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b=KsR1dFWJc6c/kpJkTR1cHeJ1sTGbTJQ5h0GXlUdBGSWEwmar8ygPoi5v4llJt9lUD 3mzxJSLkNSHX514tvqlOgnQp32jd4+WROa0gAqqwmFiBqh8v7A4+l5EdZlJonCHeLu BKOTjPJHJgzuYCeCTH4wRbSa2Qhdie0u7sqjzuEkO2+ikyOt+b9XfSNcNzO8BBzZHy TDfhgzxzwrttCFsoESxU1qHo3FStNpkD/pTnVjLpwMzriYglTdZ9GDS7ZzZ5u+91S5 TsqI+XZSiasjFKZ++KL7StsGQzZzOKRILfFvcJ9Ku90SEdBDFzwPHuXCWsUIsjbB0g uW7teinKgSxEg== Date: Wed, 18 Mar 2026 09:31:00 +0200 From: Mike Rapoport To: Pratyush Yadav Cc: Pasha Tatashin , Shuah Khan , Andrew Morton , linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org, linux-mm@kvack.org Subject: Re: [PATCH 3/6] selftests/liveupdate: add test for memfd content preservation Message-ID: References: <20260309115441.266805-1-pratyush@kernel.org> <20260309115441.266805-4-pratyush@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260309115441.266805-4-pratyush@kernel.org> X-Rspamd-Server: rspam01 X-Rspamd-Queue-Id: B9518140003 X-Stat-Signature: 6ymxmyyr85pn1ecps3hmz5jtjpync1ut X-Rspam-User: X-HE-Tag: 1773819066-853834 X-HE-Meta: U2FsdGVkX1/mhKbyjXDqkz03hBGG0ojYfSUAZf45N0vL4kkYxfzpi9RtVM9x1vq0+BQMYystKLLdtoYV1jdhHQ9G+jc4+nhfXAhIKJ9BwanEa3XMJl4TIFMsaMJVoXPSQrpWLOXx5CPBhSJsujq85v+WCboy41+VDETS1SQXVUpGbIYHqDGVCdXb038MbiFTLPhz79U5296UncjcBVcrGndKmK3Poe7ZXNNEBwIJfoEhZ5fgtl2koZszFXYYdljUxfgvHmCYyvdb4i06IkdDjGPJOHCl3bboH9Oe1Yp6rFXGvbhApIbOoH/ccir8NUNe2YwafKKKfK2KUwHoUMojqyCr94uJEB2JvVOCUiJFTTKFNspfDH46y2/FjebGOQ6YddwfkpHBXFAeUnVcWSrkSpbIO0DtEg1sOyhKEC9zoy3SXn6eWVy/2K7COLV4xG0CuyJ2+hoQGgBLbD82BaNKComSrpsHQTM126TU1V873YF/uOfwtec6nFXtyYaqDz+zW5nbYq2AUkNUv7m627a32CVvHDsr7cxWpvYKzHJc2o+5q0GK6vLGsnNB0pU89c2iCGcUxZ7Wtf70k9A+VrC4NgL9heVF2rmgkZTFQKgdaSXrsDdW9NydK3RqRccBNFxr47AG9CzKGVevajhkhzUhpJypzbC0KA5yxpck/6W9ITeQcqyg4qirSkLCbW9zGjSsAUYTG4sB7QEIyd9D6zjrxbBIHYKk5/hQu/xo4QjPkcOblMX8fwobCa7KV8EFyX5PcyLw0uLjWv6EtycaKzFxS3WUC1b8yuRnvGnPoi9pxPh0PtMbetsGjr6c0855FlQ9IzwMPh51k0IP1R5837v3JZHM88P7AY47STXN/pDdSFFvzwJGPrH+6OhTZ3kWOYYsyPYrMcbEAdT9PFhLgKmvgDVm3tf4wU0ZJNcsf3nfUgg5RHbAaXNm1TNSGcAbjAcaJQfmhwoLvNDg2tUgPCb tE5r4Bf7 VdUyWbdlL0Rua945AjIIjw+HM7rYrlTvNgDYHDiwB2yH+e2EQ+ElfKq1y09b4G/vGsFy7tXPZpMsth19+TViiB7LpVtU6I+6Cl0nSYD4+XtMxuiks8IAj81/od4r162IMJ0KzoE6L9TDm8sWzJrBjrziWc5a1EkftuD8E7jBAOE/rthe0IYSUw4CrhSnpxmScgXHQvY49lzS4IZg6FuwV2PZ3Aa0FP3gNNLrG3bcS5WG+XJqvvqztU3OaUColfdoRIgh6dk8USl7XesswD7gQwU164AnZmv/UfAXiBf8CFkHQ490= Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Mon, Mar 09, 2026 at 11:54:36AM +0000, Pratyush Yadav wrote: > From: "Pratyush Yadav (Google)" > > Add a selftest that makes sure the contents of a memfd are correctly > preserved across a live update. In stage 1, create a memfd and fill it > with random data, and preserve it. Save the random data to the file > system. This will be used by stage 2 to verify the contents are correct. There's a small caveat here, as some CI systems put selftests in tmpfs, so creating a file there won't really help. I think there should be a skip if the test runs of tmpfs. > In stage 2, retrieve the memfd and compare its contents with the > contents saved on the file system. > > Signed-off-by: Pratyush Yadav > Signed-off-by: Pratyush Yadav (Google) > --- > tools/testing/selftests/liveupdate/Makefile | 1 + > .../testing/selftests/liveupdate/luo_memfd.c | 61 +++++++++++++++++++ > 2 files changed, 62 insertions(+) > > diff --git a/tools/testing/selftests/liveupdate/Makefile b/tools/testing/selftests/liveupdate/Makefile > index 051daae55eec..8e2eb6500c07 100644 > --- a/tools/testing/selftests/liveupdate/Makefile > +++ b/tools/testing/selftests/liveupdate/Makefile > @@ -13,6 +13,7 @@ TEST_FILES += do_kexec.sh > include ../lib.mk > > CFLAGS += $(KHDR_INCLUDES) > +CFLAGS += -I$(top_srcdir)/tools/include > CFLAGS += -Wall -O2 -Wno-unused-function > CFLAGS += -MD > > diff --git a/tools/testing/selftests/liveupdate/luo_memfd.c b/tools/testing/selftests/liveupdate/luo_memfd.c > index b779eee18387..52b5f6b16e19 100644 > --- a/tools/testing/selftests/liveupdate/luo_memfd.c > +++ b/tools/testing/selftests/liveupdate/luo_memfd.c > @@ -3,6 +3,9 @@ > /* > * Copyright (c) 2026, Google LLC. > * Pratyush Yadav (Google) > + * > + * Copyright (C) 2025 Amazon.com Inc. or its affiliates. > + * Pratyush Yadav > */ > > /* > @@ -11,11 +14,14 @@ > > #include > #include > +#include > #include > #include > +#include > #include > > #include > +#include > > #include "../kselftest.h" > #include "../kselftest_harness.h" > @@ -25,9 +31,64 @@ > #define STATE_SESSION_NAME "luo-state" > #define STATE_MEMFD_TOKEN 1 > > +#define MEMFD_DATA_SESSION_NAME "memfd_data_session" > +#define MEMFD_DATA_TOKEN 1 > +#define MEMFD_DATA_BUFFER_SIZE SZ_1M > +#define RANDOM_DATA_FILE "luo_random_data.bin" Reads to me like a random file containing data :) Something like FILESYSTEM_DATA_COPY would better express the meaning. > + > #define LIVEUPDATE_DEV "/dev/liveupdate" > static int luo_fd = -1, stage; > > +/* > + * Test that a memfd with its data is preserved across live update. > + */ > +TEST(memfd_data) > +{ > + int fd, session; > + char *buffer; > + struct liveupdate_session_preserve_fd preserve_arg = { .size = sizeof(preserve_arg) }; > + struct liveupdate_session_retrieve_fd retrieve_arg = { .size = sizeof(retrieve_arg) }; > + > + buffer = malloc(MEMFD_DATA_BUFFER_SIZE); > + ASSERT_NE(buffer, NULL); > + > + switch (stage) { > + case 1: Can we please move each state to a helper function? > + session = luo_create_session(luo_fd, MEMFD_DATA_SESSION_NAME); > + ASSERT_GE(session, 0); > + > + fd = create_random_memfd("memfd_data", buffer, MEMFD_DATA_BUFFER_SIZE); > + ASSERT_GE(fd, 0); > + > + ASSERT_EQ(save_test_data(RANDOM_DATA_FILE, buffer, MEMFD_DATA_BUFFER_SIZE), 0); > + > + preserve_arg.fd = fd; > + preserve_arg.token = MEMFD_DATA_TOKEN; > + ASSERT_GE(ioctl(session, LIVEUPDATE_SESSION_PRESERVE_FD, &preserve_arg), 0); > + > + daemonize_and_wait(); > + break; > + case 2: > + session = luo_retrieve_session(luo_fd, MEMFD_DATA_SESSION_NAME); > + ASSERT_GE(session, 0); > + > + ASSERT_EQ(load_test_data(RANDOM_DATA_FILE, buffer, MEMFD_DATA_BUFFER_SIZE), 0); > + > + retrieve_arg.token = MEMFD_DATA_TOKEN; > + ASSERT_GE(ioctl(session, LIVEUPDATE_SESSION_RETRIEVE_FD, &retrieve_arg), 0); > + fd = retrieve_arg.fd; > + ASSERT_GE(fd, 0); > + > + ASSERT_EQ(verify_fd_content(fd, buffer, MEMFD_DATA_BUFFER_SIZE), 0); > + > + ASSERT_EQ(luo_session_finish(session), 0); > + break; > + default: > + TH_LOG("Unknown stage %d\n", stage); > + ASSERT_FALSE(true); > + } > +} > + > int main(int argc, char *argv[]) > { > int session, expected_stage = 0; > -- > 2.53.0.473.g4a7958ca14-goog > -- Sincerely yours, Mike.