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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 062BCC48286 for ; Sun, 4 Feb 2024 07:38:43 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References: Message-ID:Subject:Cc:To:From:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=T/jMm/Hsb8GNyd6BAct7YklzUhsNiYdNg4uYwx3wiPA=; b=OClCx2SnimDHcN TCIxkVSb02B1ml+DYSVfVfBrqXwcL6hoOgnOf6OHWJcsAs+v2bj0kZVmZjHcmbiZjsdwwzAlxRlXW p+GYOHta12ccioIaCFNVTKpL6CexL8ttz+xSbC0EK3KjY3pkwGUZAy9dATKOkUNqmpM1XzIaoDzv7 xfWYDwAKMttZO2B4y639SWDbgfJafn/wR22GVmhG3csFVdZSg43sk6AlCtRUhCyTtzPG2MXfyhlAL LK9xrz7R7yeb8KKeIcWHi9c4sRwWcuNtyod7u4g0f+bOtI99t/Jswyb373sNpaqbfY5V1rjDfmBe0 1SeiK22JnCQHflm5Xymw==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.97.1 #2 (Red Hat Linux)) id 1rWX5M-00000000Kwm-3TJT; Sun, 04 Feb 2024 07:38:40 +0000 Received: from us-smtp-delivery-124.mimecast.com ([170.10.129.124]) by bombadil.infradead.org with esmtps (Exim 4.97.1 #2 (Red Hat Linux)) id 1rWX5K-00000000KwP-0iCz for kexec@lists.infradead.org; Sun, 04 Feb 2024 07:38:39 +0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1707032316; 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=DW8SolzwMeCv8mPxutq7dUzGbNRfIdT1DwumifZIq0c=; b=TwlI4SNsWgLC5N/LApwesjcNul4WwIc5o6J7GYrFjcpCQoHIJywKc8MbxKOAriWOL2c4lK SEeK05wSnlMce4y3pa+FO3DkpnB1iU1aG1r1JncPE/dyK2O5BfJJd9i6wbIIKEkmatJbGQ wmj+i7whWcDlO6X+fxqU8DdPM5kZECQ= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-217-mn4BQlZTO5ShtAF3obfNEw-1; Sun, 04 Feb 2024 02:38:32 -0500 X-MC-Unique: mn4BQlZTO5ShtAF3obfNEw-1 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.rdu2.redhat.com [10.11.54.3]) (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 mimecast-mx02.redhat.com (Postfix) with ESMTPS id 2D97885A588; Sun, 4 Feb 2024 07:38:32 +0000 (UTC) Received: from localhost (unknown [10.72.116.13]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 376AA1121306; Sun, 4 Feb 2024 07:38:30 +0000 (UTC) Date: Sun, 4 Feb 2024 15:38:26 +0800 From: Baoquan He To: "yang.zhang" Cc: ebiederm@xmission.com, kexec@lists.infradead.org, linux-kernel@vger.kernel.org, "yang.zhang" Subject: Re: [PATCH] kexec: should use uchunk for user buffer increasing Message-ID: References: <20240130101802.23850-1-gaoshanliukou@163.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20240130101802.23850-1-gaoshanliukou@163.com> X-Scanned-By: MIMEDefang 3.4.1 on 10.11.54.3 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20240203_233838_314885_ECA2936D X-CRM114-Status: GOOD ( 17.65 ) X-BeenThere: kexec@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "kexec" Errors-To: kexec-bounces+kexec=archiver.kernel.org@lists.infradead.org On 01/30/24 at 06:18pm, yang.zhang wrote: > From: "yang.zhang" > > Because of alignment requirement in kexec-tools, there is > no problem for user buffer increasing when loading segments. > But when coping, the step is uchunk, so we should use uchunk > not mchunk. In theory, ubytes is <= mbytes. So uchunk is always <= mchunk. If ubytes is exhausted, while there's still remaining mbytes, then uchunk is 0, there's still mchunk stepping forward. If I understand it correctly, this is a good catch. Not sure if Eric has comment on this to confirm. static int kimage_load_normal_segment(struct kimage *image, struct kexec_segment *segment) { ...... ptr += maddr & ~PAGE_MASK; mchunk = min_t(size_t, mbytes, PAGE_SIZE - (maddr & ~PAGE_MASK)); uchunk = min(ubytes, mchunk); ......} > > Signed-off-by: yang.zhang > --- > kernel/kexec_core.c | 8 ++++---- > 1 file changed, 4 insertions(+), 4 deletions(-) > > diff --git a/kernel/kexec_core.c b/kernel/kexec_core.c > index d08fc7b5db97..2b8354313c85 100644 > --- a/kernel/kexec_core.c > +++ b/kernel/kexec_core.c > @@ -813,9 +813,9 @@ static int kimage_load_normal_segment(struct kimage *image, > ubytes -= uchunk; > maddr += mchunk; > if (image->file_mode) > - kbuf += mchunk; > + kbuf += uchunk; > else > - buf += mchunk; > + buf += uchunk; > mbytes -= mchunk; > > cond_resched(); > @@ -881,9 +881,9 @@ static int kimage_load_crash_segment(struct kimage *image, > ubytes -= uchunk; > maddr += mchunk; > if (image->file_mode) > - kbuf += mchunk; > + kbuf += uchunk; > else > - buf += mchunk; > + buf += uchunk; > mbytes -= mchunk; > > cond_resched(); > -- > 2.34.1 > > > _______________________________________________ > kexec mailing list > kexec@lists.infradead.org > http://lists.infradead.org/mailman/listinfo/kexec > _______________________________________________ kexec mailing list kexec@lists.infradead.org http://lists.infradead.org/mailman/listinfo/kexec