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=-9.7 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham 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 6EB28C3A5A6 for ; Mon, 23 Sep 2019 04:26:21 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 1F1CE20820 for ; Mon, 23 Sep 2019 04:26:21 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 1F1CE20820 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id C7F526B026E; Mon, 23 Sep 2019 00:26:20 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id C562A6B026F; Mon, 23 Sep 2019 00:26:20 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id B20126B0270; Mon, 23 Sep 2019 00:26:20 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0045.hostedemail.com [216.40.44.45]) by kanga.kvack.org (Postfix) with ESMTP id 899966B026E for ; Mon, 23 Sep 2019 00:26:20 -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 2B3B718DD for ; Mon, 23 Sep 2019 04:26:20 +0000 (UTC) X-FDA: 75964898520.15.chess19_7171225357857 X-HE-Tag: chess19_7171225357857 X-Filterd-Recvd-Size: 19833 Received: from mx1.redhat.com (mx1.redhat.com [209.132.183.28]) by imf22.hostedemail.com (Postfix) with ESMTP for ; Mon, 23 Sep 2019 04:26:19 +0000 (UTC) Received: from mail-pg1-f198.google.com (mail-pg1-f198.google.com [209.85.215.198]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id A28BB83F4C for ; Mon, 23 Sep 2019 04:26:18 +0000 (UTC) Received: by mail-pg1-f198.google.com with SMTP id 6so1543137pgi.10 for ; Sun, 22 Sep 2019 21:26:18 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=hIx8A3yEH181U25gCr2QcCcmLxEbF4TWpxYF9KeMWd8=; b=oPOou/vc9VyQcm25/zYqxWRGHmiqkfePDevEEzGnG2jKJoHznLnW381bttAipEqWDJ GEH6xsI9cD2jR3S+l0Erw0+K9l5x/3M7PhkBBFxo8oMrIB6o9ew9SGwE4wxUQMgKts/q cFY1iU5ESZ/l/3SfkoWKbmhKhfSoOekXXI7SRjJhTpTRuPQt+4OqLPus/NcXWeDLM2qr 0Hp+C9r5zuf7V6/LgofdriyO8cP2N1b/14cI4cIbZKL8xCWSVcUxAkd+JScWMoXQdboz S+qwJg1Od/WX9Lb9fqt5epgukr7KMi81D+KdLyBC3RPDfnKmXjqErb3AwIhmqTyNoWZD o+AA== X-Gm-Message-State: APjAAAW0lUOIPdWH0nhejApHA4rH44WxHRnJl8OABUKgEy5i7F+lR3aD cBfOjry6HSaI+A3NEzKWExO9+ktr/llgucLRCVv6uEHZ+zS3kG9nDiEKHS9HVdUzMcgFZSp4oRK TpXoeehPaRho= X-Received: by 2002:a65:60cd:: with SMTP id r13mr28136710pgv.421.1569212777795; Sun, 22 Sep 2019 21:26:17 -0700 (PDT) X-Google-Smtp-Source: APXvYqxVJBzQP25zAcUihv/H6xbRwH2tbSkGeKfHDdJtpYmYjT+2d46K1yCcnl5zTfhJFFpyjPlxuw== X-Received: by 2002:a65:60cd:: with SMTP id r13mr28136668pgv.421.1569212777310; Sun, 22 Sep 2019 21:26:17 -0700 (PDT) Received: from xz-x1.redhat.com ([209.132.188.80]) by smtp.gmail.com with ESMTPSA id x20sm11781867pfp.120.2019.09.22.21.26.10 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 22 Sep 2019 21:26:16 -0700 (PDT) From: Peter Xu To: linux-mm@kvack.org, linux-kernel@vger.kernel.org Cc: David Hildenbrand , Hugh Dickins , Maya Gokhale , Jerome Glisse , Pavel Emelyanov , Johannes Weiner , peterx@redhat.com, Martin Cracauer , Marty McFadden , Shaohua Li , Andrea Arcangeli , Mike Kravetz , Denis Plotnikov , Mike Rapoport , Linus Torvalds , Mel Gorman , "Kirill A . Shutemov" , "Dr . David Alan Gilbert" Subject: [PATCH v4 05/10] mm: Return faster for non-fatal signals in user mode faults Date: Mon, 23 Sep 2019 12:25:18 +0800 Message-Id: <20190923042523.10027-6-peterx@redhat.com> X-Mailer: git-send-email 2.21.0 In-Reply-To: <20190923042523.10027-1-peterx@redhat.com> References: <20190923042523.10027-1-peterx@redhat.com> MIME-Version: 1.0 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: 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 mm= csr, the fault. */ fault =3D handle_mm_fault(vma, address, flags); =20 - if ((fault & VM_FAULT_RETRY) && fatal_signal_pending(current)) + if ((fault & VM_FAULT_RETRY) && + fault_should_check_signal(user_mode(regs))) return; =20 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 pt_= 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 fsr,= struct pt_regs *regs) =20 fault =3D __do_page_fault(mm, addr, fsr, flags, tsk); =20 - /* 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; } =20 /* 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 ad= dr, unsigned int esr, =20 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; } =20 /* 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, s= truct pt_regs *regs) =20 fault =3D handle_mm_fault(vma, address, flags); =20 - if ((fault & VM_FAULT_RETRY) && fatal_signal_pending(current)) + if ((fault & VM_FAULT_RETRY) && + fault_should_check_signal(user_mode(regs))) return; =20 /* 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 l= ong isr, struct pt_regs *re */ fault =3D handle_mm_fault(vma, address, flags); =20 - if ((fault & VM_FAULT_RETRY) && fatal_signal_pending(current)) + if ((fault & VM_FAULT_RETRY) && + fault_should_check_signal(user_mode(regs))) return; =20 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 long= address, fault =3D handle_mm_fault(vma, address, flags); pr_debug("handle_mm_fault returns %x\n", fault); =20 - if ((fault & VM_FAULT_RETRY) && fatal_signal_pending(current)) - return 0; + if ((fault & VM_FAULT_RETRY) && + fault_should_check_signal(user_mode(regs))) + return; =20 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 lon= g address, */ fault =3D handle_mm_fault(vma, address, flags); =20 - if ((fault & VM_FAULT_RETRY) && fatal_signal_pending(current)) + if ((fault & VM_FAULT_RETRY) && + fault_should_check_signal(user_mode(regs))) return; =20 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_regs = *regs, unsigned long write, */ fault =3D handle_mm_fault(vma, address, flags); =20 - if ((fault & VM_FAULT_RETRY) && fatal_signal_pending(current)) + if ((fault & VM_FAULT_RETRY) && + fault_should_check_signal(user_mode(regs))) return; =20 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 lo= ng addr, fault =3D handle_mm_fault(vma, addr, flags); =20 /* - * 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; } =20 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, u= nsigned long cause, */ fault =3D handle_mm_fault(vma, address, flags); =20 - if ((fault & VM_FAULT_RETRY) && fatal_signal_pending(current)) + if ((fault & VM_FAULT_RETRY) && + fault_should_check_signal(user_mode(regs))) return; =20 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, u= nsigned long address, =20 fault =3D handle_mm_fault(vma, address, flags); =20 - if ((fault & VM_FAULT_RETRY) && fatal_signal_pending(current)) + if ((fault & VM_FAULT_RETRY) && + fault_should_check_signal(user_mode(regs))) return; =20 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 lon= g code, =20 fault =3D handle_mm_fault(vma, address, flags); =20 - if ((fault & VM_FAULT_RETRY) && fatal_signal_pending(current)) + if ((fault & VM_FAULT_RETRY) && + fault_should_check_signal(user_mode(regs))) return; =20 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, unsi= gned 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 *regs) fault =3D handle_mm_fault(vma, addr, flags); =20 /* - * 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; =20 if (unlikely(fault & VM_FAULT_ERROR)) { 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_regs = *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_re= gs *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); =20 - if ((fault & VM_FAULT_RETRY) && fatal_signal_pending(current)) + if ((fault & VM_FAULT_RETRY) && fault_should_check_signal(from_user)) return; =20 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 pt_= regs *regs) =20 fault =3D handle_mm_fault(vma, address, flags); =20 - 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; =20 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 l= ong ip, =20 fault =3D handle_mm_fault(vma, address, flags); =20 - if ((fault & VM_FAULT_RETRY) && fatal_signal_pending(current)) + + if ((fault & VM_FAULT_RETRY) && + fault_should_check_signal(is_user)) goto out_nosemaphore; =20 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 f= sr, struct pt_regs *regs) =20 fault =3D __do_pf(mm, addr, fsr, flags, tsk); =20 - /* 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; =20 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); =20 - if ((fault & VM_FAULT_RETRY) && fatal_signal_pending(current)) + if ((fault & VM_FAULT_RETRY) && + fault_should_check_signal(user_mode(regs))) return; =20 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, s= truct task_struct *p) return (state & TASK_INTERRUPTIBLE) || __fatal_signal_pending(p); } =20 +/* + * 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. --=20 2.21.0