From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1794061766; b=MtghPlUHxGUs9Y59PDvrQsRffXuYvfhhFFWvTlFlQhGquCFTsmc8mm22poFqCHEIT1Pq +Y1NpvDqRLm9ohyWrE8YgTETp9JFowyFhv2RlLCVzl9GbSk7VLYqL6FPR5wj95Fm4BiK8 DZaJgc23WyxnYbItbBZrqmqdg6LFGI48xkqutZgzFq59jxM5xROOyS2eWSTprbu2UKVpq 4mUv+IC0m4ia5j0+C0pwuT676U9Zho6GD9l3JHhMxvsxMfoLjjSnMT/S/xn5nwDPxZgyM 6Xy+mof6IQ17sFxitMZzoCJcbUbIJETWUhC3/2JGwPhKObGDTUy88v+JjhQyJjOAwyA== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1794061766; h=Received:DKIM-Signature:From:To:Cc:Subject:Date:Message-ID:X-Mailer: In-Reply-To:References:User-Agent:X-stable:X-Patchwork-Hint: MIME-Version:Content-Transfer-Encoding; bh=nnmflxyDcp+Hgfpx/HOgsaiuqKhznERafhVYCfDTsF0=; b=5a4+vmfHMqcYbfWGLBfxEI1TnILWaf7G6UnzSY5Ep+SBEvqIE0mQYxm/5O5HRXLClrim Gz1b0iriYGBSCQ5a+WEzL/oB9E3eyMkn0M1tXdhKcYRTfGE/DrhbZ4G1qM+ufs1LeO/PK iGsQ+4UlQAUvKFW6H4ImtJax47EvjNDePjWM6VBBXuKeDl//BVfhkxcm1e0PMsgHdwWdv Hi8daUF60coEIqvLTjiVkUXFmAZOrM9UluRBvJ0Uh4ecBpSchbLp71biA8nIuABfI87Jt Mo7LxXM/fiPe3AxvWxEpQU83KgCjiAzhiwng75iZuTcWpAxvNsw4IDSKDcs227JUXAA== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=linuxfoundation.org header.i=@linuxfoundation.org header.a=rsa-sha256 header.s=korg header.b=OYVtyD0k; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 29645606A326; Sat, 7 Nov 2026 14:29:26 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.a=rsa-sha256 header.s=korg header.b=OYVtyD0k Received: by smtp.kernel.org (Postfix) with ESMTPSA id C532D1F0089F; Sat, 7 Nov 2026 14:29:25 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1794061766; bh=nnmflxyDcp+Hgfpx/HOgsaiuqKhznERafhVYCfDTsF0=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=OYVtyD0kVAH49FYpHMthbpLDQvSWI3BTD1GnFTG2S1cUqP7z2WO2/mtz/mzDwI2VO Uwilgpt8mZEamYRmh08BYtfDYgQsjZFnahN/yMtJSw1KPh/iV141h5XL8Ihp9kpmyI ZF8TYP46cXoOh/IyXA8nuZLu+ueGLqVg5r4gC1mA= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Chengfeng Ye , Kai Huang , Sean Christopherson Subject: [PATCH 6.12 0802/1536] KVM: x86: Take SRCU in kvm_zap_gfn_range() Date: Sat, 7 Nov 2026 08:46:58 -0500 Message-ID: <20261107135020.072429163@linuxfoundation.org> X-Mailer: git-send-email 2.56.0 In-Reply-To: <20261107134957.653319350@linuxfoundation.org> References: <20261107134957.653319350@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore X-Mailing-List: stable@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.12-stable review patch. If anyone has any objections, please let me know. ------------------ From: Chengfeng Ye commit b59a87c1ba3c347e8aec5f932eb7abf13064fd62 upstream. kvm_zap_gfn_range() walks memslots and rmaps and may drop mmu_lock to reschedule. Callers that do not already hold kvm->srcu (or slots_lock) can race with memslot deletion: synchronize_srcu_expedited() does not wait, kvm_free_memslot() frees the old slot and its rmap, and the zap resumes on freed memory. The VFIO noncoherent-DMA path hits this by zapping the entire GPA space without SRCU. KASAN reported: BUG: KASAN: vmalloc-out-of-bounds in slot_rmap_walk_next+0x82/0x1c0 Read of size 8 at addr ffffc900005c1008 Call Trace: slot_rmap_walk_next+0x82/0x1c0 __kvm_rmap_zap_gfn_range+0x17a/0x280 kvm_zap_gfn_range+0x2a6/0x6a0 kvm_vfio_set_attr+0x576/0x770 kvm_device_ioctl+0x1ff/0x3b0 Take SRCU inside kvm_zap_gfn_range() so every caller is covered. Nesting with an existing kvm->srcu critical section is fine; the helper uses a local index. Drop the now-redundant SRCU pair from __kvm_set_or_clear_apicv_inhibit(). Fixes: 362ff6dca541 ("KVM: x86/mmu: Zap KVM TDP when noncoherent DMA assignment starts/stops") Cc: stable@vger.kernel.org Signed-off-by: Chengfeng Ye Reviewed-by: Kai Huang Link: https://patch.msgid.link/20260825183924.237727-1-nicoyip.dev@gmail.com Signed-off-by: Sean Christopherson Signed-off-by: Greg Kroah-Hartman --- arch/x86/kvm/mmu/mmu.c | 2 ++ arch/x86/kvm/x86.c | 2 -- 2 files changed, 2 insertions(+), 2 deletions(-) --- a/arch/x86/kvm/mmu/mmu.c +++ b/arch/x86/kvm/mmu/mmu.c @@ -6664,6 +6664,8 @@ void kvm_zap_gfn_range(struct kvm *kvm, if (WARN_ON_ONCE(gfn_end <= gfn_start)) return; + guard(srcu)(&kvm->srcu); + write_lock(&kvm->mmu_lock); kvm_mmu_invalidate_begin(kvm); --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -10207,10 +10207,8 @@ void __kvm_set_or_clear_apicv_inhibit(st kvm->arch.apicv_inhibit_reasons = new; if (new) { unsigned long gfn = gpa_to_gfn(APIC_DEFAULT_PHYS_BASE); - int idx = srcu_read_lock(&kvm->srcu); kvm_zap_gfn_range(kvm, gfn, gfn+1); - srcu_read_unlock(&kvm->srcu, idx); } } else { kvm->arch.apicv_inhibit_reasons = new;