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 18D9022A81D; Tue, 29 Apr 2025 17:07:53 +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=1745946473; cv=none; b=a1jL9RdsnfzHm4fmxl2XVHzFj7rFj948dHBriyThcgKuUdShgSXHvQOh18JiMgD8uKQ1Tpu593GTelj9VSpHNy0CJ+s7OTd4LJNdgoim8oJuAKakB5W3HAY0hJsgkLoI02Z95HPIjD8nYryY81jRZcXcXaPgjdptfygbK3NVYO0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1745946473; c=relaxed/simple; bh=MGV8m78+KD7zEnlmMKaNAlZJASIqf54v1UG+sPm2JXg=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=DYRJIbhy1tyACJfIkFLxUYtBX8nnY0oC1pKPiT8bCsmfvn/5PS8K+xqqWZl2mqSb3tXZTIvVnqwaI0Ie1oWcMFFr0o3ictfw+cgAuMFxIYVBjw24KpwgPfHqbgm0oMzQ/JoRQKLTQpHtmRaAjch6A0L9PYS+gZf0gGHQL8erWd8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=gxW9wviR; 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="gxW9wviR" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 7D50DC4CEEA; Tue, 29 Apr 2025 17:07:52 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1745946473; bh=MGV8m78+KD7zEnlmMKaNAlZJASIqf54v1UG+sPm2JXg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=gxW9wviR/jGeqaxHXysTCYnG92nSbN6rger9651svMhZQoof+4tQV0sMzmMzv1kYq 76BYU5SFcGRJoSR8fGSmJQRvbOVl/C3bAGUKkJoU4GCi658J0+JlnrI6zOR1kxBJcQ VGVWv041YkBJCLXpjt1GAHr3pc3bKllHdWfRN4XQ= 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 6.14 277/311] x86/i8253: Call clockevent_i8253_disable() with interrupts disabled Date: Tue, 29 Apr 2025 18:41:54 +0200 Message-ID: <20250429161132.364554999@linuxfoundation.org> X-Mailer: git-send-email 2.49.0 In-Reply-To: <20250429161121.011111832@linuxfoundation.org> References: <20250429161121.011111832@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 6.14-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