From nobody Sun Feb 8 11:43:12 2026 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 299D530C626; Sun, 25 Jan 2026 22:47:21 +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=1769381241; cv=none; b=rTeU3W+o3tI7wvpemFHNxBm1n2JQNpnqF8YZxosRYNh//E9XsLuoCXO7yoBgN8z3z8OdUH9/J8vbv+N6/bvXYdTs7Mvq2icj5s4YfcFKAqGKZxnuiAueB6rLpLX2KANwIazUBcTrQP/4uN/dbm9aodol3AuUsizgWWMyOdylLX8= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1769381241; c=relaxed/simple; bh=JzP68aQ+gy8MFfasMpMI/FZxkM6LDJNtU1916wSaM4Y=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=fGZBaYRrQPAebrMG3YZGgqe61Yxlocx5j+w+nF6tCKQh6gc9mh+9f4yRX/rSbc0Q1TNlTRNABEDPoCmFuknQW+6naMnos+9mH9ee1AteUb49F6LGyYQPnaM5GexzJC/9RoiNc8zchxgFCJHMcQcSPMv35IKjyIJ3xRBLIBh5VgM= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=pZH8jb1A; 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="pZH8jb1A" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 40989C2BC86; Sun, 25 Jan 2026 22:47:13 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1769381241; bh=JzP68aQ+gy8MFfasMpMI/FZxkM6LDJNtU1916wSaM4Y=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=pZH8jb1AUqc5N69sLqgEmq+QKBIiu6wiiXwzJEi5ZGmmLVjLEJyxuwz+pct9+lnSw w9njNCBXNzXQqNSoNUDSdh6XRsKeddfyc6cH30vOjz2hIdn934RKFCg1seb7tRkHI6 hB/wTPpPo+dQbJku/sCGbRXfKLCXqKbPzh6s15mJoaEYChWfkMQyimU7s3WAJfcKiz Nh+yKWa/cQ/p2I7FbwCGFvu++IydAkJCkefhTyDIJIyWM41dVxKka1ZZUJhKbzFEko EbnSL7iQ5ftw2Vdjyb68aMtE652HxefnDQ2pPkEceU8iHyxr98bucDWchvPQ1msLFi 7kaC1al7RQRuw== From: Frederic Weisbecker To: LKML Cc: Frederic Weisbecker , =?UTF-8?q?Michal=20Koutn=C3=BD?= , Andrew Morton , Bjorn Helgaas , Catalin Marinas , Chen Ridong , Danilo Krummrich , "David S . Miller" , Eric Dumazet , Gabriele Monaco , Greg Kroah-Hartman , Ingo Molnar , Jakub Kicinski , Jens Axboe , Johannes Weiner , Lai Jiangshan , Marco Crivellari , Michal Hocko , Muchun Song , Paolo Abeni , Peter Zijlstra , Phil Auld , "Rafael J . Wysocki" , Roman Gushchin , Shakeel Butt , Simon Horman , Tejun Heo , Thomas Gleixner , Vlastimil Babka , Waiman Long , Will Deacon , cgroups@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-block@vger.kernel.org, linux-mm@kvack.org, linux-pci@vger.kernel.org, netdev@vger.kernel.org Subject: [PATCH 11/33] cpu: Provide lockdep check for CPU hotplug lock write-held Date: Sun, 25 Jan 2026 23:45:18 +0100 Message-ID: <20260125224541.50226-12-frederic@kernel.org> X-Mailer: git-send-email 2.51.1 In-Reply-To: <20260125224541.50226-1-frederic@kernel.org> References: <20260125224541.50226-1-frederic@kernel.org> 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" cpuset modifies partitions, including isolated, while holding the cpu hotplug lock read-held. This means that write-holding the CPU hotplug lock is safe to synchronize against housekeeping cpumask changes. Provide a lockdep check to validate that. Signed-off-by: Frederic Weisbecker --- include/linux/cpuhplock.h | 1 + include/linux/percpu-rwsem.h | 1 + kernel/cpu.c | 5 +++++ 3 files changed, 7 insertions(+) diff --git a/include/linux/cpuhplock.h b/include/linux/cpuhplock.h index f7aa20f62b87..286b3ab92e15 100644 --- a/include/linux/cpuhplock.h +++ b/include/linux/cpuhplock.h @@ -13,6 +13,7 @@ struct device; =20 extern int lockdep_is_cpus_held(void); +extern int lockdep_is_cpus_write_held(void); =20 #ifdef CONFIG_HOTPLUG_CPU void cpus_write_lock(void); diff --git a/include/linux/percpu-rwsem.h b/include/linux/percpu-rwsem.h index 288f5235649a..c8cb010d655e 100644 --- a/include/linux/percpu-rwsem.h +++ b/include/linux/percpu-rwsem.h @@ -161,6 +161,7 @@ extern void percpu_free_rwsem(struct percpu_rw_semaphor= e *); __percpu_init_rwsem(sem, #sem, &rwsem_key); \ }) =20 +#define percpu_rwsem_is_write_held(sem) lockdep_is_held_type(sem, 0) #define percpu_rwsem_is_held(sem) lockdep_is_held(sem) #define percpu_rwsem_assert_held(sem) lockdep_assert_held(sem) =20 diff --git a/kernel/cpu.c b/kernel/cpu.c index 40b8496f47c5..01968a5c4a16 100644 --- a/kernel/cpu.c +++ b/kernel/cpu.c @@ -534,6 +534,11 @@ int lockdep_is_cpus_held(void) { return percpu_rwsem_is_held(&cpu_hotplug_lock); } + +int lockdep_is_cpus_write_held(void) +{ + return percpu_rwsem_is_write_held(&cpu_hotplug_lock); +} #endif =20 static void lockdep_acquire_cpus_lock(void) --=20 2.51.1