From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id C568FC433EF for ; Sat, 20 Nov 2021 08:34:34 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236770AbhKTIhg (ORCPT ); Sat, 20 Nov 2021 03:37:36 -0500 Received: from smtp-out2.suse.de ([195.135.220.29]:55070 "EHLO smtp-out2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S237140AbhKTIhg (ORCPT ); Sat, 20 Nov 2021 03:37:36 -0500 Received: from imap2.suse-dmz.suse.de (imap2.suse-dmz.suse.de [192.168.254.74]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-521) server-digest SHA512) (No client certificate requested) by smtp-out2.suse.de (Postfix) with ESMTPS id AD37A1FD34; Sat, 20 Nov 2021 08:34:30 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=susede1; t=1637397270; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version: content-transfer-encoding:content-transfer-encoding; bh=qMVgMFqK+ZS0CJKaUTrpx5gxLAyQi28DBAIT/KVkk8c=; b=R9clJ1kGIOqH4b2aFfVlvPUvrTmjDVbs0ILUEQQvJLmfhKotD541QbiqJDfxhT9e5/YOvF yHsj4HnqK5wa1ogQo8wm6S6aQh3jn66Hxkaui69dbnMnKbAn5ydCMS04+bQze9u+7QtYIc ILcVpEYD6s9aKG4HwaLo1XOhO27CMhk= Received: from imap2.suse-dmz.suse.de (imap2.suse-dmz.suse.de [192.168.254.74]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-521) server-digest SHA512) (No client certificate requested) by imap2.suse-dmz.suse.de (Postfix) with ESMTPS id B2CD913B16; Sat, 20 Nov 2021 08:34:29 +0000 (UTC) Received: from dovecot-director2.suse.de ([192.168.254.65]) by imap2.suse-dmz.suse.de with ESMTPSA id KApnHhWzmGHKVAAAMHmgww (envelope-from ); Sat, 20 Nov 2021 08:34:29 +0000 From: Qu Wenruo To: linux-btrfs@vger.kernel.org Cc: Josef Bacik Subject: [PATCH] btrfs: fix the memory leak caused in lzo_compress_pages() Date: Sat, 20 Nov 2021 16:34:11 +0800 Message-Id: <20211120083411.120338-1-wqu@suse.com> X-Mailer: git-send-email 2.34.0 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-btrfs@vger.kernel.org [BUG] Fstests generic/027 is pretty easy to trigger a slow but steady memory leak if run with "-o compress=lzo" mount option. Normally one single run of generic/027 is enough to eat up at least 4G ram. [CAUSE] In commit d4088803f511 ("btrfs: subpage: make lzo_compress_pages() compatible") we changed how @page_in is released. But that refactor makes @page_in only released after all pages being compressed. This leaves error path not releasing @page_in. And by "error path" things like incompressible data will also be treated as an error (-E2BIG). Thus it can leave btrfs to leak memory even there is nothing wrong happened. [FIX] Add check under @out label to release @page_in when needed, so when we hit any error, the input page is properly released. Reported-by: Josef Bacik Fixes: d4088803f511 ("btrfs: subpage: make lzo_compress_pages() compatible") Signed-off-by: Qu Wenruo --- fs/btrfs/lzo.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/fs/btrfs/lzo.c b/fs/btrfs/lzo.c index 2fdfd0904313..12a459073ea1 100644 --- a/fs/btrfs/lzo.c +++ b/fs/btrfs/lzo.c @@ -290,6 +290,8 @@ int lzo_compress_pages(struct list_head *ws, struct address_space *mapping, *total_out = cur_out; *total_in = cur_in - start; out: + if (page_in) + put_page(page_in); *out_pages = DIV_ROUND_UP(cur_out, PAGE_SIZE); return ret; } -- 2.34.0