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 B5AD42517A8; Tue, 29 Apr 2025 18:18:28 +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=1745950708; cv=none; b=FjwZnT+NRXdaOLG+KxjVwvPdIUOMuLXZf/9icA8ESsm0vQeifzpekJnbvQ8pehUtrorD9qZg5fgb5NZG3vgjpV0TEsFA22RtNZl3K/tME1AcwkuzBcS1cEcnNPFeqQQ8jNJxm9e5HV8ItuQ22turZxw/81vthzs8CsyCcajBHyg= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1745950708; c=relaxed/simple; bh=tDnr/S2bUhwXrmkCTWmyu8nAGjFfqhJZ+WYgm54Iu2k=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=KkntbcbzwdmuAH6Pz1xpDiEGUAES/KdiwdsOpxN76rdSoY5FcPBC8lKj2DU5PM4suk24bglbBjqYcl3+u0nWKt/QwAtJrQCEgKkFJDEcODTiOe6a+69tUyUq9xPf65RJaAIcR32Q6IeX+ELsvvCIfx44A7JBkcBkUDGxF557g9U= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=fyLLpf7/; 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="fyLLpf7/" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 2322AC4CEE3; Tue, 29 Apr 2025 18:18:27 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1745950708; bh=tDnr/S2bUhwXrmkCTWmyu8nAGjFfqhJZ+WYgm54Iu2k=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=fyLLpf7/eG46SLhS7dppi8if4YrhwC9es41DYU10fuwBF9di+xCFuDe5OJyw3zAjd lp4sAua+S/qXfu16HH5p8BWKNLyc1knE8IBhcvYejvcnt9rh+n1Tv8tOC+MpBRpmAQ Q/5g2tfUDHOo8RtBwU0heGGe5Lvbb70YJJ32K55E= 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 6.6 179/204] x86/i8253: Call clockevent_i8253_disable() with interrupts disabled Date: Tue, 29 Apr 2025 18:44:27 +0200 Message-ID: <20250429161106.720471296@linuxfoundation.org> X-Mailer: git-send-email 2.49.0 In-Reply-To: <20250429161059.396852607@linuxfoundation.org> References: <20250429161059.396852607@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 6.6-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