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[209.85.220.65]) by mx.google.com with SMTPS id l22sor5407981ljg.23.2019.05.27.07.02.49 for (Google Transport Security); Mon, 27 May 2019 07:02:49 -0700 (PDT) Received-SPF: pass (google.com: domain of urezki@gmail.com designates 209.85.220.65 as permitted sender) client-ip=209.85.220.65; Authentication-Results: mx.google.com; dkim=pass header.i=@gmail.com header.s=20161025 header.b=CJ2irMJK; spf=pass (google.com: domain of urezki@gmail.com designates 209.85.220.65 as permitted sender) smtp.mailfrom=urezki@gmail.com; dmarc=pass (p=NONE sp=QUARANTINE dis=NONE) header.from=gmail.com DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:date:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to:user-agent; bh=nCMqcLWyCA+4Q/MEIIgUaDC50B6QNtxtBMlc97ZOozY=; b=CJ2irMJKh684KUcwCc9e3mRWyJ3si0NiJuPS8075E4MvXvGMVcYFMOXShhgQ6jQ65m 5ZT8nQuRaOztT3vV1jR1mOBIKUw3uFP111pf95gc1AWajJpwzTjYYE3a8pNrNFx8YM3G qF+VgZDKakhfXS6vsoAA15xxhlI70teCFJXoQOhdt+aB+nwDh+M1AUnaMOaH2u4iowZF M9RDJ51+OJf4FjpByIo02Fg5yIq6EfeQVZk5SdkqFnA4eQFbHfJ3XquqOWlYbMC024Gc vgdX3QYfA4UtbUxk8wiLe15FW8s3SdFjoTNbTQfmI/ASsEOrqluE4QTc3bmQiVdMTCm3 diYQ== X-Google-Smtp-Source: APXvYqzXY+tlQxq7QCiBnJ+JYYpe6XAxMrsHVoWpLgb9r76XvPQ1r14R5z8LOJLwEgnfZ3qF0GJRWg== X-Received: by 2002:a2e:81d9:: with SMTP id s25mr21926270ljg.139.1558965768729; Mon, 27 May 2019 07:02:48 -0700 (PDT) Received: from pc636 ([37.139.158.167]) by smtp.gmail.com with ESMTPSA id r62sm2335963lja.48.2019.05.27.07.02.47 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Mon, 27 May 2019 07:02:47 -0700 (PDT) From: Uladzislau Rezki X-Google-Original-From: Uladzislau Rezki Date: Mon, 27 May 2019 16:02:40 +0200 To: Steven Rostedt Cc: "Uladzislau Rezki (Sony)" , Andrew Morton , linux-mm@kvack.org, Roman Gushchin , Hillf Danton , Michal Hocko , Matthew Wilcox , LKML , Thomas Garnier , Oleksiy Avramchenko , Joel Fernandes , Thomas Gleixner , Ingo Molnar , Tejun Heo Subject: Re: [PATCH v3 4/4] mm/vmap: move BUG_ON() check to the unlink_va() Message-ID: <20190527140240.6lzhunbc4py573yl@pc636> References: <20190527093842.10701-1-urezki@gmail.com> <20190527093842.10701-5-urezki@gmail.com> <20190527085927.19152502@gandalf.local.home> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190527085927.19152502@gandalf.local.home> User-Agent: NeoMutt/20170113 (1.7.2) 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: > > Move the BUG_ON()/RB_EMPTY_NODE() check under unlink_va() > > function, it means if an empty node gets freed it is a BUG > > thus is considered as faulty behaviour. > > Can we switch it to a WARN_ON(). We are trying to remove all BUG_ON()s. > If a user wants to crash on warning, there's a sysctl for that. But > crashing the system can make it hard to debug. Especially if it is hit > by someone without a serial console, and the machine just hangs in X. > That is very annoying. > > With a WARN_ON, you at least get a chance to see the crash dump. Yes we can. Even though it is considered as faulty behavior it is not a good reason to trigger a BUG. I will fix that. Thank you! -- Vlad Rezki