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=1793831309; b=y8cH+nmJcXhMBI9uHrXNjfHIESh3kKswFs/AciSW2L8scKK/Z1JNgJAEwulkf6XUwqXj 4tOs+aK46jTB/MXF6vhrengYi414aE5trGTU/wHfN6il5Yqi+yZ5Z6iTqOmTIp1ZsvHMS 7xS+8eIeRYoopH/u2KfK562VHZpXSxA5gKmI8DOmTVQGazKueowZrBVETFK5j+WSDYCht 7JikF4vZ3Ohi4AZcGu51W9PyoirpImo+OjhYedYC7vp5QqZcQQB65oTK3TpYeVVeDPEkd RuD1rXgADFmI5O4Gd1r1Jsclk+uuGSYWaZLvrTY4FwFXgQPm5p2zIPFwCLSBcDABTEQ== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1793831309; 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=pAW/eo/h+kW6AOeEAEqNajoXODwnd6U5Db2bpDwBW3E=; b=sNAk4gL3CYUTT4enOCpuSnn4nlQ04FiWKD0jvE1rWgKMoHWwBKPKxF5lL1LXDFpJUjzM 9nrtev0hOt20lkbs9E5bBgF+QUFQIQTim7IipF0APrkMfHFSuGySilGwv1vO1tYqSMwR7 Wy+hQxrjde7mlq07vg5eO7OFjPQiBXqk9zjriQ8/RMXG5/HulcqaM+pgohQe23GMicCqU BB+MoHmB4lBREQjsgwo0AoqAJGKBNLUQeFi36qWr68iEhRxxD8/1+yD1L/2wqv1pDgaI5 pM9bZxmHchuq+cIRQo7u480b/8KywmecsJpb69AsmcKSJhnIEaWRiHeB1EN9cOcjuFA== 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=gBub2xbG; 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 D5429606B2F8; Wed, 4 Nov 2026 22:28:28 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key, unprotected) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.a=rsa-sha256 header.s=korg header.b=gBub2xbG Received: by smtp.kernel.org (Postfix) with ESMTPSA id 7CF8B1F00919; Wed, 4 Nov 2026 22:28:28 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1793831308; bh=pAW/eo/h+kW6AOeEAEqNajoXODwnd6U5Db2bpDwBW3E=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=gBub2xbGAPHyByRs86r0+ywQPNiEKZHkNy5pgoUimDg3IfVhwU/VD4EQ8HvNp061F dlmi99oyozCDAzCJt7k4ISXl+lEd5tIA6I0YPkKLxCh9QNn1cmVYk/fvcnoo+WINi/ Z7+PVgh1RWLMRDRY72LS4Pt5HPWG1h/hFLdeCsJM= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Jiakai Xu , Jiakai Xu , Nutty Liu , Andrew Jones , Anup Patel , Sasha Levin Subject: [PATCH 6.18 0624/1005] RISC-V: KVM: Fix double-free of sdata in kvm_pmu_clear_snapshot_area() Date: Wed, 4 Nov 2026 16:05:57 -0500 Message-ID: <20261104211101.288487360@linuxfoundation.org> X-Mailer: git-send-email 2.56.0 In-Reply-To: <20261104211043.516122098@linuxfoundation.org> References: <20261104211043.516122098@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore X-Mailing-List: patches@lists.linux.dev List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: Jiakai Xu [ Upstream commit 310e2096b082ae0010e7afef666073b966ac2fa7 ] In kvm_riscv_vcpu_pmu_snapshot_set_shmem(), when kvm_vcpu_write_guest() fails, kvpmu->sdata is freed but not set to NULL. This leaves a dangling pointer that will be freed again when kvm_pmu_clear_snapshot_area() is called during vcpu teardown, triggering a KASAN double-free report. First free occurs in kvm_riscv_vcpu_pmu_snapshot_set_shmem(): kvm_riscv_vcpu_pmu_snapshot_set_shmem arch/riscv/kvm/vcpu_pmu.c:443 kvm_sbi_ext_pmu_handler arch/riscv/kvm/vcpu_sbi_pmu.c:74 kvm_riscv_vcpu_sbi_ecall arch/riscv/kvm/vcpu_sbi.c:608 kvm_riscv_vcpu_exit arch/riscv/kvm/vcpu_exit.c:240 kvm_arch_vcpu_ioctl_run arch/riscv/kvm/vcpu.c:1008 kvm_vcpu_ioctl virt/kvm/kvm_main.c:4476 Second free (double-free) occurs in kvm_pmu_clear_snapshot_area(): kvm_pmu_clear_snapshot_area arch/riscv/kvm/vcpu_pmu.c:403 [inline] kvm_riscv_vcpu_pmu_deinit.part arch/riscv/kvm/vcpu_pmu.c:905 kvm_riscv_vcpu_pmu_deinit arch/riscv/kvm/vcpu_pmu.c:893 kvm_arch_vcpu_destroy arch/riscv/kvm/vcpu.c:199 kvm_vcpu_destroy virt/kvm/kvm_main.c:469 [inline] kvm_destroy_vcpus virt/kvm/kvm_main.c:489 kvm_arch_destroy_vm arch/riscv/kvm/vm.c:54 kvm_destroy_vm virt/kvm/kvm_main.c:1301 [inline] kvm_put_kvm virt/kvm/kvm_main.c:1338 kvm_vm_release virt/kvm/kvm_main.c:1361 Fix it by setting kvpmu->sdata to NULL after kfree() in kvm_riscv_vcpu_pmu_snapshot_set_shmem(), so that the subsequent kfree(NULL) in kvm_pmu_clear_snapshot_area() becomes a safe no-op. This bug was found by fuzzing the KVM RISC-V PMU interface. Fixes: c2f41ddbcdd756 ("RISC-V: KVM: Implement SBI PMU Snapshot feature") Signed-off-by: Jiakai Xu Signed-off-by: Jiakai Xu Reviewed-by: Nutty Liu Reviewed-by: Andrew Jones Link: https://lore.kernel.org/r/20260318092956.708246-1-xujiakai2025@iscas.ac.cn Signed-off-by: Anup Patel Signed-off-by: Sasha Levin --- arch/riscv/kvm/vcpu_pmu.c | 1 + 1 file changed, 1 insertion(+) diff --git a/arch/riscv/kvm/vcpu_pmu.c b/arch/riscv/kvm/vcpu_pmu.c index d5a0a3a33f6b2..b3ce82cfd78f3 100644 --- a/arch/riscv/kvm/vcpu_pmu.c +++ b/arch/riscv/kvm/vcpu_pmu.c @@ -454,6 +454,7 @@ int kvm_riscv_vcpu_pmu_snapshot_set_shmem(struct kvm_vcpu *vcpu, unsigned long s /* No need to check writable slot explicitly as kvm_vcpu_write_guest does it internally */ if (kvm_vcpu_write_guest(vcpu, saddr, kvpmu->sdata, snapshot_area_size)) { kfree(kvpmu->sdata); + kvpmu->sdata = NULL; sbiret = SBI_ERR_INVALID_ADDRESS; goto out; } -- 2.53.0