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[209.85.167.46]) by smtp.gmail.com with ESMTPSA id j18sm7441357lfh.6.2019.12.06.20.01.46 for (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Fri, 06 Dec 2019 20:01:46 -0800 (PST) Received: by mail-lf1-f46.google.com with SMTP id m30so6769279lfp.8 for ; Fri, 06 Dec 2019 20:01:46 -0800 (PST) X-Received: by 2002:ac2:465e:: with SMTP id s30mr6736611lfo.134.1575691305722; Fri, 06 Dec 2019 20:01:45 -0800 (PST) MIME-Version: 1.0 References: <157558502272.10278.8718685637610645781.stgit@warthog.procyon.org.uk> <20191206135604.GB2734@twin.jikos.cz> In-Reply-To: From: Linus Torvalds Date: Fri, 6 Dec 2019 20:01:29 -0800 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: [PATCH 0/2] pipe: Fixes [ver #2] To: David Sterba , David Howells , Linus Torvalds , Eric Biggers , Al Viro , linux-fsdevel , Linux Kernel Mailing List Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Dec 6, 2019 at 7:50 PM Linus Torvalds wrote: > > I assume it's the added "do_wakeup = 0" (not the spinlock) that ends > up having some subtle issue. Ahh, and then later that is removed, but when it is removed it also remote the wakeup before the pipe_wait(). So whatever issue that commit introduces ends up remaining. I wonder if the extra wakeups ended up hiding some other bug. We do extra wakeups on the write side too, with a "FIXME! Is this really true?" comment.. Linus