From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 7198339F185 for ; Mon, 20 Apr 2026 13:07:44 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1776690464; cv=none; b=WvOGZsqmH1XKuXX2k3f/Yz7dzzdEptsknxHZ2tDhYfd53DCZfH5KLna33831wv/NC77zEiEIws3ormzRBs4CD4ZO8tckVvf/4bjo57oOCbgbwOy0IE7nbP/29zBms2x9yLxhxhU9uotoWGhWBLR+h3jFsXo2KfDFNEW1D9gCdxw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1776690464; c=relaxed/simple; bh=zMovZN4T5fea1JaOyGlFzDM0a7uqbqOo4g1UgSsP1oQ=; h=Subject:To:Cc:From:Date:Message-ID:MIME-Version:Content-Type; b=ubF7pARufBezw8SvDgGGOPAiV4Yb5mg7KCYyWaAkQmH9xifxy7cP1Lzt7B8TzU/JIumPwm2SEjUHuHTpVqYf3C8OvYgDbFkb0jJ4wJbn7HkQbgjLttQ/Dt2SlX1T5NhAjUtePxw4JhJp/uMVv+DeqWSgCJUwFB3LzAfa5utvHt0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=z+5Gj1vg; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="z+5Gj1vg" Received: by smtp.kernel.org (Postfix) with ESMTPSA id CE0F8C19425; Mon, 20 Apr 2026 13:07:43 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1776690464; bh=zMovZN4T5fea1JaOyGlFzDM0a7uqbqOo4g1UgSsP1oQ=; h=Subject:To:Cc:From:Date:From; b=z+5Gj1vg0uQqwoC1xAcVdspTi9O5opd6VYT7itotZGJ0fJ4EAYK9oT+N1WCFxAx6q iDYG8PSa4tzfLTj4jIq32SgPN69N6valzRjEJi3hnQvCAu5sNVzauFXI0v+NkiYsi0 N6kfR8Bs+Lymt3169LGn1/gMXxb2pm7u/KADg2Ac= Subject: FAILED: patch "[PATCH] KVM: SEV: Protect *all* of sev_mem_enc_register_region() with" failed to apply to 6.1-stable tree To: seanjc@google.com,glider@google.com Cc: From: Date: Mon, 20 Apr 2026 15:07:38 +0200 Message-ID: <2026042038-cable-curly-8e1b@gregkh> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 Content-Transfer-Encoding: 8bit The patch below does not apply to the 6.1-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to . To reproduce the conflict and resubmit, you may use the following commands: git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.1.y git checkout FETCH_HEAD git cherry-pick -x b6408b6cec5df76a165575777800ef2aba12b109 # git commit -s git send-email --to '' --in-reply-to '2026042038-cable-curly-8e1b@gregkh' --subject-prefix 'PATCH 6.1.y' HEAD^.. Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ >From b6408b6cec5df76a165575777800ef2aba12b109 Mon Sep 17 00:00:00 2001 From: Sean Christopherson Date: Tue, 10 Mar 2026 16:48:11 -0700 Subject: [PATCH] KVM: SEV: Protect *all* of sev_mem_enc_register_region() with kvm->lock Take and hold kvm->lock for before checking sev_guest() in sev_mem_enc_register_region(), as sev_guest() isn't stable unless kvm->lock is held (or KVM can guarantee KVM_SEV_INIT{2} has completed and can't rollack state). If KVM_SEV_INIT{2} fails, KVM can end up trying to add to a not-yet-initialized sev->regions_list, e.g. triggering a #GP Oops: general protection fault, probably for non-canonical address 0xdffffc0000000000: 0000 [#1] SMP KASAN NOPTI KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007] CPU: 110 UID: 0 PID: 72717 Comm: syz.15.11462 Tainted: G U W O 6.16.0-smp-DEV #1 NONE Tainted: [U]=USER, [W]=WARN, [O]=OOT_MODULE Hardware name: Google, Inc. Arcadia_IT_80/Arcadia_IT_80, BIOS 12.52.0-0 10/28/2024 RIP: 0010:sev_mem_enc_register_region+0x3f0/0x4f0 ../include/linux/list.h:83 Code: <41> 80 3c 04 00 74 08 4c 89 ff e8 f1 c7 a2 00 49 39 ed 0f 84 c6 00 RSP: 0018:ffff88838647fbb8 EFLAGS: 00010256 RAX: dffffc0000000000 RBX: 1ffff92015cf1e0b RCX: dffffc0000000000 RDX: 0000000000000000 RSI: 0000000000001000 RDI: ffff888367870000 RBP: ffffc900ae78f050 R08: ffffea000d9e0007 R09: 1ffffd4001b3c000 R10: dffffc0000000000 R11: fffff94001b3c001 R12: 0000000000000000 R13: ffff8982ab0bde00 R14: ffffc900ae78f058 R15: 0000000000000000 FS: 00007f34e9dc66c0(0000) GS:ffff89ee64d33000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fe180adef98 CR3: 000000047210e000 CR4: 0000000000350ef0 Call Trace: kvm_arch_vm_ioctl+0xa72/0x1240 ../arch/x86/kvm/x86.c:7371 kvm_vm_ioctl+0x649/0x990 ../virt/kvm/kvm_main.c:5363 __se_sys_ioctl+0x101/0x170 ../fs/ioctl.c:51 do_syscall_x64 ../arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x6f/0x1f0 ../arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x76/0x7e RIP: 0033:0x7f34e9f7e9a9 Code: <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f34e9dc6038 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007f34ea1a6080 RCX: 00007f34e9f7e9a9 RDX: 0000200000000280 RSI: 000000008010aebb RDI: 0000000000000007 RBP: 00007f34ea000d69 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 00007f34ea1a6080 R15: 00007ffce77197a8 with a syzlang reproducer that looks like: syz_kvm_add_vcpu$x86(0x0, &(0x7f0000000040)={0x0, &(0x7f0000000180)=ANY=[], 0x70}) (async) syz_kvm_add_vcpu$x86(0x0, &(0x7f0000000080)={0x0, &(0x7f0000000180)=ANY=[@ANYBLOB="..."], 0x4f}) (async) r0 = openat$kvm(0xffffffffffffff9c, &(0x7f0000000200), 0x0, 0x0) r1 = ioctl$KVM_CREATE_VM(r0, 0xae01, 0x0) r2 = openat$kvm(0xffffffffffffff9c, &(0x7f0000000240), 0x0, 0x0) r3 = ioctl$KVM_CREATE_VM(r2, 0xae01, 0x0) ioctl$KVM_SET_CLOCK(r3, 0xc008aeba, &(0x7f0000000040)={0x1, 0x8, 0x0, 0x5625e9b0}) (async) ioctl$KVM_SET_PIT2(r3, 0x8010aebb, &(0x7f0000000280)={[...], 0x5}) (async) ioctl$KVM_SET_PIT2(r1, 0x4070aea0, 0x0) (async) r4 = ioctl$KVM_CREATE_VM(0xffffffffffffffff, 0xae01, 0x0) openat$kvm(0xffffffffffffff9c, 0x0, 0x0, 0x0) (async) ioctl$KVM_SET_USER_MEMORY_REGION(r4, 0x4020ae46, &(0x7f0000000400)={0x0, 0x0, 0x0, 0x2000, &(0x7f0000001000/0x2000)=nil}) (async) r5 = ioctl$KVM_CREATE_VCPU(r4, 0xae41, 0x2) close(r0) (async) openat$kvm(0xffffffffffffff9c, &(0x7f0000000000), 0x8000, 0x0) (async) ioctl$KVM_SET_GUEST_DEBUG(r5, 0x4048ae9b, &(0x7f0000000300)={0x4376ea830d46549b, 0x0, [0x46, 0x0, 0x0, 0x0, 0x0, 0x1000]}) (async) ioctl$KVM_RUN(r5, 0xae80, 0x0) Opportunistically use guard() to avoid having to define a new error label and goto usage. Fixes: 1e80fdc09d12 ("KVM: SVM: Pin guest memory when SEV is active") Cc: stable@vger.kernel.org Reported-by: Alexander Potapenko Tested-by: Alexander Potapenko Link: https://patch.msgid.link/20260310234829.2608037-4-seanjc@google.com Signed-off-by: Sean Christopherson diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c index d29783c3075a..9265ebd9aa18 100644 --- a/arch/x86/kvm/svm/sev.c +++ b/arch/x86/kvm/svm/sev.c @@ -2706,6 +2706,8 @@ int sev_mem_enc_register_region(struct kvm *kvm, struct enc_region *region; int ret = 0; + guard(mutex)(&kvm->lock); + if (!sev_guest(kvm)) return -ENOTTY; @@ -2717,12 +2719,10 @@ int sev_mem_enc_register_region(struct kvm *kvm, if (!region) return -ENOMEM; - mutex_lock(&kvm->lock); region->pages = sev_pin_memory(kvm, range->addr, range->size, ®ion->npages, FOLL_WRITE | FOLL_LONGTERM); if (IS_ERR(region->pages)) { ret = PTR_ERR(region->pages); - mutex_unlock(&kvm->lock); goto e_free; } @@ -2740,8 +2740,6 @@ int sev_mem_enc_register_region(struct kvm *kvm, region->size = range->size; list_add_tail(®ion->list, &sev->regions_list); - mutex_unlock(&kvm->lock); - return ret; e_free: