The following commit has been merged into the locking/core branch of tip: Commit-ID: eb1f00237aca2e368b93db79303f8433d1976d10 Gitweb: https://git.kernel.org/tip/eb1f00237aca2e368b93db79303f8433d1976d10 Author: Peter Zijlstra <[email protected]> AuthorDate: Fri, 07 Aug 2020 20:53:16 +02:00 Committer: Peter Zijlstra <[email protected]> CommitterDate: Wed, 26 Aug 2020 12:41:56 +02:00
lockdep,trace: Expose tracepoints 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] --- kernel/locking/lockdep.c | 14 +++++++++----- 1 file changed, 9 insertions(+), 5 deletions(-) diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c index c872e95..54b74fa 100644 --- a/kernel/locking/lockdep.c +++ b/kernel/locking/lockdep.c @@ -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;
