From nobody Thu Apr 9 10:53:32 2026 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 0F477C4332F for ; Fri, 4 Nov 2022 18:33:00 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232135AbiKDSc6 (ORCPT ); Fri, 4 Nov 2022 14:32:58 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:51860 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232112AbiKDScy (ORCPT ); Fri, 4 Nov 2022 14:32:54 -0400 Received: from mail-pl1-x64a.google.com (mail-pl1-x64a.google.com [IPv6:2607:f8b0:4864:20::64a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 2E06A40918 for ; Fri, 4 Nov 2022 11:32:54 -0700 (PDT) Received: by mail-pl1-x64a.google.com with SMTP id n12-20020a170902e54c00b00188515e81a6so4126621plf.23 for ; Fri, 04 Nov 2022 11:32:54 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:reply-to:from:to:cc:subject:date:message-id:reply-to; bh=XS7y2dqHGNcxgJtQwV0riGq39Rt6nVME96ygRYhND24=; b=oN6YQDqk6ql/yuJpP2UHc5AJeq/0ASHaTsGwHNuH0ViA1j3iC6PG06JEXvHvu2Zbm/ Mo8YEDWCn2wPXsZ8oYKUa9/1Nor0gac9QNs/GUXtA+mK7eRoaRSnVehZBrhJSDqPMWjb p73JoT41qN6YwQNuOHWvDEkGb4XNQTaPkaUVY/adqR1MoTAMN2OJ/3xR+yEAPhkF1iaK XmDC09ZwkPcj/dlWtOizwlMnqqe+rVYLgREo5yJpcmOuMdsODCZq2MttWV4wmy7xKFR8 8HFFEUDjIKncdnXQ9XTvZAZHHi7Mmywz351zvd6tXPhK5EO5gNq1Wvr8SXN0wg2poWdg z7gg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:reply-to:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=XS7y2dqHGNcxgJtQwV0riGq39Rt6nVME96ygRYhND24=; b=SgNyp/n69zwutwAlElIzVirCLUyI10Px2WAeQSNzrh8VUDgSY8/+uDKZUHeLZvyO3q OD5bVnVfVkwOnVgexkIQA66iPl8iuR8mvAHbfn6LX5LOXb1Pt//AtByKXtMhWS67T7Gk N846uoHq56EnrZ1lFkGTRGFMPNY2F6mStBpAuhF0SgFR5awXJkX3BZNz7hJ14HL7u140 OaL1yUxx5V/nt7y69NB9x9k8Z3CaMccfsdpIXDwmxnEjXDJ9QzVJa3EF6vlaMY4jJD/H gjdqrjMcc27x2Ha0Z6vpD8euCTuI6KUFbK8jC0aPiHJYcSVXPkE6xwpPDvbBHQZmsRcQ s9cw== X-Gm-Message-State: ACrzQf1d7hisF9B2XrqV4BzrYw42kFp0t0QX7WDmWcsI+aooVj8cJ1rT 7jwWJwM+3+HE/YKPwpKyoAGhEzjj55w= X-Google-Smtp-Source: AMsMyM5jBLHsdg5VE1uhO3ecnvExGMWNVad3CWCtLAIUktoktpVNhX9REt3v9pHpmml/q4NjkJXkXlsso0o= X-Received: from zagreus.c.googlers.com ([fda3:e722:ac3:cc00:7f:e700:c0a8:5c37]) (user=seanjc job=sendgmr) by 2002:aa7:9527:0:b0:563:b1bc:7f98 with SMTP id c7-20020aa79527000000b00563b1bc7f98mr367586pfp.29.1667586773676; Fri, 04 Nov 2022 11:32:53 -0700 (PDT) Reply-To: Sean Christopherson Date: Fri, 4 Nov 2022 18:32:45 +0000 In-Reply-To: <20221104183247.834988-1-seanjc@google.com> Mime-Version: 1.0 References: <20221104183247.834988-1-seanjc@google.com> X-Mailer: git-send-email 2.38.1.431.g37b22c650d-goog Message-ID: <20221104183247.834988-2-seanjc@google.com> Subject: [PATCH 1/3] x86/kasan: Rename local CPU_ENTRY_AREA variables to shorten names From: Sean Christopherson To: Andrey Ryabinin , Dave Hansen , Andy Lutomirski , Peter Zijlstra , Thomas Gleixner , Ingo Molnar , Borislav Petkov , x86@kernel.org Cc: Alexander Potapenko , Andrey Konovalov , Dmitry Vyukov , Vincenzo Frascino , "H. Peter Anvin" , kasan-dev@googlegroups.com, linux-kernel@vger.kernel.org, Sean Christopherson , syzbot+8cdd16fd5a6c0565e227@syzkaller.appspotmail.com Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Rename the CPU entry area variables in kasan_init() to shorten their names, a future fix will reference the beginning of the per-CPU portion of the CPU entry area, and shadow_cpu_entry_per_cpu_begin is a bit much. No functional change intended. Signed-off-by: Sean Christopherson --- arch/x86/mm/kasan_init_64.c | 22 +++++++++++----------- 1 file changed, 11 insertions(+), 11 deletions(-) diff --git a/arch/x86/mm/kasan_init_64.c b/arch/x86/mm/kasan_init_64.c index d1416926ad52..ad7872ae10ed 100644 --- a/arch/x86/mm/kasan_init_64.c +++ b/arch/x86/mm/kasan_init_64.c @@ -331,7 +331,7 @@ void __init kasan_populate_shadow_for_vaddr(void *va, s= ize_t size, int nid) void __init kasan_init(void) { int i; - void *shadow_cpu_entry_begin, *shadow_cpu_entry_end; + void *shadow_cea_begin, *shadow_cea_end; =20 memcpy(early_top_pgt, init_top_pgt, sizeof(early_top_pgt)); =20 @@ -372,16 +372,16 @@ void __init kasan_init(void) map_range(&pfn_mapped[i]); } =20 - shadow_cpu_entry_begin =3D (void *)CPU_ENTRY_AREA_BASE; - shadow_cpu_entry_begin =3D kasan_mem_to_shadow(shadow_cpu_entry_begin); - shadow_cpu_entry_begin =3D (void *)round_down( - (unsigned long)shadow_cpu_entry_begin, PAGE_SIZE); + shadow_cea_begin =3D (void *)CPU_ENTRY_AREA_BASE; + shadow_cea_begin =3D kasan_mem_to_shadow(shadow_cea_begin); + shadow_cea_begin =3D (void *)round_down( + (unsigned long)shadow_cea_begin, PAGE_SIZE); =20 - shadow_cpu_entry_end =3D (void *)(CPU_ENTRY_AREA_BASE + + shadow_cea_end =3D (void *)(CPU_ENTRY_AREA_BASE + CPU_ENTRY_AREA_MAP_SIZE); - shadow_cpu_entry_end =3D kasan_mem_to_shadow(shadow_cpu_entry_end); - shadow_cpu_entry_end =3D (void *)round_up( - (unsigned long)shadow_cpu_entry_end, PAGE_SIZE); + shadow_cea_end =3D kasan_mem_to_shadow(shadow_cea_end); + shadow_cea_end =3D (void *)round_up( + (unsigned long)shadow_cea_end, PAGE_SIZE); =20 kasan_populate_early_shadow( kasan_mem_to_shadow((void *)PAGE_OFFSET + MAXMEM), @@ -403,9 +403,9 @@ void __init kasan_init(void) =20 kasan_populate_early_shadow( kasan_mem_to_shadow((void *)VMALLOC_END + 1), - shadow_cpu_entry_begin); + shadow_cea_begin); =20 - kasan_populate_early_shadow(shadow_cpu_entry_end, + kasan_populate_early_shadow(shadow_cea_end, kasan_mem_to_shadow((void *)__START_KERNEL_map)); =20 kasan_populate_shadow((unsigned long)kasan_mem_to_shadow(_stext), --=20 2.38.1.431.g37b22c650d-goog From nobody Thu Apr 9 10:53:32 2026 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 1E27FC4332F for ; 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Fri, 04 Nov 2022 11:32:55 -0700 (PDT) Reply-To: Sean Christopherson Date: Fri, 4 Nov 2022 18:32:46 +0000 In-Reply-To: <20221104183247.834988-1-seanjc@google.com> Mime-Version: 1.0 References: <20221104183247.834988-1-seanjc@google.com> X-Mailer: git-send-email 2.38.1.431.g37b22c650d-goog Message-ID: <20221104183247.834988-3-seanjc@google.com> Subject: [PATCH 2/3] x86/kasan: Add helpers to align shadow addresses up and down From: Sean Christopherson To: Andrey Ryabinin , Dave Hansen , Andy Lutomirski , Peter Zijlstra , Thomas Gleixner , Ingo Molnar , Borislav Petkov , x86@kernel.org Cc: Alexander Potapenko , Andrey Konovalov , Dmitry Vyukov , Vincenzo Frascino , "H. Peter Anvin" , kasan-dev@googlegroups.com, linux-kernel@vger.kernel.org, Sean Christopherson , syzbot+8cdd16fd5a6c0565e227@syzkaller.appspotmail.com Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Add helpers to dedup code for aligning shadow address up/down to page boundaries when translating an address to its shadow. No functional change intended. Signed-off-by: Sean Christopherson --- arch/x86/mm/kasan_init_64.c | 40 ++++++++++++++++++++----------------- 1 file changed, 22 insertions(+), 18 deletions(-) diff --git a/arch/x86/mm/kasan_init_64.c b/arch/x86/mm/kasan_init_64.c index ad7872ae10ed..afc5e129ca7b 100644 --- a/arch/x86/mm/kasan_init_64.c +++ b/arch/x86/mm/kasan_init_64.c @@ -316,22 +316,33 @@ void __init kasan_early_init(void) kasan_map_early_shadow(init_top_pgt); } =20 +static unsigned long kasan_mem_to_shadow_align_down(unsigned long va) +{ + unsigned long shadow =3D (unsigned long)kasan_mem_to_shadow((void *)va); + + return round_down(shadow, PAGE_SIZE); +} + +static unsigned long kasan_mem_to_shadow_align_up(unsigned long va) +{ + unsigned long shadow =3D (unsigned long)kasan_mem_to_shadow((void *)va); + + return round_up(shadow, PAGE_SIZE); +} + void __init kasan_populate_shadow_for_vaddr(void *va, size_t size, int nid) { unsigned long shadow_start, shadow_end; =20 - shadow_start =3D (unsigned long)kasan_mem_to_shadow(va); - shadow_start =3D round_down(shadow_start, PAGE_SIZE); - shadow_end =3D (unsigned long)kasan_mem_to_shadow(va + size); - shadow_end =3D round_up(shadow_end, PAGE_SIZE); - + shadow_start =3D kasan_mem_to_shadow_align_down((unsigned long)va); + shadow_end =3D kasan_mem_to_shadow_align_up((unsigned long)va + size); kasan_populate_shadow(shadow_start, shadow_end, nid); } =20 void __init kasan_init(void) { + unsigned long shadow_cea_begin, shadow_cea_end; int i; - void *shadow_cea_begin, *shadow_cea_end; =20 memcpy(early_top_pgt, init_top_pgt, sizeof(early_top_pgt)); =20 @@ -372,16 +383,9 @@ void __init kasan_init(void) map_range(&pfn_mapped[i]); } =20 - shadow_cea_begin =3D (void *)CPU_ENTRY_AREA_BASE; - shadow_cea_begin =3D kasan_mem_to_shadow(shadow_cea_begin); - shadow_cea_begin =3D (void *)round_down( - (unsigned long)shadow_cea_begin, PAGE_SIZE); - - shadow_cea_end =3D (void *)(CPU_ENTRY_AREA_BASE + - CPU_ENTRY_AREA_MAP_SIZE); - shadow_cea_end =3D kasan_mem_to_shadow(shadow_cea_end); - shadow_cea_end =3D (void *)round_up( - (unsigned long)shadow_cea_end, PAGE_SIZE); + shadow_cea_begin =3D kasan_mem_to_shadow_align_down(CPU_ENTRY_AREA_BASE); + shadow_cea_end =3D kasan_mem_to_shadow_align_up(CPU_ENTRY_AREA_BASE + + CPU_ENTRY_AREA_MAP_SIZE); =20 kasan_populate_early_shadow( kasan_mem_to_shadow((void *)PAGE_OFFSET + MAXMEM), @@ -403,9 +407,9 @@ void __init kasan_init(void) =20 kasan_populate_early_shadow( kasan_mem_to_shadow((void *)VMALLOC_END + 1), - shadow_cea_begin); + (void *)shadow_cea_begin); =20 - kasan_populate_early_shadow(shadow_cea_end, + kasan_populate_early_shadow((void *)shadow_cea_end, kasan_mem_to_shadow((void *)__START_KERNEL_map)); =20 kasan_populate_shadow((unsigned long)kasan_mem_to_shadow(_stext), --=20 2.38.1.431.g37b22c650d-goog From nobody Thu Apr 9 10:53:32 2026 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 863F7C4332F for ; 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Fri, 04 Nov 2022 11:32:57 -0700 (PDT) Reply-To: Sean Christopherson Date: Fri, 4 Nov 2022 18:32:47 +0000 In-Reply-To: <20221104183247.834988-1-seanjc@google.com> Mime-Version: 1.0 References: <20221104183247.834988-1-seanjc@google.com> X-Mailer: git-send-email 2.38.1.431.g37b22c650d-goog Message-ID: <20221104183247.834988-4-seanjc@google.com> Subject: [PATCH 3/3] x86/kasan: Populate shadow for shared chunk of the CPU entry area From: Sean Christopherson To: Andrey Ryabinin , Dave Hansen , Andy Lutomirski , Peter Zijlstra , Thomas Gleixner , Ingo Molnar , Borislav Petkov , x86@kernel.org Cc: Alexander Potapenko , Andrey Konovalov , Dmitry Vyukov , Vincenzo Frascino , "H. Peter Anvin" , kasan-dev@googlegroups.com, linux-kernel@vger.kernel.org, Sean Christopherson , syzbot+8cdd16fd5a6c0565e227@syzkaller.appspotmail.com Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Popuplate the shadow for the shared portion of the CPU entry area, i.e. the read-only IDT mapping, during KASAN initialization. A recent change modified KASAN to map the per-CPU areas on-demand, but forgot to keep a shadow for the common area that is shared amongst all CPUs. Map the common area in KASAN init instead of letting idt_map_in_cea() do the dirty work so that it Just Works in the unlikely event more shared data is shoved into the CPU entry area. The bug manifests as a not-present #PF when software attempts to lookup an IDT entry, e.g. when KVM is handling IRQs on Intel CPUs (KVM performs direct CALL to the IRQ handler to avoid the overhead of INTn): BUG: unable to handle page fault for address: fffffbc0000001d8 #PF: supervisor read access in kernel mode #PF: error_code(0x0000) - not-present page PGD 16c03a067 P4D 16c03a067 PUD 0 Oops: 0000 [#1] PREEMPT SMP KASAN CPU: 5 PID: 901 Comm: repro Tainted: G W 6.1.0-rc3+ #410 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 0.0.0 02/06/2015 RIP: 0010:kasan_check_range+0xdf/0x190 vmx_handle_exit_irqoff+0x152/0x290 [kvm_intel] vcpu_run+0x1d89/0x2bd0 [kvm] kvm_arch_vcpu_ioctl_run+0x3ce/0xa70 [kvm] kvm_vcpu_ioctl+0x349/0x900 [kvm] __x64_sys_ioctl+0xb8/0xf0 do_syscall_64+0x2b/0x50 entry_SYSCALL_64_after_hwframe+0x46/0xb0 Fixes: 9fd429c28073 ("x86/kasan: Map shadow for percpu pages on demand") Reported-by: syzbot+8cdd16fd5a6c0565e227@syzkaller.appspotmail.com Cc: Andrey Ryabinin Signed-off-by: Sean Christopherson --- arch/x86/mm/kasan_init_64.c | 12 +++++++++++- 1 file changed, 11 insertions(+), 1 deletion(-) diff --git a/arch/x86/mm/kasan_init_64.c b/arch/x86/mm/kasan_init_64.c index afc5e129ca7b..0302491d799d 100644 --- a/arch/x86/mm/kasan_init_64.c +++ b/arch/x86/mm/kasan_init_64.c @@ -341,7 +341,7 @@ void __init kasan_populate_shadow_for_vaddr(void *va, s= ize_t size, int nid) =20 void __init kasan_init(void) { - unsigned long shadow_cea_begin, shadow_cea_end; + unsigned long shadow_cea_begin, shadow_cea_per_cpu_begin, shadow_cea_end; int i; =20 memcpy(early_top_pgt, init_top_pgt, sizeof(early_top_pgt)); @@ -384,6 +384,7 @@ void __init kasan_init(void) } =20 shadow_cea_begin =3D kasan_mem_to_shadow_align_down(CPU_ENTRY_AREA_BASE); + shadow_cea_per_cpu_begin =3D kasan_mem_to_shadow_align_up(CPU_ENTRY_AREA_= PER_CPU); shadow_cea_end =3D kasan_mem_to_shadow_align_up(CPU_ENTRY_AREA_BASE + CPU_ENTRY_AREA_MAP_SIZE); =20 @@ -409,6 +410,15 @@ void __init kasan_init(void) kasan_mem_to_shadow((void *)VMALLOC_END + 1), (void *)shadow_cea_begin); =20 + /* + * Populate the shadow for the shared portion of the CPU entry area. + * Shadows for the per-CPU areas are mapped on-demand, as each CPU's + * area is randomly placed somewhere in the 512GiB range and mapping + * the entire 512GiB range is prohibitively expensive. + */ + kasan_populate_shadow(shadow_cea_begin, + shadow_cea_per_cpu_begin, 0); + kasan_populate_early_shadow((void *)shadow_cea_end, kasan_mem_to_shadow((void *)__START_KERNEL_map)); =20 --=20 2.38.1.431.g37b22c650d-goog