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 A4429EB64DA for ; Mon, 19 Jun 2023 10:11:21 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231193AbjFSKLT (ORCPT ); Mon, 19 Jun 2023 06:11:19 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:54238 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231740AbjFSKLH (ORCPT ); Mon, 19 Jun 2023 06:11:07 -0400 Received: from mout.gmx.net (mout.gmx.net [212.227.17.22]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 94BBC10CE; Mon, 19 Jun 2023 03:10:41 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=gmx.de; s=s31663417; t=1687169428; x=1687774228; i=deller@gmx.de; bh=qGeiVrX793s0DZYEPdtucWfg8cVq1CsOldhtd9/eL3w=; h=X-UI-Sender-Class:Date:Subject:To:References:From:In-Reply-To; b=N7Px8AjvhL4+znxRqKxz+lSA270421k2rcZysgGpUOdCoRMhGTVOjDqDGLH1s0EkpQD0ZFf P8X6a67UPCgBtqINFV+8/+O48QhEDhGdWFL8S2dc7nWGUbJOPu9FHjuAF/MwnelAJRj70ooke TF0kgPe8dAPr5xLyNrzU7eQOpE1eD3kp57dGR93RygOq7/7ZzHsan29gdI/D6roYCEefuxco/ Po6GiDXT+7WReQvdM1U5aRmkRt1Y+JRjARR3yIt3/ipmtXPE3rWn4HHtSismb6F+asv/8Oj/G auQPLsmcFpQoUStnyLN72oawOJVSUjfcDxuz1ekj35RKbozKmoNw== X-UI-Sender-Class: 724b4f7f-cbec-4199-ad4e-598c01a50d3a Received: from [192.168.20.60] ([94.134.144.204]) by mail.gmx.net (mrgmx105 [212.227.17.168]) with ESMTPSA (Nemesis) id 1N2E1G-1q6PTW2kcI-013i1Z; Mon, 19 Jun 2023 12:10:28 +0200 Message-ID: <6c7a0ca2-003b-c724-6ef1-4d756d05d2f0@gmx.de> Date: Mon, 19 Jun 2023 12:10:26 +0200 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.10.0 Subject: Re: [PATCH 2/3] nios2: Fix flush_dcache_page() for usage from irq context Content-Language: en-US To: Dinh Nguyen , linux@armlinux.org.uk, linux-kernel@vger.kernel.org, linux-parisc@vger.kernel.org References: <20230524152633.203927-1-deller@gmx.de> <20230524152633.203927-3-deller@gmx.de> From: Helge Deller In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: quoted-printable X-Provags-ID: V03:K1:6Ip6mm7Bsw+/cTJsBB4pvMFdzoEQcOBCpy8pF0iNolDQnV9g6xO Kaxf/VhnOD/qaECrj4ihQZK7zgQ12RoTTOe4jXea6vqDj52E3/ZKrkEyrgE9bJE95StLKUk QjkBoizdPUV2f9C0Z87Kh61nOR5xeXswAU5iMrMr1RJvzmAdHxRas4oyMhkBjaXaGZw8LHv QDCTMPCq1u49IMf8wx2Uw== UI-OutboundReport: notjunk:1;M01:P0:qmtmZJb+fTI=;ofiShLOTJd+FmbyF/cxgXTjj6/m 1c50isGBSSmpooU3EBnDLlKYI6pj+dvZ0InRMF/IW/qHNTJZewNtxjQsIMM9OZW7pY0jCvk2L iqNZaA0oMrvA3DCEKKI8OOqVOuGnTiyAso9B+TklqkrfVaOBFX05Bft6wHSAF8CwbCYe7YOtl bb/3WduWfTG7xrC+uDZCRTMeHxHB9aWJ7/HlBs/ykMO+LlGlqcSMoMMkyNz4PGHCNZ/UyAs1F TbDQr7/eqHQvhfGTwyGDSy6uQ4nd//mCctuedjPtJbOSmCe6KtLsaJ9wGczSN8IXj0S6GLUEN GkcRqQXSBDSzbaQMf/QGJ2wdsrO+fvyf4QQu8iNiVvBk4RyIWBZGgpopPyxI3zK3QRjHzF981 svk5BLTXhXPDSeYu6zqVziOGDW5sgjUOcVS/Nbs18/3ASCIdZ9seorxIz4kJfrwO4kXFa1O0B ROldqmDjv4esQsHt5EeCuKlHy81gbImu5Ke8NbTId9sZGmRk9fDC6yScSVDEyF4O/gTEvzNxX rslfj4/Sbvz/yRWafBLg/JnzZd9aYEft7Jzrynp8KXdGTzS6V/y9sbmScAyhiFlTy54KFd16F YXFj4OVNsyQV3cL3IPG2TtHZN3A+7jrBHqPQAZuJNAJ7rnOO/+0f1cK+UWa6v27sn+I8kI6TY wv873yemxhmLdNsa9RiPzrSwVTsvDGaI87WQowmJsraROW7xfPrIZGrZMf2GW3D1lyQG7gv6K wGa8vtSr+02jhURb9OTv3taZquBs5FKqqleDcCgjgcpwTLcPAPFYUTDBEscZmk3RiKOjgfKzo JM4r6Em1G7TxXBlDuvy6139O3KQs6y+yTNCS/9vRXfJoXc5wl68vGrsoolhILfsyz6kbnnlUa R4TRS0FnSXSdmxbEhcsiePledct/I9QIDWljgktylsRoYZXEgiHbQwQ2IfCTjC6nUs4ui+JDD DLWuOKYQEquTAZo2nHeE+5ZSk0s= Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Dinh, On 6/14/23 00:39, Dinh Nguyen wrote: > Thanks for the patch. Does it need a Fixes tag? I did not add a fixes tag for the parisc or arm version. The code was originally correct, but later patches then suddenly started using cache flushes from irq context (e.g. 21b40200cfe96 ("aio: use flush_dcache_page()")) which then triggers the bug. So, it's hard to say that it fixes one specific commit. I suggest you backport it as far as possible. Helge > Dinh > > On 5/24/23 10:26, Helge Deller wrote: >> Since at least kernel 6.1, flush_dcache_page() is called with IRQs >> disabled, e.g. from aio_complete(). >> >> But the current implementation for flush_dcache_page() on NIOS2 >> unintentionally re-enables IRQs, which may lead to deadlocks. >> >> Fix it by using xa_lock_irqsave() and xa_unlock_irqrestore() >> for the flush_dcache_mmap_*lock() macros instead. >> >> Cc: Dinh Nguyen >> Signed-off-by: Helge Deller >> --- >> =C2=A0 arch/nios2/include/asm/cacheflush.h | 4 ++++ >> =C2=A0 arch/nios2/mm/cacheflush.c=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0= =C2=A0=C2=A0=C2=A0 | 5 +++-- >> =C2=A0 2 files changed, 7 insertions(+), 2 deletions(-) >> >> diff --git a/arch/nios2/include/asm/cacheflush.h b/arch/nios2/include/a= sm/cacheflush.h >> index d0b71dd71287..a37242662809 100644 >> --- a/arch/nios2/include/asm/cacheflush.h >> +++ b/arch/nios2/include/asm/cacheflush.h >> @@ -48,5 +48,9 @@ extern void invalidate_dcache_range(unsigned long sta= rt, unsigned long end); >> >> =C2=A0 #define flush_dcache_mmap_lock(mapping)=C2=A0=C2=A0=C2=A0=C2=A0= =C2=A0=C2=A0=C2=A0 xa_lock_irq(&mapping->i_pages) >> =C2=A0 #define flush_dcache_mmap_unlock(mapping)=C2=A0=C2=A0=C2=A0 xa_u= nlock_irq(&mapping->i_pages) >> +#define flush_dcache_mmap_lock_irqsave(mapping, flags)=C2=A0=C2=A0=C2= =A0=C2=A0=C2=A0=C2=A0=C2=A0 \ >> +=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 xa_lock_irqsave(&mapping->i= _pages, flags) >> +#define flush_dcache_mmap_unlock_irqrestore(mapping, flags)=C2=A0=C2= =A0=C2=A0 \ >> +=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 xa_unlock_irqrestore(&mappi= ng->i_pages, flags) >> >> =C2=A0 #endif /* _ASM_NIOS2_CACHEFLUSH_H */ >> diff --git a/arch/nios2/mm/cacheflush.c b/arch/nios2/mm/cacheflush.c >> index 6aa9257c3ede..35f3b599187f 100644 >> --- a/arch/nios2/mm/cacheflush.c >> +++ b/arch/nios2/mm/cacheflush.c >> @@ -75,11 +75,12 @@ static void flush_aliases(struct address_space *map= ping, struct page *page) >> =C2=A0 { >> =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 struct mm_struct *mm =3D current->active= _mm; >> =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 struct vm_area_struct *mpnt; >> +=C2=A0=C2=A0=C2=A0 unsigned long flags; >> =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 pgoff_t pgoff; >> >> =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 pgoff =3D page->index; >> >> -=C2=A0=C2=A0=C2=A0 flush_dcache_mmap_lock(mapping); >> +=C2=A0=C2=A0=C2=A0 flush_dcache_mmap_lock_irqsave(mapping, flags); >> =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 vma_interval_tree_foreach(mpnt, &mapping= ->i_mmap, pgoff, pgoff) { >> =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 unsigned long of= fset; >> >> @@ -92,7 +93,7 @@ static void flush_aliases(struct address_space *mappi= ng, struct page *page) >> =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 flush_cache_page= (mpnt, mpnt->vm_start + offset, >> =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2= =A0=C2=A0 page_to_pfn(page)); >> =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 } >> -=C2=A0=C2=A0=C2=A0 flush_dcache_mmap_unlock(mapping); >> +=C2=A0=C2=A0=C2=A0 flush_dcache_mmap_unlock_irqrestore(mapping, flags)= ; >> =C2=A0 } >> >> =C2=A0 void flush_cache_all(void) >> -- >> 2.38.1 >>