linux-kernel - Re: [PATCH v4] mm: Avoid unnecessary page fault retires on shared memory types

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <YpTHSNQxzQxwJ4vQ@arm.com>
Date:   Mon, 30 May 2022 14:31:52 +0100
From:   Catalin Marinas <catalin.marinas@....com>
To:     Peter Xu <peterx@...hat.com>
Cc:     linux-kernel@...r.kernel.org, linux-mm@...ck.org,
        Will Deacon <will@...nel.org>,
        Matt Turner <mattst88@...il.com>, linux-s390@...r.kernel.org,
        Andrew Morton <akpm@...ux-foundation.org>,
        Brian Cain <bcain@...cinc.com>, Borislav Petkov <bp@...en8.de>,
        linux-alpha@...r.kernel.org, Alistair Popple <apopple@...dia.com>,
        Jonas Bonn <jonas@...thpole.se>,
        linux-arm-kernel@...ts.infradead.org, linux-ia64@...r.kernel.org,
        Michael Ellerman <mpe@...erman.id.au>,
        Stefan Kristiansson <stefan.kristiansson@...nalahti.fi>,
        linux-snps-arc@...ts.infradead.org,
        Vineet Gupta <vgupta@...nel.org>,
        Vasily Gorbik <gor@...ux.ibm.com>,
        Vlastimil Babka <vbabka@...e.cz>,
        Ivan Kokshaysky <ink@...assic.park.msu.ru>,
        Rich Felker <dalias@...c.org>, sparclinux@...r.kernel.org,
        Russell King <linux@...linux.org.uk>,
        David Hildenbrand <david@...hat.com>,
        Benjamin Herrenschmidt <benh@...nel.crashing.org>,
        Nicholas Piggin <npiggin@...il.com>,
        "James E . J . Bottomley" <James.Bottomley@...senpartnership.com>,
        linux-xtensa@...ux-xtensa.org, linux-sh@...r.kernel.org,
        Paul Walmsley <paul.walmsley@...ive.com>,
        linux-m68k@...ts.linux-m68k.org, linuxppc-dev@...ts.ozlabs.org,
        Richard Henderson <rth@...ddle.net>,
        Guo Ren <guoren@...nel.org>, linux-parisc@...r.kernel.org,
        Andrea Arcangeli <aarcange@...hat.com>,
        Helge Deller <deller@....de>,
        Al Viro <viro@...iv.linux.org.uk>,
        Albert Ou <aou@...s.berkeley.edu>,
        linux-um@...ts.infradead.org, "H . Peter Anvin" <hpa@...or.com>,
        Janosch Frank <frankja@...ux.ibm.com>,
        Sven Schnelle <svens@...ux.ibm.com>,
        Anton Ivanov <anton.ivanov@...bridgegreys.com>,
        openrisc@...ts.librecores.org,
        Thomas Bogendoerfer <tsbogend@...ha.franken.de>,
        linux-hexagon@...r.kernel.org, Andy Lutomirski <luto@...nel.org>,
        Stafford Horne <shorne@...il.com>, linux-csky@...r.kernel.org,
        Heiko Carstens <hca@...ux.ibm.com>,
        Thomas Gleixner <tglx@...utronix.de>,
        linux-mips@...r.kernel.org, Paul Mackerras <paulus@...ba.org>,
        Alexander Gordeev <agordeev@...ux.ibm.com>,
        Dinh Nguyen <dinguyen@...nel.org>,
        Palmer Dabbelt <palmer@...belt.com>,
        "David S . Miller" <davem@...emloft.net>,
        Johannes Weiner <hannes@...xchg.org>,
        Hugh Dickins <hughd@...gle.com>,
        Ingo Molnar <mingo@...hat.com>,
        Peter Zijlstra <peterz@...radead.org>,
        linux-riscv@...ts.infradead.org, Max Filippov <jcmvbkbc@...il.com>,
        Geert Uytterhoeven <geert@...ux-m68k.org>,
        Christian Borntraeger <borntraeger@...ux.ibm.com>,
        Johannes Berg <johannes@...solutions.net>,
        Chris Zankel <chris@...kel.net>,
        Michal Simek <monstr@...str.eu>, x86@...nel.org,
        Yoshinori Sato <ysato@...rs.sourceforge.jp>,
        Dave Hansen <dave.hansen@...ux.intel.com>,
        Richard Weinberger <richard@....at>,
        Ingo Molnar <mingo@...nel.org>
Subject: Re: [PATCH v4] mm: Avoid unnecessary page fault retires on shared
 memory types

On Fri, May 27, 2022 at 03:39:36PM -0400, Peter Xu wrote:
> diff --git a/arch/arm64/mm/fault.c b/arch/arm64/mm/fault.c
> index 77341b160aca..e401d416bbd6 100644
> --- a/arch/arm64/mm/fault.c
> +++ b/arch/arm64/mm/fault.c
> @@ -607,6 +607,10 @@ static int __kprobes do_page_fault(unsigned long far, unsigned int esr,
>  		return 0;
>  	}
>  
> +	/* The fault is fully completed (including releasing mmap lock) */
> +	if (fault & VM_FAULT_COMPLETED)
> +		return 0;
> +
>  	if (fault & VM_FAULT_RETRY) {
>  		mm_flags |= FAULT_FLAG_TRIED;
>  		goto retry;

For arm64:

Acked-by: Catalin Marinas <catalin.marinas@....com>