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 5EF873BB9F4; Thu, 15 Jan 2026 17:07:07 +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=1768496827; cv=none; b=cguSiwE+pzor4yu9u34EP6FirbnWdmWWQZ4cgw0RGu9Az9Yxl1L4z9jl7WRiF3ByVfy1ZSKgQWXF8Z5f7DD/xzJzzpJ6Gx6HxCn17DXDh80BAk2MVKkWyHpSQ9HYvxuOfG223Kj5RXNNx3+75lGYm2X2mpnUndNc8MJUdO44LrY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1768496827; c=relaxed/simple; bh=/RwHM9lte/Xjb3olM7Mn8JMfa0B3h6VDLg7KM/fMIIU=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=NgwgH4DCncVdyvmvvenhaUdEvx9WvgLfhwkbOjwrBOkaMNQ+wfQKAfw3yVKLBsdjr9dGB5uXi+ZG8XYhm7hGXosx8K0D0csDRg9g7mISN667eUCV6RxqxFsQWQsTCchu4n2YD8wzvNbLSOOwNHAbTgOd1Gt17haktWnK8WH6tcc= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=pvfEHrkD; 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="pvfEHrkD" Received: by smtp.kernel.org (Postfix) with ESMTPSA id DE8D6C116D0; Thu, 15 Jan 2026 17:07:06 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1768496827; bh=/RwHM9lte/Xjb3olM7Mn8JMfa0B3h6VDLg7KM/fMIIU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=pvfEHrkDYqbVWZtW6KnySZCMOtfNSv2KOkxxAh/8ZLUqp7Q1CaQxyhrTimVTokzq4 bo3m/2Co8wH8LbUatodKGUpTltGtCdTpD2a29JRQ4WPcPGwz0I2VAdCKPQuvmASWQ2 s/E8Jtu7VepPtW4lqfeDyJ//jZLsTDiODDLwxWoU= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Linus Walleij , Arnd Bergmann , Sebastian Andrzej Siewior , "Russell King (Oracle)" , Sasha Levin Subject: [PATCH 6.6 29/88] ARM: 9461/1: Disable HIGHPTE on PREEMPT_RT kernels Date: Thu, 15 Jan 2026 17:48:12 +0100 Message-ID: <20260115164147.367851909@linuxfoundation.org> X-Mailer: git-send-email 2.52.0 In-Reply-To: <20260115164146.312481509@linuxfoundation.org> References: <20260115164146.312481509@linuxfoundation.org> User-Agent: quilt/0.69 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: Sebastian Andrzej Siewior [ Upstream commit fedadc4137234c3d00c4785eeed3e747fe9036ae ] gup_pgd_range() is invoked with disabled interrupts and invokes __kmap_local_page_prot() via pte_offset_map(), gup_p4d_range(). With HIGHPTE enabled, __kmap_local_page_prot() invokes kmap_high_get() which uses a spinlock_t via lock_kmap_any(). This leads to an sleeping-while-atomic error on PREEMPT_RT because spinlock_t becomes a sleeping lock and must not be acquired in atomic context. The loop in map_new_virtual() uses wait_queue_head_t for wake up which also is using a spinlock_t. Since HIGHPTE is rarely needed at all, turn it off for PREEMPT_RT to allow the use of get_user_pages_fast(). [arnd: rework patch to turn off HIGHPTE instead of HAVE_PAST_GUP] Co-developed-by: Arnd Bergmann Acked-by: Linus Walleij Reviewed-by: Arnd Bergmann Signed-off-by: Sebastian Andrzej Siewior Signed-off-by: Russell King (Oracle) Signed-off-by: Sasha Levin --- arch/arm/Kconfig | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig index 57c0448d017a1..be3b0f83eee57 100644 --- a/arch/arm/Kconfig +++ b/arch/arm/Kconfig @@ -1308,7 +1308,7 @@ config HIGHMEM config HIGHPTE bool "Allocate 2nd-level pagetables from highmem" if EXPERT - depends on HIGHMEM + depends on HIGHMEM && !PREEMPT_RT default y help The VM uses one page of physical memory for each page table. -- 2.51.0