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Merge tag 'locking-core-2020-08-03' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Browse Source 
Pull locking updates from Ingo Molnar:

 - LKMM updates: mostly documentation changes, but also some new litmus
   tests for atomic ops.

 - KCSAN updates: the most important change is that GCC 11 now has all
   fixes in place to support KCSAN, so GCC support can be enabled again.
   Also more annotations.

 - futex updates: minor cleanups and simplifications

 - seqlock updates: merge preparatory changes/cleanups for the
   'associated locks' facilities.

 - lockdep updates:
    - simplify IRQ trace event handling
    - add various new debug checks
    - simplify header dependencies, split out <linux/lockdep_types.h>,
      decouple lockdep from other low level headers some more
    - fix NMI handling

 - misc cleanups and smaller fixes

* tag 'locking-core-2020-08-03' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (60 commits)
  kcsan: Improve IRQ state trace reporting
  lockdep: Refactor IRQ trace events fields into struct
  seqlock: lockdep assert non-preemptibility on seqcount_t write
  lockdep: Add preemption enabled/disabled assertion APIs
  seqlock: Implement raw_seqcount_begin() in terms of raw_read_seqcount()
  seqlock: Add kernel-doc for seqcount_t and seqlock_t APIs
  seqlock: Reorder seqcount_t and seqlock_t API definitions
  seqlock: seqcount_t latch: End read sections with read_seqcount_retry()
  seqlock: Properly format kernel-doc code samples
  Documentation: locking: Describe seqlock design and usage
  locking/qspinlock: Do not include atomic.h from qspinlock_types.h
  locking/atomic: Move ATOMIC_INIT into linux/types.h
  lockdep: Move list.h inclusion into lockdep.h
  locking/lockdep: Fix TRACE_IRQFLAGS vs. NMIs
  futex: Remove unused or redundant includes
  futex: Consistently use fshared as boolean
  futex: Remove needless goto's
  futex: Remove put_futex_key()
  rwsem: fix commas in initialisation
  docs: locking: Replace HTTP links with HTTPS ones
  ...
This commit is contained in:
Linus Torvalds
2020-08-03 14:39:35 -07:00
parent 8f0cb6660a 992414a18c
commit 9ba19ccd2d
86 changed files with 2807 additions and 864 deletions
Download Patch File Download Diff File Expand all files Collapse all files

142
kernel/locking/lockdep.c
View File

@@ -395,7 +395,7 @@ void lockdep_init_task(struct task_struct *task)
static __always_inline void lockdep_recursion_finish(void)
{
if (WARN_ON_ONCE(--current->lockdep_recursion))
if (WARN_ON_ONCE((--current->lockdep_recursion) & LOCKDEP_RECURSION_MASK))
current->lockdep_recursion = 0;
}
@@ -2062,9 +2062,9 @@ print_bad_irq_dependency(struct task_struct *curr,
pr_warn("-----------------------------------------------------\n");
pr_warn("%s/%d [HC%u[%lu]:SC%u[%lu]:HE%u:SE%u] is trying to acquire:\n",
curr->comm, task_pid_nr(curr),
curr->hardirq_context, hardirq_count() >> HARDIRQ_SHIFT,
lockdep_hardirq_context(), hardirq_count() >> HARDIRQ_SHIFT,
curr->softirq_context, softirq_count() >> SOFTIRQ_SHIFT,
curr->hardirqs_enabled,
lockdep_hardirqs_enabled(),
curr->softirqs_enabled);
print_lock(next);
@@ -3331,9 +3331,9 @@ print_usage_bug(struct task_struct *curr, struct held_lock *this,
pr_warn("%s/%d [HC%u[%lu]:SC%u[%lu]:HE%u:SE%u] takes:\n",
curr->comm, task_pid_nr(curr),
lockdep_hardirq_context(curr), hardirq_count() >> HARDIRQ_SHIFT,
lockdep_hardirq_context(), hardirq_count() >> HARDIRQ_SHIFT,
lockdep_softirq_context(curr), softirq_count() >> SOFTIRQ_SHIFT,
lockdep_hardirqs_enabled(curr),
lockdep_hardirqs_enabled(),
lockdep_softirqs_enabled(curr));
print_lock(this);
@@ -3484,19 +3484,21 @@ check_usage_backwards(struct task_struct *curr, struct held_lock *this,
void print_irqtrace_events(struct task_struct *curr)
{
printk("irq event stamp: %u\n", curr->irq_events);
const struct irqtrace_events *trace = &curr->irqtrace;
printk("irq event stamp: %u\n", trace->irq_events);
printk("hardirqs last enabled at (%u): [<%px>] %pS\n",
curr->hardirq_enable_event, (void *)curr->hardirq_enable_ip,
(void *)curr->hardirq_enable_ip);
trace->hardirq_enable_event, (void *)trace->hardirq_enable_ip,
(void *)trace->hardirq_enable_ip);
printk("hardirqs last disabled at (%u): [<%px>] %pS\n",
curr->hardirq_disable_event, (void *)curr->hardirq_disable_ip,
(void *)curr->hardirq_disable_ip);
trace->hardirq_disable_event, (void *)trace->hardirq_disable_ip,
(void *)trace->hardirq_disable_ip);
printk("softirqs last enabled at (%u): [<%px>] %pS\n",
curr->softirq_enable_event, (void *)curr->softirq_enable_ip,
(void *)curr->softirq_enable_ip);
trace->softirq_enable_event, (void *)trace->softirq_enable_ip,
(void *)trace->softirq_enable_ip);
printk("softirqs last disabled at (%u): [<%px>] %pS\n",
curr->softirq_disable_event, (void *)curr->softirq_disable_ip,
(void *)curr->softirq_disable_ip);
trace->softirq_disable_event, (void *)trace->softirq_disable_ip,
(void *)trace->softirq_disable_ip);
}
static int HARDIRQ_verbose(struct lock_class *class)
@@ -3646,10 +3648,19 @@ static void __trace_hardirqs_on_caller(void)
*/
void lockdep_hardirqs_on_prepare(unsigned long ip)
{
if (unlikely(!debug_locks || current->lockdep_recursion))
if (unlikely(!debug_locks))
return;
if (unlikely(current->hardirqs_enabled)) {
/*
* NMIs do not (and cannot) track lock dependencies, nothing to do.
*/
if (unlikely(in_nmi()))
return;
if (unlikely(current->lockdep_recursion & LOCKDEP_RECURSION_MASK))
return;
if (unlikely(lockdep_hardirqs_enabled())) {
/*
* Neither irq nor preemption are disabled here
* so this is racy by nature but losing one hit
@@ -3677,7 +3688,7 @@ void lockdep_hardirqs_on_prepare(unsigned long ip)
* Can't allow enabling interrupts while in an interrupt handler,
* that's general bad form and such. Recursion, limited stack etc..
*/
if (DEBUG_LOCKS_WARN_ON(current->hardirq_context))
if (DEBUG_LOCKS_WARN_ON(lockdep_hardirq_context()))
return;
current->hardirq_chain_key = current->curr_chain_key;
@@ -3690,12 +3701,35 @@ EXPORT_SYMBOL_GPL(lockdep_hardirqs_on_prepare);
void noinstr lockdep_hardirqs_on(unsigned long ip)
{
struct task_struct *curr = current;
struct irqtrace_events *trace = &current->irqtrace;
if (unlikely(!debug_locks || curr->lockdep_recursion))
if (unlikely(!debug_locks))
return;
if (curr->hardirqs_enabled) {
/*
* NMIs can happen in the middle of local_irq_{en,dis}able() where the
* tracking state and hardware state are out of sync.
*
* NMIs must save lockdep_hardirqs_enabled() to restore IRQ state from,
* and not rely on hardware state like normal interrupts.
*/
if (unlikely(in_nmi())) {
if (!IS_ENABLED(CONFIG_TRACE_IRQFLAGS_NMI))
return;
/*
* Skip:
* - recursion check, because NMI can hit lockdep;
* - hardware state check, because above;
* - chain_key check, see lockdep_hardirqs_on_prepare().
*/
goto skip_checks;
}
if (unlikely(current->lockdep_recursion & LOCKDEP_RECURSION_MASK))
return;
if (lockdep_hardirqs_enabled()) {
/*
* Neither irq nor preemption are disabled here
* so this is racy by nature but losing one hit
@@ -3720,10 +3754,11 @@ void noinstr lockdep_hardirqs_on(unsigned long ip)
DEBUG_LOCKS_WARN_ON(current->hardirq_chain_key !=
current->curr_chain_key);
skip_checks:
/* we'll do an OFF -> ON transition: */
curr->hardirqs_enabled = 1;
curr->hardirq_enable_ip = ip;
curr->hardirq_enable_event = ++curr->irq_events;
this_cpu_write(hardirqs_enabled, 1);
trace->hardirq_enable_ip = ip;
trace->hardirq_enable_event = ++trace->irq_events;
debug_atomic_inc(hardirqs_on_events);
}
EXPORT_SYMBOL_GPL(lockdep_hardirqs_on);
@@ -3733,9 +3768,18 @@ EXPORT_SYMBOL_GPL(lockdep_hardirqs_on);
*/
void noinstr lockdep_hardirqs_off(unsigned long ip)
{
struct task_struct *curr = current;
if (unlikely(!debug_locks))
return;
if (unlikely(!debug_locks || curr->lockdep_recursion))
/*
* Matching lockdep_hardirqs_on(), allow NMIs in the middle of lockdep;
* they will restore the software state. This ensures the software
* state is consistent inside NMIs as well.
*/
if (in_nmi()) {
if (!IS_ENABLED(CONFIG_TRACE_IRQFLAGS_NMI))
return;
} else if (current->lockdep_recursion & LOCKDEP_RECURSION_MASK)
return;
/*
@@ -3745,13 +3789,15 @@ void noinstr lockdep_hardirqs_off(unsigned long ip)
if (DEBUG_LOCKS_WARN_ON(!irqs_disabled()))
return;
if (curr->hardirqs_enabled) {
if (lockdep_hardirqs_enabled()) {
struct irqtrace_events *trace = &current->irqtrace;
/*
* We have done an ON -> OFF transition:
*/
curr->hardirqs_enabled = 0;
curr->hardirq_disable_ip = ip;
curr->hardirq_disable_event = ++curr->irq_events;
this_cpu_write(hardirqs_enabled, 0);
trace->hardirq_disable_ip = ip;
trace->hardirq_disable_event = ++trace->irq_events;
debug_atomic_inc(hardirqs_off_events);
} else {
debug_atomic_inc(redundant_hardirqs_off);
@@ -3764,7 +3810,7 @@ EXPORT_SYMBOL_GPL(lockdep_hardirqs_off);
*/
void lockdep_softirqs_on(unsigned long ip)
{
struct task_struct *curr = current;
struct irqtrace_events *trace = &current->irqtrace;
if (unlikely(!debug_locks || current->lockdep_recursion))
return;
@@ -3776,7 +3822,7 @@ void lockdep_softirqs_on(unsigned long ip)
if (DEBUG_LOCKS_WARN_ON(!irqs_disabled()))
return;
if (curr->softirqs_enabled) {
if (current->softirqs_enabled) {
debug_atomic_inc(redundant_softirqs_on);
return;
}
@@ -3785,17 +3831,17 @@ void lockdep_softirqs_on(unsigned long ip)
/*
* We'll do an OFF -> ON transition:
*/
curr->softirqs_enabled = 1;
curr->softirq_enable_ip = ip;
curr->softirq_enable_event = ++curr->irq_events;
current->softirqs_enabled = 1;
trace->softirq_enable_ip = ip;
trace->softirq_enable_event = ++trace->irq_events;
debug_atomic_inc(softirqs_on_events);
/*
* We are going to turn softirqs on, so set the
* usage bit for all held locks, if hardirqs are
* enabled too:
*/
if (curr->hardirqs_enabled)
mark_held_locks(curr, LOCK_ENABLED_SOFTIRQ);
if (lockdep_hardirqs_enabled())
mark_held_locks(current, LOCK_ENABLED_SOFTIRQ);
lockdep_recursion_finish();
}
@@ -3804,8 +3850,6 @@ void lockdep_softirqs_on(unsigned long ip)
*/
void lockdep_softirqs_off(unsigned long ip)
{
struct task_struct *curr = current;
if (unlikely(!debug_locks || current->lockdep_recursion))
return;
@@ -3815,13 +3859,15 @@ void lockdep_softirqs_off(unsigned long ip)
if (DEBUG_LOCKS_WARN_ON(!irqs_disabled()))
return;
if (curr->softirqs_enabled) {
if (current->softirqs_enabled) {
struct irqtrace_events *trace = &current->irqtrace;
/*
* We have done an ON -> OFF transition:
*/
curr->softirqs_enabled = 0;
curr->softirq_disable_ip = ip;
curr->softirq_disable_event = ++curr->irq_events;
current->softirqs_enabled = 0;
trace->softirq_disable_ip = ip;
trace->softirq_disable_event = ++trace->irq_events;
debug_atomic_inc(softirqs_off_events);
/*
* Whoops, we wanted softirqs off, so why aren't they?
@@ -3843,7 +3889,7 @@ mark_usage(struct task_struct *curr, struct held_lock *hlock, int check)
*/
if (!hlock->trylock) {
if (hlock->read) {
if (curr->hardirq_context)
if (lockdep_hardirq_context())
if (!mark_lock(curr, hlock,
LOCK_USED_IN_HARDIRQ_READ))
return 0;
@@ -3852,7 +3898,7 @@ mark_usage(struct task_struct *curr, struct held_lock *hlock, int check)
LOCK_USED_IN_SOFTIRQ_READ))
return 0;
} else {
if (curr->hardirq_context)
if (lockdep_hardirq_context())
if (!mark_lock(curr, hlock, LOCK_USED_IN_HARDIRQ))
return 0;
if (curr->softirq_context)
@@ -3890,7 +3936,7 @@ lock_used:
static inline unsigned int task_irq_context(struct task_struct *task)
{
return LOCK_CHAIN_HARDIRQ_CONTEXT * !!task->hardirq_context +
return LOCK_CHAIN_HARDIRQ_CONTEXT * !!lockdep_hardirq_context() +
LOCK_CHAIN_SOFTIRQ_CONTEXT * !!task->softirq_context;
}
@@ -3983,7 +4029,7 @@ static inline short task_wait_context(struct task_struct *curr)
* Set appropriate wait type for the context; for IRQs we have to take
* into account force_irqthread as that is implied by PREEMPT_RT.
*/
if (curr->hardirq_context) {
if (lockdep_hardirq_context()) {
/*
* Check if force_irqthreads will run us threaded.
*/
@@ -4826,11 +4872,11 @@ static void check_flags(unsigned long flags)
return;
if (irqs_disabled_flags(flags)) {
if (DEBUG_LOCKS_WARN_ON(current->hardirqs_enabled)) {
if (DEBUG_LOCKS_WARN_ON(lockdep_hardirqs_enabled())) {
printk("possible reason: unannotated irqs-off.\n");
}
} else {
if (DEBUG_LOCKS_WARN_ON(!current->hardirqs_enabled)) {
if (DEBUG_LOCKS_WARN_ON(!lockdep_hardirqs_enabled())) {
printk("possible reason: unannotated irqs-on.\n");
}
}