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[2607:7c80:54:e::133]) by mx.google.com with ESMTPS id i17si7413384pju.96.2019.08.02.15.59.44 for (version=TLS1_3 cipher=AEAD-AES256-GCM-SHA384 bits=256/256); Fri, 02 Aug 2019 15:59:44 -0700 (PDT) Received-SPF: pass (google.com: best guess record for domain of willy@infradead.org designates 2607:7c80:54:e::133 as permitted sender) client-ip=2607:7c80:54:e::133; Authentication-Results: mx.google.com; dkim=pass header.i=@infradead.org header.s=bombadil.20170209 header.b=qKZqH04Z; spf=pass (google.com: best guess record for domain of willy@infradead.org designates 2607:7c80:54:e::133 as permitted sender) smtp.mailfrom=willy@infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20170209; h=In-Reply-To:Content-Transfer-Encoding :Content-Type:MIME-Version:References:Message-ID:Subject:Cc:To:From:Date: Sender:Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id:List-Help: List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=4Vp/kqP9japOy3ACodrJwRs1V+FSeqYXiepD5OU8/Pg=; b=qKZqH04Z5Il/hHnxT/u/iLha8B WenSRYxHMj0u1ZloMPhq0g6W3hB7+FE9AQ4R30P1C3J7aQa1ytNC2T/N26tNJ4FWsBGlkijfYHsxX UEYJBazuzGCdPoFBysXcXrkbSYWFkTNL4K38eV3n1fbdQu8ikuBK2gQmnFVnlCPpbd/DKS7xrlcCm 1jHEuppTBrazcYe0A57CpIROQcyKrNvjl9ZNdspZPTx3AI2PaMDyJ1tWm2MLZyhre7wPX4USF933R kiVnEgHWD2atTokkjOx8fRL+uNE2pbJYu0R28sazP4B2iXaGpcwJjh2I8ADyClABJaInyn+mM7FQZ qUD5+fAw==; Received: from willy by bombadil.infradead.org with local (Exim 4.92 #3 (Red Hat Linux)) id 1htgWR-0004QR-HV; Fri, 02 Aug 2019 22:59:39 +0000 Date: Fri, 2 Aug 2019 15:59:39 -0700 From: Matthew Wilcox To: Qian Cai Cc: Andrew Morton , petr@vandrovec.name, bugzilla-daemon@bugzilla.kernel.org, Christian Koenig , Huang Rui , David Airlie , Daniel Vetter , dri-devel@lists.freedesktop.org, linux-mm@kvack.org Subject: Re: [Bug 204407] New: Bad page state in process Xorg Message-ID: <20190802225939.GE5597@bombadil.infradead.org> References: <20190802132306.e945f4420bc2dcddd8d34f75@linux-foundation.org> <20190802203344.GD5597@bombadil.infradead.org> <1564780650.11067.50.camel@lca.pw> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <1564780650.11067.50.camel@lca.pw> User-Agent: Mutt/1.11.4 (2019-03-13) 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 Fri, Aug 02, 2019 at 05:17:30PM -0400, Qian Cai wrote: > On Fri, 2019-08-02 at 13:33 -0700, Matthew Wilcox wrote: > > It occurs to me that when a page is freed, we could record some useful bits > > of information in the page from the stack trace to help debug double-free  > > situations.  Even just stashing __builtin_return_address in page->mapping > > would be helpful, I think. > > Sounds like need to enable "page_owner", so it will do  __dump_page_owner(). That doesn't help because we call reset_page_owner() in the free page path. We could turn on tracing because we call trace_mm_page_free() in this path. That requires the reporter to be able to reproduce the problem, and it's not clear to me whether this is a "happened once" or "every time I do this, it happens" problem.