From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from www262.sakura.ne.jp (www262.sakura.ne.jp [202.181.97.72]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id EEEDB58ABA for ; Fri, 1 Mar 2024 22:52:52 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=202.181.97.72 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1709333575; cv=none; b=Ywv5BUSGNVqyo74YIh86JCyzM2WwxnKGllEBJMItNsn5Zigjdj6AMnIc3quV68jU3091I9gla4gYnPolwCgQXINtQSajlEFZhuL+t549CSCuoam4hcZ75ivrx4lwo7MmALhv4k0ZJ5vzFYLlFIM+uM26b0Sik9x3FWLuYeNdUEE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1709333575; c=relaxed/simple; bh=h7u+V/a49gDC3kOpBKD2JWBdLjdDqCdnslQEF8xrLYA=; h=Message-ID:Date:MIME-Version:To:Cc:From:Subject:Content-Type; b=MLQBWzO/XKNfB/66QIbK8k4sUcdKCOP3cet7eaS0hE2mSxv1BMh0yqwD9gcPa9vKnQJe+Mv11vYvlGfyJIb1XHLxO2ZhUeRpcd6s4gpE5K1yB6qlk5lPrhZKLiL1m2fahwl/+31sbBTR4oaNtlqmUtG16qdIWpyP4jqUhpom4Ak= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=I-love.SAKURA.ne.jp; spf=pass smtp.mailfrom=I-love.SAKURA.ne.jp; arc=none smtp.client-ip=202.181.97.72 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=I-love.SAKURA.ne.jp Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=I-love.SAKURA.ne.jp Received: from fsav111.sakura.ne.jp (fsav111.sakura.ne.jp [27.133.134.238]) by www262.sakura.ne.jp (8.15.2/8.15.2) with ESMTP id 421MqM1A094475; Sat, 2 Mar 2024 07:52:22 +0900 (JST) (envelope-from penguin-kernel@I-love.SAKURA.ne.jp) Received: from www262.sakura.ne.jp (202.181.97.72) by fsav111.sakura.ne.jp (F-Secure/fsigk_smtp/550/fsav111.sakura.ne.jp); Sat, 02 Mar 2024 07:52:22 +0900 (JST) X-Virus-Status: clean(F-Secure/fsigk_smtp/550/fsav111.sakura.ne.jp) Received: from [192.168.1.6] (M106072142033.v4.enabler.ne.jp [106.72.142.33]) (authenticated bits=0) by www262.sakura.ne.jp (8.15.2/8.15.2) with ESMTPSA id 421MqMRc094468 (version=TLSv1.2 cipher=AES256-GCM-SHA384 bits=256 verify=NO); Sat, 2 Mar 2024 07:52:22 +0900 (JST) (envelope-from penguin-kernel@I-love.SAKURA.ne.jp) Message-ID: <3b7dbd88-0861-4638-b2d2-911c97a4cadf@I-love.SAKURA.ne.jp> Date: Sat, 2 Mar 2024 07:52:23 +0900 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Content-Language: en-US To: LKML , the arch/x86 maintainers Cc: Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , "H. Peter Anvin" From: Tetsuo Handa Subject: [PATCH v2] x86: disable non-instrumented version of copy_mc when KMSAN is enabled Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit dump_emit_page() caused a false-positive KMSAN warning, for memcpy_from_iter_mc() is called via iterate_bvec() by setting "struct iov_iter"->copy_mc to true. Fallback to memcpy()/copy_user_generic() when KMSAN is enabled. Reported-by: syzbot Closes: https://syzkaller.appspot.com/bug?extid=d7521c1e3841ed075a42 Signed-off-by: Tetsuo Handa Tested-by: syzbot Reviewed-by: Alexander Potapenko --- Changes in v2: Update description. arch/x86/lib/copy_mc.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff --git a/arch/x86/lib/copy_mc.c b/arch/x86/lib/copy_mc.c index 6e8b7e600def..c6a0b8dbf58d 100644 --- a/arch/x86/lib/copy_mc.c +++ b/arch/x86/lib/copy_mc.c @@ -61,9 +61,9 @@ unsigned long copy_mc_enhanced_fast_string(void *dst, const void *src, unsigned */ unsigned long __must_check copy_mc_to_kernel(void *dst, const void *src, unsigned len) { - if (copy_mc_fragile_enabled) + if (!IS_ENABLED(CONFIG_KMSAN) && copy_mc_fragile_enabled) return copy_mc_fragile(dst, src, len); - if (static_cpu_has(X86_FEATURE_ERMS)) + if (!IS_ENABLED(CONFIG_KMSAN) && static_cpu_has(X86_FEATURE_ERMS)) return copy_mc_enhanced_fast_string(dst, src, len); memcpy(dst, src, len); return 0; @@ -74,14 +74,14 @@ unsigned long __must_check copy_mc_to_user(void __user *dst, const void *src, un { unsigned long ret; - if (copy_mc_fragile_enabled) { + if (!IS_ENABLED(CONFIG_KMSAN) && copy_mc_fragile_enabled) { __uaccess_begin(); ret = copy_mc_fragile((__force void *)dst, src, len); __uaccess_end(); return ret; } - if (static_cpu_has(X86_FEATURE_ERMS)) { + if (!IS_ENABLED(CONFIG_KMSAN) && static_cpu_has(X86_FEATURE_ERMS)) { __uaccess_begin(); ret = copy_mc_enhanced_fast_string((__force void *)dst, src, len); __uaccess_end(); -- 2.34.1