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[209.85.167.52]) by smtp.gmail.com with ESMTPSA id d39sm188754lfv.73.2021.10.25.10.00.38 for (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 25 Oct 2021 10:00:38 -0700 (PDT) Received: by mail-lf1-f52.google.com with SMTP id bq11so11396704lfb.10 for ; Mon, 25 Oct 2021 10:00:38 -0700 (PDT) X-Received: by 2002:a05:6512:13a5:: with SMTP id p37mr17105725lfa.474.1635181238328; Mon, 25 Oct 2021 10:00:38 -0700 (PDT) MIME-Version: 1.0 References: <00000000000064451505cf0a3aa2@google.com> In-Reply-To: From: Linus Torvalds Date: Mon, 25 Oct 2021 10:00:22 -0700 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: [syzbot] WARNING: refcount bug in memfd_secret To: Matthew Wilcox Cc: syzbot , Andrew Morton , jordy@jordyzomer.github.io, jordy@pwning.systems, Linux Kernel Mailing List , Linux-MM , syzkaller-bugs Content-Type: text/plain; charset="UTF-8" X-Rspamd-Server: rspam05 X-Rspamd-Queue-Id: 86DC5B00080B X-Stat-Signature: jyogerpuuyjza68wczryet6pfhgjmgx3 Authentication-Results: imf24.hostedemail.com; dkim=pass header.d=linux-foundation.org header.s=google header.b="bE/Bst06"; spf=pass (imf24.hostedemail.com: domain of torvalds@linuxfoundation.org designates 209.85.208.170 as permitted sender) smtp.mailfrom=torvalds@linuxfoundation.org; dmarc=none X-HE-Tag: 1635181241-105922 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Sun, Oct 24, 2021 at 1:10 PM Matthew Wilcox wrote: > > I agree with you and suggested that if anybody really cares (I mean, > you need a multi-TB machine to produce this problem) that we simply do > what we did with the page refcount: Ack. That looks like the right thing to do. > + if (atomic_read(&secretmem_users) < 0) > + return -ENFILE; If somebody sends me a proper patch with a sign-off etc, I'll happily apply that two-liner. Hint hint. Linus