From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 27AC21E0B63; Wed, 6 Nov 2024 13:12:19 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1730898740; cv=none; b=Dfqe1yZFsuLa1MKJWVqCJCsJHx8y86uzORHLb19KrSJb+C9KnGSyCVQW6xU5B5cv1NsHtFYjDLn5ywbVpH8+3T4lc9iynRZBIW17KfJAy5eGIn2L2mZJG7zI58DzLcYYuQ38ocWkZGmT6V7jzxXJt6GSEWUXvESMQbp6/+iMraY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1730898740; c=relaxed/simple; bh=VmLX4p8G0cVQeIwD0AB/v46tTLudkg/u3Fpwx+kzre0=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=ZJYX7ZceNCIC2hwkjw6sWNQ9cspUCeoK5kB4jYQOjJIogK/2IpQ0NljBbK8lr35a/8b8glukc2MpsD9f5J12mhAciiCHL2WHyXLAsyaTF65s3BAs2hiaXOAT5IDFZR359+4kboCwsJMZjvmxHhipfr7i9UFV9e03lLBWkzU5QWw= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=w9yFyO3w; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="w9yFyO3w" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 5217AC4CECD; Wed, 6 Nov 2024 13:12:19 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1730898739; bh=VmLX4p8G0cVQeIwD0AB/v46tTLudkg/u3Fpwx+kzre0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=w9yFyO3wlXMhNKxG5khpF6nHmp/mqXAf15fPZ8LgS/QXc0/6l3B/RrZ5ihP5222SJ AzyxRdWUURxa9iy9r/iUVwF3W9btjdEf7U/r0dGguG5Kf3u4pIDUTIqcWb25++MYkI eUAnheN6l1FoqMq9B5FwtvzS0DIm9TmMl5k9ptZI= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, "Peter Zijlstra (Intel)" , Carlos Llamas , Sasha Levin Subject: [PATCH 5.4 338/462] locking/lockdep: Fix bad recursion pattern Date: Wed, 6 Nov 2024 13:03:51 +0100 Message-ID: <20241106120339.873257461@linuxfoundation.org> X-Mailer: git-send-email 2.47.0 In-Reply-To: <20241106120331.497003148@linuxfoundation.org> References: <20241106120331.497003148@linuxfoundation.org> User-Agent: quilt/0.67 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 5.4-stable review patch. If anyone has any objections, please let me know. ------------------ From: Peter Zijlstra commit 10476e6304222ced7df9b3d5fb0a043b3c2a1ad8 upstream. There were two patterns for lockdep_recursion: Pattern-A: if (current->lockdep_recursion) return current->lockdep_recursion = 1; /* do stuff */ current->lockdep_recursion = 0; Pattern-B: current->lockdep_recursion++; /* do stuff */ current->lockdep_recursion--; But a third pattern has emerged: Pattern-C: current->lockdep_recursion = 1; /* do stuff */ current->lockdep_recursion = 0; And while this isn't broken per-se, it is highly dangerous because it doesn't nest properly. Get rid of all Pattern-C instances and shore up Pattern-A with a warning. Signed-off-by: Peter Zijlstra (Intel) Link: https://lkml.kernel.org/r/20200313093325.GW12561@hirez.programming.kicks-ass.net Signed-off-by: Carlos Llamas Signed-off-by: Sasha Levin --- kernel/locking/lockdep.c | 74 ++++++++++++++++++++++------------------ 1 file changed, 40 insertions(+), 34 deletions(-) diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c index 0d9ff8b621e6d..0a2be60e4aa7b 100644 --- a/kernel/locking/lockdep.c +++ b/kernel/locking/lockdep.c @@ -389,6 +389,12 @@ void lockdep_on(void) } EXPORT_SYMBOL(lockdep_on); +static inline void lockdep_recursion_finish(void) +{ + if (WARN_ON_ONCE(--current->lockdep_recursion)) + current->lockdep_recursion = 0; +} + void lockdep_set_selftest_task(struct task_struct *task) { lockdep_selftest_task_struct = task; @@ -1720,11 +1726,11 @@ unsigned long lockdep_count_forward_deps(struct lock_class *class) this.class = class; raw_local_irq_save(flags); - current->lockdep_recursion = 1; + current->lockdep_recursion++; arch_spin_lock(&lockdep_lock); ret = __lockdep_count_forward_deps(&this); arch_spin_unlock(&lockdep_lock); - current->lockdep_recursion = 0; + current->lockdep_recursion--; raw_local_irq_restore(flags); return ret; @@ -1749,11 +1755,11 @@ unsigned long lockdep_count_backward_deps(struct lock_class *class) this.class = class; raw_local_irq_save(flags); - current->lockdep_recursion = 1; + current->lockdep_recursion++; arch_spin_lock(&lockdep_lock); ret = __lockdep_count_backward_deps(&this); arch_spin_unlock(&lockdep_lock); - current->lockdep_recursion = 0; + current->lockdep_recursion--; raw_local_irq_restore(flags); return ret; @@ -3550,9 +3556,9 @@ void lockdep_hardirqs_on(unsigned long ip) if (DEBUG_LOCKS_WARN_ON(current->hardirq_context)) return; - current->lockdep_recursion = 1; + current->lockdep_recursion++; __trace_hardirqs_on_caller(ip); - current->lockdep_recursion = 0; + lockdep_recursion_finish(); } NOKPROBE_SYMBOL(lockdep_hardirqs_on); @@ -3608,7 +3614,7 @@ void trace_softirqs_on(unsigned long ip) return; } - current->lockdep_recursion = 1; + current->lockdep_recursion++; /* * We'll do an OFF -> ON transition: */ @@ -3623,7 +3629,7 @@ void trace_softirqs_on(unsigned long ip) */ if (curr->hardirqs_enabled) mark_held_locks(curr, LOCK_ENABLED_SOFTIRQ); - current->lockdep_recursion = 0; + lockdep_recursion_finish(); } /* @@ -3877,9 +3883,9 @@ void lockdep_init_map(struct lockdep_map *lock, const char *name, return; raw_local_irq_save(flags); - current->lockdep_recursion = 1; + current->lockdep_recursion++; register_lock_class(lock, subclass, 1); - current->lockdep_recursion = 0; + lockdep_recursion_finish(); raw_local_irq_restore(flags); } } @@ -4561,11 +4567,11 @@ void lock_set_class(struct lockdep_map *lock, const char *name, return; raw_local_irq_save(flags); - current->lockdep_recursion = 1; + current->lockdep_recursion++; check_flags(flags); if (__lock_set_class(lock, name, key, subclass, ip)) check_chain_key(current); - current->lockdep_recursion = 0; + lockdep_recursion_finish(); raw_local_irq_restore(flags); } EXPORT_SYMBOL_GPL(lock_set_class); @@ -4578,11 +4584,11 @@ void lock_downgrade(struct lockdep_map *lock, unsigned long ip) return; raw_local_irq_save(flags); - current->lockdep_recursion = 1; + current->lockdep_recursion++; check_flags(flags); if (__lock_downgrade(lock, ip)) check_chain_key(current); - current->lockdep_recursion = 0; + lockdep_recursion_finish(); raw_local_irq_restore(flags); } EXPORT_SYMBOL_GPL(lock_downgrade); @@ -4603,11 +4609,11 @@ void lock_acquire(struct lockdep_map *lock, unsigned int subclass, raw_local_irq_save(flags); check_flags(flags); - current->lockdep_recursion = 1; + 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); - current->lockdep_recursion = 0; + lockdep_recursion_finish(); raw_local_irq_restore(flags); } EXPORT_SYMBOL_GPL(lock_acquire); @@ -4622,11 +4628,11 @@ void lock_release(struct lockdep_map *lock, int nested, raw_local_irq_save(flags); check_flags(flags); - current->lockdep_recursion = 1; + current->lockdep_recursion++; trace_lock_release(lock, ip); if (__lock_release(lock, ip)) check_chain_key(current); - current->lockdep_recursion = 0; + lockdep_recursion_finish(); raw_local_irq_restore(flags); } EXPORT_SYMBOL_GPL(lock_release); @@ -4642,9 +4648,9 @@ int lock_is_held_type(const struct lockdep_map *lock, int read) raw_local_irq_save(flags); check_flags(flags); - current->lockdep_recursion = 1; + current->lockdep_recursion++; ret = __lock_is_held(lock, read); - current->lockdep_recursion = 0; + lockdep_recursion_finish(); raw_local_irq_restore(flags); return ret; @@ -4663,9 +4669,9 @@ struct pin_cookie lock_pin_lock(struct lockdep_map *lock) raw_local_irq_save(flags); check_flags(flags); - current->lockdep_recursion = 1; + current->lockdep_recursion++; cookie = __lock_pin_lock(lock); - current->lockdep_recursion = 0; + lockdep_recursion_finish(); raw_local_irq_restore(flags); return cookie; @@ -4682,9 +4688,9 @@ void lock_repin_lock(struct lockdep_map *lock, struct pin_cookie cookie) raw_local_irq_save(flags); check_flags(flags); - current->lockdep_recursion = 1; + current->lockdep_recursion++; __lock_repin_lock(lock, cookie); - current->lockdep_recursion = 0; + lockdep_recursion_finish(); raw_local_irq_restore(flags); } EXPORT_SYMBOL_GPL(lock_repin_lock); @@ -4699,9 +4705,9 @@ void lock_unpin_lock(struct lockdep_map *lock, struct pin_cookie cookie) raw_local_irq_save(flags); check_flags(flags); - current->lockdep_recursion = 1; + current->lockdep_recursion++; __lock_unpin_lock(lock, cookie); - current->lockdep_recursion = 0; + lockdep_recursion_finish(); raw_local_irq_restore(flags); } EXPORT_SYMBOL_GPL(lock_unpin_lock); @@ -4837,10 +4843,10 @@ void lock_contended(struct lockdep_map *lock, unsigned long ip) raw_local_irq_save(flags); check_flags(flags); - current->lockdep_recursion = 1; + current->lockdep_recursion++; trace_lock_contended(lock, ip); __lock_contended(lock, ip); - current->lockdep_recursion = 0; + lockdep_recursion_finish(); raw_local_irq_restore(flags); } EXPORT_SYMBOL_GPL(lock_contended); @@ -4857,9 +4863,9 @@ void lock_acquired(struct lockdep_map *lock, unsigned long ip) raw_local_irq_save(flags); check_flags(flags); - current->lockdep_recursion = 1; + current->lockdep_recursion++; __lock_acquired(lock, ip); - current->lockdep_recursion = 0; + lockdep_recursion_finish(); raw_local_irq_restore(flags); } EXPORT_SYMBOL_GPL(lock_acquired); @@ -5087,7 +5093,7 @@ static void free_zapped_rcu(struct rcu_head *ch) raw_local_irq_save(flags); arch_spin_lock(&lockdep_lock); - current->lockdep_recursion = 1; + current->lockdep_recursion++; /* closed head */ pf = delayed_free.pf + (delayed_free.index ^ 1); @@ -5099,7 +5105,7 @@ static void free_zapped_rcu(struct rcu_head *ch) */ call_rcu_zapped(delayed_free.pf + delayed_free.index); - current->lockdep_recursion = 0; + current->lockdep_recursion--; arch_spin_unlock(&lockdep_lock); raw_local_irq_restore(flags); } @@ -5146,11 +5152,11 @@ static void lockdep_free_key_range_reg(void *start, unsigned long size) raw_local_irq_save(flags); arch_spin_lock(&lockdep_lock); - current->lockdep_recursion = 1; + current->lockdep_recursion++; pf = get_pending_free(); __lockdep_free_key_range(pf, start, size); call_rcu_zapped(pf); - current->lockdep_recursion = 0; + current->lockdep_recursion--; arch_spin_unlock(&lockdep_lock); raw_local_irq_restore(flags); -- 2.43.0