T: git git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git locking/core

4
drivers/s390/char/sclp_early_core.c
View File

@ -66,13 +66,13 @@ int sclp_early_cmd(sclp_cmdw_t cmd, void *sccb)
unsigned long flags;
int rc;
raw_local_irq_save(flags);
flags = arch_local_irq_save();
rc = sclp_service_call(cmd, sccb);
if (rc)
goto out;
sclp_early_wait_irq();
out:
raw_local_irq_restore(flags);
arch_local_irq_restore(flags);
return rc;
}

2
include/linux/compiler.h
View File

@ -76,6 +76,8 @@ void ftrace_likely_update(struct ftrace_likely_data *f, int val,
#else
# define likely(x) __builtin_expect(!!(x), 1)
# define unlikely(x) __builtin_expect(!!(x), 0)
# define likely_notrace(x) likely(x)
# define unlikely_notrace(x) unlikely(x)
#endif
/* Optimization barrier */

12
include/linux/irqflags.h
View File

@ -149,6 +149,17 @@ do { \
# define start_critical_timings() do { } while (0)
#endif
#ifdef CONFIG_DEBUG_IRQFLAGS
extern void warn_bogus_irq_restore(void);
#define raw_check_bogus_irq_restore() \
do { \
if (unlikely(!arch_irqs_disabled())) \
warn_bogus_irq_restore(); \
} while (0)
#else
#define raw_check_bogus_irq_restore() do { } while (0)
#endif
/*
* Wrap the arch provided IRQ routines to provide appropriate checks.
*/
@ -162,6 +173,7 @@ do { \
#define raw_local_irq_restore(flags) \
do { \
typecheck(unsigned long, flags); \
raw_check_bogus_irq_restore(); \
arch_local_irq_restore(flags); \
} while (0)
#define raw_local_save_flags(flags) \

12
include/linux/jump_label.h
View File

@ -261,14 +261,14 @@ static __always_inline void jump_label_init(void)
static __always_inline bool static_key_false(struct static_key *key)
{
if (unlikely(static_key_count(key) > 0))
if (unlikely_notrace(static_key_count(key) > 0))
return true;
return false;
}
static __always_inline bool static_key_true(struct static_key *key)
{
if (likely(static_key_count(key) > 0))
if (likely_notrace(static_key_count(key) > 0))
return true;
return false;
}
@ -460,7 +460,7 @@ extern bool ____wrong_branch_error(void);
branch = !arch_static_branch_jump(&(x)->key, true); \
else \
branch = ____wrong_branch_error(); \
likely(branch); \
likely_notrace(branch); \
})
#define static_branch_unlikely(x) \
@ -472,13 +472,13 @@ extern bool ____wrong_branch_error(void);
branch = arch_static_branch(&(x)->key, false); \
else \
branch = ____wrong_branch_error(); \
unlikely(branch); \
unlikely_notrace(branch); \
})
#else /* !CONFIG_JUMP_LABEL */
#define static_branch_likely(x) likely(static_key_enabled(&(x)->key))
#define static_branch_unlikely(x) unlikely(static_key_enabled(&(x)->key))
#define static_branch_likely(x) likely_notrace(static_key_enabled(&(x)->key))
#define static_branch_unlikely(x) unlikely_notrace(static_key_enabled(&(x)->key))
#endif /* CONFIG_JUMP_LABEL */

5
include/linux/local_lock_internal.h
View File

@ -18,6 +18,7 @@ typedef struct {
.dep_map = { \
.name = #lockname, \
.wait_type_inner = LD_WAIT_CONFIG, \
.lock_type = LD_LOCK_PERCPU, \
}
#else
# define LL_DEP_MAP_INIT(lockname)
@ -30,7 +31,9 @@ do { \
static struct lock_class_key __key; \
\
debug_check_no_locks_freed((void *)lock, sizeof(*lock));\
lockdep_init_map_wait(&(lock)->dep_map, #lock, &__key, 0, LD_WAIT_CONFIG);\
lockdep_init_map_type(&(lock)->dep_map, #lock, &__key, 0, \
LD_WAIT_CONFIG, LD_WAIT_INV, \
LD_LOCK_PERCPU); \
} while (0)
#ifdef CONFIG_DEBUG_LOCK_ALLOC

15
include/linux/lockdep.h
View File

@ -185,12 +185,19 @@ extern void lockdep_unregister_key(struct lock_class_key *key);
* to lockdep:
*/
extern void lockdep_init_map_waits(struct lockdep_map *lock, const char *name,
struct lock_class_key *key, int subclass, short inner, short outer);
extern void lockdep_init_map_type(struct lockdep_map *lock, const char *name,
struct lock_class_key *key, int subclass, u8 inner, u8 outer, u8 lock_type);
static inline void
lockdep_init_map_waits(struct lockdep_map *lock, const char *name,
struct lock_class_key *key, int subclass, u8 inner, u8 outer)
{
lockdep_init_map_type(lock, name, key, subclass, inner, LD_WAIT_INV, LD_LOCK_NORMAL);
}
static inline void
lockdep_init_map_wait(struct lockdep_map *lock, const char *name,
struct lock_class_key *key, int subclass, short inner)
struct lock_class_key *key, int subclass, u8 inner)
{
lockdep_init_map_waits(lock, name, key, subclass, inner, LD_WAIT_INV);
}
@ -340,6 +347,8 @@ static inline void lockdep_set_selftest_task(struct task_struct *task)
# define lock_set_class(l, n, k, s, i) do { } while (0)
# define lock_set_subclass(l, s, i) do { } while (0)
# define lockdep_init() do { } while (0)
# define lockdep_init_map_type(lock, name, key, sub, inner, outer, type) \
do { (void)(name); (void)(key); } while (0)
# define lockdep_init_map_waits(lock, name, key, sub, inner, outer) \
do { (void)(name); (void)(key); } while (0)
# define lockdep_init_map_wait(lock, name, key, sub, inner) \

18
include/linux/lockdep_types.h
View File

@ -30,6 +30,12 @@ enum lockdep_wait_type {
LD_WAIT_MAX, /* must be last */
};
enum lockdep_lock_type {
LD_LOCK_NORMAL = 0, /* normal, catch all */
LD_LOCK_PERCPU, /* percpu */
LD_LOCK_MAX,
};
#ifdef CONFIG_LOCKDEP
/*
@ -119,8 +125,10 @@ struct lock_class {
int name_version;
const char *name;
short wait_type_inner;
short wait_type_outer;
u8 wait_type_inner;
u8 wait_type_outer;
u8 lock_type;
/* u8 hole; */
#ifdef CONFIG_LOCK_STAT
unsigned long contention_point[LOCKSTAT_POINTS];
@ -169,8 +177,10 @@ struct lockdep_map {
struct lock_class_key *key;
struct lock_class *class_cache[NR_LOCKDEP_CACHING_CLASSES];
const char *name;
short wait_type_outer; /* can be taken in this context */
short wait_type_inner; /* presents this context */
u8 wait_type_outer; /* can be taken in this context */
u8 wait_type_inner; /* presents this context */
u8 lock_type;
/* u8 hole; */
#ifdef CONFIG_LOCK_STAT
int cpu;
unsigned long ip;

25
include/linux/mutex.h
View File

@ -199,29 +199,4 @@ extern void mutex_unlock(struct mutex *lock);
extern int atomic_dec_and_mutex_lock(atomic_t *cnt, struct mutex *lock);
/*
* These values are chosen such that FAIL and SUCCESS match the
* values of the regular mutex_trylock().
*/
enum mutex_trylock_recursive_enum {
MUTEX_TRYLOCK_FAILED = 0,
MUTEX_TRYLOCK_SUCCESS = 1,
MUTEX_TRYLOCK_RECURSIVE,
};
/**
* mutex_trylock_recursive - trylock variant that allows recursive locking
* @lock: mutex to be locked
*
* This function should not be used, _ever_. It is purely for hysterical GEM
* raisins, and once those are gone this will be removed.
*
* Returns:
* - MUTEX_TRYLOCK_FAILED - trylock failed,
* - MUTEX_TRYLOCK_SUCCESS - lock acquired,
* - MUTEX_TRYLOCK_RECURSIVE - we already owned the lock.
*/
extern /* __deprecated */ __must_check enum mutex_trylock_recursive_enum
mutex_trylock_recursive(struct mutex *lock);
#endif /* __LINUX_MUTEX_H */

8
include/linux/syscalls.h
View File

@ -607,11 +607,11 @@ asmlinkage long sys_unshare(unsigned long unshare_flags);
/* kernel/futex.c */
asmlinkage long sys_futex(u32 __user *uaddr, int op, u32 val,
struct __kernel_timespec __user *utime, u32 __user *uaddr2,
u32 val3);
const struct __kernel_timespec __user *utime,
u32 __user *uaddr2, u32 val3);
asmlinkage long sys_futex_time32(u32 __user *uaddr, int op, u32 val,
struct old_timespec32 __user *utime, u32 __user *uaddr2,
u32 val3);
const struct old_timespec32 __user *utime,
u32 __user *uaddr2, u32 val3);
asmlinkage long sys_get_robust_list(int pid,
struct robust_list_head __user * __user *head_ptr,
size_t __user *len_ptr);

13
kernel/futex.c
View File

@ -3012,7 +3012,7 @@ retry:
* Success, we're done! No tricky corner cases.
*/
if (!ret)
goto out_putkey;
return ret;
/*
* The atomic access to the futex value generated a
* pagefault, so retry the user-access and the wakeup:
@ -3029,7 +3029,7 @@ retry:
* wake_futex_pi has detected invalid state. Tell user
* space.
*/
goto out_putkey;
return ret;
}
/*
@ -3050,7 +3050,7 @@ retry:
default:
WARN_ON_ONCE(1);
goto out_putkey;
return ret;
}
}
@ -3061,7 +3061,6 @@ retry:
out_unlock:
spin_unlock(&hb->lock);
out_putkey:
return ret;
pi_retry:
@ -3763,8 +3762,8 @@ long do_futex(u32 __user *uaddr, int op, u32 val, ktime_t *timeout,
SYSCALL_DEFINE6(futex, u32 __user *, uaddr, int, op, u32, val,
struct __kernel_timespec __user *, utime, u32 __user *, uaddr2,
u32, val3)
const struct __kernel_timespec __user *, utime,
u32 __user *, uaddr2, u32, val3)
{
struct timespec64 ts;
ktime_t t, *tp = NULL;
@ -3959,7 +3958,7 @@ err_unlock:
#ifdef CONFIG_COMPAT_32BIT_TIME
SYSCALL_DEFINE6(futex_time32, u32 __user *, uaddr, int, op, u32, val,
struct old_timespec32 __user *, utime, u32 __user *, uaddr2,
const struct old_timespec32 __user *, utime, u32 __user *, uaddr2,
u32, val3)
{
struct timespec64 ts;

26
kernel/kcsan/core.c
View File

@ -12,7 +12,6 @@
#include <linux/moduleparam.h>
#include <linux/percpu.h>
#include <linux/preempt.h>
#include <linux/random.h>
#include <linux/sched.h>
#include <linux/uaccess.h>
@ -101,7 +100,7 @@ static atomic_long_t watchpoints[CONFIG_KCSAN_NUM_WATCHPOINTS + NUM_SLOTS-1];
static DEFINE_PER_CPU(long, kcsan_skip);
/* For kcsan_prandom_u32_max(). */
static DEFINE_PER_CPU(struct rnd_state, kcsan_rand_state);
static DEFINE_PER_CPU(u32, kcsan_rand_state);
static __always_inline atomic_long_t *find_watchpoint(unsigned long addr,
size_t size,
@ -275,20 +274,17 @@ should_watch(const volatile void *ptr, size_t size, int type, struct kcsan_ctx *
}
/*
* Returns a pseudo-random number in interval [0, ep_ro). See prandom_u32_max()
* for more details.
*
* The open-coded version here is using only safe primitives for all contexts
* where we can have KCSAN instrumentation. In particular, we cannot use
* prandom_u32() directly, as its tracepoint could cause recursion.
* Returns a pseudo-random number in interval [0, ep_ro). Simple linear
* congruential generator, using constants from "Numerical Recipes".
*/
static u32 kcsan_prandom_u32_max(u32 ep_ro)
{
struct rnd_state *state = &get_cpu_var(kcsan_rand_state);
const u32 res = prandom_u32_state(state);
u32 state = this_cpu_read(kcsan_rand_state);
put_cpu_var(kcsan_rand_state);
return (u32)(((u64) res * ep_ro) >> 32);
state = 1664525 * state + 1013904223;
this_cpu_write(kcsan_rand_state, state);
return state % ep_ro;
}
static inline void reset_kcsan_skip(void)
@ -639,10 +635,14 @@ static __always_inline void check_access(const volatile void *ptr, size_t size,
void __init kcsan_init(void)
{
int cpu;
BUG_ON(!in_task());
kcsan_debugfs_init();
prandom_seed_full_state(&kcsan_rand_state);
for_each_possible_cpu(cpu)
per_cpu(kcsan_rand_state, cpu) = (u32)get_cycles();
/*
* We are in the init task, and no other tasks should be running;

1
kernel/locking/Makefile
View File

@ -15,6 +15,7 @@ CFLAGS_REMOVE_mutex-debug.o = $(CC_FLAGS_FTRACE)
CFLAGS_REMOVE_rtmutex-debug.o = $(CC_FLAGS_FTRACE)
endif
obj-$(CONFIG_DEBUG_IRQFLAGS) += irqflag-debug.o
obj-$(CONFIG_DEBUG_MUTEXES) += mutex-debug.o
obj-$(CONFIG_LOCKDEP) += lockdep.o
ifeq ($(CONFIG_PROC_FS),y)

13
kernel/locking/irqflag-debug.c Normal file
View File

@ -0,0 +1,13 @@
// SPDX-License-Identifier: GPL-2.0-only
#include <linux/bug.h>
#include <linux/export.h>
#include <linux/irqflags.h>
noinstr void warn_bogus_irq_restore(void)
{
instrumentation_begin();
WARN_ONCE(1, "raw_local_irq_restore() called with IRQs enabled\n");
instrumentation_end();
}
EXPORT_SYMBOL(warn_bogus_irq_restore);

186
kernel/locking/lockdep.c
View File

@ -1290,6 +1290,7 @@ register_lock_class(struct lockdep_map *lock, unsigned int subclass, int force)
class->name_version = count_matching_names(class);
class->wait_type_inner = lock->wait_type_inner;
class->wait_type_outer = lock->wait_type_outer;
class->lock_type = lock->lock_type;
/*
* We use RCU's safe list-add method to make
* parallel walking of the hash-list safe:
@ -1671,6 +1672,7 @@ static inline struct lock_list *__bfs_next(struct lock_list *lock, int offset)
static enum bfs_result __bfs(struct lock_list *source_entry,
void *data,
bool (*match)(struct lock_list *entry, void *data),
bool (*skip)(struct lock_list *entry, void *data),
struct lock_list **target_entry,
int offset)
{
@ -1731,7 +1733,12 @@ static enum bfs_result __bfs(struct lock_list *source_entry,
/*
* Step 3: we haven't visited this and there is a strong
* dependency path to this, so check with @match.
* If @skip is provide and returns true, we skip this
* lock (and any path this lock is in).
*/
if (skip && skip(lock, data))
continue;
if (match(lock, data)) {
*target_entry = lock;
return BFS_RMATCH;
@ -1774,9 +1781,10 @@ static inline enum bfs_result
__bfs_forwards(struct lock_list *src_entry,
void *data,
bool (*match)(struct lock_list *entry, void *data),
bool (*skip)(struct lock_list *entry, void *data),
struct lock_list **target_entry)
{
return __bfs(src_entry, data, match, target_entry,
return __bfs(src_entry, data, match, skip, target_entry,
offsetof(struct lock_class, locks_after));
}
@ -1785,9 +1793,10 @@ static inline enum bfs_result
__bfs_backwards(struct lock_list *src_entry,
void *data,
bool (*match)(struct lock_list *entry, void *data),
bool (*skip)(struct lock_list *entry, void *data),
struct lock_list **target_entry)
{
return __bfs(src_entry, data, match, target_entry,
return __bfs(src_entry, data, match, skip, target_entry,
offsetof(struct lock_class, locks_before));
}
@ -2018,7 +2027,7 @@ static unsigned long __lockdep_count_forward_deps(struct lock_list *this)
unsigned long count = 0;
struct lock_list *target_entry;
__bfs_forwards(this, (void *)&count, noop_count, &target_entry);
__bfs_forwards(this, (void *)&count, noop_count, NULL, &target_entry);
return count;
}
@ -2043,7 +2052,7 @@ static unsigned long __lockdep_count_backward_deps(struct lock_list *this)
unsigned long count = 0;
struct lock_list *target_entry;
__bfs_backwards(this, (void *)&count, noop_count, &target_entry);
__bfs_backwards(this, (void *)&count, noop_count, NULL, &target_entry);
return count;
}
@ -2071,11 +2080,12 @@ unsigned long lockdep_count_backward_deps(struct lock_class *class)
static noinline enum bfs_result
check_path(struct held_lock *target, struct lock_list *src_entry,
bool (*match)(struct lock_list *entry, void *data),
bool (*skip)(struct lock_list *entry, void *data),
struct lock_list **target_entry)
{
enum bfs_result ret;
ret = __bfs_forwards(src_entry, target, match, target_entry);
ret = __bfs_forwards(src_entry, target, match, skip, target_entry);
if (unlikely(bfs_error(ret)))
print_bfs_bug(ret);
@ -2102,7 +2112,7 @@ check_noncircular(struct held_lock *src, struct held_lock *target,
debug_atomic_inc(nr_cyclic_checks);
ret = check_path(target, &src_entry, hlock_conflict, &target_entry);
ret = check_path(target, &src_entry, hlock_conflict, NULL, &target_entry);
if (unlikely(ret == BFS_RMATCH)) {
if (!*trace) {
@ -2120,46 +2130,6 @@ check_noncircular(struct held_lock *src, struct held_lock *target,
return ret;
}
#ifdef CONFIG_LOCKDEP_SMALL
/*
* Check that the dependency graph starting at <src> can lead to
* <target> or not. If it can, <src> -> <target> dependency is already
* in the graph.
*
* Return BFS_RMATCH if it does, or BFS_RMATCH if it does not, return BFS_E* if
* any error appears in the bfs search.
*/
static noinline enum bfs_result
check_redundant(struct held_lock *src, struct held_lock *target)
{
enum bfs_result ret;
struct lock_list *target_entry;
struct lock_list src_entry;
bfs_init_root(&src_entry, src);
/*
* Special setup for check_redundant().
*
* To report redundant, we need to find a strong dependency path that
* is equal to or stronger than <src> -> <target>. So if <src> is E,
* we need to let __bfs() only search for a path starting at a -(E*)->,
* we achieve this by setting the initial node's ->only_xr to true in
* that case. And if <prev> is S, we set initial ->only_xr to false
* because both -(S*)-> (equal) and -(E*)-> (stronger) are redundant.
*/
src_entry.only_xr = src->read == 0;
debug_atomic_inc(nr_redundant_checks);
ret = check_path(target, &src_entry, hlock_equal, &target_entry);
if (ret == BFS_RMATCH)
debug_atomic_inc(nr_redundant);
return ret;
}
#endif
#ifdef CONFIG_TRACE_IRQFLAGS
/*
@ -2230,6 +2200,44 @@ static inline bool usage_match(struct lock_list *entry, void *mask)
return !!((entry->class->usage_mask & LOCKF_IRQ) & *(unsigned long *)mask);
}
static inline bool usage_skip(struct lock_list *entry, void *mask)
{
/*
* Skip local_lock() for irq inversion detection.
*
* For !RT, local_lock() is not a real lock, so it won't carry any
* dependency.
*
* For RT, an irq inversion happens when we have lock A and B, and on
* some CPU we can have:
*
* lock(A);
* <interrupted>
* lock(B);
*
* where lock(B) cannot sleep, and we have a dependency B -> ... -> A.
*
* Now we prove local_lock() cannot exist in that dependency. First we
* have the observation for any lock chain L1 -> ... -> Ln, for any
* 1 <= i <= n, Li.inner_wait_type <= L1.inner_wait_type, otherwise
* wait context check will complain. And since B is not a sleep lock,
* therefore B.inner_wait_type >= 2, and since the inner_wait_type of
* local_lock() is 3, which is greater than 2, therefore there is no
* way the local_lock() exists in the dependency B -> ... -> A.
*
* As a result, we will skip local_lock(), when we search for irq
* inversion bugs.
*/
if (entry->class->lock_type == LD_LOCK_PERCPU) {
if (DEBUG_LOCKS_WARN_ON(entry->class->wait_type_inner < LD_WAIT_CONFIG))
return false;
return true;
}
return false;
}
/*
* Find a node in the forwards-direction dependency sub-graph starting
* at @root->class that matches @bit.
@ -2245,7 +2253,7 @@ find_usage_forwards(struct lock_list *root, unsigned long usage_mask,
debug_atomic_inc(nr_find_usage_forwards_checks);
result = __bfs_forwards(root, &usage_mask, usage_match, target_entry);
result = __bfs_forwards(root, &usage_mask, usage_match, usage_skip, target_entry);
return result;
}
@ -2262,7 +2270,7 @@ find_usage_backwards(struct lock_list *root, unsigned long usage_mask,
debug_atomic_inc(nr_find_usage_backwards_checks);
result = __bfs_backwards(root, &usage_mask, usage_match, target_entry);
result = __bfs_backwards(root, &usage_mask, usage_match, usage_skip, target_entry);
return result;
}
@ -2627,7 +2635,7 @@ static int check_irq_usage(struct task_struct *curr, struct held_lock *prev,
*/
bfs_init_rootb(&this, prev);
ret = __bfs_backwards(&this, &usage_mask, usage_accumulate, NULL);
ret = __bfs_backwards(&this, &usage_mask, usage_accumulate, usage_skip, NULL);
if (bfs_error(ret)) {
print_bfs_bug(ret);
return 0;
@ -2694,8 +2702,68 @@ static inline int check_irq_usage(struct task_struct *curr,
{
return 1;
}
static inline bool usage_skip(struct lock_list *entry, void *mask)
{
return false;
}
#endif /* CONFIG_TRACE_IRQFLAGS */
#ifdef CONFIG_LOCKDEP_SMALL
/*
* Check that the dependency graph starting at <src> can lead to
* <target> or not. If it can, <src> -> <target> dependency is already
* in the graph.
*
* Return BFS_RMATCH if it does, or BFS_RMATCH if it does not, return BFS_E* if
* any error appears in the bfs search.
*/
static noinline enum bfs_result
check_redundant(struct held_lock *src, struct held_lock *target)
{
enum bfs_result ret;
struct lock_list *target_entry;
struct lock_list src_entry;
bfs_init_root(&src_entry, src);
/*
* Special setup for check_redundant().
*
* To report redundant, we need to find a strong dependency path that
* is equal to or stronger than <src> -> <target>. So if <src> is E,
* we need to let __bfs() only search for a path starting at a -(E*)->,
* we achieve this by setting the initial node's ->only_xr to true in
* that case. And if <prev> is S, we set initial ->only_xr to false
* because both -(S*)-> (equal) and -(E*)-> (stronger) are redundant.
*/
src_entry.only_xr = src->read == 0;
debug_atomic_inc(nr_redundant_checks);
/*
* Note: we skip local_lock() for redundant check, because as the
* comment in usage_skip(), A -> local_lock() -> B and A -> B are not
* the same.
*/
ret = check_path(target, &src_entry, hlock_equal, usage_skip, &target_entry);
if (ret == BFS_RMATCH)
debug_atomic_inc(nr_redundant);
return ret;
}
#else
static inline enum bfs_result
check_redundant(struct held_lock *src, struct held_lock *target)
{
return BFS_RNOMATCH;
}
#endif
static void inc_chains(int irq_context)
{
if (irq_context & LOCK_CHAIN_HARDIRQ_CONTEXT)
@ -2916,7 +2984,6 @@ check_prev_add(struct task_struct *curr, struct held_lock *prev,
}
}
#ifdef CONFIG_LOCKDEP_SMALL
/*
* Is the <prev> -> <next> link redundant?
*/
@ -2925,7 +2992,6 @@ check_prev_add(struct task_struct *curr, struct held_lock *prev,
return 0;
else if (ret == BFS_RMATCH)
return 2;
#endif
if (!*trace) {
*trace = save_trace();
@ -3707,7 +3773,7 @@ static void
print_usage_bug(struct task_struct *curr, struct held_lock *this,
enum lock_usage_bit prev_bit, enum lock_usage_bit new_bit)
{
if (!debug_locks_off_graph_unlock() || debug_locks_silent)
if (!debug_locks_off() || debug_locks_silent)
return;
pr_warn("\n");
@ -3748,6 +3814,7 @@ valid_state(struct task_struct *curr, struct held_lock *this,
enum lock_usage_bit new_bit, enum lock_usage_bit bad_bit)
{
if (unlikely(hlock_class(this)->usage_mask & (1 << bad_bit))) {
graph_unlock();
print_usage_bug(curr, this, bad_bit, new_bit);
return 0;
}
@ -4503,9 +4570,9 @@ print_lock_invalid_wait_context(struct task_struct *curr,
*/
static int check_wait_context(struct task_struct *curr, struct held_lock *next)
{
short next_inner = hlock_class(next)->wait_type_inner;
short next_outer = hlock_class(next)->wait_type_outer;
short curr_inner;
u8 next_inner = hlock_class(next)->wait_type_inner;
u8 next_outer = hlock_class(next)->wait_type_outer;
u8 curr_inner;
int depth;
if (!curr->lockdep_depth || !next_inner || next->trylock)
@ -4528,7 +4595,7 @@ static int check_wait_context(struct task_struct *curr, struct held_lock *next)
for (; depth < curr->lockdep_depth; depth++) {
struct held_lock *prev = curr->held_locks + depth;
short prev_inner = hlock_class(prev)->wait_type_inner;
u8 prev_inner = hlock_class(prev)->wait_type_inner;
if (prev_inner) {
/*
@ -4577,9 +4644,9 @@ static inline int check_wait_context(struct task_struct *curr,
/*
* Initialize a lock instance's lock-class mapping info:
*/
void lockdep_init_map_waits(struct lockdep_map *lock, const char *name,
void lockdep_init_map_type(struct lockdep_map *lock, const char *name,
struct lock_class_key *key, int subclass,
short inner, short outer)
u8 inner, u8 outer, u8 lock_type)
{
int i;
@ -4602,6 +4669,7 @@ void lockdep_init_map_waits(struct lockdep_map *lock, const char *name,
lock->wait_type_outer = outer;
lock->wait_type_inner = inner;
lock->lock_type = lock_type;
/*
* No key, no joy, we need to hash something.
@ -4636,7 +4704,7 @@ void lockdep_init_map_waits(struct lockdep_map *lock, const char *name,
raw_local_irq_restore(flags);
}
}
EXPORT_SYMBOL_GPL(lockdep_init_map_waits);
EXPORT_SYMBOL_GPL(lockdep_init_map_type);
struct lock_class_key __lockdep_no_validate__;
EXPORT_SYMBOL_GPL(__lockdep_no_validate__);

10
kernel/locking/mutex.c
View File

@ -86,16 +86,6 @@ bool mutex_is_locked(struct mutex *lock)
}
EXPORT_SYMBOL(mutex_is_locked);
__must_check enum mutex_trylock_recursive_enum
mutex_trylock_recursive(struct mutex *lock)
{
if (unlikely(__mutex_owner(lock) == current))
return MUTEX_TRYLOCK_RECURSIVE;
return mutex_trylock(lock);
}
EXPORT_SYMBOL(mutex_trylock_recursive);
static inline unsigned long __owner_flags(unsigned long owner)
{
return owner & MUTEX_FLAGS;

17
kernel/locking/rtmutex.c
View File

@ -1604,8 +1604,11 @@ void __sched rt_mutex_unlock(struct rt_mutex *lock)
EXPORT_SYMBOL_GPL(rt_mutex_unlock);
/**
* Futex variant, that since futex variants do not use the fast-path, can be
* simple and will not need to retry.
* __rt_mutex_futex_unlock - Futex variant, that since futex variants
* do not use the fast-path, can be simple and will not need to retry.
*
* @lock: The rt_mutex to be unlocked
* @wake_q: The wake queue head from which to get the next lock waiter
*/
bool __sched __rt_mutex_futex_unlock(struct rt_mutex *lock,
struct wake_q_head *wake_q)
@ -1662,13 +1665,15 @@ void rt_mutex_destroy(struct rt_mutex *lock)
EXPORT_SYMBOL_GPL(rt_mutex_destroy);
/**
* __rt_mutex_init - initialize the rt lock
* __rt_mutex_init - initialize the rt_mutex
*
* @lock: the rt lock to be initialized
* @lock: The rt_mutex to be initialized
* @name: The lock name used for debugging
* @key: The lock class key used for debugging
*
* Initialize the rt lock to unlocked state.
* Initialize the rt_mutex to unlocked state.
*
* Initializing of a locked rt lock is not allowed
* Initializing of a locked rt_mutex is not allowed
*/
void __rt_mutex_init(struct rt_mutex *lock, const char *name,
struct lock_class_key *key)

0
kernel/locking/rwsem.h
View File

8
lib/Kconfig.debug
View File

@ -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

3
lib/Makefile
View File

@ -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 \

334
lib/locking-selftest.c
View File

@ -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;

6
scripts/checkpatch.pl
View File

@ -7062,12 +7062,6 @@ sub process {
}
}
# check for mutex_trylock_recursive usage
if ($line =~ /mutex_trylock_recursive/) {
ERROR("LOCKING",
"recursive locking is bad, do not use this ever.\n" . $herecurr);
}
# check for lockdep_set_novalidate_class
if ($line =~ /^.\s*lockdep_set_novalidate_class\s*\(/ ||
$line =~ /__lockdep_no_validate__\s*\)/ ) {

12
tools/memory-model/Documentation/glossary.txt
View File

@ -33,10 +33,11 @@ Acquire: With respect to a lock, acquiring that lock, for example,
acquire loads.
When an acquire load returns the value stored by a release store
to that same variable, then all operations preceding that store
happen before any operations following that load acquire.
to that same variable, (in other words, the acquire load "reads
from" the release store), then all operations preceding that
store "happen before" any operations following that load acquire.
See also "Relaxed" and "Release".
See also "Happens-Before", "Reads-From", "Relaxed", and "Release".
Coherence (co): When one CPU's store to a given variable overwrites
either the value from another CPU's store or some later value,
@ -119,6 +120,11 @@ Fully Ordered: An operation such as smp_mb() that orders all of
that orders all of its CPU's prior accesses, itself, and
all of its CPU's subsequent accesses.
Happens-Before (hb): A relation between two accesses in which LKMM
guarantees the first access precedes the second. For more
detail, please see the "THE HAPPENS-BEFORE RELATION: hb"
section of explanation.txt.
Marked Access: An access to a variable that uses an special function or
macro such as "r1 = READ_ONCE(x)" or "smp_store_release(&a, 1)".

2
tools/memory-model/README
View File

@ -51,7 +51,7 @@ klitmus7 Compatibility Table
============ ==========
target Linux herdtools7
------------ ----------
-- 4.18 7.48 --
-- 4.14 7.48 --
4.15 -- 4.19 7.49 --
4.20 -- 5.5 7.54 --
5.6 -- 7.56 --

4
tools/memory-model/litmus-tests/CoRR+poonceonce+Once.litmus
View File

@ -7,9 +7,7 @@ C CoRR+poonceonce+Once
* reads from the same variable are ordered.
*)
{
int x;
}
{}
P0(int *x)
{

4
tools/memory-model/litmus-tests/CoRW+poonceonce+Once.litmus
View File

@ -7,9 +7,7 @@ C CoRW+poonceonce+Once
* a given variable and a later write to that same variable are ordered.
*)
{
int x;
}
{}
P0(int *x)
{

4
tools/memory-model/litmus-tests/CoWR+poonceonce+Once.litmus
View File

@ -7,9 +7,7 @@ C CoWR+poonceonce+Once
* given variable and a later read from that same variable are ordered.
*)
{
int x;
}
{}
P0(int *x)
{

4
tools/memory-model/litmus-tests/CoWW+poonceonce.litmus
View File

@ -7,9 +7,7 @@ C CoWW+poonceonce
* writes to the same variable are ordered.
*)
{
int x;
}
{}
P0(int *x)
{

5
tools/memory-model/litmus-tests/IRIW+fencembonceonces+OnceOnce.litmus
View File

@ -10,10 +10,7 @@ C IRIW+fencembonceonces+OnceOnce
* process? This litmus test exercises LKMM's "propagation" rule.
*)
{
int x;
int y;
}
{}
P0(int *x)
{

5
tools/memory-model/litmus-tests/IRIW+poonceonces+OnceOnce.litmus
View File

@ -10,10 +10,7 @@ C IRIW+poonceonces+OnceOnce
* different process?
*)
{
int x;
int y;
}
{}
P0(int *x)
{

7
tools/memory-model/litmus-tests/ISA2+pooncelock+pooncelock+pombonce.litmus
View File

@ -7,12 +7,7 @@ C ISA2+pooncelock+pooncelock+pombonce
* (in P0() and P1()) is visible to external process P2().
*)
{
spinlock_t mylock;
int x;
int y;
int z;
}
{}
P0(int *x, int *y, spinlock_t *mylock)
{

6
tools/memory-model/litmus-tests/ISA2+poonceonces.litmus
View File

@ -9,11 +9,7 @@ C ISA2+poonceonces
* of the smp_load_acquire() invocations are replaced by READ_ONCE()?
*)
{
int x;
int y;
int z;
}
{}
P0(int *x, int *y)
{

6
tools/memory-model/litmus-tests/ISA2+pooncerelease+poacquirerelease+poacquireonce.litmus
View File

@ -11,11 +11,7 @@ C ISA2+pooncerelease+poacquirerelease+poacquireonce
* (AKA non-rf) link, so release-acquire is all that is needed.
*)
{
int x;
int y;
int z;
}
{}
P0(int *x, int *y)
{

5
tools/memory-model/litmus-tests/LB+fencembonceonce+ctrlonceonce.litmus
View File

@ -11,10 +11,7 @@ C LB+fencembonceonce+ctrlonceonce
* another control dependency and order would still be maintained.)
*)
{
int x;
int y;
}
{}
P0(int *x, int *y)
{

5
tools/memory-model/litmus-tests/LB+poacquireonce+pooncerelease.litmus
View File

@ -8,10 +8,7 @@ C LB+poacquireonce+pooncerelease
* to the other?
*)
{
int x;
int y;
}
{}
P0(int *x, int *y)
{

5
tools/memory-model/litmus-tests/LB+poonceonces.litmus
View File

@ -7,10 +7,7 @@ C LB+poonceonces
* be prevented even with no explicit ordering?
*)
{
int x;
int y;
}
{}
P0(int *x, int *y)
{

5
tools/memory-model/litmus-tests/MP+fencewmbonceonce+fencermbonceonce.litmus
View File

@ -8,10 +8,7 @@ C MP+fencewmbonceonce+fencermbonceonce
* is usually better to use smp_store_release() and smp_load_acquire().
*)
{
int buf;
int flag;
}
{}
P0(int *buf, int *flag) // Producer
{

4
tools/memory-model/litmus-tests/MP+onceassign+derefonce.litmus
View File

@ -10,9 +10,7 @@ C MP+onceassign+derefonce
*)
{
int *p=y;
int x;
int y=0;
p=y;
}
P0(int *x, int **p) // Producer

5
tools/memory-model/litmus-tests/MP+polockmbonce+poacquiresilsil.litmus
View File

@ -10,10 +10,7 @@ C MP+polockmbonce+poacquiresilsil
* executed before the lock was acquired (loosely speaking).
*)
{
spinlock_t lo;
int x;
}
{}
P0(spinlock_t *lo, int *x) // Producer
{

5
tools/memory-model/litmus-tests/MP+polockonce+poacquiresilsil.litmus
View File

@ -10,10 +10,7 @@ C MP+polockonce+poacquiresilsil
* speaking).
*)
{
spinlock_t lo;
int x;
}
{}
P0(spinlock_t *lo, int *x) // Producer
{

6
tools/memory-model/litmus-tests/MP+polocks.litmus
View File

@ -11,11 +11,7 @@ C MP+polocks
* to see all prior accesses by those other CPUs.
*)
{
spinlock_t mylock;
int buf;
int flag;
}
{}
P0(int *buf, int *flag, spinlock_t *mylock) // Producer
{

5
tools/memory-model/litmus-tests/MP+poonceonces.litmus
View File

@ -7,10 +7,7 @@ C MP+poonceonces
* no ordering at all?
*)
{
int buf;
int flag;
}
{}
P0(int *buf, int *flag) // Producer
{

5
tools/memory-model/litmus-tests/MP+pooncerelease+poacquireonce.litmus
View File

@ -8,10 +8,7 @@ C MP+pooncerelease+poacquireonce
* pattern.
*)
{
int buf;
int flag;
}
{}
P0(int *buf, int *flag) // Producer
{

6
tools/memory-model/litmus-tests/MP+porevlocks.litmus
View File

@ -11,11 +11,7 @@ C MP+porevlocks
* see all prior accesses by those other CPUs.
*)
{
spinlock_t mylock;
int buf;
int flag;
}
{}
P0(int *buf, int *flag, spinlock_t *mylock) // Consumer
{

5
tools/memory-model/litmus-tests/R+fencembonceonces.litmus
View File

@ -9,10 +9,7 @@ C R+fencembonceonces
* cause the resulting test to be allowed.
*)
{
int x;
int y;
}
{}
P0(int *x, int *y)
{

5
tools/memory-model/litmus-tests/R+poonceonces.litmus
View File

@ -8,10 +8,7 @@ C R+poonceonces
* store propagation delays.
*)
{
int x;
int y;
}
{}
P0(int *x, int *y)
{

5
tools/memory-model/litmus-tests/S+fencewmbonceonce+poacquireonce.litmus
View File

@ -7,10 +7,7 @@ C S+fencewmbonceonce+poacquireonce
* store against a subsequent store?
*)
{
int x;
int y;
}
{}
P0(int *x, int *y)
{

5
tools/memory-model/litmus-tests/S+poonceonces.litmus
View File

@ -9,10 +9,7 @@ C S+poonceonces
* READ_ONCE(), is ordering preserved?
*)
{
int x;
int y;
}
{}
P0(int *x, int *y)
{

5
tools/memory-model/litmus-tests/SB+fencembonceonces.litmus
View File

@ -9,10 +9,7 @@ C SB+fencembonceonces
* suffice, but not much else.)
*)
{
int x;
int y;
}
{}
P0(int *x, int *y)
{

5
tools/memory-model/litmus-tests/SB+poonceonces.litmus
View File

@ -8,10 +8,7 @@ C SB+poonceonces
* variable that the preceding process reads.
*)
{
int x;
int y;
}
{}
P0(int *x, int *y)
{

5
tools/memory-model/litmus-tests/SB+rfionceonce-poonceonces.litmus
View File

@ -6,10 +6,7 @@ C SB+rfionceonce-poonceonces
* This litmus test demonstrates that LKMM is not fully multicopy atomic.
*)
{
int x;
int y;
}
{}
P0(int *x, int *y)
{

5
tools/memory-model/litmus-tests/WRC+poonceonces+Once.litmus
View File

@ -8,10 +8,7 @@ C WRC+poonceonces+Once
* test has no ordering at all.
*)
{
int x;
int y;
}
{}
P0(int *x)
{

5
tools/memory-model/litmus-tests/WRC+pooncerelease+fencermbonceonce+Once.litmus
View File

@ -10,10 +10,7 @@ C WRC+pooncerelease+fencermbonceonce+Once
* is A-cumulative in LKMM.
*)
{
int x;
int y;
}
{}
P0(int *x)
{

7
tools/memory-model/litmus-tests/Z6.0+pooncelock+poonceLock+pombonce.litmus
View File

@ -9,12 +9,7 @@ C Z6.0+pooncelock+poonceLock+pombonce
* by CPUs not holding that lock.
*)
{
spinlock_t mylock;
int x;
int y;
int z;
}
{}
P0(int *x, int *y, spinlock_t *mylock)
{

7
tools/memory-model/litmus-tests/Z6.0+pooncelock+pooncelock+pombonce.litmus
View File

@ -8,12 +8,7 @@ C Z6.0+pooncelock+pooncelock+pombonce
* seen as ordered by a third process not holding that lock.
*)
{
spinlock_t mylock;
int x;
int y;
int z;
}
{}
P0(int *x, int *y, spinlock_t *mylock)
{

6
tools/memory-model/litmus-tests/Z6.0+pooncerelease+poacquirerelease+fencembonceonce.litmus
View File

@ -14,11 +14,7 @@ C Z6.0+pooncerelease+poacquirerelease+fencembonceonce
* involving locking.)
*)
{
int x;
int y;
int z;
}
{}
P0(int *x, int *y)
{