On Mon, Mar 09, 2026 at 11:54:36AM +0000, Pratyush Yadav wrote: > From: "Pratyush Yadav (Google)" <[email protected]> > > 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 <[email protected]> > Signed-off-by: Pratyush Yadav (Google) <[email protected]> > --- > 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) <[email protected]> > + * > + * Copyright (C) 2025 Amazon.com Inc. or its affiliates. > + * Pratyush Yadav <[email protected]> > */ > > /* > @@ -11,11 +14,14 @@ > > #include <errno.h> > #include <fcntl.h> > +#include <stdlib.h> > #include <string.h> > #include <sys/ioctl.h> > +#include <sys/mman.h> > #include <unistd.h> > > #include <linux/liveupdate.h> > +#include <linux/sizes.h> > > #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.
