From nobody Thu Oct 2 10:53:53 2025 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 D3BEE2882CE; Thu, 18 Sep 2025 10:26:47 +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=1758191207; cv=none; b=WEvUMNfjmRJU52//fXsBrKMRq+PRSSA9pVwKsQ5kBhAZX6yBKIvZTdx/LfXDYNrXIcH/mw9PC0jQHERUeLzOGu1BkbKG0IUnYOozk9vJP6WsA0Ye4U4YIkJir3RXvpDNAvBFEYIEpfrA7V6Nu3fFHkqGJjWrHILo0uKPuRta9ys= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1758191207; c=relaxed/simple; bh=pvHoXIq/XZZkE26WZ9PeQrCmEPRe5uY95ng191EMoZw=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=ixZ+B6FVSmVZ8Eb2tVqjBOnhtDvGjG0Zu+iZhGSPtNbbAV1iJlRiwNsR5cxQOptLFTeEVVDMiIXi6G3+rexpzU2wdc07CeZ0MKits4xEQlEFwqx7QMm9ZI1mdLB9yT5hQruwr0DNmdG5Ns/8hgPCbjzCz5h48DAUiX4WlvGQmpI= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=jrccNUEn; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="jrccNUEn" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 67114C4CEE7; Thu, 18 Sep 2025 10:26:47 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1758191207; bh=pvHoXIq/XZZkE26WZ9PeQrCmEPRe5uY95ng191EMoZw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=jrccNUEnjRHl9F8GDoKa1N7ClgGg/k52t4ZIFLCJsgVvQodJ7XqcwB1tCju/s6bBP syJQj+LS13u3dJXauOPTERhSy3GtobNeAzPHwOPhrkwiaWcxW/O32zSgyRz8vqK33s XGID4k2J13SxEaLCZl11tNOmhoHFOvz9jeeb046Uobepzy7K6JPaPc6UlTk+uixdd2 Rb5jHDozj3OhMMr1LH4G+PPEkQhT92vb1tlUr3C9un8FgwCkFNMHNqIfbek3aoWSoG QdSYCJY/FQxfsCxQZTubHz4tPTIfChWF8bMXPfOtBo4tqxiVF2wgKDoQL9gBI1Aw6L 5mjxG66EZn0mQ== Received: by paulmck-ThinkPad-P17-Gen-1.home (Postfix, from userid 1000) id E31D0CE0B32; Thu, 18 Sep 2025 03:26:46 -0700 (PDT) From: "Paul E. McKenney" To: rcu@vger.kernel.org Cc: linux-kernel@vger.kernel.org, kernel-team@meta.com, rostedt@goodmis.org, "Paul E. McKenney" , Joel Fernandes , Mathieu Desnoyers , Sebastian Andrzej Siewior , bpf@vger.kernel.org Subject: [PATCH v2 1/6] srcu: Move rcu_is_watching() checks to srcu_read_{,un}lock_fast() Date: Thu, 18 Sep 2025 03:26:41 -0700 Message-Id: <20250918102646.2592821-1-paulmck@kernel.org> X-Mailer: git-send-email 2.40.1 In-Reply-To: <89b6f92e-2aa6-4869-ad4f-47bb3fbadfbb@paulmck-laptop> References: <89b6f92e-2aa6-4869-ad4f-47bb3fbadfbb@paulmck-laptop> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" The rcu_is_watching() warnings are currently in the SRCU-tree implementations of __srcu_read_lock_fast() and __srcu_read_unlock_fast(). However, this makes it difficult to create _notrace variants of srcu_read_lock_fast() and srcu_read_unlock_fast(). This commit therefore moves these checks to srcu_read_lock_fast(), srcu_read_unlock_fast(), srcu_down_read_fast(), and srcu_up_read_fast(). Signed-off-by: Paul E. McKenney Reviewed-by: Joel Fernandes Cc: Mathieu Desnoyers Cc: Steven Rostedt Cc: Sebastian Andrzej Siewior Cc: --- include/linux/srcu.h | 4 ++++ include/linux/srcutree.h | 2 -- 2 files changed, 4 insertions(+), 2 deletions(-) diff --git a/include/linux/srcu.h b/include/linux/srcu.h index f179700fecafb8..478c73d067f7d3 100644 --- a/include/linux/srcu.h +++ b/include/linux/srcu.h @@ -275,6 +275,7 @@ static inline struct srcu_ctr __percpu *srcu_read_lock_= fast(struct srcu_struct * { struct srcu_ctr __percpu *retval; =20 + RCU_LOCKDEP_WARN(!rcu_is_watching(), "RCU must be watching srcu_read_lock= _fast()."); srcu_check_read_flavor_force(ssp, SRCU_READ_FLAVOR_FAST); retval =3D __srcu_read_lock_fast(ssp); rcu_try_lock_acquire(&ssp->dep_map); @@ -295,6 +296,7 @@ static inline struct srcu_ctr __percpu *srcu_read_lock_= fast(struct srcu_struct * static inline struct srcu_ctr __percpu *srcu_down_read_fast(struct srcu_st= ruct *ssp) __acquires(ssp) { WARN_ON_ONCE(IS_ENABLED(CONFIG_PROVE_RCU) && in_nmi()); + RCU_LOCKDEP_WARN(!rcu_is_watching(), "RCU must be watching srcu_down_read= _fast()."); srcu_check_read_flavor_force(ssp, SRCU_READ_FLAVOR_FAST); return __srcu_read_lock_fast(ssp); } @@ -389,6 +391,7 @@ static inline void srcu_read_unlock_fast(struct srcu_st= ruct *ssp, struct srcu_ct srcu_check_read_flavor(ssp, SRCU_READ_FLAVOR_FAST); srcu_lock_release(&ssp->dep_map); __srcu_read_unlock_fast(ssp, scp); + RCU_LOCKDEP_WARN(!rcu_is_watching(), "RCU must be watching srcu_read_unlo= ck_fast()."); } =20 /** @@ -405,6 +408,7 @@ static inline void srcu_up_read_fast(struct srcu_struct= *ssp, struct srcu_ctr __ WARN_ON_ONCE(IS_ENABLED(CONFIG_PROVE_RCU) && in_nmi()); srcu_check_read_flavor(ssp, SRCU_READ_FLAVOR_FAST); __srcu_read_unlock_fast(ssp, scp); + RCU_LOCKDEP_WARN(!rcu_is_watching(), "RCU must be watching srcu_up_read_f= ast()."); } =20 /** diff --git a/include/linux/srcutree.h b/include/linux/srcutree.h index bf44d8d1e69eab..043b5a67ef71eb 100644 --- a/include/linux/srcutree.h +++ b/include/linux/srcutree.h @@ -244,7 +244,6 @@ static inline struct srcu_ctr __percpu *__srcu_read_loc= k_fast(struct srcu_struct { struct srcu_ctr __percpu *scp =3D READ_ONCE(ssp->srcu_ctrp); =20 - RCU_LOCKDEP_WARN(!rcu_is_watching(), "RCU must be watching srcu_read_lock= _fast()."); if (!IS_ENABLED(CONFIG_NEED_SRCU_NMI_SAFE)) this_cpu_inc(scp->srcu_locks.counter); /* Y */ else @@ -275,7 +274,6 @@ static inline void __srcu_read_unlock_fast(struct srcu_= struct *ssp, struct srcu_ this_cpu_inc(scp->srcu_unlocks.counter); /* Z */ else atomic_long_inc(raw_cpu_ptr(&scp->srcu_unlocks)); /* Z */ - RCU_LOCKDEP_WARN(!rcu_is_watching(), "RCU must be watching srcu_read_unlo= ck_fast()."); } =20 void __srcu_check_read_flavor(struct srcu_struct *ssp, int read_flavor); --=20 2.40.1