[PATCH v1 7/7] selftests: liveupdate: Add test coverage for tmpfs preservation and retrieval
Pasha Tatashin
pasha.tatashin at soleen.com
Thu Oct 15 02:38:16 PDT 2026
From: David Matlack <dmatlack at google.com>
Extend the multi-session LUO test to verify preserving a path-backed
tmpfs file and retrieving its contents to a newly created empty tmpfs
file post-kexec using struct liveupdate_memfd_retrieve_arg with
LIVEUPDATE_SESSION_RETRIEVE_FD. Also verify that retrieve argument
validation errors (passing an argument when retrieving a memfd, omitting
the argument when retrieving a tmpfs file, or passing a read-only target
tmpfs FD) are retryable and allow a subsequent valid retrieve call to
succeed.
Signed-off-by: David Matlack <dmatlack at google.com>
Co-developed-by: Pasha Tatashin <pasha.tatashin at soleen.com>
Signed-off-by: Pasha Tatashin <pasha.tatashin at soleen.com>
---
.../liveupdate/lib/include/libliveupdate.h | 2 +
.../selftests/liveupdate/lib/lu_utils.c | 44 +++++++
.../selftests/liveupdate/luo_multi_session.c | 110 ++++++++++++++++--
3 files changed, 147 insertions(+), 9 deletions(-)
diff --git a/tools/testing/selftests/liveupdate/lib/include/libliveupdate.h b/tools/testing/selftests/liveupdate/lib/include/libliveupdate.h
index 8a38268e89dee..dc5c01408462d 100644
--- a/tools/testing/selftests/liveupdate/lib/include/libliveupdate.h
+++ b/tools/testing/selftests/liveupdate/lib/include/libliveupdate.h
@@ -37,6 +37,8 @@ int luo_session_retrieve_fd_arg(int session_fd, __u64 token, __u64 user_arg);
int create_and_preserve_memfd(int session_fd, int token, const char *data);
int restore_and_verify_memfd(int session_fd, int token, const char *expected_data);
+int restore_and_verify_tmpfs(int session_fd, int token, int fd,
+ const char *expected_data);
void create_state_file(int luo_fd, const char *session_name, int token,
int next_stage);
diff --git a/tools/testing/selftests/liveupdate/lib/lu_utils.c b/tools/testing/selftests/liveupdate/lib/lu_utils.c
index 5c6f8bf80b297..1b1a556287d3a 100644
--- a/tools/testing/selftests/liveupdate/lib/lu_utils.c
+++ b/tools/testing/selftests/liveupdate/lib/lu_utils.c
@@ -347,3 +347,47 @@ int luo_test(int argc, char *argv[],
return 0;
}
+
+int restore_and_verify_tmpfs(int session_fd, int token, int fd,
+ const char *expected_data)
+{
+ struct liveupdate_memfd_retrieve_arg rarg = {
+ .size = sizeof(rarg),
+ .fd = fd,
+ };
+ long page_size = getpagesize();
+ void *map = MAP_FAILED;
+ struct stat st;
+ int ret_fd;
+
+ ret_fd = luo_session_retrieve_fd_arg(session_fd, token,
+ (unsigned long)&rarg);
+ if (ret_fd < 0) {
+ ksft_print_msg("luo_session_retrieve_fd_arg failed: %d\n",
+ ret_fd);
+ return ret_fd;
+ }
+ close(ret_fd);
+
+ if (fstat(fd, &st) < 0)
+ return -errno;
+ if (st.st_size != page_size) {
+ ksft_print_msg("Size mismatch! Expected %ld, Got %lld\n",
+ page_size, (long long)st.st_size);
+ return -EINVAL;
+ }
+
+ map = mmap(NULL, page_size, PROT_READ, MAP_SHARED, fd, 0);
+ if (map == MAP_FAILED)
+ return -errno;
+
+ if (expected_data && strcmp(expected_data, map) != 0) {
+ ksft_print_msg("Data mismatch! Expected '%s', Got '%s'\n",
+ expected_data, (char *)map);
+ munmap(map, page_size);
+ return -EINVAL;
+ }
+
+ munmap(map, page_size);
+ return 0;
+}
diff --git a/tools/testing/selftests/liveupdate/luo_multi_session.c b/tools/testing/selftests/liveupdate/luo_multi_session.c
index aac24a5f5ce3c..46889676d9f52 100644
--- a/tools/testing/selftests/liveupdate/luo_multi_session.c
+++ b/tools/testing/selftests/liveupdate/luo_multi_session.c
@@ -9,7 +9,15 @@
* files.
*/
+#include <errno.h>
+#include <fcntl.h>
+#include <sys/mman.h>
+#include <sys/mount.h>
+#include <sys/stat.h>
+#include <unistd.h>
+
#include <libliveupdate.h>
+#include <linux/liveupdate.h>
#define SESSION_EMPTY_1 "multi-test-empty-1"
#define SESSION_EMPTY_2 "multi-test-empty-2"
@@ -23,6 +31,7 @@
#define MFD1_DATA "Data for session files 1"
#define MFD2_DATA "First file for session files 2"
#define MFD3_DATA "Second file for session files 2"
+#define MFD3_POS 42
#define STATE_SESSION_NAME "kexec_multi_state"
#define STATE_MEMFD_TOKEN 998
@@ -31,6 +40,8 @@
static void run_stage_1(int luo_fd)
{
int s_empty1_fd, s_empty2_fd, s_files1_fd, s_files2_fd;
+ int tmpfs_fd;
+ void *map;
ksft_print_msg("[STAGE 1] Starting pre-kexec setup for multi-session test...\n");
@@ -53,25 +64,50 @@ static void run_stage_1(int luo_fd)
s_files1_fd = luo_create_session(luo_fd, SESSION_FILES_1);
if (s_files1_fd < 0)
fail_exit("luo_create_session for '%s'", SESSION_FILES_1);
+ ksft_print_msg(" -> Preserving memfd (token %#x, content: \"%s\")\n",
+ MFD1_TOKEN, MFD1_DATA);
if (create_and_preserve_memfd(s_files1_fd, MFD1_TOKEN, MFD1_DATA) < 0) {
fail_exit("create_and_preserve_memfd for token %#x",
MFD1_TOKEN);
}
- ksft_print_msg("[STAGE 1] Creating session '%s' with two memfds...\n",
+ ksft_print_msg("[STAGE 1] Creating session '%s' with memfd and tmpfs file...\n",
SESSION_FILES_2);
s_files2_fd = luo_create_session(luo_fd, SESSION_FILES_2);
if (s_files2_fd < 0)
fail_exit("luo_create_session for '%s'", SESSION_FILES_2);
+ ksft_print_msg(" -> Preserving memfd (token %#x, content: \"%s\")\n",
+ MFD2_TOKEN, MFD2_DATA);
if (create_and_preserve_memfd(s_files2_fd, MFD2_TOKEN, MFD2_DATA) < 0) {
fail_exit("create_and_preserve_memfd for token %#x",
MFD2_TOKEN);
}
- if (create_and_preserve_memfd(s_files2_fd, MFD3_TOKEN, MFD3_DATA) < 0) {
- fail_exit("create_and_preserve_memfd for token %#x",
- MFD3_TOKEN);
- }
+
+ ksft_print_msg(" -> Populating tmpfs file at /mnt/mfd3...\n");
+ if (mkdir("/mnt", 0777) < 0 && errno != EEXIST)
+ fail_exit("mkdir /mnt");
+ if (mount("tmpfs", "/mnt", "tmpfs", 0, NULL) < 0)
+ fail_exit("mount tmpfs");
+ tmpfs_fd = open("/mnt/mfd3", O_CREAT | O_RDWR, 0666);
+ if (tmpfs_fd < 0)
+ fail_exit("failed to open tmpfs_fd");
+ ksft_print_msg(" -> Preserving generic tmpfs file (token %#x, content: \"%s\")\n",
+ MFD3_TOKEN, MFD3_DATA);
+ if (ftruncate(tmpfs_fd, getpagesize()) < 0)
+ fail_exit("ftruncate tmpfs_fd");
+ map = mmap(NULL, getpagesize(), PROT_WRITE, MAP_SHARED, tmpfs_fd, 0);
+ if (map == MAP_FAILED)
+ fail_exit("mmap tmpfs_fd");
+ strcpy(map, MFD3_DATA);
+ munmap(map, getpagesize());
+ if (lseek(tmpfs_fd, MFD3_POS, SEEK_SET) != MFD3_POS)
+ fail_exit("lseek tmpfs_fd");
+
+ if (luo_session_preserve_fd(s_files2_fd, tmpfs_fd, MFD3_TOKEN) < 0)
+ fail_exit("preserve tmpfs fd");
+
+ close(tmpfs_fd);
close(luo_fd);
daemonize_and_wait();
@@ -81,7 +117,10 @@ static void run_stage_1(int luo_fd)
static void run_stage_2(int luo_fd, int state_session_fd)
{
int s_empty1_fd, s_empty2_fd, s_files1_fd, s_files2_fd;
- int mfd1, mfd2, mfd3, stage;
+ struct liveupdate_memfd_retrieve_arg rarg = {
+ .size = sizeof(rarg),
+ };
+ int mfd1, mfd2, mfd3, ro_fd, ret, stage;
ksft_print_msg("[STAGE 2] Starting post-kexec verification...\n");
@@ -110,6 +149,8 @@ static void run_stage_2(int luo_fd, int state_session_fd)
ksft_print_msg("[STAGE 2] Verifying contents of session '%s'...\n",
SESSION_FILES_1);
+ ksft_print_msg(" -> Retrieving memfd (token %#x) from session...\n",
+ MFD1_TOKEN);
mfd1 = restore_and_verify_memfd(s_files1_fd, MFD1_TOKEN, MFD1_DATA);
if (mfd1 < 0)
fail_exit("restore_and_verify_memfd for token %#x", MFD1_TOKEN);
@@ -118,14 +159,65 @@ static void run_stage_2(int luo_fd, int state_session_fd)
ksft_print_msg("[STAGE 2] Verifying contents of session '%s'...\n",
SESSION_FILES_2);
+ ksft_print_msg(" -> Creating empty tmpfs file at /mnt/mfd3...\n");
+ if (mkdir("/mnt", 0777) < 0 && errno != EEXIST)
+ fail_exit("mkdir /mnt");
+ if (mount("tmpfs", "/mnt", "tmpfs", 0, NULL) < 0)
+ fail_exit("mount tmpfs");
+ mfd3 = open("/mnt/mfd3", O_CREAT | O_RDWR, 0666);
+ if (mfd3 < 0)
+ fail_exit("open tmpfs file");
+ ro_fd = open("/mnt/mfd3", O_RDONLY);
+ if (ro_fd < 0)
+ fail_exit("open read-only tmpfs file");
+
+ ksft_print_msg(" -> Verifying retryable retrieve errors for memfd and tmpfs...\n");
+ rarg.fd = mfd3;
+ ret = luo_session_retrieve_fd_arg(s_files2_fd, MFD2_TOKEN,
+ (uintptr_t)&rarg);
+ if (ret != -EINVAL)
+ fail_exit("expected -EINVAL when passing arg to memfd retrieve, got %d",
+ ret);
+
+ ksft_print_msg(" -> Retrieving memfd (token %#x) from session...\n",
+ MFD2_TOKEN);
mfd2 = restore_and_verify_memfd(s_files2_fd, MFD2_TOKEN, MFD2_DATA);
if (mfd2 < 0)
fail_exit("restore_and_verify_memfd for token %#x", MFD2_TOKEN);
close(mfd2);
- mfd3 = restore_and_verify_memfd(s_files2_fd, MFD3_TOKEN, MFD3_DATA);
- if (mfd3 < 0)
- fail_exit("restore_and_verify_memfd for token %#x", MFD3_TOKEN);
+ ret = luo_session_retrieve_fd(s_files2_fd, MFD3_TOKEN);
+ if (ret != -EINVAL)
+ fail_exit("expected -EINVAL when retrieving tmpfs without arg, got %d",
+ ret);
+
+ rarg.fd = ro_fd;
+ ret = luo_session_retrieve_fd_arg(s_files2_fd, MFD3_TOKEN,
+ (uintptr_t)&rarg);
+ if (ret != -EACCES)
+ fail_exit("expected -EACCES when retrieving tmpfs into read-only fd, got %d",
+ ret);
+ close(ro_fd);
+
+ if (ftruncate(mfd3, 1) < 0)
+ fail_exit("ftruncate non-empty tmpfs file");
+ rarg.fd = mfd3;
+ ret = luo_session_retrieve_fd_arg(s_files2_fd, MFD3_TOKEN,
+ (uintptr_t)&rarg);
+ if (ret != -EBUSY)
+ fail_exit("expected -EBUSY when retrieving tmpfs into non-empty fd, got %d",
+ ret);
+ if (ftruncate(mfd3, 0) < 0)
+ fail_exit("ftruncate empty tmpfs file");
+
+ ksft_print_msg(" -> Retrieving tmpfs file (token %#x) from session...\n",
+ MFD3_TOKEN);
+ if (restore_and_verify_tmpfs(s_files2_fd, MFD3_TOKEN, mfd3,
+ MFD3_DATA) < 0)
+ fail_exit("restore_and_verify_tmpfs for token %#x",
+ MFD3_TOKEN);
+ if (lseek(mfd3, 0, SEEK_CUR) != MFD3_POS)
+ fail_exit("expected f_pos %d on restored tmpfs file", MFD3_POS);
close(mfd3);
ksft_print_msg("[STAGE 2] Test data verified successfully.\n");
--
2.56.0.385.gd3acb90ef8-goog
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