From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-oi1-f198.google.com (mail-oi1-f198.google.com [209.85.167.198]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 9D72C42A7A5 for ; Mon, 20 Jul 2026 14:27:34 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.167.198 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784557657; cv=none; b=RSOQH5lLaJI+mjdouxsj4o7tgs3+wRanOkDVMml8AWXX1ko6hlzVTJaSuXnVi6XFtUatG8Z0snrSbpSsm6yBlfU1giC8mk9O5a1s8jjmSnFQyJtyyGxdaftUNAP/xAOGuMaM61V2NicS77dRU6wAkx3cWrl6GPKlThPSPQ9KZ2A= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784557657; c=relaxed/simple; bh=BpB94hQ1QJu8QhOQVo3UMUsII1RCO9BzKNOXF2LBx94=; h=MIME-Version:Date:In-Reply-To:Message-ID:Subject:From:To: Content-Type; b=NM2MColbCNrT8kmVeCvJqd1NTwP1VaxFKyUaW9JpBxMTxKQ2gt9uXuYKQsSB4F6UlPWL6fAL1KICKaK5UDq/dS5GbWqrXIMa9dkZRVkXJSQxdnmEhMPWwLfckAtAs0A5N4lO829vnSj+3kng9b7C3VTw9t6g9V1UEctte/5XpFQ= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=fail (p=none dis=none) header.from=syzkaller.appspotmail.com; spf=pass smtp.mailfrom=M3KW2WVRGUFZ5GODRSRYTGD7.apphosting.bounces.google.com; arc=none smtp.client-ip=209.85.167.198 Authentication-Results: smtp.subspace.kernel.org; dmarc=fail (p=none dis=none) header.from=syzkaller.appspotmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=M3KW2WVRGUFZ5GODRSRYTGD7.apphosting.bounces.google.com Received: by mail-oi1-f198.google.com with SMTP id 5614622812f47-4a441e90050so5487436b6e.1 for ; Mon, 20 Jul 2026 07:27:34 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1784557653; x=1785162453; h=content-type:to:from:subject:message-id:in-reply-to:date :mime-version:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to:content-type; bh=bMC1d2n0UqsqgTJHcdrSAlQ8dfSDhTGiUc5sUZtjLgA=; b=pR3mWoqndgd8K0NXiKBPqW9w7fed2kwBZIA4IU26oPFUw2ehWSpoDgac9WP6Yo4L96 s97gO0XV0UJgoJdFxCWgyNy0/mdP3WYSefA07nwvWB9Z0mFKlU/9hFzyRuUfdEybHecw BQnpFf3tWsdfoRQJKedLVYNrR5CXxZzYcDmRl7qFAG8Ziix0FAsQFVeYbU0UukdF5C+Y +OWQTa8TDFmHRiNR72/a3bdR2GI0Vhf7TDb74zw/ECieeYIeHeVrOhc9BIRD624MDSU6 q/ICqzm1wHgRwYi0VGXhTVJg8TdUHnEbOl4jztPFWvB9O6CvgpRdtSxyPmX3OrTkVh0i X4Ig== X-Gm-Message-State: AOJu0YwE4aAx7sjB30LDxEaXTderSE9vErc7xlUxHGCSV6e4KpSp7YDf mNyvuhH3EdIC/Y66vQAubX6BPE96nMRgV+aYk2mUJ+7G1uorc4N46yvYndszoNZ6WhAfdj+Ztz3 ByirmFSzwMty97uM1cWYN2vnXWJ8+2mlkLHc325/h0dVSfoZjejHsNkxbX/Q= Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Received: by 2002:a05:6808:159c:b0:496:9ee:e538 with SMTP id 5614622812f47-4a4b2067c63mr14134427b6e.5.1784557653409; Mon, 20 Jul 2026 07:27:33 -0700 (PDT) Date: Mon, 20 Jul 2026 07:27:33 -0700 In-Reply-To: <6a426dd2.854d4ab9.360e1d.0008.GAE@google.com> X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <6a5e3055.f1649fcc.2a4208.0573.GAE@google.com> Subject: Forwarded: Re: KASAN: use-after-free Read in kvm_setup_guest_pvclock From: syzbot To: linux-kernel@vger.kernel.org, syzkaller-bugs@googlegroups.com Content-Type: text/plain; charset="UTF-8" For archival purposes, forwarding an incoming command email to linux-kernel@vger.kernel.org, syzkaller-bugs@googlegroups.com. *** Subject: Re: KASAN: use-after-free Read in kvm_setup_guest_pvclock Author: halves@igalia.com #syz test: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master Reported-by: syzbot+fb7c2dd166d3ea63df2a@syzkaller.appspotmail.com Link: https://syzkaller.appspot.com/bug?extid=fb7c2dd166d3ea63df2a Signed-off-by: Heitor Alves de Siqueira --- virt/kvm/pfncache.c | 28 ++++++++++++++++++++++++++++ 1 file changed, 28 insertions(+) diff --git a/virt/kvm/pfncache.c b/virt/kvm/pfncache.c index 728d2c1b488a..8a766c4cd4bd 100644 --- a/virt/kvm/pfncache.c +++ b/virt/kvm/pfncache.c @@ -152,6 +152,32 @@ static inline bool mmu_notifier_retry_cache(struct kvm *kvm, unsigned long mmu_s return kvm->mmu_invalidate_seq != mmu_seq; } +static void kvm_gpc_invalidate_pfn(struct kvm *kvm, kvm_pfn_t pfn) +{ + struct gfn_to_pfn_cache *gpc; + + if (is_error_noslot_pfn(pfn)) + return; + + spin_lock(&kvm->gpc_lock); + list_for_each_entry(gpc, &kvm->gpc_list, list) { + read_lock_irq(&gpc->lock); + + if (gpc->valid && gpc->pfn == pfn) { + read_unlock_irq(&gpc->lock); + + write_lock_irq(&gpc->lock); + if (gpc->valid && gpc->pfn == pfn) + gpc->valid = false; + write_unlock_irq(&gpc->lock); + continue; + } + + read_unlock_irq(&gpc->lock); + } + spin_unlock(&kvm->gpc_lock); +} + static kvm_pfn_t hva_to_pfn_retry(struct gfn_to_pfn_cache *gpc) { /* Note, the new page offset may be different than the old! */ @@ -201,6 +227,7 @@ static kvm_pfn_t hva_to_pfn_retry(struct gfn_to_pfn_cache *gpc) if (new_khva != old_khva) gpc_unmap(new_pfn, new_khva); + kvm_gpc_invalidate_pfn(gpc->kvm, new_pfn); kvm_release_page_unused(page); cond_resched(); @@ -221,6 +248,7 @@ static kvm_pfn_t hva_to_pfn_retry(struct gfn_to_pfn_cache *gpc) new_khva = gpc_map(new_pfn); if (!new_khva) { + kvm_gpc_invalidate_pfn(gpc->kvm, new_pfn); kvm_release_page_unused(page); goto out_error; } -- 2.55.0