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lockdep,trace: Expose tracepoints

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The lockdep tracepoints are under the lockdep recursion counter, this
has a bunch of nasty side effects:

 - TRACE_IRQFLAGS doesn't work across the entire tracepoint

 - RCU-lockdep doesn't see the tracepoints either, hiding numerous
   "suspicious RCU usage" warnings.

Pull the trace_lock_*() tracepoints completely out from under the
lockdep recursion handling and completely rely on the trace level
recusion handling -- also, tracing *SHOULD* not be taking locks in any
case.

Signed-off-by: Peter Zijlstra (Intel) <[email protected]>
Reviewed-by: Steven Rostedt (VMware) <[email protected]>
Reviewed-by: Thomas Gleixner <[email protected]>
Acked-by: Rafael J. Wysocki <[email protected]>
Tested-by: Marco Elver <[email protected]>
Link: https://lkml.kernel.org/r/[email protected]
This commit is contained in:
Peter Zijlstra committed 2020-08-26 12:41:56 +02:00
1 parent 044d0d6de9
commit eb1f00237a
1 file changed
+9 -5
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kernel/locking/lockdep.c
+9 -5
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@@ -4977,6 +4977,8 @@ void lock_acquire(struct lockdep_map *lock, unsigned int subclass,
{
unsigned long flags;
trace_lock_acquire(lock, subclass, trylock, read, check, nest_lock, ip);
if (unlikely(current->lockdep_recursion)) {
/* XXX allow trylock from NMI ?!? */
if (lockdep_nmi() && !trylock) {
@@ -5001,7 +5003,6 @@ void lock_acquire(struct lockdep_map *lock, unsigned int subclass,
check_flags(flags);
current->lockdep_recursion++;
trace_lock_acquire(lock, subclass, trylock, read, check, nest_lock, ip);
__lock_acquire(lock, subclass, trylock, read, check,
irqs_disabled_flags(flags), nest_lock, ip, 0, 0);
lockdep_recursion_finish();
@@ -5013,13 +5014,15 @@ void lock_release(struct lockdep_map *lock, unsigned long ip)
{
unsigned long flags;
trace_lock_release(lock, ip);
if (unlikely(current->lockdep_recursion))
return;
raw_local_irq_save(flags);
check_flags(flags);
current->lockdep_recursion++;
trace_lock_release(lock, ip);
if (__lock_release(lock, ip))
check_chain_key(current);
lockdep_recursion_finish();
@@ -5205,8 +5208,6 @@ __lock_acquired(struct lockdep_map *lock, unsigned long ip)
hlock->holdtime_stamp = now;
}
trace_lock_acquired(lock, ip);
stats = get_lock_stats(hlock_class(hlock));
if (waittime) {
if (hlock->read)
@@ -5225,6 +5226,8 @@ void lock_contended(struct lockdep_map *lock, unsigned long ip)
{
unsigned long flags;
trace_lock_acquired(lock, ip);
if (unlikely(!lock_stat || !debug_locks))
return;
@@ -5234,7 +5237,6 @@ void lock_contended(struct lockdep_map *lock, unsigned long ip)
raw_local_irq_save(flags);
check_flags(flags);
current->lockdep_recursion++;
trace_lock_contended(lock, ip);
__lock_contended(lock, ip);
lockdep_recursion_finish();
raw_local_irq_restore(flags);
@@ -5245,6 +5247,8 @@ void lock_acquired(struct lockdep_map *lock, unsigned long ip)
{
unsigned long flags;
trace_lock_contended(lock, ip);
if (unlikely(!lock_stat || !debug_locks))
return;