From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtpout.efficios.com (smtpout.efficios.com [158.69.130.18]) (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 07E5F3B3C17; Sun, 27 Sep 2026 15:51:59 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=158.69.130.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790524326; cv=none; b=jSCVAHQKHX0PJkijPypq+5FDSLVIQwlV3eyfbADwlnuhd/KYrT1N6IMGCENRXXqhplEXIVhJuYvuO5V4tARJbAUoncTJWImQyak8u9HVE4Sn1NjjXkmbuKoQbXvxvPawGVrAmm/TQ1ugPHgGT2ZnxWhcJeDotGXviwPHRyTSLdM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790524326; c=relaxed/simple; bh=uh5+QEAXdQ3aJXm/rqc9gITsrLpFRNWUPTWZarD8gdM=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=BR2tRbWRsrxMRwzABYgovo3NAxamisTUMJm5zr8R1uTYt0va/oAHWcapep4u3NTeD7TpJ+sL2KPFuDrhsB4o5FppY4M899UApL9XJxv6EUG5/tURQ0S587vAXlyYle7jLUv1JSPmEb/fuzwRMrxjfCgSL8XscAalkCGnorm//+o= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=efficios.com; spf=pass smtp.mailfrom=efficios.com; dkim=pass (2048-bit key) header.d=efficios.com header.i=@efficios.com header.b=bmIDR/qr; arc=none smtp.client-ip=158.69.130.18 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=efficios.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=efficios.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=efficios.com header.i=@efficios.com header.b="bmIDR/qr" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=efficios.com; s=smtpout1; t=1790524309; bh=CqnBE3DkErZugH/qRMaxksgb/KGywMpNP3MlUQmQoBg=; h=From:To:Cc:Subject:Date:From; b=bmIDR/qrFr/fRf4Pol38ucLoQfHlpCHL9H+ba80x+ulrGRXxJTQ2Wq2jZocUBOL30 Tg92XEFACjTF+HkwXK0mQrDvXxzLextcxsmchBfv5Dg4eb5OjTCfMCFjmVzHDoUfHm JTHBKwbzWLKQQ2xHIipfdhuzp0Ynalf6wKq3l1j2hcwurvUfaAtkOfman61Wb7ynmy G4Pq6QFNLGVNwptPiblXxOQZOvQ9DoQFVKto1aYk58vXb8lUDQQPOyMEqo5P/eJfIo 5ZYnEHKINZJm9wdQNP7jr1NJOZFm7UWXoEKm+aS23CbnUwVFoRtHLILWHBfWdLaWCk flkNeuyM3UGlA== Received: from compudjdev.. (mtl.efficios.com [216.120.195.104]) by smtpout.efficios.com (Postfix) with ESMTPSA id 4ht87n2SHZzhGw; Sun, 27 Sep 2026 11:51:49 -0400 (EDT) From: Mathieu Desnoyers To: "Paul E . McKenney" Cc: linux-kernel@vger.kernel.org, Mathieu Desnoyers , Boqun Feng , Bradley Morgan , Gary Guo , rcu@vger.kernel.org, lkmm@lists.linux.dev Subject: [PATCH hazptr 0/4] Hazard pointer updates Date: Sun, 27 Sep 2026 11:51:27 -0400 Message-ID: <20260927155134.4740-1-mathieu.desnoyers@efficios.com> X-Mailer: git-send-email 2.43.0 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Hi Paul, This series applies on top of "hazptr: handle NULL address in hazptr_detach" you have in your rcu dev tree. This first patch addresses a race identified by Boqun Feng in the two-phase wildcard scheme. Patches 2-3 are prerequisites for using ptr_eq() in the 4th patch. Those were discussed at length in a prior version of hazard pointer patches. Patch 4 introduces a "try acquire" helper to allow the fast path to not rely on wildcards, while keeping the wildcard forward progress guarantees in the acquire slow path, used on fast path failure. Thanks, Mathieu Mathieu Desnoyers (4): hazptr: Fix two-phase hazptr_synchronize race with detach compiler.h: Introduce ptr_eq() to preserve address dependency Documentation: RCU: Refer to ptr_eq() hazptr: Introduce "try acquire" fast path, fallback to overflow list Cc: Paul E. McKenney Cc: Boqun Feng Cc: Bradley Morgan Cc: Gary Guo Cc: Cc: Documentation/RCU/rcu_dereference.rst | 38 +++++++- include/linux/compiler.h | 63 ++++++++++++ include/linux/hazptr.h | 47 +++++---- kernel/hazptr.c | 135 +++++++++++++++----------- 4 files changed, 203 insertions(+), 80 deletions(-) -- 2.43.0