From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-oo1-f70.google.com (mail-oo1-f70.google.com [209.85.161.70]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 637772FDC28 for ; Mon, 17 Aug 2026 04:21:05 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.161.70 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786940467; cv=none; b=FGbRzVDuzplN5TXN3iiB+kc+a66jqPSxo204eKbsggdcGHeCkTLiqti0rrDTDTU3R1YB4iqiIXF3y7W3/tP5l/7Qmc6JjCpDgqhz265RJUVLcCxXnzAnmdzuG8y1QeqRAQ5UgUTgH2ORVX7gvCbD0fJNTkNKh2U3CyDQAM/1Qvk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786940467; c=relaxed/simple; bh=ua6URTtpR5hNOIdWlAMkKlywe5eRMh+7ftq1EDn7Vvc=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=V1d65IDRaBG7kZrgt2Iz/4w2N8jyZ1WdOXYXyx5M5KowVM8Z6rwO/ZdCV0wcNW1AmwK6x1HRICqd7mRjSipzTxlkrXBAmsYE+jfXV+JylmPKoTMs7rbRqxV7rjEzbkDJPfC4h3itP626MePnaiKHPqgMlTCFjfYV8eWN+TxzFqg= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com; spf=pass smtp.mailfrom=flex--avagin.bounces.google.com; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b=Aa+WH6SW; arc=none smtp.client-ip=209.85.161.70 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=flex--avagin.bounces.google.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="Aa+WH6SW" Received: by mail-oo1-f70.google.com with SMTP id 006d021491bc7-6ab4aec4a14so3003599eaf.2 for ; Sun, 16 Aug 2026 21:21:05 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20251104; t=1786940464; x=1787545264; darn=vger.kernel.org; h=content-type:cc:to:from:subject:message-id:references:mime-version :in-reply-to:date:from:to:cc:subject:date:message-id:reply-to :content-type; bh=fGTueokr9JHsHAyyUBEdstVedHWswEXJTEA+EvRHyTg=; b=Aa+WH6SWECpQ+AEerlcZs8IwR55KFmMwnGZuZxDO+Ky8Kb9xyKmKSHvSJty7Ct4XQt GPYN98UjDMI6YD8O9eW7rsjiEW0zp+kmbwlq6WvK0oB/LcP/QO0RyjSkHbfvIiIVLUvE BKFRTD7NHDS4ih7AtwfmmmoYMBJf6ZjfM7mTkkiWdJHyk2wJ/b8RmcwmoRIOPi+iLdXI 6v8qqJGg3maMhmE7zcfuVvrnCebqcGUq5LGlsG+tuF+vs+VVLqZ0VUMiaWHOc+opuslm T4699x/9LY8NyODyxxIJ28cOkZ9gycJpjh0fToVytg6h5ql32UhMm06dp3MijNd3l2po xfVg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1786940464; x=1787545264; h=content-type:cc:to:from:subject:message-id:references:mime-version :in-reply-to:date:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to:content-type; bh=fGTueokr9JHsHAyyUBEdstVedHWswEXJTEA+EvRHyTg=; b=WNXQarpHNhL+uIYgF7fUQ+sY+e3rk+WsSQfI8c/70JYoSfNZn4baIHDVv8oCWn0zLf 5Dt+t66xwBt2B6cgI0mwk2/ykXYRvaW5hzNE+9SPEFdYGwjODSc42f3h1N73Sh0jsjO2 aaF5lhaQ2CWGq3S1ErQRp8lT+TgMHBVh+/2AL1aOjQdzPUOWBZEv8fB8GZIsXyCWh/mC ekSq4jebbyC8gL/Vp89uEEUlEp3QpCHAalfUZ4Iw2UwHlIt1YZOJB4IMa5fxXCfm3rXS SDdpbLbSxSPTubPtbHyB+aJGzRp3EdKHVKAjgA1hx6/rdy/WzRIrZDta69/uQr6oGDuG ANsQ== X-Gm-Message-State: AOJu0YyNWcKXE7mQv7czLERHXzqUuEs+C8UFYNOkuqIWhO7g1lQ8fPIT Z4I/Egweh+Aoev75sR0rpm9XIaYPNuLOyokPOUVcpvmZyNh0kFcFAl9GcdB6N2pOx4pAan2seZN YKOnEcg== X-Received: from ilbej10-n1.prod.google.com ([2002:a05:6e02:4e0a:10b0:508:1635:6e4c]) (user=avagin job=prod-delivery.src-stubby-dispatcher) by 2002:a05:6820:1627:b0:6b0:5bd1:4722 with SMTP id 006d021491bc7-6b0d6176dedmr18012014eaf.13.1786940464182; Sun, 16 Aug 2026 21:21:04 -0700 (PDT) Date: Mon, 17 Aug 2026 04:20:48 +0000 In-Reply-To: <20260817042048.1579415-1-avagin@google.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20260817042048.1579415-1-avagin@google.com> X-Mailer: git-send-email 2.55.0.691.gc56d675ccc-goog Message-ID: <20260817042048.1579415-9-avagin@google.com> Subject: [PATCH 8/8] selftests/x86: Add a sigframe insufficient xstate_size test From: Andrei Vagin To: Thomas Gleixner , Ingo Molnar , Borislav Petkov , "Chang S. Bae" Cc: linux-kernel@vger.kernel.org, criu@lists.linux.dev, Dave Hansen , x86@kernel.org, Andrei Vagin , Alexander Mikhalitsyn , "H. Peter Anvin" Content-Type: text/plain; charset="UTF-8" Extend sigframe_fpu_portability to include an insufficient xstate_size check (test_insufficient_xstate_size). Verify that the kernel correctly rejects signal frames where the xstate_size is too small for the enabled features in the xfeatures mask. Reviewed-by: Alexander Mikhalitsyn Signed-off-by: Andrei Vagin --- .../selftests/x86/sigframe_fpu_portability.c | 79 +++++++++++++++++-- 1 file changed, 73 insertions(+), 6 deletions(-) diff --git a/tools/testing/selftests/x86/sigframe_fpu_portability.c b/tools/testing/selftests/x86/sigframe_fpu_portability.c index 169548892f92..59d5c6049892 100644 --- a/tools/testing/selftests/x86/sigframe_fpu_portability.c +++ b/tools/testing/selftests/x86/sigframe_fpu_portability.c @@ -12,19 +12,24 @@ #include #include #include +#include #include "helpers.h" #include "xstate.h" /* - * This test verifies the FPU portability of the signal frame. - * It verifies that the kernel correctly restores the xstate context even - * if the frame size has been manually reduced (shrunk), as long as the - * FP_XSTATE_MAGIC2 marker is correctly placed. + * This test verifies the FPU portability and consistency of the signal frame. + * + * - test_shrunk_xstate_size: + * Verifies that the kernel restores state from a frame with xstate_size + * shrunk to only include active features. + * + * - test_insufficient_xstate_size: + * Verifies that the kernel rejects a frame if xstate_size is too small for + * the features enabled in xfeatures. */ #define SIGFRAME_XSTATE_HDR_OFFSET 512 - #define XSTATE_SSE_ONLY_SIZE (SIGFRAME_XSTATE_HDR_OFFSET + XSAVE_HDR_SIZE) #define XFEATURE_MASK_FPSSE ((1 << XFEATURE_FP) | (1 << XFEATURE_SSE)) @@ -148,15 +153,77 @@ static void test_shrunk_xstate_size(void) clearhandler(SIGUSR1); } +static sigjmp_buf segv_jmpbuf; + +static void handle_segv(int sig, siginfo_t *si, void *ucp) +{ + siglongjmp(segv_jmpbuf, 1); +} + +static void handle_insufficient_xstate_size(int sig, siginfo_t *si, void *ucp) +{ + ucontext_t *uc = ucp; + void *fp = uc->uc_mcontext.fpregs; + struct _fpx_sw_bytes *sw; + + if (!fp) { + sig_print("fpregs is NULL\n"); + return; + } + + sw = get_fpx_sw_bytes(fp); + if (sw->magic1 != FP_XSTATE_MAGIC1) { + sig_print("magic1 is not valid\n"); + return; + } + + /* The origin frame contains an AVX state. */ + sw->xstate_size = XSTATE_SSE_ONLY_SIZE; + + *(uint32_t *)(fp + sw->xstate_size) = FP_XSTATE_MAGIC2; +} + +static void test_insufficient_xstate_size(void) +{ + uint64_t v[4] = {0, 0, 0, 0}; + + sig_err_buf[0] = 0; + sethandler(SIGUSR1, handle_insufficient_xstate_size, 0); + sethandler(SIGSEGV, handle_segv, 0); + + v[0] = 0x1111111111111111ULL; + v[1] = 0x2222222222222222ULL; + v[2] = 0x3333333333333333ULL; + v[3] = 0x4444444444444444ULL; + write_ymm0(v); + + if (sigsetjmp(segv_jmpbuf, 1) == 0) { + raise(SIGUSR1); + sig_print("Inconsistent size was NOT rejected\n"); + } + + clearhandler(SIGUSR1); + clearhandler(SIGSEGV); + + if (sig_err_buf[0]) + ksft_test_result_fail("%s\n", sig_err_buf); + else + ksft_test_result_pass("Inconsistent size correctly rejected\n"); + + clearhandler(SIGUSR1); + clearhandler(SIGSEGV); +} int main(void) { ksft_print_header(); - ksft_set_plan(1); + ksft_set_plan(2); check_avx_support(); test_shrunk_xstate_size(); + test_insufficient_xstate_size(); + ksft_finished(); return 0; } -- 2.55.0.691.gc56d675ccc-goog