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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 3F5DDC77B7A for ; Wed, 24 May 2023 13:38:06 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234997AbjEXNiF (ORCPT ); Wed, 24 May 2023 09:38:05 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34444 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231609AbjEXNiC (ORCPT ); Wed, 24 May 2023 09:38:02 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A79B4A7 for ; Wed, 24 May 2023 06:37:59 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 3C4616336A for ; Wed, 24 May 2023 13:37:59 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 9F45DC433EF; Wed, 24 May 2023 13:37:57 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1684935478; bh=udO4xQRdc8S2NhttV8djXD6oLRQpuOmuBKmlvUUbirw=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=jg7VmnK33x6K7forkPCab3heYrUAkktLh0Hzw8o9GdXEteGIprM+Uiq2WzkjRypyW fkrEklV1WOzUTl5PSbJBAQccxC+CbE0ljv0DdJ7Xfo7I3oiGo9AHB/TevKAnglp42d ZZUnho6U3yWjO4YNTCTflW3jXAaU2X+MLaahtTq2JhyT32mReDYKp6FneIVXk4OqQR Bq3plFLeRHvmqTYUBD86yXJXdRPE5TOdTrV1LeKYvxO8IytQUME0i7aGGHCX+9d/9V TDuc8DUdGyKpqrBD1ZwZElTbwaz2in5piXH0waHGacLfX1E2nSE+IIH9Vo4JyPuXdj haLwXSGzUKeBw== Date: Wed, 24 May 2023 21:26:46 +0800 From: Jisheng Zhang To: Catalin Marinas , Will Deacon Cc: linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] arm64: mm: pass original fault address to handle_mm_fault() in PER_VMA_LOCK block Message-ID: References: <20230524131238.2791-1-jszhang@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20230524131238.2791-1-jszhang@kernel.org> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, May 24, 2023 at 09:12:38PM +0800, Jisheng Zhang wrote: > When reading the arm64's PER_VMA_LOCK support code, I found a bit > difference between arm64 and other arch when calling handle_mm_fault() > during VMA lock-based page fault handling: the fault address is masked > before passing to handle_mm_fault(). This is also different from the > usage in mmap_lock-based handling. I think we need to pass the > original fault address to handle_mm_fault() as we did in > commit 84c5e23edecd ("arm64: mm: Pass original fault address to > handle_mm_fault()"). > > If we go through the code path further, we can find that the "masked" > fault address can cause mismatched fault address between perf sw > major/minor page fault sw event and perf page fault sw event: OOPS, sorry please ignore this one. I pressed ctrl-c to interrupt the git send-mail, but it's still sent out ;) Instead, let's focus on https://lore.kernel.org/linux-arm-kernel/20230524131305.2808-1-jszhang@kernel.org/T/#u The two patches are the same, I just added Suren into CC list. > > do_page_fault > perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS, ..., addr) // orig addr > handle_mm_fault > mm_account_fault > perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MAJ, ...) // masked addr > > Fixes: cd7f176aea5f ("arm64/mm: try VMA lock-based page fault handling first") > Signed-off-by: Jisheng Zhang > --- > arch/arm64/mm/fault.c | 3 +-- > 1 file changed, 1 insertion(+), 2 deletions(-) > > diff --git a/arch/arm64/mm/fault.c b/arch/arm64/mm/fault.c > index cb21ccd7940d..6045a5117ac1 100644 > --- a/arch/arm64/mm/fault.c > +++ b/arch/arm64/mm/fault.c > @@ -600,8 +600,7 @@ static int __kprobes do_page_fault(unsigned long far, unsigned long esr, > vma_end_read(vma); > goto lock_mmap; > } > - fault = handle_mm_fault(vma, addr & PAGE_MASK, > - mm_flags | FAULT_FLAG_VMA_LOCK, regs); > + fault = handle_mm_fault(vma, addr, mm_flags | FAULT_FLAG_VMA_LOCK, regs); > vma_end_read(vma); > > if (!(fault & VM_FAULT_RETRY)) { > -- > 2.40.1 > > > _______________________________________________ > linux-arm-kernel mailing list > linux-arm-kernel@lists.infradead.org > http://lists.infradead.org/mailman/listinfo/linux-arm-kernel