From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 4D1544BCAC1; Tue, 12 May 2026 11:13:24 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=217.140.110.172 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1778584407; cv=none; b=gZvbsWrvgGYtE5mUXH0M+X7smJr2fknqLW7xEY6sOCmJe8reons9tzapBECnyXf9ex/HKCoMG/wsHhhYmPtbOBOrIIGob53mt7ETYdu8vvUm+itdCYrUp/vm2Ct69tgwTAvexAfcd9Wq6D6zZ2/Iv1BByeGX01Zr5z6l3QUII1c= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1778584407; c=relaxed/simple; bh=rBzh25T0xairjqFtgwirNaUtmwEFujCzK8ALPjS6dRg=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=TIBn2ilnBOo7FmT3i4WjjUL9UYzLQvbtKps9steo8mgwA0DnE/T+vMgMCYPzXRnLv6dEGV5WbX6HyNmyWlMqNnMs75XYppPaXExPP2GpC6N6xjhA4Q10hnxhK67ESENAxvAd9qWIA9iAnJSqxCUW2TWjaNcv8QRsSVnUXOdVNvs= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com; spf=pass smtp.mailfrom=arm.com; dkim=pass (1024-bit key) header.d=arm.com header.i=@arm.com header.b=gV7TN+Db; arc=none smtp.client-ip=217.140.110.172 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=arm.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=arm.com header.i=@arm.com header.b="gV7TN+Db" Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 26C6C1691; Tue, 12 May 2026 04:13:18 -0700 (PDT) Received: from [10.164.148.42] (MacBook-Pro.blr.arm.com [10.164.148.42]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 1A1773F85F; Tue, 12 May 2026 04:13:18 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=arm.com; s=foss; t=1778584403; bh=rBzh25T0xairjqFtgwirNaUtmwEFujCzK8ALPjS6dRg=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=gV7TN+Dbz5tzaOrAbCMWHlB+ykfhxbyPEdM4wcjGYq+0I1X2m8RQcA7h/EnzXTodh shob5b98AgeVYcZX7fZWcMf6PGfj7nb0xTIc/7Y+kJAluCLYK6muaymcTD0KUEIcvS /vTSpdtMRdxyAQJQtmQ1brWsFwyRQPX10X+gxOYc= Message-ID: Date: Tue, 12 May 2026 16:43:15 +0530 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH] selftests/mm: Fix mmap() return value check in run_migration_benchmark To: Hongfu Li , jgg@ziepe.ca, leon@kernel.org, akpm@linux-foundation.org, david@kernel.org, ljs@kernel.org, vbabka@kernel.org, rppt@kernel.org, surenb@google.com, mhocko@suse.com, shuah@kernel.org Cc: linux-mm@kvack.org, linux-kselftest@vger.kernel.org, linux-kernel@vger.kernel.org References: <20260512101305.139509-1-lihongfu@kylinos.cn> Content-Language: en-US From: Dev Jain In-Reply-To: <20260512101305.139509-1-lihongfu@kylinos.cn> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 12/05/26 3:43 pm, Hongfu Li wrote: > mmap() returns MAP_FAILED on error, not NULL. The current check uses > !buffer->ptr, which evaluates to false when mmap() fails (since > MAP_FAILED is (void *)-1, not 0), so the error path is never taken. > > Signed-off-by: Hongfu Li > --- Reviewed-by: Dev Jain > tools/testing/selftests/mm/hmm-tests.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/tools/testing/selftests/mm/hmm-tests.c b/tools/testing/selftests/mm/hmm-tests.c > index 788689497e92..d72adba5c74e 100644 > --- a/tools/testing/selftests/mm/hmm-tests.c > +++ b/tools/testing/selftests/mm/hmm-tests.c > @@ -2688,7 +2688,7 @@ static inline int run_migration_benchmark(int fd, int use_thp, size_t buffer_siz > buffer->ptr = mmap(NULL, buffer_size, PROT_READ | PROT_WRITE, > MAP_PRIVATE | MAP_ANONYMOUS, -1, 0); > > - if (!buffer->ptr) > + if (buffer->ptr == MAP_FAILED) > return -1; > > /* Apply THP hint if requested */