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=1792774686; b=YZtJsiQwVvn0If16+Pnq7MdIFRxQzOjA3H6/LhwSZwuGewciG6BPjPthfCy8CQvRpbo/ HMdgmUNTyXkTJsZvo/TgK6idPOEjh3Bfk3NOcNq0vwCtuSJbR5FLhrjpgUPXX8B8sZZRS 6mp+PbpPMlzZ+LqkNbcVhGI/pUVUTcWkZuRAqWs/xDng9yTJrYECYGzlAOT7cKriccp3r 61+pLue+ArmHId1LMtnAuof0FVNC4WOZnRyeJsZ0dSAVNTG2JQ0ADNcPoi5STKwI2jNYh KK/stbhWW1EM04E36DVookvHrFSB9XPScayPDkGqKXHFP6b1A8NqXc0bRKg+/JcGquQ== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1792774686; 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=JJ7shCIwaikpfRnRpheyPKWspDD/yOnO8SEhEsEbvzE=; b=HVvuv6ejMK9Kj3GkR+/8n/If6w4gka8TJS3PswJZAKoyxI52Vv6QwdnTGROtN+WnlmLw qTuRJWJJOOw6imsnOUCl1audHMItTA6TWOgl81F7Lp6KwYFe8fp4iRd1ynOXhfEyHuX0S sY4iG9cpU8kSv6TMAQdP29Qpw7nBIVSDfQ20QKwRaL6zLvxqX2rkP4/uydPUdugA/iu/0 j2qcDd1mdr/XHicEXEEUjB5slo+v7sopcIZjGE8ezdAKsUHfw2jXLr45IgQF53pYmadOO /t4tsTJJRCBolW16uyCuzRTw451ymBTJu3i7yyXQLz6JGLxEu8uL3TkjVKGZCy8TG2w== 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="G4ASk3/L"; 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 11335606A31A; Fri, 23 Oct 2026 16:58:06 +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=G4ASk3/L Received: by smtp.kernel.org (Postfix) with ESMTPSA id 5DE901F01825; Fri, 23 Oct 2026 16:58:05 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1792774685; bh=JJ7shCIwaikpfRnRpheyPKWspDD/yOnO8SEhEsEbvzE=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=G4ASk3/LEdauKvHiqwp2ouJNN8lL1TjS3h6NcXvmEPEfi670VHgV0ILfRau9Xj/L4 ROwPM5lQG5+0zWJeADh5aiftIX+eWwksgKPKubJP6vmTqruTwiUxxxsCvupUysDatE tSuNY1PoYetiSzyl8Zn4Q1NOY+IvvzTm8Dqw0xhs= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Hardik Garg , Naman Jain , Wei Liu Subject: [PATCH 7.2 123/242] mshv_vtl: Check per-CPU register page before mmap Date: Fri, 23 Oct 2026 18:39:25 +0200 Message-ID: <20261023163716.690338490@linuxfoundation.org> X-Mailer: git-send-email 2.56.0 In-Reply-To: <20261023163713.816071858@linuxfoundation.org> References: <20261023163713.816071858@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 7.2-stable review patch. If anyone has any objections, please let me know. ------------------ From: Hardik Garg commit 874194a8de75fc2f4d1fb70c670b289b7e48f93e upstream. Register-page setup is optional for each CPU. If allocation or registration fails, mshv_vtl_configure_reg_page() warns and leaves that CPU's reg_page NULL, but initial context setup continues successfully. Meanwhile, successful setup on another CPU sets the global mshv_has_reg_page flag. mshv_vtl_fault() checks this global flag before selecting the requested CPU's register page. With mixed setup results across online CPUs, the check passes even for a CPU with no register page, reaching get_page(NULL) when userspace faults in that mapping. Check the selected per-CPU register page before taking its reference and return VM_FAULT_SIGBUS if it is absent. Fixes: 7bfe3b8ea6e3 ("Drivers: hv: Introduce mshv_vtl driver") Cc: stable@vger.kernel.org Signed-off-by: Hardik Garg Reviewed-by: Naman Jain Signed-off-by: Wei Liu Signed-off-by: Greg Kroah-Hartman --- drivers/hv/mshv_vtl_main.c | 3 +++ 1 file changed, 3 insertions(+) --- a/drivers/hv/mshv_vtl_main.c +++ b/drivers/hv/mshv_vtl_main.c @@ -819,6 +819,9 @@ static vm_fault_t mshv_vtl_fault(struct return VM_FAULT_NOPAGE; } + if (!page) + return VM_FAULT_SIGBUS; + get_page(page); vmf->page = page;