From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) (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 018771990DE for ; Mon, 23 Sep 2024 13:27:06 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.133.124 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1727098028; cv=none; b=VFU88irmJNrVrfHHND7+QqKal8WFt53edA1tHN9FI0Vmw8vVvcApaVU9KycSfQBBGQ/eVRB/UDrMOUIpXSTP4ZJPzWIAdDILyl7kHS4yP7FgqJPbFP4ZC6k5XmLuzNefPDpuYzZT/uJe39vm7o/8AeAYu4ba3VIlDRcN0IteF3o= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1727098028; c=relaxed/simple; bh=dI2jexkoav3yhz6acugRW9+a907CmM5inGbCMhqpRXo=; h=Date:From:To:cc:Subject:In-Reply-To:Message-ID:References: MIME-Version:Content-Type; b=PHi93LNJ9VI+UB6qPrACsAIncpHl+kFCMVDErSyHlSXXXnIqEFe7rQstiAzzaeMXeNtO8uSI6aqaw9uCDVrXqsArHLCl9woE23XEXb6QyaQOINbqnI/5e/OHAXKfk9qNvXbwREyEg1tAq9xz5f18AV00zd6hr+/8X6CB1AJ2mq4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=redhat.com; spf=pass smtp.mailfrom=redhat.com; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b=FXuZGyHF; arc=none smtp.client-ip=170.10.133.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=redhat.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=redhat.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="FXuZGyHF" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1727098025; 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: in-reply-to:in-reply-to:references:references; bh=Uxrw8H9RJR3IFfbc3l75F3IOlJFRvDC/cWL5VOkjHL0=; b=FXuZGyHFXWZGQZ0HbsglXTDVO+Mq5OFRruEBp41NEOP9UOV/sbjgADJHQSiiG3IWcBslAt wXLeF5jo0+NvCYQWNBLx+YeXkqg4m7qnggZNPXdLJe/2yddNX9MLzTKD1stQXXCZlGn5k1 dA700CgdvO63fLTZYfVR5+kcV532hdk= Received: from mx-prod-mc-05.mail-002.prod.us-west-2.aws.redhat.com (ec2-54-186-198-63.us-west-2.compute.amazonaws.com [54.186.198.63]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-286-BHMPsk0nOumgYKwG6ROz5A-1; Mon, 23 Sep 2024 09:27:02 -0400 X-MC-Unique: BHMPsk0nOumgYKwG6ROz5A-1 Received: from mx-prod-int-03.mail-002.prod.us-west-2.aws.redhat.com (unknown [10.30.177.12]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mx-prod-mc-05.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 58DC718FFA5C; Mon, 23 Sep 2024 13:27:00 +0000 (UTC) Received: from [10.45.226.79] (unknown [10.45.226.79]) by mx-prod-int-03.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id BC39619560AA; Mon, 23 Sep 2024 13:26:58 +0000 (UTC) Date: Mon, 23 Sep 2024 15:26:56 +0200 (CEST) From: Mikulas Patocka To: Dipendra Khadka cc: agk@redhat.com, snitzer@kernel.org, dm-devel@lists.linux.dev, linux-kernel@vger.kernel.org Subject: Re: [PATCH] Return error code for failure input for sscanf in parse_cblock_range() In-Reply-To: <20240922164702.49615-1-kdipendra88@gmail.com> Message-ID: <5c258e04-10b4-749d-6f15-94a432ab652e@redhat.com> References: <20240922164702.49615-1-kdipendra88@gmail.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII X-Scanned-By: MIMEDefang 3.0 on 10.30.177.12 Hi I skimmed through the sscanf source code and it seems that it can't return a negative value at all. I think, this should be: r = sscanf(str, "%llu-%llu%c", &b, &e, &dummy); if (r != 2) return -EINVAL; Mikulas On Sun, 22 Sep 2024, Dipendra Khadka wrote: > Smatch reported following: > ''' > drivers/md/dm-cache-target.c:3204 parse_cblock_range() warn: sscanf doesn't return error codes > drivers/md/dm-cache-target.c:3217 parse_cblock_range() warn: sscanf doesn't return error codes > ''' > > Since, the only negative value that is returned by sscanf is -1. > Returning -ENVAL when sscanf returns -1. > > Signed-off-by: Dipendra Khadka > --- > drivers/md/dm-cache-target.c | 8 ++++---- > 1 file changed, 4 insertions(+), 4 deletions(-) > > diff --git a/drivers/md/dm-cache-target.c b/drivers/md/dm-cache-target.c > index 17f0fab1e254..c35d65e310d6 100644 > --- a/drivers/md/dm-cache-target.c > +++ b/drivers/md/dm-cache-target.c > @@ -3200,8 +3200,8 @@ static int parse_cblock_range(struct cache *cache, const char *str, > * Try and parse form (ii) first. > */ > r = sscanf(str, "%llu-%llu%c", &b, &e, &dummy); > - if (r < 0) > - return r; > + if (r == -1) > + return -EINVAL; > > if (r == 2) { > result->begin = to_cblock(b); > @@ -3213,8 +3213,8 @@ static int parse_cblock_range(struct cache *cache, const char *str, > * That didn't work, try form (i). > */ > r = sscanf(str, "%llu%c", &b, &dummy); > - if (r < 0) > - return r; > + if (r == -1) > + return -EINVAL; > > if (r == 1) { > result->begin = to_cblock(b); > -- > 2.43.0 >