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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> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260512101305.139509-1-lihongfu@kylinos.cn> X-Rspamd-Server: rspam03 X-Rspamd-Queue-Id: CB9C740019 X-Stat-Signature: nf57ow9fyyhumwkxwjqn7xhg5d4e14eu X-Rspam-User: X-HE-Tag: 1778594803-346559 X-HE-Meta: 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 dKrkF2BA PlfwWZFD229vuq2NJCOKVnlYsSr24Am9ZeTHiRgCNRiVTty0+ELq7oG8px7fo6cIfVQ0bXKwUM2+bWPKIDWgQzj0+whGCqUI2sv+St0YpZf8SosUHpHYf2SbuJ/v26LNrFxDHFae4XUpYkcvYdSo1nKl16K+fWot1uNFqSWtNPLsNZgcts45BnOYjD7BbZ3RwQlBAlKRcBXeezhvgeQv7Za183UdTLKV93oucI5uymORbkWxa/NeiBjpphW805vg8RgW4cvegQ/6v2Bc6yjy+3QOQuImaBJCWdKZprphqtG2hKdZQVvsF1Z9SBi9WbM2hdnij Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: 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 >