From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 CA9963A48C8; Tue, 12 May 2026 14:06:42 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1778594802; cv=none; b=iwY2RXXu2P+4niyHdDRnjYUS8rTEJRzBco/2dS2EQVn+ewWGojGabBNzQajMXFhJzLS7eMt+nbQEcu0LRitK6sntJGHl7Y7NOs0zzNbVg8+chE1fKRWA8EIivY1xU+p310SK7ye1lp9JPtux8YixT//adQwx8n2upRfS+QB1iks= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1778594802; c=relaxed/simple; bh=l8rlIftvUwZSA3nVW/yOkWdGvGYk/uXyMrRJvJWFUmg=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=rEr1Vtb1yZvVTvg3hCaD/W9/XsQGNzpQdypVPgeMp57DzO1ybo3/N+uwfUnBAES6asgILmR0Dr/1KKpN2RG6iF+b86OHBAKC1RuFgunP0dFlX1kLd3YnpljvB5jObcGvrWk3C5vuDiw7v8OtOf/A8qnwSex73eCfxGhX31Z/05A= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=VMwv/PYL; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="VMwv/PYL" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 64388C2BCF5; Tue, 12 May 2026 14:06:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1778594802; bh=l8rlIftvUwZSA3nVW/yOkWdGvGYk/uXyMrRJvJWFUmg=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=VMwv/PYLaQ69DlNxjWQ2j43T1AFY79ij4iokB7EeOKbyrAWlwfRbBkMabIl17U6uL XSXRDqVBrTa9CHG5VeHjNo5Y9U4cC7eSw5/z8TYlfjSwpakekcUlQnKEKUsL3/XBuL XsK2Lr5UzPMQ5ZQNxwhPq51f/NxNcp6XcDP6iz6JS1qTCZD25Jx257dT1OWmnRcJBL JcZTbWbhR1erUZ1cmbILgtIYEXbHjARiWXdprmsXJflT8pn4XdZJzmmYGFkviv+WAK HB/ATVzZl/YdXZ3LRXUiIMs2Vm7GVsl81DI5nAohxGZd2n5kxJa6h4RUjLcEM+Yhif y89q5NsyUreYA== Date: Tue, 12 May 2026 15:06:37 +0100 From: Lorenzo Stoakes To: Hongfu Li Cc: jgg@ziepe.ca, leon@kernel.org, akpm@linux-foundation.org, david@kernel.org, vbabka@kernel.org, rppt@kernel.org, surenb@google.com, mhocko@suse.com, shuah@kernel.org, linux-mm@kvack.org, linux-kselftest@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] selftests/mm: Fix mmap() return value check in run_migration_benchmark Message-ID: References: <20260512101305.139509-1-lihongfu@kylinos.cn> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260512101305.139509-1-lihongfu@kylinos.cn> On Tue, May 12, 2026 at 06:13:05PM +0800, 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 LGTM, so: Reviewed-by: Lorenzo Stoakes > --- > 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 */ > -- > 2.25.1 >