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 9C1AA238C21; Tue, 29 Apr 2025 17:39:15 +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=1745948355; cv=none; b=BWMbGlikWxKYniGWIVOic4GGx/fJyXOmbQij7o1KXNhoXwq/QHCXbe5mO77iZEuGx701xDKKfGkzxwgCD6yQnQraScowlga5U8zZ+fRWiVz9ZPILISj3A615B3DBOXP78sLnp9HAKH4DD7DV+DWbtiGmcPVGZr/0wl5Z1clhVeg= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1745948355; c=relaxed/simple; bh=rmEWZLlZjbnpO0EAkTGZ4SoMpdGmdIbXOnq+jgmXLlo=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=IBFDDipH1rTxpdOnu9Jv/2lY1SEDjSa+0b58hoxtP+Pnl6iTW6PhtG2cCcXVY2YqvIso69EghSyt3hD8GTAHFXPKvBIl061KE1XZWY+d2IqZTL611KV6voisMVZe5iUAQd+opLqErsF4JGm9lV0ykanCZZRP+bDBdppZWvNhKUc= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=cwEMIZ6P; 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="cwEMIZ6P" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 08180C4CEE3; Tue, 29 Apr 2025 17:39:14 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1745948355; bh=rmEWZLlZjbnpO0EAkTGZ4SoMpdGmdIbXOnq+jgmXLlo=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=cwEMIZ6Pqsw0wvJKQQNC+pR0OQBVYCJQmzOrgFkSGpuBJKicytok2cjqwsZ/KMn++ CC/JMcUCOjvNM/j66aMoPGgOhQP6o1CI0B2/2jR35L3QqVRVJdhz3780zK2yZXJpq3 016SzKBK1EdM1ukVJwDMYSwURBYBogoMY87Zpcq0= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Thomas Gleixner , Fernando Fernandez Mancera , Ingo Molnar , Sasha Levin Subject: [PATCH 6.12 235/280] x86/i8253: Call clockevent_i8253_disable() with interrupts disabled Date: Tue, 29 Apr 2025 18:42:56 +0200 Message-ID: <20250429161124.733296013@linuxfoundation.org> X-Mailer: git-send-email 2.49.0 In-Reply-To: <20250429161115.008747050@linuxfoundation.org> References: <20250429161115.008747050@linuxfoundation.org> User-Agent: quilt/0.68 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.12-stable review patch. If anyone has any objections, please let me know. ------------------ From: Fernando Fernandez Mancera [ Upstream commit 3940f5349b476197fb079c5aa19c9a988de64efb ] There's a lockdep false positive warning related to i8253_lock: WARNING: HARDIRQ-safe -> HARDIRQ-unsafe lock order detected ... systemd-sleep/3324 [HC0[0]:SC0[0]:HE0:SE1] is trying to acquire: ffffffffb2c23398 (i8253_lock){+.+.}-{2:2}, at: pcspkr_event+0x3f/0xe0 [pcspkr] ... ... which became HARDIRQ-irq-unsafe at: ... lock_acquire+0xd0/0x2f0 _raw_spin_lock+0x30/0x40 clockevent_i8253_disable+0x1c/0x60 pit_timer_init+0x25/0x50 hpet_time_init+0x46/0x50 x86_late_time_init+0x1b/0x40 start_kernel+0x962/0xa00 x86_64_start_reservations+0x24/0x30 x86_64_start_kernel+0xed/0xf0 common_startup_64+0x13e/0x141 ... Lockdep complains due pit_timer_init() using the lock in an IRQ-unsafe fashion, but it's a false positive, because there is no deadlock possible at that point due to init ordering: at the point where pit_timer_init() is called there is no other possible usage of i8253_lock because the system is still in the very early boot stage with no interrupts. But in any case, pit_timer_init() should disable interrupts before calling clockevent_i8253_disable() out of general principle, and to keep lockdep working even in this scenario. Use scoped_guard() for that, as suggested by Thomas Gleixner. [ mingo: Cleaned up the changelog. ] Suggested-by: Thomas Gleixner Signed-off-by: Fernando Fernandez Mancera Signed-off-by: Ingo Molnar Reviewed-by: Thomas Gleixner Link: https://lore.kernel.org/r/Z-uwd4Bnn7FcCShX@gmail.com Signed-off-by: Sasha Levin --- arch/x86/kernel/i8253.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/arch/x86/kernel/i8253.c b/arch/x86/kernel/i8253.c index 80e262bb627fe..cb9852ad60989 100644 --- a/arch/x86/kernel/i8253.c +++ b/arch/x86/kernel/i8253.c @@ -46,7 +46,8 @@ bool __init pit_timer_init(void) * VMMs otherwise steal CPU time just to pointlessly waggle * the (masked) IRQ. */ - clockevent_i8253_disable(); + scoped_guard(irq) + clockevent_i8253_disable(); return false; } clockevent_i8253_init(true); -- 2.39.5