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 X-Spam-Level: X-Spam-Status: No, score=-6.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id ED555C10F14 for ; Tue, 8 Oct 2019 22:43:24 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 951B121835 for ; Tue, 8 Oct 2019 22:43:24 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 951B121835 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=sifive.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 1B4538E0005; Tue, 8 Oct 2019 18:43:24 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 165A68E0003; Tue, 8 Oct 2019 18:43:24 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 02D398E0005; Tue, 8 Oct 2019 18:43:23 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0251.hostedemail.com [216.40.44.251]) by kanga.kvack.org (Postfix) with ESMTP id D18E98E0003 for ; Tue, 8 Oct 2019 18:43:23 -0400 (EDT) Received: from smtpin15.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay04.hostedemail.com (Postfix) with SMTP id 55D9040D3 for ; Tue, 8 Oct 2019 22:43:23 +0000 (UTC) X-FDA: 76022095086.15.fowl38_57adef7036759 X-HE-Tag: fowl38_57adef7036759 X-Filterd-Recvd-Size: 20101 Received: from mail-pf1-f196.google.com (mail-pf1-f196.google.com [209.85.210.196]) by imf09.hostedemail.com (Postfix) with ESMTP for ; Tue, 8 Oct 2019 22:43:22 +0000 (UTC) Received: by mail-pf1-f196.google.com with SMTP id q12so261608pff.9 for ; Tue, 08 Oct 2019 15:43:22 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:subject:in-reply-to:cc:from:to:message-id :mime-version:content-transfer-encoding; bh=e68usEf58iDVSKP+d4E8UDoTBexUzFRigoqA3Uk2Lnc=; b=qbwBBHKVwlOlXAn5ucYIyU5RAcemGL5xJOFRMJUtUIuGnj9sIFDxkr0GX3OA9nL2kN POCXr+eoTu0XZEODMsryZO+4TzA9OsyPAgX1wn0B8U9nzWPJ+jUHNslqIBR43Z/HIceV OB4kwxFB1/IL8ev4aiZMpvu8Tmvc0d1MJUCHJ/rOpftfxVNp83iQrPQS8WTVQSddfzAK 2CfcSV27f4tpneZAYrpUKFnMHawMqGZv9kY++VoiaMfYc21S90pEdBcm2B+PID5Pw+3t PuZgpwQLT/Uyb3eunpLsY0AuqXrhkjClaWqORQK/2F4KhDce6Aycly2TNH5j/ZElfJZi 25qg== X-Gm-Message-State: APjAAAW2oCaQfpz39iKfT2I1foxojR4eYrJ9r+mmA+zJ00m/gWlhH0aD TeIM5MqZE2tOM3RXZUX7VUrvx/T/3X+yBw== X-Google-Smtp-Source: APXvYqwc1aa/sybWMsR2BA3Lo7SgcBDomYDrZUUUUNmLKw/60SgO1cBLaz315acEcnSKKpGBZtIIoQ== X-Received: by 2002:a65:420d:: with SMTP id c13mr823092pgq.420.1570574600295; Tue, 08 Oct 2019 15:43:20 -0700 (PDT) Received: from localhost ([12.206.222.5]) by smtp.gmail.com with ESMTPSA id t21sm205140pgi.87.2019.10.08.15.43.19 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 08 Oct 2019 15:43:19 -0700 (PDT) Date: Tue, 08 Oct 2019 15:43:19 -0700 (PDT) X-Google-Original-Date: Tue, 08 Oct 2019 15:41:34 PDT (-0700) Subject: Re: [PATCH v4 05/10] mm: Return faster for non-fatal signals in user mode faults In-Reply-To: <20190923042523.10027-6-peterx@redhat.com> CC: linux-mm@kvack.org, linux-kernel@vger.kernel.org, david@redhat.com, hughd@google.com, gokhale2@llnl.gov, jglisse@redhat.com, xemul@virtuozzo.com, hannes@cmpxchg.org, peterx@redhat.com, cracauer@cons.org, mcfadden8@llnl.gov, shli@fb.com, aarcange@redhat.com, mike.kravetz@oracle.com, dplotnikov@virtuozzo.com, rppt@linux.vnet.ibm.com, Linus Torvalds , mgorman@suse.de, kirill@shutemov.name, dgilbert@redhat.com From: Palmer Dabbelt To: peterx@redhat.com Message-ID: Mime-Version: 1.0 (MHng) Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: quoted-printable X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Sun, 22 Sep 2019 21:25:18 PDT (-0700), peterx@redhat.com wrote: > The idea comes from the upstream discussion between Linus and Andrea: > > https://lore.kernel.org/lkml/20171102193644.GB22686@redhat.com/ > > A summary to the issue: there was a special path in handle_userfault() > in the past that we'll return a VM_FAULT_NOPAGE when we detected > non-fatal signals when waiting for userfault handling. We did that by > reacquiring the mmap_sem before returning. However that brings a risk > in that the vmas might have changed when we retake the mmap_sem and > even we could be holding an invalid vma structure. > > This patch is a preparation of removing that special path by allowing > the page fault to return even faster if we were interrupted by a > non-fatal signal during a user-mode page fault handling routine. > > Suggested-by: Linus Torvalds > Suggested-by: Andrea Arcangeli > Signed-off-by: Peter Xu > --- > arch/alpha/mm/fault.c | 3 ++- > arch/arc/mm/fault.c | 5 +++++ > arch/arm/mm/fault.c | 9 +++++---- > arch/arm64/mm/fault.c | 9 +++++---- > arch/hexagon/mm/vm_fault.c | 3 ++- > arch/ia64/mm/fault.c | 3 ++- > arch/m68k/mm/fault.c | 5 +++-- > arch/microblaze/mm/fault.c | 3 ++- > arch/mips/mm/fault.c | 3 ++- > arch/nds32/mm/fault.c | 9 +++++---- > arch/nios2/mm/fault.c | 3 ++- > arch/openrisc/mm/fault.c | 3 ++- > arch/parisc/mm/fault.c | 3 ++- > arch/powerpc/mm/fault.c | 2 ++ > arch/riscv/mm/fault.c | 5 +++-- > arch/s390/mm/fault.c | 4 ++-- > arch/sh/mm/fault.c | 4 ++++ > arch/sparc/mm/fault_32.c | 2 +- > arch/sparc/mm/fault_64.c | 3 ++- > arch/um/kernel/trap.c | 4 +++- > arch/unicore32/mm/fault.c | 5 +++-- > arch/x86/mm/fault.c | 2 ++ > arch/xtensa/mm/fault.c | 3 ++- > include/linux/sched/signal.h | 12 ++++++++++++ > 24 files changed, 75 insertions(+), 32 deletions(-) > > diff --git a/arch/alpha/mm/fault.c b/arch/alpha/mm/fault.c > index de4cc6936391..ab1d4212d658 100644 > --- a/arch/alpha/mm/fault.c > +++ b/arch/alpha/mm/fault.c > @@ -150,7 +150,8 @@ do_page_fault(unsigned long address, unsigned long = mmcsr, > the fault. */ > fault =3D handle_mm_fault(vma, address, flags); > > - if ((fault & VM_FAULT_RETRY) && fatal_signal_pending(current)) > + if ((fault & VM_FAULT_RETRY) && > + fault_should_check_signal(user_mode(regs))) > return; > > if (unlikely(fault & VM_FAULT_ERROR)) { > diff --git a/arch/arc/mm/fault.c b/arch/arc/mm/fault.c > index 61919e4e4eec..27adf4e608e4 100644 > --- a/arch/arc/mm/fault.c > +++ b/arch/arc/mm/fault.c > @@ -142,6 +142,11 @@ void do_page_fault(unsigned long address, struct p= t_regs *regs) > goto no_context; > return; > } > + > + /* Allow user to handle non-fatal signals first */ > + if (signal_pending(current) && user_mode(regs)) > + return; > + > /* > * retry state machine > */ > diff --git a/arch/arm/mm/fault.c b/arch/arm/mm/fault.c > index 2ae28ffec622..f00fb4eafe54 100644 > --- a/arch/arm/mm/fault.c > +++ b/arch/arm/mm/fault.c > @@ -291,14 +291,15 @@ do_page_fault(unsigned long addr, unsigned int fs= r, struct pt_regs *regs) > > fault =3D __do_page_fault(mm, addr, fsr, flags, tsk); > > - /* If we need to retry but a fatal signal is pending, handle the > + /* If we need to retry but a signal is pending, try to handle the > * signal first. We do not need to release the mmap_sem because > * it would already be released in __lock_page_or_retry in > * mm/filemap.c. */ > - if ((fault & VM_FAULT_RETRY) && fatal_signal_pending(current)) { > - if (!user_mode(regs)) > + if (unlikely(fault & VM_FAULT_RETRY && signal_pending(current))) { > + if (fatal_signal_pending(current) && !user_mode(regs)) > goto no_context; > - return 0; > + if (user_mode(regs)) > + return 0; > } > > /* > diff --git a/arch/arm64/mm/fault.c b/arch/arm64/mm/fault.c > index 613e7434c208..0d3fe0ea6a70 100644 > --- a/arch/arm64/mm/fault.c > +++ b/arch/arm64/mm/fault.c > @@ -479,15 +479,16 @@ static int __kprobes do_page_fault(unsigned long = addr, unsigned int esr, > > if (fault & VM_FAULT_RETRY) { > /* > - * If we need to retry but a fatal signal is pending, > + * If we need to retry but a signal is pending, try to > * handle the signal first. We do not need to release > * the mmap_sem because it would already be released > * in __lock_page_or_retry in mm/filemap.c. > */ > - if (fatal_signal_pending(current)) { > - if (!user_mode(regs)) > + if (signal_pending(current)) { > + if (fatal_signal_pending(current) && !user_mode(regs)) > goto no_context; > - return 0; > + if (user_mode(regs)) > + return 0; > } > > /* > diff --git a/arch/hexagon/mm/vm_fault.c b/arch/hexagon/mm/vm_fault.c > index 223787e01bdd..88a2e5635bfb 100644 > --- a/arch/hexagon/mm/vm_fault.c > +++ b/arch/hexagon/mm/vm_fault.c > @@ -91,7 +91,8 @@ void do_page_fault(unsigned long address, long cause,= struct pt_regs *regs) > > fault =3D handle_mm_fault(vma, address, flags); > > - if ((fault & VM_FAULT_RETRY) && fatal_signal_pending(current)) > + if ((fault & VM_FAULT_RETRY) && > + fault_should_check_signal(user_mode(regs))) > return; > > /* The most common case -- we are done. */ > diff --git a/arch/ia64/mm/fault.c b/arch/ia64/mm/fault.c > index d039b846f671..8d47acf50fda 100644 > --- a/arch/ia64/mm/fault.c > +++ b/arch/ia64/mm/fault.c > @@ -141,7 +141,8 @@ ia64_do_page_fault (unsigned long address, unsigned= long isr, struct pt_regs *re > */ > fault =3D handle_mm_fault(vma, address, flags); > > - if ((fault & VM_FAULT_RETRY) && fatal_signal_pending(current)) > + if ((fault & VM_FAULT_RETRY) && > + fault_should_check_signal(user_mode(regs))) > return; > > if (unlikely(fault & VM_FAULT_ERROR)) { > diff --git a/arch/m68k/mm/fault.c b/arch/m68k/mm/fault.c > index 8e734309ace9..103f93ba8139 100644 > --- a/arch/m68k/mm/fault.c > +++ b/arch/m68k/mm/fault.c > @@ -138,8 +138,9 @@ int do_page_fault(struct pt_regs *regs, unsigned lo= ng address, > fault =3D handle_mm_fault(vma, address, flags); > pr_debug("handle_mm_fault returns %x\n", fault); > > - if ((fault & VM_FAULT_RETRY) && fatal_signal_pending(current)) > - return 0; > + if ((fault & VM_FAULT_RETRY) && > + fault_should_check_signal(user_mode(regs))) > + return; > > if (unlikely(fault & VM_FAULT_ERROR)) { > if (fault & VM_FAULT_OOM) > diff --git a/arch/microblaze/mm/fault.c b/arch/microblaze/mm/fault.c > index 45c9f66c1dbc..8b0615eab4b6 100644 > --- a/arch/microblaze/mm/fault.c > +++ b/arch/microblaze/mm/fault.c > @@ -217,7 +217,8 @@ void do_page_fault(struct pt_regs *regs, unsigned l= ong address, > */ > fault =3D handle_mm_fault(vma, address, flags); > > - if ((fault & VM_FAULT_RETRY) && fatal_signal_pending(current)) > + if ((fault & VM_FAULT_RETRY) && > + fault_should_check_signal(user_mode(regs))) > return; > > if (unlikely(fault & VM_FAULT_ERROR)) { > diff --git a/arch/mips/mm/fault.c b/arch/mips/mm/fault.c > index 6660b77ff8f3..48aac20a1ded 100644 > --- a/arch/mips/mm/fault.c > +++ b/arch/mips/mm/fault.c > @@ -154,7 +154,8 @@ static void __kprobes __do_page_fault(struct pt_reg= s *regs, unsigned long write, > */ > fault =3D handle_mm_fault(vma, address, flags); > > - if ((fault & VM_FAULT_RETRY) && fatal_signal_pending(current)) > + if ((fault & VM_FAULT_RETRY) && > + fault_should_check_signal(user_mode(regs))) > return; > > perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS, 1, regs, address); > diff --git a/arch/nds32/mm/fault.c b/arch/nds32/mm/fault.c > index a40de112a23a..baa44f9d0b4a 100644 > --- a/arch/nds32/mm/fault.c > +++ b/arch/nds32/mm/fault.c > @@ -206,14 +206,15 @@ void do_page_fault(unsigned long entry, unsigned = long addr, > fault =3D handle_mm_fault(vma, addr, flags); > > /* > - * If we need to retry but a fatal signal is pending, handle the > + * If we need to retry but a signal is pending, try to handle the > * signal first. We do not need to release the mmap_sem because it > * would already be released in __lock_page_or_retry in mm/filemap.c. > */ > - if ((fault & VM_FAULT_RETRY) && fatal_signal_pending(current)) { > - if (!user_mode(regs)) > + if ((fault & VM_FAULT_RETRY) && signal_pending(current)) { > + if (fatal_signal_pending(current) && !user_mode(regs)) > goto no_context; > - return; > + if (user_mode(regs)) > + return; > } > > if (unlikely(fault & VM_FAULT_ERROR)) { > diff --git a/arch/nios2/mm/fault.c b/arch/nios2/mm/fault.c > index a401b45cae47..f9f178484184 100644 > --- a/arch/nios2/mm/fault.c > +++ b/arch/nios2/mm/fault.c > @@ -133,7 +133,8 @@ asmlinkage void do_page_fault(struct pt_regs *regs,= unsigned long cause, > */ > fault =3D handle_mm_fault(vma, address, flags); > > - if ((fault & VM_FAULT_RETRY) && fatal_signal_pending(current)) > + if ((fault & VM_FAULT_RETRY) && > + fault_should_check_signal(user_mode(regs))) > return; > > if (unlikely(fault & VM_FAULT_ERROR)) { > diff --git a/arch/openrisc/mm/fault.c b/arch/openrisc/mm/fault.c > index fd1592a56238..8ba3696dd10c 100644 > --- a/arch/openrisc/mm/fault.c > +++ b/arch/openrisc/mm/fault.c > @@ -161,7 +161,8 @@ asmlinkage void do_page_fault(struct pt_regs *regs,= unsigned long address, > > fault =3D handle_mm_fault(vma, address, flags); > > - if ((fault & VM_FAULT_RETRY) && fatal_signal_pending(current)) > + if ((fault & VM_FAULT_RETRY) && > + fault_should_check_signal(user_mode(regs))) > return; > > if (unlikely(fault & VM_FAULT_ERROR)) { > diff --git a/arch/parisc/mm/fault.c b/arch/parisc/mm/fault.c > index 355e3e13fa72..163dcb080c7b 100644 > --- a/arch/parisc/mm/fault.c > +++ b/arch/parisc/mm/fault.c > @@ -304,7 +304,8 @@ void do_page_fault(struct pt_regs *regs, unsigned l= ong code, > > fault =3D handle_mm_fault(vma, address, flags); > > - if ((fault & VM_FAULT_RETRY) && fatal_signal_pending(current)) > + if ((fault & VM_FAULT_RETRY) && > + fault_should_check_signal(user_mode(regs))) > return; > > if (unlikely(fault & VM_FAULT_ERROR)) { > diff --git a/arch/powerpc/mm/fault.c b/arch/powerpc/mm/fault.c > index 408ee769c470..d321a6c5fe62 100644 > --- a/arch/powerpc/mm/fault.c > +++ b/arch/powerpc/mm/fault.c > @@ -596,6 +596,8 @@ static int __do_page_fault(struct pt_regs *regs, un= signed long address, > */ > flags &=3D ~FAULT_FLAG_ALLOW_RETRY; > flags |=3D FAULT_FLAG_TRIED; > + if (is_user && signal_pending(current)) > + return 0; > if (!fatal_signal_pending(current)) > goto retry; > } > diff --git a/arch/riscv/mm/fault.c b/arch/riscv/mm/fault.c > index deeb820bd855..ea8f301de65b 100644 > --- a/arch/riscv/mm/fault.c > +++ b/arch/riscv/mm/fault.c > @@ -111,11 +111,12 @@ asmlinkage void do_page_fault(struct pt_regs *reg= s) > fault =3D handle_mm_fault(vma, addr, flags); > > /* > - * If we need to retry but a fatal signal is pending, handle the > + * If we need to retry but a signal is pending, try to handle the > * signal first. We do not need to release the mmap_sem because it > * would already be released in __lock_page_or_retry in mm/filemap.c. > */ > - if ((fault & VM_FAULT_RETRY) && fatal_signal_pending(tsk)) > + if ((fault & VM_FAULT_RETRY) && > + fault_should_check_signal(user_mode(regs))) > return; > > if (unlikely(fault & VM_FAULT_ERROR)) { Acked-by: Palmer Dabbelt # RISC-V parts I'm assuming this is going in through some other tree. > diff --git a/arch/s390/mm/fault.c b/arch/s390/mm/fault.c > index 74a77b2bca75..3ad77501deef 100644 > --- a/arch/s390/mm/fault.c > +++ b/arch/s390/mm/fault.c > @@ -480,8 +480,8 @@ static inline vm_fault_t do_exception(struct pt_reg= s *regs, int access) > * the fault. > */ > fault =3D handle_mm_fault(vma, address, flags); > - /* No reason to continue if interrupted by SIGKILL. */ > - if ((fault & VM_FAULT_RETRY) && fatal_signal_pending(current)) { > + if ((fault & VM_FAULT_RETRY) && > + fault_should_check_signal(user_mode(regs))) { > fault =3D VM_FAULT_SIGNAL; > if (flags & FAULT_FLAG_RETRY_NOWAIT) > goto out_up; > diff --git a/arch/sh/mm/fault.c b/arch/sh/mm/fault.c > index becf0be267bb..f620282a37fd 100644 > --- a/arch/sh/mm/fault.c > +++ b/arch/sh/mm/fault.c > @@ -489,6 +489,10 @@ asmlinkage void __kprobes do_page_fault(struct pt_= regs *regs, > * have already released it in __lock_page_or_retry > * in mm/filemap.c. > */ > + > + if (user_mode(regs) && signal_pending(tsk)) > + return; > + > goto retry; > } > } > diff --git a/arch/sparc/mm/fault_32.c b/arch/sparc/mm/fault_32.c > index 0863f6fdd2c5..9af0c3ad50d6 100644 > --- a/arch/sparc/mm/fault_32.c > +++ b/arch/sparc/mm/fault_32.c > @@ -237,7 +237,7 @@ asmlinkage void do_sparc_fault(struct pt_regs *regs= , int text_fault, int write, > */ > fault =3D handle_mm_fault(vma, address, flags); > > - if ((fault & VM_FAULT_RETRY) && fatal_signal_pending(current)) > + if ((fault & VM_FAULT_RETRY) && fault_should_check_signal(from_user)) > return; > > if (unlikely(fault & VM_FAULT_ERROR)) { > diff --git a/arch/sparc/mm/fault_64.c b/arch/sparc/mm/fault_64.c > index a1cba3eef79e..566f05f9040b 100644 > --- a/arch/sparc/mm/fault_64.c > +++ b/arch/sparc/mm/fault_64.c > @@ -421,7 +421,8 @@ asmlinkage void __kprobes do_sparc64_fault(struct p= t_regs *regs) > > fault =3D handle_mm_fault(vma, address, flags); > > - if ((fault & VM_FAULT_RETRY) && fatal_signal_pending(current)) > + if ((fault & VM_FAULT_RETRY) && > + fault_should_check_signal(flags & FAULT_FLAG_USER)) > goto exit_exception; > > if (unlikely(fault & VM_FAULT_ERROR)) { > diff --git a/arch/um/kernel/trap.c b/arch/um/kernel/trap.c > index bc2756782d64..3c72111f27e9 100644 > --- a/arch/um/kernel/trap.c > +++ b/arch/um/kernel/trap.c > @@ -76,7 +76,9 @@ int handle_page_fault(unsigned long address, unsigned= long ip, > > fault =3D handle_mm_fault(vma, address, flags); > > - if ((fault & VM_FAULT_RETRY) && fatal_signal_pending(current)) > + > + if ((fault & VM_FAULT_RETRY) && > + fault_should_check_signal(is_user)) > goto out_nosemaphore; > > if (unlikely(fault & VM_FAULT_ERROR)) { > diff --git a/arch/unicore32/mm/fault.c b/arch/unicore32/mm/fault.c > index 60453c892c51..04c193439c97 100644 > --- a/arch/unicore32/mm/fault.c > +++ b/arch/unicore32/mm/fault.c > @@ -246,11 +246,12 @@ static int do_pf(unsigned long addr, unsigned int= fsr, struct pt_regs *regs) > > fault =3D __do_pf(mm, addr, fsr, flags, tsk); > > - /* If we need to retry but a fatal signal is pending, handle the > + /* If we need to retry but a signal is pending, try to handle the > * signal first. We do not need to release the mmap_sem because > * it would already be released in __lock_page_or_retry in > * mm/filemap.c. */ > - if ((fault & VM_FAULT_RETRY) && fatal_signal_pending(current)) > + if ((fault & VM_FAULT_RETRY) && > + fault_should_check_signal(user_mode(regs))) > return 0; > > if (!(fault & VM_FAULT_ERROR) && (flags & FAULT_FLAG_ALLOW_RETRY)) { > diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c > index 994c860ac2d8..f7836472961e 100644 > --- a/arch/x86/mm/fault.c > +++ b/arch/x86/mm/fault.c > @@ -1451,6 +1451,8 @@ void do_user_addr_fault(struct pt_regs *regs, > if (flags & FAULT_FLAG_ALLOW_RETRY) { > flags &=3D ~FAULT_FLAG_ALLOW_RETRY; > flags |=3D FAULT_FLAG_TRIED; > + if ((flags & FAULT_FLAG_USER) && signal_pending(tsk)) > + return; > if (!fatal_signal_pending(tsk)) > goto retry; > } > diff --git a/arch/xtensa/mm/fault.c b/arch/xtensa/mm/fault.c > index d2b082908538..094606676c36 100644 > --- a/arch/xtensa/mm/fault.c > +++ b/arch/xtensa/mm/fault.c > @@ -110,7 +110,8 @@ void do_page_fault(struct pt_regs *regs) > */ > fault =3D handle_mm_fault(vma, address, flags); > > - if ((fault & VM_FAULT_RETRY) && fatal_signal_pending(current)) > + if ((fault & VM_FAULT_RETRY) && > + fault_should_check_signal(user_mode(regs))) > return; > > if (unlikely(fault & VM_FAULT_ERROR)) { > diff --git a/include/linux/sched/signal.h b/include/linux/sched/signal.= h > index efd8ce7675ed..ccce63f2822d 100644 > --- a/include/linux/sched/signal.h > +++ b/include/linux/sched/signal.h > @@ -377,6 +377,18 @@ static inline int signal_pending_state(long state,= struct task_struct *p) > return (state & TASK_INTERRUPTIBLE) || __fatal_signal_pending(p); > } > > +/* > + * This should only be used in fault handlers to decide whether we > + * should stop the current fault routine to handle the signals > + * instead. It should normally be used when a signal interrupted a > + * page fault which can lead to a VM_FAULT_RETRY. > + */ > +static inline bool fault_should_check_signal(bool is_user) > +{ > + return (fatal_signal_pending(current) || > + (is_user && signal_pending(current))); > +} > + > /* > * Reevaluate whether the task has signals pending delivery. > * Wake the task if so.