From patchwork Mon Jan 31 20:35:04 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: William McVicker X-Patchwork-Id: 12731125 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 kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id 63693C433F5 for ; Mon, 31 Jan 2022 20:35:37 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id DB19B6B00FA; Mon, 31 Jan 2022 15:35:36 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id D60736B00FC; Mon, 31 Jan 2022 15:35:36 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id C018F6B00FD; Mon, 31 Jan 2022 15:35:36 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0237.hostedemail.com [216.40.44.237]) by kanga.kvack.org (Postfix) with ESMTP id B19A66B00FA for ; Mon, 31 Jan 2022 15:35:36 -0500 (EST) Received: from smtpin24.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay04.hostedemail.com (Postfix) with ESMTP id 6755D9790C for ; Mon, 31 Jan 2022 20:35:36 +0000 (UTC) X-FDA: 79091737872.24.C725815 Received: from mail-pg1-f202.google.com (mail-pg1-f202.google.com [209.85.215.202]) by imf03.hostedemail.com (Postfix) with ESMTP id EEFC620014 for ; Mon, 31 Jan 2022 20:35:35 +0000 (UTC) Received: by mail-pg1-f202.google.com with SMTP id i23-20020a635417000000b00364c29f39aaso2464978pgb.8 for ; Mon, 31 Jan 2022 12:35:35 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=date:message-id:mime-version:subject:from:to:cc; bh=HEysl+0+HIw/m+20ELUKT2iKO4bE+cT13hE3Duhm1jA=; b=SUxYirimv4gQq3ABnzJ5B0QaYJRNSGEfIPZT/dEvQHSegXWyWhXkLNUOamQcvVBbv6 MaFafaldt9GH2lQHFgMyaI5PTxyfXC1iVQN1w6cv2eZB1hGqWU8y1Wwu9rcymWTlqRyI UZm0msX2zv5voyAyRpfvf0Q+zUjpKwbYpmboAbWDZnDiLyshtP27jDUpjaQcG3UEnuob xUEHrJUrWw3OQcytt74br0j0q2GDeK9rYh2QL6IxHxhwUA+zw19RBLpKxulUXvHe0Nh2 bPjNO+Wk8YvoS8njtutL/nOt4LZkzMnRE35m7jQQQfNuez77Je1eOpbCOSj+fp2mXDjR UhaA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:date:message-id:mime-version:subject:from:to:cc; bh=HEysl+0+HIw/m+20ELUKT2iKO4bE+cT13hE3Duhm1jA=; b=JsdUjQI6iw1LDak0Yaf20pGobLV3sIIRLRlQa/uphsxa2Qcn5IgxUclTGI2jYWzCV0 oK9/ALsIa0QsJK46bCg2bLr0U86aD6j6BTNNOjRKmQYUCDnHf+Rw5Qa8Ht6VwHrbczNf KfaX8IvivQPvrw3Zj/CY6P9eDv51aGcyU5srzxNJlkr+IkpSTmjnP9TyPY7dl1UB+/d9 Y+yuLXP+Pw7gxWdo9Tk9RjP1Nw+Il3KsrDYrlZSp7AejsM/Eoad8T/9B0Iw98lBLwoPM +9B0P0Oh2MJkLXAu+CcXi86Oz7aUSjmdTMWonXvuboXg5mb18RLBnHAkyOWRMLTMbds5 ziBA== X-Gm-Message-State: AOAM530AGPpMdRpn7OkipQZzporYDc7+B9ZBpLGMAwnXTXHGbQ8rfsHb Jr/pRetI7hKiAWcTS1CKXZOGxziBxXfL6sL/wE4= X-Google-Smtp-Source: ABdhPJy/BfcZXYa8lXHZT/EKiFqFtCV/5/t+HzMAv5CRnmV4FrWiZ86QTm/APzTpK045HZ4KQLqLo7tedoWL9J84a3Q= X-Received: from willmcvicker.c.googlers.com ([fda3:e722:ac3:cc00:24:72f4:c0a8:2dd0]) (user=willmcvicker job=sendgmr) by 2002:a17:90a:694d:: with SMTP id j13mr36654464pjm.10.1643661334747; Mon, 31 Jan 2022 12:35:34 -0800 (PST) Date: Mon, 31 Jan 2022 20:35:04 +0000 Message-Id: <20220131203504.3458775-1-willmcvicker@google.com> Mime-Version: 1.0 X-Mailer: git-send-email 2.35.0.rc2.247.g8bbb082509-goog Subject: [PATCH v1 1/1] mm/gup: skip pinnable check for refs==1 From: Will McVicker To: Andrew Morton , John Hubbard Cc: kernel-team@android.com, Will McVicker , Minchan Kim , linux-mm@kvack.org, linux-kernel@vger.kernel.org X-Rspamd-Server: rspam03 X-Rspamd-Queue-Id: EEFC620014 X-Stat-Signature: z1h7abf9e8aayg4c5ag4hbppoiffaytg Authentication-Results: imf03.hostedemail.com; dkim=pass header.d=google.com header.s=20210112 header.b=SUxYirim; dmarc=pass (policy=reject) header.from=google.com; spf=pass (imf03.hostedemail.com: domain of 3Fkj4YQwKCJ0TFIIJ9SF9HBODLLDIB.9LJIFKRU-JJHS79H.LOD@flex--willmcvicker.bounces.google.com designates 209.85.215.202 as permitted sender) smtp.mailfrom=3Fkj4YQwKCJ0TFIIJ9SF9HBODLLDIB.9LJIFKRU-JJHS79H.LOD@flex--willmcvicker.bounces.google.com X-Rspam-User: nil X-HE-Tag: 1643661335-273568 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000106, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: This fixes commit 54d516b1d62f ("mm/gup: small refactoring: simplify try_grab_page()") which refactors try_grab_page() to call try_grab_compound_head() with refs=1. The refactor commit is causing pin_user_pages() to return -ENOMEM when we try to pin one user page that is migratable and not in the movable zone. Previously, try_grab_page() didn't check if the page was pinnable for FOLL_PIN. To match the same functionality, this fix adds the check `refs > 1 &&` to skip the call to is_pinnable_page(). This issue is reproducible with the Pixel 6 on the 5.15 LTS kernel. Here is the call stack to reproduce the -ENOMEM error: Call trace: : dump_backtrace.cfi_jt+0x0/0x8 : show_stack+0x1c/0x2c : dump_stack_lvl+0x68/0x98 : try_grab_compound_head+0x298/0x3c4 : follow_page_pte+0x1dc/0x330 : follow_page_mask+0x174/0x340 : __get_user_pages+0x158/0x34c : __gup_longterm_locked+0xfc/0x194 : __gup_longterm_unlocked+0x80/0xf4 : internal_get_user_pages_fast+0xf0/0x15c : pin_user_pages_fast+0x24/0x40 : edgetpu_device_group_map+0x130/0x584 [abrolhos] : edgetpu_ioctl_map_buffer+0x110/0x3b4 [abrolhos] : edgetpu_ioctl+0x238/0x408 [abrolhos] : edgetpu_fs_ioctl+0x14/0x24 [abrolhos] Fixes: 54d516b1d62f ("mm/gup: small refactoring: simplify try_grab_page()") Cc: John Hubbard Cc: Minchan Kim Signed-off-by: Will McVicker --- mm/gup.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/mm/gup.c b/mm/gup.c index f0af462ac1e2..0509c49c46a3 100644 --- a/mm/gup.c +++ b/mm/gup.c @@ -135,7 +135,7 @@ struct page *try_grab_compound_head(struct page *page, * right zone, so fail and let the caller fall back to the slow * path. */ - if (unlikely((flags & FOLL_LONGTERM) && + if (refs > 1 && unlikely((flags & FOLL_LONGTERM) && !is_pinnable_page(page))) return NULL;