From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from out-183.mta0.migadu.com (out-183.mta0.migadu.com [91.218.175.183]) (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 E1548205513 for ; Fri, 25 Apr 2025 04:06:57 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=91.218.175.183 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1745554021; cv=none; b=FcbaVgHPmzMb+YIV+1E2vQjfr/qCP0WjiG6qo7mKThfKvYZ0Ddle/rhCHppIYBT+brgL4YhtN/tqM0gDraCY3VEWfuTP5PLY+ejNb/Nk7v8gBxgKwAwIn9xqmPF5W6FAjb7ZCnVpuEAvng8SJwfpEJoQoNdAaoyju79eRHty6Ns= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1745554021; c=relaxed/simple; bh=WtJMnjwowPfe+6KgXjjmyyZyeGpcViFHXukmWXOJLbQ=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=WKaENH6bYu4np2weEW/CS62isG0+DS6KOrS25VkrpQPlt18j3Qow8sYzrRaqVz3T3Mer7l0R8RaaC3ARojkvVIzUo0j3va+IRM/mWl6Mh5+QvFDfiNgw5ILJ331CtUVuUnzUsZLp5TgbItYRrHZXzgQrV1qihQSKwGPLn1WshkI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev; spf=pass smtp.mailfrom=linux.dev; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b=e7mlQmc5; arc=none smtp.client-ip=91.218.175.183 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.dev Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b="e7mlQmc5" Message-ID: <8352c76d-ad30-4c2e-91bd-9676df21b293@linux.dev> DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1745554015; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=McgZG3+kgRVX1m1JTnpDAlQQ4f5/9JzIXvGUQ0n2AG8=; b=e7mlQmc5secbcKyizKg9GNyiWPCUKFVJxMmaikba9aLEHzAw03yTr5rJrlS0h2qx4tnOk1 qmFn7/hxKlzyHOhynFgHAODkM6HYsMLFfRHzSD4IODbaxEM2jQlgJxV/CFjDAxhni0oGW2 seUQ99KLl3t0+NCpWikuVSaaD5Prtuc= Date: Fri, 25 Apr 2025 06:06:51 +0200 Precedence: bulk X-Mailing-List: linux-block@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Subject: Re: [PATCH] loop: Add sanity check for read/write_iter To: Lizhi Xu , syzbot+6af973a3b8dfd2faefdc@syzkaller.appspotmail.com Cc: axboe@kernel.dk, linux-block@vger.kernel.org, linux-kernel@vger.kernel.org, syzkaller-bugs@googlegroups.com References: <680a45db.050a0220.10d98e.000a.GAE@google.com> <20250425034057.3133195-1-lizhi.xu@windriver.com> X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. From: Zhu Yanjun In-Reply-To: <20250425034057.3133195-1-lizhi.xu@windriver.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit X-Migadu-Flow: FLOW_OUT 在 2025/4/25 5:40, Lizhi Xu 写道: > Some file systems do not support read_iter or write_iter, such as selinuxfs > in this issue. > So before calling them, first confirm that the interface is supported and > then call it. > > Reported-by: syzbot+6af973a3b8dfd2faefdc@syzkaller.appspotmail.com > Closes: https://syzkaller.appspot.com/bug?extid=6af973a3b8dfd2faefdc > Signed-off-by: Lizhi Xu > --- > drivers/block/loop.c | 13 +++++++++---- > 1 file changed, 9 insertions(+), 4 deletions(-) > > diff --git a/drivers/block/loop.c b/drivers/block/loop.c > index 674527d770dc..4f968e3071ed 100644 > --- a/drivers/block/loop.c > +++ b/drivers/block/loop.c > @@ -449,10 +449,15 @@ static int lo_rw_aio(struct loop_device *lo, struct loop_cmd *cmd, > cmd->iocb.ki_flags = IOCB_DIRECT; > cmd->iocb.ki_ioprio = IOPRIO_PRIO_VALUE(IOPRIO_CLASS_NONE, 0); > > - if (rw == ITER_SOURCE) > - ret = file->f_op->write_iter(&cmd->iocb, &iter); > - else > - ret = file->f_op->read_iter(&cmd->iocb, &iter); > + ret = 0; > + if (rw == ITER_SOURCE) { > + if (likely(file->f_op->write_iter)) > + ret = file->f_op->write_iter(&cmd->iocb, &iter); > + } > + else { > + if (likely(file->f_op->read_iter)) "else if" is better? Zhu Yanjun > + ret = file->f_op->read_iter(&cmd->iocb, &iter); > + } > > lo_rw_aio_do_completion(cmd); >