From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1794063774; b=uTSV5H+m6qxb3Ak+lu5yQvmhOvqHQCTcmDimu9ZUDbV84Cje3wpvBnzWY94lqYW4Pixq kKUQCCbJlHmeZe+QwY1CCu758R+wbDas5idxvY6eFyhJTtyo7LIPtVZN6aOagnDGKZofk 1Vue7/I49lJK9080xn67gA67PsWMtkhoW1o+kUDBz5GstdAEAsEpkZAVyLcfRycWhcEU1 sqoN84kFpJapvVNtgAtQb1b4aiS/6tV6o/iaeORshVWWHPi3uL+ZYCWx0pcODVnf8jbLG 6JvLyubZPh1eWxFw9oiVsvckpoKxaiXWQERaQ3R19HAGt7fL0ANVnb1jnsB3WV9AYew== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1794063774; h=Received:DKIM-Signature:From:To:Cc:Subject:Date:Message-ID:X-Mailer: In-Reply-To:References:User-Agent:X-stable:X-Patchwork-Hint: MIME-Version:Content-Transfer-Encoding; bh=RAxu54Lt0c44tgqqkCDwBSbpEkLw/g5uQBqUXzDf9fs=; b=iDKIvk5v/gMa0zovPp4QlwKFcgDX4h7GU6r6i4STsdL02SnYAKWWTrbuBvy/pWeIavaq JguZsdM9M3WH6N8JPpPlUbv8Ahi2y2+wOOUzPpgvIbQVTuzdIzcALki5J9Wh6Bu+X9JBI QVN/380IpBdzgYJk7EvpXex06vWwJy1ViTMNe8B8MMSvLDE5QSw3vZDWVmdz8S+GOewaA FNY1BbBjipKAQADpygLcuzmiG4sR6eWqHPj88Q4dCgJTECCSqGcZoNkk9us95FSeFiG6K K/ZvwOfpKipkLJznBytShDAzbNkoUXT/KX0lqPrqzHVtZ25Ux16YJLiYCWevvBKV1Hw== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=linuxfoundation.org header.i=@linuxfoundation.org header.a=rsa-sha256 header.s=korg header.b=sCeL0UAS; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 1077960A2615; Sat, 7 Nov 2026 15:02:54 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.a=rsa-sha256 header.s=korg header.b=sCeL0UAS Received: by smtp.kernel.org (Postfix) with ESMTPSA id B03541F0089F; Sat, 7 Nov 2026 15:02:53 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1794063773; bh=RAxu54Lt0c44tgqqkCDwBSbpEkLw/g5uQBqUXzDf9fs=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=sCeL0UASEm4tr69DN/S13u2kaPScj3IWdSG6dMJZWL5T4YtZ8hl3VtMr2e/lN3zbm K/eAAMBPNC5Fk10NdxorznR6mGN1f3Dfe6IwHXFPCu1kyzabepKdw3BVs1OEDAMHh6 C1Kuz2mGXAnPE3RRDSPdzmxtCdCg05GhQvVR3qww= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Hungyu Lin , Amir Goldstein , "Christian Brauner (Amutable)" , Sasha Levin Subject: [PATCH 6.18 864/869] fs: skip copy_file_range write limits when there is no data Date: Sat, 7 Nov 2026 08:59:06 -0500 Message-ID: <20261107134922.109239239@linuxfoundation.org> X-Mailer: git-send-email 2.56.0 In-Reply-To: <20261107134852.069646174@linuxfoundation.org> References: <20261107134852.069646174@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore X-Mailing-List: stable@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: Hungyu Lin [ Upstream commit 81dfa035891f0502674332ee97db348a16486de0 ] generic_copy_file_checks() reduces count to zero for a source offset at or beyond EOF, but still checks the destination write limits. If pos_out is at RLIMIT_FSIZE, this sends SIGXFSZ and returns -EFBIG even though there is no data to write. For example, GNU cat copying a 1024-byte regular file to another regular file with RLIMIT_FSIZE=1024 copies all bytes and is then killed by its next copy_file_range() call at EOF. A zero-length request can fail in the same way. Check write limits only when count is nonzero, as the ordinary write checks already do. Keep the other copy validation in place. Fixes: 96e6e8f4a68d ("vfs: add missing checks to copy_file_range") Cc: stable@vger.kernel.org Signed-off-by: Hungyu Lin Link: https://patch.msgid.link/20261026015738.46230-1-dennylin0707@gmail.com Reviewed-by: Amir Goldstein Signed-off-by: Christian Brauner (Amutable) Signed-off-by: Sasha Levin --- fs/read_write.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) diff --git a/fs/read_write.c b/fs/read_write.c index 833bae068770a..011fe55c94cdb 100644 --- a/fs/read_write.c +++ b/fs/read_write.c @@ -1530,9 +1530,11 @@ static int generic_copy_file_checks(struct file *file_in, loff_t pos_in, else count = min(count, size_in - (uint64_t)pos_in); - ret = generic_write_check_limits(file_out, pos_out, &count); - if (ret) - return ret; + if (count) { + ret = generic_write_check_limits(file_out, pos_out, &count); + if (ret) + return ret; + } /* Don't allow overlapped copying within the same file. */ if (inode_in == inode_out && -- 2.53.0