Re: [PATCH 3/5] selftests/liveupdate: Test session and file limit removal

[Pratyush Yadav <pratyush@kernel.org>]

On Tue, Apr 14 2026, Pasha Tatashin wrote:

> With the removal of static limits on the number of sessions and files per
> session, the orchestrator now uses dynamic allocation.
>
> Add new test cases to verify that the system can handle a large number of
> sessions and files. These tests ensure that the dynamic block allocation
> and reuse logic for session metadata and outgoing files work correctly
> beyond the previous static limits.
>
> Signed-off-by: Pasha Tatashin <pasha.tatashin@soleen.com>
> ---
>  .../testing/selftests/liveupdate/liveupdate.c | 99 +++++++++++++++++++
>  1 file changed, 99 insertions(+)
>
> diff --git a/tools/testing/selftests/liveupdate/liveupdate.c b/tools/testing/selftests/liveupdate/liveupdate.c
> index 37c808fbe1e9..0eaf97b19267 100644
> --- a/tools/testing/selftests/liveupdate/liveupdate.c
> +++ b/tools/testing/selftests/liveupdate/liveupdate.c
> @@ -22,6 +22,7 @@
>  #include <fcntl.h>
>  #include <string.h>
>  #include <sys/ioctl.h>
> +#include <sys/resource.h>
>  #include <unistd.h>
>  
>  #include <linux/liveupdate.h>
> @@ -386,4 +387,102 @@ TEST_F(liveupdate_device, prevent_double_preservation)
>  	ASSERT_EQ(close(session_fd2), 0);
>  }
>  
> +static void ensure_nofile_limit(struct __test_metadata *_metadata,
> +				long min_limit)
> +{
> +	struct rlimit hl;
> +
> +	if (getrlimit(RLIMIT_NOFILE, &hl) < 0)
> +		ksft_exit_fail_msg("getrlimit failed: %s\n", strerror(errno));
> +
> +	if (hl.rlim_cur >= min_limit)
> +		return;
> +
> +	hl.rlim_cur = min_limit;
> +	if (hl.rlim_cur > hl.rlim_max)
> +		hl.rlim_max = hl.rlim_cur;
> +
> +	if (setrlimit(RLIMIT_NOFILE, &hl) < 0) {
> +		if (errno == EPERM) {
> +			SKIP(return, "Insufficient privileges to set RLIMIT_NOFILE to %ld",
> +			     hl.rlim_cur);
> +		}
> +		ksft_exit_fail_msg("setrlimit to %ld failed: %s\n",
> +				   hl.rlim_cur, strerror(errno));
> +	}
> +}
> +
> +/*
> + * Test Case: Manage Many Sessions
> + *
> + * Verifies that a large number of sessions can be created and then
> + * destroyed during normal system operation. This specifically tests the
> + * dynamic block allocation and reuse logic for session metadata management
> + * without preserving any files.
> + */
> +TEST_F(liveupdate_device, preserve_many_sessions)
> +{
> +#define MANY_SESSIONS 2000
> +	int session_fds[MANY_SESSIONS];
> +	int i;
> +
> +	self->fd1 = open(LIVEUPDATE_DEV, O_RDWR);
> +	if (self->fd1 < 0 && errno == ENOENT)
> +		SKIP(return, "%s does not exist", LIVEUPDATE_DEV);
> +	ASSERT_GE(self->fd1, 0);
> +
> +	ensure_nofile_limit(_metadata, MANY_SESSIONS + 10);
> +	if (_metadata->exit_code == KSFT_SKIP)
> +		return;

Nit: This is strange. Why not just return errno in ensure_nofile_limit()
and handle the skipping here? Same below.

LGTM otherwise.

> +
> +	for (i = 0; i < MANY_SESSIONS; i++) {
> +		char name[64];
> +
> +		snprintf(name, sizeof(name), "many-session-%d", i);
> +		session_fds[i] = create_session(self->fd1, name);
> +		ASSERT_GE(session_fds[i], 0);
> +	}
> +
> +	for (i = 0; i < MANY_SESSIONS; i++)
> +		ASSERT_EQ(close(session_fds[i]), 0);
> +}
> +
> +/*
> + * Test Case: Preserve Many Files
> + *
> + * Verifies that a large number of files can be preserved in a single session
> + * and then destroyed during normal system operation. This tests the dynamic
> + * block allocation and management for outgoing files.
> + */
> +TEST_F(liveupdate_device, preserve_many_files)
> +{
> +#define MANY_FILES 500
> +	int mem_fds[MANY_FILES];
> +	int session_fd;
> +	int i;
> +
> +	self->fd1 = open(LIVEUPDATE_DEV, O_RDWR);
> +	if (self->fd1 < 0 && errno == ENOENT)
> +		SKIP(return, "%s does not exist", LIVEUPDATE_DEV);
> +	ASSERT_GE(self->fd1, 0);
> +
> +	session_fd = create_session(self->fd1, "many-files-test");
> +	ASSERT_GE(session_fd, 0);
> +
> +	ensure_nofile_limit(_metadata, MANY_FILES + 10);
> +	if (_metadata->exit_code == KSFT_SKIP)
> +		return;
> +
> +	for (i = 0; i < MANY_FILES; i++) {
> +		mem_fds[i] = memfd_create("test-memfd", 0);
> +		ASSERT_GE(mem_fds[i], 0);
> +		ASSERT_EQ(preserve_fd(session_fd, mem_fds[i], i), 0);
> +	}
> +
> +	for (i = 0; i < MANY_FILES; i++)
> +		ASSERT_EQ(close(mem_fds[i]), 0);
> +
> +	ASSERT_EQ(close(session_fd), 0);
> +}
> +
>  TEST_HARNESS_MAIN

-- 
Regards,
Pratyush Yadav