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 0C2E525228D; Thu, 15 Jan 2026 16:53:35 +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=1768496015; cv=none; b=CatSd2gZ5ZGKbYnqA5YxraF9GU2jBqUpMaST0RsvABRO2o8ycVjY81pRAEFcOJE5AAMbrIg/Oby0Lyr4QS08C+Icp0z/iLY8xVnOdM4MYZjSklWjDzun3Q0rr6uSn4bt5Rjpp5lnL/ZrHr5PJ4pCILjytatI/RryrxTNDzxd/kQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1768496015; c=relaxed/simple; bh=siXYHAh5+Sri5zpcv3sWS5jMRC+Z5/s6lR669dEXmf8=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=Y8RFGH+RoubA6o2gIy0dwrltHOmuWbiE4oJGmctHqcmLZXlUrJ/t0+nBA3jREugzWNhvNQdyjsanoOT7e0g31oHJQZykI528QOhI7zosONV4b/3g3zSblCIvhlmOw5FbgreLRk98ZnPQ3/+R3rLwae//tw18vm18a5x1UDXWQ+Y= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=FymhsykY; 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="FymhsykY" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 8DE01C116D0; Thu, 15 Jan 2026 16:53:34 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1768496014; bh=siXYHAh5+Sri5zpcv3sWS5jMRC+Z5/s6lR669dEXmf8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=FymhsykYfRgYlMWgRXIm5wqjfjvGxC02RhBwbYUFm3/MK8ljD6H7AyXCTUNnS2GS/ xC4XHHiIEDWaxWuILr8nmPnLsiwCrdLSB8hwSgW8BUdCmiylcLVZD9InlJj6yGVxYy UFLxFXKm4msWNe8B+6unyBt8WUz8ja0q0C5OoKBg= 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 6.18 048/181] ARM: 9461/1: Disable HIGHPTE on PREEMPT_RT kernels Date: Thu, 15 Jan 2026 17:46:25 +0100 Message-ID: <20260115164204.063997700@linuxfoundation.org> X-Mailer: git-send-email 2.52.0 In-Reply-To: <20260115164202.305475649@linuxfoundation.org> References: <20260115164202.305475649@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 6.18-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 4fb985b76e97f..70cd3b5b5a059 100644 --- a/arch/arm/Kconfig +++ b/arch/arm/Kconfig @@ -1215,7 +1215,7 @@ 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