From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-lf0-f72.google.com (mail-lf0-f72.google.com [209.85.215.72]) by kanga.kvack.org (Postfix) with ESMTP id 64EBA6B0069 for ; Wed, 18 Jan 2017 20:37:12 -0500 (EST) Received: by mail-lf0-f72.google.com with SMTP id z134so12753593lff.5 for ; Wed, 18 Jan 2017 17:37:12 -0800 (PST) Received: from mail-lf0-x244.google.com (mail-lf0-x244.google.com. [2a00:1450:4010:c07::244]) by mx.google.com with ESMTPS id o69si1296112lfo.123.2017.01.18.17.37.10 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 18 Jan 2017 17:37:10 -0800 (PST) Received: by mail-lf0-x244.google.com with SMTP id q89so3736002lfi.1 for ; Wed, 18 Jan 2017 17:37:10 -0800 (PST) MIME-Version: 1.0 In-Reply-To: <20170118131711.GA7021@dhcp22.suse.cz> References: <20170117122249.815342d95117c3f444acc952@linux-foundation.org> <20170118013948.GA580@jagdpanzerIV.localdomain> <20170118131711.GA7021@dhcp22.suse.cz> From: Dan Streetman Date: Wed, 18 Jan 2017 20:36:29 -0500 Message-ID: Subject: Re: [Bug 192571] zswap + zram enabled BUG Content-Type: text/plain; charset=UTF-8 Sender: owner-linux-mm@kvack.org List-ID: To: Michal Hocko Cc: Sergey Senozhatsky , sss123next@list.ru, Seth Jennings , Minchan Kim , bugzilla-daemon@bugzilla.kernel.org, Linux-MM , Andrew Morton On Wed, Jan 18, 2017 at 8:17 AM, Michal Hocko wrote: > On Wed 18-01-17 10:39:48, Sergey Senozhatsky wrote: >> Cc Dan >> >> On (01/17/17 12:22), Andrew Morton wrote: >> > > https://bugzilla.kernel.org/show_bug.cgi?id=192571 >> > > >> > > --- Comment #1 from Gluzskiy Alexandr --- >> > > [199961.576604] ------------[ cut here ]------------ >> > > [199961.577830] kernel BUG at mm/zswap.c:1108! >> >> zswap didn't manage to decompress the page: >> >> static int zswap_frontswap_load(unsigned type, pgoff_t offset, >> struct page *page) >> { >> ... >> dst = kmap_atomic(page); >> tfm = *get_cpu_ptr(entry->pool->tfm); >> ret = crypto_comp_decompress(tfm, src, entry->length, dst, &dlen); >> put_cpu_ptr(entry->pool->tfm); >> kunmap_atomic(dst); >> zpool_unmap_handle(entry->pool->zpool, entry->handle); >> BUG_ON(ret); >> ^^^^^^^^^^^ > > Ugh, why do we even do that? This is not the way how to handle error > situations. AFAIU propagating the error out wouldn't be a big deal > because we would just fallback to regular swap, right? yeah this function definitely should never bug; it's just a callback from the zpool to try to write a page back to the swapcache so the zpool can free a page. It's definitely ok for it to return an error. > -- > Michal Hocko > SUSE Labs > > -- > To unsubscribe, send a message with 'unsubscribe linux-mm' in > the body to majordomo@kvack.org. For more info on Linux MM, > see: http://www.linux-mm.org/ . > Don't email: email@kvack.org > -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org