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 4F816EB64D8 for ; Tue, 20 Jun 2023 23:57:39 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229849AbjFTX5i (ORCPT ); Tue, 20 Jun 2023 19:57:38 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:38036 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229482AbjFTX5d (ORCPT ); Tue, 20 Jun 2023 19:57:33 -0400 Received: from mail-yb1-xb49.google.com (mail-yb1-xb49.google.com [IPv6:2607:f8b0:4864:20::b49]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A47F4184 for ; Tue, 20 Jun 2023 16:57:32 -0700 (PDT) Received: by mail-yb1-xb49.google.com with SMTP id 3f1490d57ef6-bfee66a6398so214603276.3 for ; Tue, 20 Jun 2023 16:57:32 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20221208; t=1687305452; x=1689897452; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc:subject:date:message-id:reply-to; bh=a/KyKqe8FdTi+g9/IKt8G5I/SC33PtSDDTh0FPFRaVQ=; b=djOCkf7sRmJEOqkBFJ1FAWr8LXWtr4BdpV1egpT43a8UfDOVBoBIuOCLxFedXjFa5b 1QOybvoapiGbw4NqKAvUWz+Fu19NBYstRwQlaC9K679sBdbRylerMVN2GPJl6f40HGRd jkUzOBouUCpguF36dwOGv4Mqx54tXxWhHGK35MaM5gY/XnL1tOp4MMdkKJjbjpszTSXG +MmeKpVWaqVgIGvTyv3WvYXc4kg3IolRfClLe0BDvx9p80AJntMQZuo8Dm0Z5JpwnDBm eulTjrH/K/rDevjtJ8yQo2HNk4iADzua7QHUx9I7o9do4iwPamwNMonQ11jiZ1XTlxGC ivrw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1687305452; x=1689897452; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=a/KyKqe8FdTi+g9/IKt8G5I/SC33PtSDDTh0FPFRaVQ=; b=ILxhMeoka364MTW8DlMmduAN6PS8plGVx+/66KdujYXbGkF2A+mHD6p0pV96PZeY9l zJyn0rzky+sh/c62el62FOTp2hVt+2qLp8r88M0+AEgpSp6Hz6MdmyKd046pJ78i7iao TAnoSrUojGyP9QOrkgxCBIiTNDtPPFZYbNJPbXOZqrxnW27vEkJcKKTbmO9ZHsVucYno 7zu4uHXY5X+qW67PRgWPJz8fRrLld72cBSf3+AQzTinlNGZYOIodoQuadUM3V+WGddBY 1NrM7+6YkcvI6wmQrqlOXfWo1ZJeqadCucUalBHnVrzVronGDWOrcxeKIkNaUerhU2ZI Sxrw== X-Gm-Message-State: AC+VfDyQjNRB9Yx+B17nRlQXRFTn1L+sPTk5Co7SY0nBr3hGAGzlu4z2 rgE5AcZisQXQD5td0tGSZlEUQ3HQGeU= X-Google-Smtp-Source: ACHHUZ6RGKpgQ9EJdSN1FRj/ySFNHpQNXjGlsvUEbgvZMHU1XkTWuCp5dJ4lnRJ4a/8Ly/xUzjteixKvrs4= X-Received: from surenb-desktop.mtv.corp.google.com ([2620:15c:211:201:3f57:9854:e19:8906]) (user=surenb job=sendgmr) by 2002:a25:fc28:0:b0:ba8:5bc9:80fe with SMTP id v40-20020a25fc28000000b00ba85bc980femr5330222ybd.1.1687305451896; Tue, 20 Jun 2023 16:57:31 -0700 (PDT) Date: Tue, 20 Jun 2023 16:57:25 -0700 In-Reply-To: <20230620235726.3873043-1-surenb@google.com> Mime-Version: 1.0 References: <20230620235726.3873043-1-surenb@google.com> X-Mailer: git-send-email 2.41.0.162.gfafddb0af9-goog Message-ID: <20230620235726.3873043-2-surenb@google.com> Subject: [PATCH 2/3] mm: change vma_start_read to fail to lock a detached VMA From: Suren Baghdasaryan To: akpm@linux-foundation.org Cc: willy@infradead.org, torvalds@linuxfoundation.org, vegard.nossum@oracle.com, mpe@ellerman.id.au, Liam.Howlett@oracle.com, lrh2000@pku.edu.cn, mgorman@suse.de, linux-mm@kvack.org, linux-kernel@vger.kernel.org, kernel-team@android.com, surenb@google.com Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org vma_start_read can successfully lock a detached VMA relying on its caller to check for vma->detached. Change vma_start_read to include that check and fail if the VMA got detached. Suggested-by: Linus Torvalds Signed-off-by: Suren Baghdasaryan --- include/linux/mm.h | 4 ++-- include/linux/vm_event_item.h | 1 - mm/memory.c | 10 +--------- mm/vmstat.c | 1 - 4 files changed, 3 insertions(+), 13 deletions(-) diff --git a/include/linux/mm.h b/include/linux/mm.h index 8410da79c570..74e3033c9fc2 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -651,8 +651,8 @@ static inline bool vma_start_read(struct vm_area_struct *vma) if (unlikely(down_read_trylock(&vma->vm_lock->lock) == 0)) return false; - /* Fail if VMA was write-locked after we checked it earlier */ - if (unlikely(vm_lock_seq != READ_ONCE(vma->vm_lock_seq))) { + /* Fail if VMA is detached or was write-locked after we checked it earlier */ + if (unlikely(vma->detached || vm_lock_seq != READ_ONCE(vma->vm_lock_seq))) { up_read(&vma->vm_lock->lock); return false; } diff --git a/include/linux/vm_event_item.h b/include/linux/vm_event_item.h index 8abfa1240040..e741098954ff 100644 --- a/include/linux/vm_event_item.h +++ b/include/linux/vm_event_item.h @@ -154,7 +154,6 @@ enum vm_event_item { PGPGIN, PGPGOUT, PSWPIN, PSWPOUT, VMA_LOCK_SUCCESS, VMA_LOCK_ABORT, VMA_LOCK_RETRY, - VMA_LOCK_MISS, #endif NR_VM_EVENT_ITEMS }; diff --git a/mm/memory.c b/mm/memory.c index f69fbc251198..bd666fa20748 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -5275,7 +5275,7 @@ struct vm_area_struct *lock_vma_under_rcu(struct mm_struct *mm, struct vm_area_struct *vma; rcu_read_lock(); -retry: + vma = mas_walk(&mas); if (!vma) goto inval; @@ -5306,14 +5306,6 @@ struct vm_area_struct *lock_vma_under_rcu(struct mm_struct *mm, goto inval; } - /* Check if the VMA got isolated after we found it */ - if (vma->detached) { - vma_end_read(vma); - count_vm_vma_lock_event(VMA_LOCK_MISS); - /* The area was replaced with another one */ - goto retry; - } - rcu_read_unlock(); return vma; inval: diff --git a/mm/vmstat.c b/mm/vmstat.c index c28046371b45..5d6acdb1b611 100644 --- a/mm/vmstat.c +++ b/mm/vmstat.c @@ -1403,7 +1403,6 @@ const char * const vmstat_text[] = { "vma_lock_success", "vma_lock_abort", "vma_lock_retry", - "vma_lock_miss", #endif #endif /* CONFIG_VM_EVENT_COUNTERS || CONFIG_MEMCG */ }; -- 2.41.0.162.gfafddb0af9-goog