From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=95.215.58.174 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1794349124; b=RI7w85FC4Xi6UmMTvZOlr0kT/TUjYOq/tqi1aoh3AjvDYbXigk4N0Fr/Lx/6XT5dq+FK SRrkZzksg9pLq+Sg7cSuuNipWI0NSaimUqL6MbQJBQgJ+mprH3RZjFXAV3PEezWtzsJvS fPxcMtuquN6N+Wo11q00puJ1GDNKKUJ0YVk+z0aK+6GMLOn0NYtQb2AZ2yM79X3q37GZ3 5l9ZbAzNJyhGiz4999YyuqqEzlqJPoJcQmXlqoVbgdPq15KMM0K074WqBkdVT8fLKah58 1ihBUqyoKrE4PAg10qONBhbiHl+3nPT1bIYWkV6eu0GRjctvON0Ba9cXM+a6lwpWlsQ== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1794349124; h=DMARC-Filter:X-Envelope-To:DKIM-Signature:X-Envelope-To:Received: X-Mizu-Trace-ID:X-Migadu-Flow:From:To:Cc:Subject:Date:Message-ID: X-Mailer:In-Reply-To:References:MIME-Version: Content-Transfer-Encoding; bh=fDbH24IqyXGeJwrHjekd3y0pkWs6pa3ajDlC4H0B9Rs=; b=xm44Kj+e6tEswoj5B6jalyltvyF0EssSoetMICWZ6ZbgYjespQ0o2J4RiI6L23wUW0CT clkQVwogtgIFDfnkoXM39jUBluDIjJZMxx88GPJKp5i+123R97P1uSIErut55ftINcgYf LXGm/VIPUsaTZSxc5rs2AUS68QfNCJ2aXQgRdr1h8ND0FgXovUBctf9aH+zL4rGh3WSyr BcxGXJ0RCuZV/1xfpUivWCzKxRmlFoqQ0GDqwGeB4G6V93PrjPjFM0qV/2CdCbZnsxFaC 1ZwGye45CIcOD4Lj0AQNRwPPCp2fKXLoUy1I8lfdp9A+WPMzTFot4v+RQNvtwGHGsbg== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass header.from=linux.dev; spf=pass smtp.mailfrom=linux.dev; dkim=pass header.d=linux.dev header.i=@linux.dev header.a=rsa-sha256 header.s=key1 header.b=KATnxScb; arc=none smtp.remote-ip=95.215.58.174 Received: from mta1.migadu.com (out-174.mta1.migadu.com [95.215.58.174]) (using TLSv1.3 with cipher TLS_AES_128_GCM_SHA256 (128/128 bits) key-exchange X25519 server-signature ECDSA (prime256v1) server-digest SHA256) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id A15EE606A330 for ; Tue, 10 Nov 2026 22:18:43 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.2 smtp.subspace.kernel.org A15EE606A330 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.dev Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key, unprotected) header.d=linux.dev header.i=@linux.dev header.a=rsa-sha256 header.s=key1 header.b=KATnxScb X-Envelope-To: linux-kernel@vger.kernel.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-kernel@vger.kernel.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-Mailing-List: linux-kernel@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 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