From mboxrd@z Thu Jan 1 00:00:00 1970 From: Stephen Boyd Subject: Re: [PATCH] tracing: Fix unmapping loop in tracing_mark_write Date: Mon, 09 Feb 2015 15:33:58 -0800 Message-ID: <54D943E6.1030404@codeaurora.org> References: <1418871056-6614-1-git-send-email-markivx@codeaurora.org> Mime-Version: 1.0 Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Return-path: Received: from smtp.codeaurora.org ([198.145.29.96]:34896 "EHLO smtp.codeaurora.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1761535AbbBIXeA (ORCPT ); Mon, 9 Feb 2015 18:34:00 -0500 In-Reply-To: <1418871056-6614-1-git-send-email-markivx@codeaurora.org> Sender: linux-arm-msm-owner@vger.kernel.org List-Id: linux-arm-msm@vger.kernel.org To: Vikram Mulukutla , Steven Rostedt , Ingo Molnar Cc: linux-kernel@vger.kernel.org, linux-arm-msm@vger.kernel.org, Lime Yang On 12/17/14 18:50, Vikram Mulukutla wrote: > Commit 6edb2a8a385f0cdef51dae37ff23e74d76d8a6ce introduced > an array map_pages that contains the addresses returned by > kmap_atomic. However, when unmapping those pages, map_pages[0] > is unmapped before map_pages[1], breaking the nesting requirement > as specified in the documentation for kmap_atomic/kunmap_atomic. > > This was caught by the highmem debug code present in kunmap_atomic. > Fix the loop to do the unmapping properly. > > Reviewed-by: Stephen Boyd > Reported-by: Lime Yang > Signed-off-by: Vikram Mulukutla > --- ping? What happened to this patch? > kernel/trace/trace.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c > index ab76b7b..bceed34 100644 > --- a/kernel/trace/trace.c > +++ b/kernel/trace/trace.c > @@ -4931,7 +4931,7 @@ tracing_mark_write(struct file *filp, const char __user *ubuf, > *fpos += written; > > out_unlock: > - for (i = 0; i < nr_pages; i++){ > + for (i = nr_pages - 1; i >= 0; i--) { > kunmap_atomic(map_page[i]); > put_page(pages[i]); > } -- Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, a Linux Foundation Collaborative Project