From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 8CF29EE4993 for ; Wed, 23 Aug 2023 16:42:00 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S237354AbjHWQmA (ORCPT ); Wed, 23 Aug 2023 12:42:00 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49190 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231450AbjHWQl7 (ORCPT ); Wed, 23 Aug 2023 12:41:59 -0400 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 35B15CE for ; Wed, 23 Aug 2023 09:41:08 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1692808868; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=YW0EDZCY0m8+/dZecu2djclRs+GAoB7p8AH+s2fFlNo=; b=CZDKvRWzrcWocFds9vYM9TNtm3r/Is5wMXYrcd7V6MgBpP5rj+rkzrJJWKuluK3sJ+f9IV o7FW6YevIrEHFIVhGx9Vyzv2sM8vUSUg/10J0fL4+jxEo8FVA9b7Ndb0Z+nqZkGGy5p+10 QJSSUiRlVhvEbIZ7IsIGIgGx+G8qZGg= Received: from mail-qv1-f69.google.com (mail-qv1-f69.google.com [209.85.219.69]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-518-AFwa0AN6PKepvU3wlzhGlQ-1; Wed, 23 Aug 2023 12:41:04 -0400 X-MC-Unique: AFwa0AN6PKepvU3wlzhGlQ-1 Received: by mail-qv1-f69.google.com with SMTP id 6a1803df08f44-63d2b88325bso13913856d6.1 for ; Wed, 23 Aug 2023 09:41:04 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1692808864; x=1693413664; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to; bh=YW0EDZCY0m8+/dZecu2djclRs+GAoB7p8AH+s2fFlNo=; b=k92jVmlZX1TYPIeA89CpuqiwTqs4ElKaPrIn22tGjhtziFIvgCXLu5CFAO4jOOQBOh lQW/79TXVmMysfwsJvY2wnJ1ZdIthyl1vTs1UlQq34yXQIltB+61JWprIJPo1GYQWCMA s7DJ0YNmCx6IQdTAEINqFsO94lCQ4giLwvcdV3ynq6O0GwUad0lm1U/+oHu/SrUdjdak obw9jQsj/m0k2EhtMTSun3qMvwwa0l90J4mx4exwzsGPZ3E2lJfKKnnjZ92E20Ey3oAl HaosNYRcOFHlXzea5+RCLF7aw8JDNTkIBoIBR9rEcYLvfxj7Wp74/eM7/f5COtAoS39V ZUzQ== X-Gm-Message-State: AOJu0Yx3NClMqyjyaAS3g+JKnI0rGpIkpK/uKq8DTZU9v0/zZ6ZWPNCP dCjMJ9c/4YHvxsYOGq0/UK2iJf94+eOOOSei1cp9/1H7KWkANjjMlZg1mtHoikcy4y+cLp4OmS4 bbJApNIBJ1NRvhp5Admto5TSv X-Received: by 2002:ad4:5c63:0:b0:645:3c6:56ab with SMTP id i3-20020ad45c63000000b0064503c656abmr15349101qvh.1.1692808864537; Wed, 23 Aug 2023 09:41:04 -0700 (PDT) X-Google-Smtp-Source: AGHT+IGY59trkyfeqoHva+BRsUTu+ef1zBDxPgp/+hPFtlZY7Syl2yVvoX/z+RQuT4WgRq8pYA809Q== X-Received: by 2002:ad4:5c63:0:b0:645:3c6:56ab with SMTP id i3-20020ad45c63000000b0064503c656abmr15349095qvh.1.1692808864306; Wed, 23 Aug 2023 09:41:04 -0700 (PDT) Received: from x1n (cpe5c7695f3aee0-cm5c7695f3aede.cpe.net.cable.rogers.com. [99.254.144.39]) by smtp.gmail.com with ESMTPSA id j26-20020a0cae9a000000b0064f3d5cbbb6sm2926202qvd.114.2023.08.23.09.41.03 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 23 Aug 2023 09:41:03 -0700 (PDT) Date: Wed, 23 Aug 2023 12:41:00 -0400 From: Peter Xu To: Hugh Dickins Cc: Andrew Morton , Edward Liaw , linux-kernel@vger.kernel.org, linux-mm@kvack.org Subject: Re: [PATCH mm-hotfixes-unstable] shmem: fix smaps BUG sleeping while atomic Message-ID: References: <6fe3b3ec-abdf-332f-5c23-6a3b3a3b11a9@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <6fe3b3ec-abdf-332f-5c23-6a3b3a3b11a9@google.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Aug 22, 2023 at 10:14:47PM -0700, Hugh Dickins wrote: > smaps_pte_hole_lookup() is calling shmem_partial_swap_usage() with page > table lock held: but shmem_partial_swap_usage() does cond_resched_rcu() > if need_resched(): "BUG: sleeping function called from invalid context". > > Since shmem_partial_swap_usage() is designed to count across a range, but > smaps_pte_hole_lookup() only calls it for a single page slot, just break > out of the loop on the last or only page, before checking need_resched(). > > Fixes: 230100321518 ("mm/smaps: simplify shmem handling of pte holes") > Signed-off-by: Hugh Dickins > Cc: stable@vger.kernel.org # 5.16+ Oops.. thanks Hugh. Acked-by: Peter Xu -- Peter Xu