From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from casper.infradead.org (casper.infradead.org [90.155.50.34]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 19ACC22301 for ; Fri, 26 Jan 2024 18:34:57 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=90.155.50.34 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1706294100; cv=none; b=JmuhGthS7uciqlJFaS3LYfbktDXGQPhiIV8scN6d0xfgAIR/4wTVBrgRbzV2X/B4soJyrJGz4p1cssuhEEGcW633fo2Gca+hHrhn+TN1JpCfsreSGoAvhqYKqX6cu7KZrEiKMO1lqScEiJxyg2vtCmcbvXmMV9xDyjd+/8gDqKY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1706294100; c=relaxed/simple; bh=preSX0quXvFKX+sSbZN+zc+SigzkAHZEJzhFhllCae8=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=M/mEaUcucl0l+iDtXDQC1TtB3zaBVS8nkiWmoj2bDqEJBbkKk+hkFUZsAKSOCvPa1+4RHPeTrdghpSZRN3xYzZaLaj1G5Gcg3QPNfk3LxRp511iIb06GxTpARn9aC8iuD2Yfl2efX8wwUnSHDQu4RdWW/Cblovbo5FmsHXtzOi0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org; spf=none smtp.mailfrom=infradead.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b=UwcRX1yS; arc=none smtp.client-ip=90.155.50.34 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=infradead.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="UwcRX1yS" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=g8fiwmPSySU4eNFj55g0a5/9A7qTajzirLf5GX98rOs=; b=UwcRX1ySFi1nbOK5g7PfabK6sw 7qXUH+5DP3RGvhMrBAH0NjHlQc18EsMIs0fBXguuVmmtNX0wzGAfNlnMvUje8wBU+WjtdLUhB6iCQ KJvKSPFA5F09x4naLxMx5rOD5iMJe3KtPiYgA63p5KOPhRVXY4UK8gFkb027dTcs41tTiYN5HacPQ /PHL4ZkTZ66AOtgPszGnjv6LLLcWfD80omFft65a3af/c+r+fX6ndJzRJg95EBB7bLI0VUSd+CbB+ i4dfFnte4jYPjSFzzvcNgfJYY7OcnwAkjC41ojscIBOG/Soct19joxB42DElNMezqgtaRpc6DRmgu qXHqzJyQ==; Received: from willy by casper.infradead.org with local (Exim 4.97.1 #2 (Red Hat Linux)) id 1rTR2U-0000000EUM5-3YYE; Fri, 26 Jan 2024 18:34:55 +0000 Date: Fri, 26 Jan 2024 18:34:54 +0000 From: Matthew Wilcox To: Chenyuan Yang Cc: akpm@linux-foundation.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, syzkaller@googlegroups.com, Zijie Zhao , John Hubbard Subject: Re: [Linux Kernel Bug][mm/gup] 3 Warning Crashes: kmalloc bug in gup_test_ioctl, is_valid_gup_args, pin_user_pages_fast Message-ID: References: Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: On Fri, Jan 26, 2024 at 11:31:26AM -0600, Chenyuan Yang wrote: > In this context, I would like to seek your valued opinion. Do you > believe it would be more prudent to avoid fuzz testing the > `gup_test_ioctl`, or are the warnings in `gup_test_ioctl` an > anticipated outcome? It seems like a waste of time. Debian certainly disables it, so unless you can find a distro who enables it, I wouldn't bother. > It seems that `gup_test_ioctl` can indeed be exposed in the kernel by > accessing /sys/kernel/debug/gup_test. If someone wants to fix these things, they can, but it just doesn't seem worth doing. Part of the art of fuzz testing is finding things that are worth testing.