From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Google-Smtp-Source: AH8x227ev9NZiM5sazxJf6LL9pGvLNjca61u1E0is/lpworbpqauLqfEpMLMI4odUI/5HZt8xtsu ARC-Seal: i=1; a=rsa-sha256; t=1518119350; cv=none; d=google.com; s=arc-20160816; b=Oa9yJeWb8fHU/Mwtj/82fkAqbKsTMsYGFUGO+Yraxfe7QqG8grNrUHEfQzrPolVa2W Z8H0vBH4Mc9nzPQDNMzfvENjLlI2inbWp4LewTsCx+PyGcROqDwXGX5do+F5Ma257QAo OWke/o5SEIIfCqT8R+meRByxVTIEXZbjSAa7WChi4P99wltNCRup4ioDPBfzT5xCqzqN ixkj+gxgXHxaeODZQgLU5MUatz6Iw8KJR/cq1F1fn8VneuXZPKZDfCIFnVuS9zN5R8/h MgxxPGi2ZVTuIWsGUHijh5duasQiBS6X0PCozcFnDzlQ0yxTlG7wRt0TNrkWlprJ1pU6 TXDg== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=cc:to:subject:message-id:date:from:references:in-reply-to :mime-version:dkim-signature:delivered-to:list-id:list-subscribe :list-unsubscribe:list-help:list-post:precedence:mailing-list :arc-authentication-results; bh=N87gWHO8k70aJKthVtETyV6A+k6fUOLBXESmNII6ULc=; b=DOJT1vrsmoLOAYq2IgBFNywCcBuKKyXoy1fn3rvuz2u+SV7qk29DFPZniQF0mR2QZF YnpoWiqigE7ALEthkDsiSI+snssqmC3xMvxAsdsXv6a8w/pY84hyAu3uIVCnJX7iRU1J zufPfzXJLLzWhkArpbfjBn8rw1ywgj0eTmQwJ6nXccZw7DtYEvfFWEil59VAa4aTidPc N9muPEPl/pWYUCAl5zeIJxVXbbBtWp9dLTdf1SqWxTEufQhoy5iscMcnHz+4jq36hHe4 Fx85VXXBjfKFXzq4MbsEvcH0HehiuDlIqwu/eT+mHzOCreaQDR+dJUARzaB0Uf5cP91I 0Rug== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass header.i=@gmail.com header.s=20161025 header.b=iiZuNtlU; spf=pass (google.com: domain of kernel-hardening-return-11662-gregkh=linuxfoundation.org@lists.openwall.com designates 195.42.179.200 as permitted sender) smtp.mailfrom=kernel-hardening-return-11662-gregkh=linuxfoundation.org@lists.openwall.com; dmarc=pass (p=NONE sp=QUARANTINE dis=NONE) header.from=gmail.com Authentication-Results: mx.google.com; dkim=pass header.i=@gmail.com header.s=20161025 header.b=iiZuNtlU; spf=pass (google.com: domain of kernel-hardening-return-11662-gregkh=linuxfoundation.org@lists.openwall.com designates 195.42.179.200 as permitted sender) smtp.mailfrom=kernel-hardening-return-11662-gregkh=linuxfoundation.org@lists.openwall.com; dmarc=pass (p=NONE sp=QUARANTINE dis=NONE) header.from=gmail.com Mailing-List: contact kernel-hardening-help@lists.openwall.com; run by ezmlm List-Post: List-Help: List-Unsubscribe: List-Subscribe: MIME-Version: 1.0 In-Reply-To: <20180208194235.GA3424@bombadil.infradead.org> References: <20180208021112.GB14918@bombadil.infradead.org> <20180208185648.GB9524@bombadil.infradead.org> <20180208194235.GA3424@bombadil.infradead.org> From: Daniel Micay Date: Thu, 8 Feb 2018 14:48:52 -0500 Message-ID: Subject: Re: [RFC] Warn the user when they could overflow mapcount To: Matthew Wilcox Cc: Jann Horn , linux-mm@kvack.org, Kernel Hardening , kernel list , "Kirill A. Shutemov" Content-Type: text/plain; charset="UTF-8" X-getmail-retrieved-from-mailbox: INBOX X-GMAIL-THRID: =?utf-8?q?1591796976786547518?= X-GMAIL-MSGID: =?utf-8?q?1591863515358550442?= X-Mailing-List: linux-kernel@vger.kernel.org List-ID: I guess it could saturate and then switch to tracking the count via an object pointer -> count mapping with a global lock? Whatever the solution is should probably be a generic one since it's a recurring issue.