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 2C5A6C4321E for ; Tue, 30 Nov 2021 15:03:57 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S245306AbhK3PHO (ORCPT ); Tue, 30 Nov 2021 10:07:14 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33906 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S244205AbhK3PAb (ORCPT ); Tue, 30 Nov 2021 10:00:31 -0500 Received: from sin.source.kernel.org (sin.source.kernel.org [IPv6:2604:1380:40e1:4800::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 4F59EC08C5CD; Tue, 30 Nov 2021 06:52:40 -0800 (PST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by sin.source.kernel.org (Postfix) with ESMTPS id 9D269CE1A50; Tue, 30 Nov 2021 14:52:38 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id EB839C8D184; Tue, 30 Nov 2021 14:52:35 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1638283956; bh=NnAPbCD7mBQ1Qzi/AdkZz0qT1lf82Yd1rb55YQRD8t4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Uqj0FKY7KmEfqFbOtieB+BSkUcWE7YGKaZzqXih+GlckLdv3Q6+5zwbDrIXVvgwXE Y9GceiszGtFD+UFXsBDD88hBu5Uo1nhCXdjs3W9V3XixCnUSgv2Fqulv1ETeM//P71 7GilUJQ/lk++9avJ+NGkku/uBJd0CAf7oY5E0uvSHi7ocUxEFT6qiL6Md9FWYfuomu g7V+midFv/U/o3zb5fYZqaCw2yYF6+ZtM0BxVrUuQ2rNsR7m8uFNTZSeC+xsX/TCb4 22l+jDw0OjdGwCR2McWRsULAQPyhm9xcIzvb/eBDx+FRzYpLK0kyhePwB1rv27jPvK dk1LOYUzBrN8w== From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Evan Green , "Rafael J . Wysocki" , Sasha Levin , rafael@kernel.org, pavel@ucw.cz, len.brown@intel.com, linux-pm@vger.kernel.org Subject: [PATCH AUTOSEL 5.4 22/25] PM: hibernate: Fix snapshot partial write lengths Date: Tue, 30 Nov 2021 09:51:52 -0500 Message-Id: <20211130145156.946083-22-sashal@kernel.org> X-Mailer: git-send-email 2.33.0 In-Reply-To: <20211130145156.946083-1-sashal@kernel.org> References: <20211130145156.946083-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Evan Green [ Upstream commit 88a5045f176b78c33a269a30a7b146e99c550bd9 ] snapshot_write() is inappropriately limiting the amount of data that can be written in cases where a partial page has already been written. For example, one would expect to be able to write 1 byte, then 4095 bytes to the snapshot device, and have both of those complete fully (since now we're aligned to a page again). But what ends up happening is we write 1 byte, then 4094/4095 bytes complete successfully. The reason is that simple_write_to_buffer()'s second argument is the total size of the buffer, not the size of the buffer minus the offset. Since simple_write_to_buffer() accounts for the offset in its implementation, snapshot_write() can just pass the full page size directly down. Signed-off-by: Evan Green Signed-off-by: Rafael J. Wysocki Signed-off-by: Sasha Levin --- kernel/power/user.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/kernel/power/user.c b/kernel/power/user.c index 77438954cc2b0..8f678cd567a62 100644 --- a/kernel/power/user.c +++ b/kernel/power/user.c @@ -180,7 +180,7 @@ static ssize_t snapshot_write(struct file *filp, const char __user *buf, if (res <= 0) goto unlock; } else { - res = PAGE_SIZE - pg_offp; + res = PAGE_SIZE; } if (!data_of(data->handle)) { -- 2.33.0