From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1) server-digest SHA256) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id D7337606A31C for ; Tue, 10 Nov 2026 22:18:54 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.a=rsa-sha256 header.s=bombadil.20210309 header.b=RdXPvIng; dkim=pass (1024-bit key, unprotected) header.d=linux.dev header.i=@linux.dev header.a=rsa-sha256 header.s=key1 header.b=KATnxScb DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Transfer-Encoding: MIME-Version:References:In-Reply-To:Message-ID:Date:Subject:Cc:To:From: Reply-To:Content-Type:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Unsubscribe-Post: List-Owner; bh=fDbH24IqyXGeJwrHjekd3y0pkWs6pa3ajDlC4H0B9Rs=; b=RdXPvIngN/A2EE KDwtnsQF5JqXjLgU8gBSp/nWwHPLShBNdfPlq2RCutrPA6aQ5R01FjEkrK0TWz0N0dZsCQAdd5aS9 3Xg34CSuLzVFM4wPrsTSEnDD1J+vjrFvtsaNFhZ0pja+yO9ICN1Yri8hgVj/JED8Auncbu75QZk4D S6RMoRytahHRp06EbDdympdBjThilycu4DUIec/zUKPmjl32GI5B4nqx3ZXto1LvS3nFfgCElkcIL fLeT5VdZNIZ9ouLG+BI2qPpIbHsWrwHgzYRtbWJBECUKiXlEPXPxN6Cm3UNboKm/EIfukFNkNyvK9 877YZ/RcdARVvVBiJyGg==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.100.1 #2 (Red Hat Linux)) id 1xQuAy-000000058tV-1Nqg; Tue, 10 Nov 2026 22:18:48 +0000 Received: from out-174.mta1.migadu.com ([95.215.58.174] helo=mta1.migadu.com) by bombadil.infradead.org with esmtps (Exim 4.100.1 #2 (Red Hat Linux)) id 1xQuAt-000000058rf-1PF3 for linux-arm-kernel@lists.infradead.org; Tue, 10 Nov 2026 22:18:44 +0000 X-Envelope-To: linux-arm-kernel@lists.infradead.org DKIM-Signature: a=rsa-sha256; bh=ucW0CbkgsYickmF4J+LbDhp0k/VR5j5+Ym5RT6WHGS0=; c=simple/simple; d=linux.dev; h=from:to:subject:date:message-id:mime-version:content-type; s=key1; t=1794349121; v=1; x=1794953921; b=KATnxScbwb64vWmiiVtuCVXVGjDEVGbtOnd1iqIBXx5KJnfO9Nb2ZxFJWUwTE+Hrs5AEsKsz yvZnA0NemMEkt04T/1BB5QczwompSqODfu9lYqlkfYdD18QVO8OuW1fqx+vivQ2Cfce1t8fSzha 5xT7yCctpxAYjRm1CitCAV7o= X-Envelope-To: linux-arm-kernel@lists.infradead.org Received: by mta11.migadu.com with ESMTPS id 53003b696ba808b5; Tue, 10 Nov 2026 22:18:41 +0000 X-Mizu-Trace-ID: 53003b696ba808b5 X-Migadu-Flow: FLOW_OUT From: Bradley Morgan To: Catalin Marinas , Will Deacon Cc: Mark Rutland , Mark Brown , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, bradley.morgan@linux.dev, stable@vger.kernel.org Subject: [PATCH 1/2] arm64/fpsimd: signal: Require ZA context when restoring ZT context Date: Tue, 10 Nov 2026 22:18:35 +0000 Message-ID: <20261110221836.3265929-2-bradley.morgan@linux.dev> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20261110221836.3265929-1-bradley.morgan@linux.dev> References: <20261110221836.3265929-1-bradley.morgan@linux.dev> X-Archived-By: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.9.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20261110_141843_517859_98A34BB9 X-CRM114-Status: GOOD ( 12.49 ) X-Spam-Score: -2.8 (--) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" X-Spam-Status: No, score=-18.9 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=ham autolearn_force=no version=4.0.1 X-Spam-Checker-Version: SpamAssassin 4.0.1 (2024-03-26) on aws-us-west-2-korg-listserv-alma10-1 When restoring the signal frame, restore_zt_context() checks whether ZA is enabled via thread_za_enabled(¤t->thread). However, if user.za is omitted from the signal frame, restore_za_context() is skipped entirely. If the signal handler touched SME prior to rt_sigreturn(), ZA remains enabled in current->thread.svcr from the handler context, causing thread_za_enabled() to succeed and restore_zt_context() to write userspace ZT data without restoring ZA state. Require user->za to be present in the signal frame before restoring ZT. Fixes: ee072cf70804 ("arm64/sme: Implement signal handling for ZT") Cc: stable@vger.kernel.org Signed-off-by: Bradley Morgan --- arch/arm64/kernel/signal.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/arm64/kernel/signal.c b/arch/arm64/kernel/signal.c index 6a06a4e352b1d..20d5f19921e0d 100644 --- a/arch/arm64/kernel/signal.c +++ b/arch/arm64/kernel/signal.c @@ -678,7 +678,7 @@ static int restore_zt_context(struct user_ctxs *user) u16 nregs; /* ZA must be restored first for this check to be valid */ - if (!thread_za_enabled(¤t->thread)) + if (!user->za || !thread_za_enabled(¤t->thread)) return -EINVAL; if (user->zt_size != ZT_SIG_CONTEXT_SIZE(1)) -- 2.53.0