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[209.85.208.176]) by smtp.gmail.com with ESMTPSA id q26sm3365256ljg.47.2020.04.29.19.20.39 for (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 29 Apr 2020 19:20:39 -0700 (PDT) Received: by mail-lj1-f176.google.com with SMTP id l19so4763383lje.10 for ; Wed, 29 Apr 2020 19:20:39 -0700 (PDT) X-Received: by 2002:a05:651c:319:: with SMTP id a25mr608213ljp.209.1588213238646; Wed, 29 Apr 2020 19:20:38 -0700 (PDT) MIME-Version: 1.0 References: <20200428190836.GC29960@redhat.com> In-Reply-To: From: Linus Torvalds Date: Wed, 29 Apr 2020 19:20:22 -0700 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: [GIT PULL] Please pull proc and exec work for 5.7-rc1 To: Bernd Edlinger Cc: Jann Horn , Oleg Nesterov , "Eric W. Biederman" , Waiman Long , Ingo Molnar , Will Deacon , Linux Kernel Mailing List , Alexey Gladkov 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 Wed, Apr 29, 2020 at 6:08 PM Bernd Edlinger wrote: > > I added the BIG FAT WARNNIG comments as a mitigation for that. > Did you like those comments? No. What's the point olf saying "THIS CODE IS GARBAGE" and then expecting that to make it ok? No,m that doesn't make it ok. It just means that it should have been done differently. > Yes, exactly, the point is the caller is expected to call wait in that > scenario, otherwise the -EAGAIN just repeats forever, that is an API > change, yes, but something unavoidable, and the patch tries hard to > limit it to cases where the live-lock or pseudo-dead-lock is unavoidable > anyway. I'm getting really fed up with your insistence on that KNOWN BROKEN garbage test-case. It's shit. The test-case is wrong. I've told you before. Your patch as-is breaks other cases that are *not* wrong in the kernel currently, and that don't have test-cases because they JustWork(tm). The livelock isn't interesting. The test-case that shows it is pure garbage, and is written wrong. IF that test-case hadn't been buggy in the first place, it would have had ignored its child (or had a handler for SIGCHLD), and not livelocked. Linus