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=1794061465; b=pizpJIYX08CGQ5WLhk6BMNKRSRzz3SD3jyFiCF+VcSt0JRSq+1rd/cv/h7XPUVj9Q1Hm GSmkbrF7rq9Xbsc3KMGuntcJeTUjGoHjB1GJhSa3PFccSFi5LOvoSJDEtmPnP1EqCb1Cp 31kPG6Uuooq6YlO32t9l32pB5cm5Qrf70tfpNl3cwpLxBuKAfJkyeGWc5N1w8/mCMpwdy N2dbaD3Y4k0TJAsqpcWIdJoExB9HjIjNTV4v6jFcBhV/e82VDWtgZfsg/mqXasSWWY3Tu Y9IyW4aqFDFldsjjyGlSlZk5K6vGHXdo21PtUbMEyswIZ0Zb2/CFaftr2BS5Pp9PhOw== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1794061465; 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=ACzd6TSiitx002leitP2gTN+9ommgBh0IF3cl91Qo3s=; b=aZmZfygKQ7c7JI+UR19P6N+/PzX9xx/p/EBK4USoTZ3a6YU/xtehcPJVw5fP6Ci8YPNW 6KW8u5tmNF5CpRY4aSa6RAWa+/YilSBz1ychrRyDCNsODqFsyhTSmCdcoxMzVpjoV3q5R oGbjmYA9DgAY/Y6M9QZV+f+SAXuUBOglrHG0lXDYZWZdsegJ1zDRFcGIuAr4/0TuSLg5u L/kLd8reUeUXg/xvBZ5iHISA6exMC+rNo+sq5JYni2wPIu3ZsRJyO4Poi5iLQrFG/dF6l lZ7ckOGCET02D0h3pTflem3H8Y3O9QaKMTD4Lr4cjb1ydHmrdaulT+KDZv1iWPjB5dw== 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=rJwn1mba; 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 2325A606A331; Sat, 7 Nov 2026 14:24:25 +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=rJwn1mba Received: by smtp.kernel.org (Postfix) with ESMTPSA id CB7B81F0089F; Sat, 7 Nov 2026 14:24:24 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1794061465; bh=ACzd6TSiitx002leitP2gTN+9ommgBh0IF3cl91Qo3s=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=rJwn1mbauM4i1SMjSsvU54FwHyrtRJ3Sq6Vzf5NfiPDKzqBXF6RvLkcpkMXClXuCU rIgtNdUwafE2otiOU5CfkVjkQeUA5zfBBA54NFW7fqqsbZLxaN9VUqRsh54bBLDCd2 u8Jt7VHCf+FgNlvKjm4j49LSdbuiUrVSq11gR/FQ= 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 6.12 0566/1536] RISC-V: KVM: Fix double-free of sdata in kvm_pmu_clear_snapshot_area() Date: Sat, 7 Nov 2026 08:43:02 -0500 Message-ID: <20261107135013.475942608@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: 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 [ sashal: Kept the local SBI_ERR_FAILURE error code in the context line, since upstream has SBI_ERR_INVALID_ADDRESS there, and added the same kvpmu->sdata = NULL; line. ] 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 516a0570bdf6a..9270119cd44da 100644 --- a/arch/riscv/kvm/vcpu_pmu.c +++ b/arch/riscv/kvm/vcpu_pmu.c @@ -451,6 +451,7 @@ int kvm_riscv_vcpu_pmu_snapshot_set_shmem(struct kvm_vcpu *vcpu, unsigned long s if (kvm_vcpu_write_guest(vcpu, saddr, kvpmu->sdata, snapshot_area_size)) { kfree(kvpmu->sdata); + kvpmu->sdata = NULL; sbiret = SBI_ERR_FAILURE; goto out; } -- 2.53.0