On Fri, Nov 14, 2025 at 7:50 AM Mike Rapoport [off-list ref] wrote:

On Fri, Nov 07, 2025 at 04:03:04PM -0500, Pasha Tatashin wrote:

quoted

Introduce concept of "Live Update Sessions" within the LUO framework.
LUO sessions provide a mechanism to group and manage `struct file *`
instances (representing file descriptors) that need to be preserved
across a kexec-based live update.

Each session is identified by a unique name and acts as a container
for file objects whose state is critical to a userspace workload, such
as a virtual machine or a high-performance database, aiming to maintain
their functionality across a kernel transition.

This groundwork establishes the framework for preserving file-backed
state across kernel updates, with the actual file data preservation
mechanisms to be implemented in subsequent patches.

Signed-off-by: Pasha Tatashin <pasha.tatashin@soleen.com>
---
 include/linux/liveupdate/abi/luo.h |  81 ++++++
 include/uapi/linux/liveupdate.h    |   3 +
 kernel/liveupdate/Makefile         |   3 +-
 kernel/liveupdate/luo_core.c       |   9 +
 kernel/liveupdate/luo_internal.h   |  39 +++
 kernel/liveupdate/luo_session.c    | 405 +++++++++++++++++++++++++++++
 6 files changed, 539 insertions(+), 1 deletion(-)
 create mode 100644 kernel/liveupdate/luo_session.c

diff --git a/include/linux/liveupdate/abi/luo.h b/include/linux/liveupdate/abi/luo.h
index 9483a294287f..37b9fecef3f7 100644
--- a/include/linux/liveupdate/abi/luo.h
+++ b/include/linux/liveupdate/abi/luo.h

@@ -28,6 +28,11 @@
  *     / {
  *         compatible = "luo-v1";
  *         liveupdate-number = <...>;
+ *
+ *         luo-session {
+ *             compatible = "luo-session-v1";
+ *             luo-session-head = <phys_addr_of_session_head_ser>;
+ *         };
  *     };
  *
  * Main LUO Node (/):

@@ -36,11 +41,37 @@
  *     Identifies the overall LUO ABI version.
  *   - liveupdate-number: u64
  *     A counter tracking the number of successful live updates performed.
+ *
+ * Session Node (luo-session):
+ *   This node describes all preserved user-space sessions.
+ *
+ *   - compatible: "luo-session-v1"
+ *     Identifies the session ABI version.
+ *   - luo-session-head: u64
+ *     The physical address of a `struct luo_session_head_ser`. This structure is
+ *     the header for a contiguous block of memory containing an array of
+ *     `struct luo_session_ser`, one for each preserved session.
+ *
+ * Serialization Structures:
+ *   The FDT properties point to memory regions containing arrays of simple,
+ *   `__packed` structures. These structures contain the actual preserved state.
+ *
+ *   - struct luo_session_head_ser:
+ *     Header for the session array. Contains the total page count of the
+ *     preserved memory block and the number of `struct luo_session_ser`
+ *     entries that follow.
+ *
+ *   - struct luo_session_ser:
+ *     Metadata for a single session, including its name and a physical pointer
+ *     to another preserved memory block containing an array of
+ *     `struct luo_file_ser` for all files in that session.
  */

 #ifndef _LINUX_LIVEUPDATE_ABI_LUO_H
 #define _LINUX_LIVEUPDATE_ABI_LUO_H

+#include <uapi/linux/liveupdate.h>
+
 /*
  * The LUO FDT hooks all LUO state for sessions, fds, etc.
  * In the root it allso carries "liveupdate-number" 64-bit property that

@@ -51,4 +82,54 @@
 #define LUO_FDT_COMPATIBLE   "luo-v1"
 #define LUO_FDT_LIVEUPDATE_NUM       "liveupdate-number"

+/*
+ * LUO FDT session node
+ * LUO_FDT_SESSION_HEAD:  is a u64 physical address of struct
+ *                        luo_session_head_ser
+ */
+#define LUO_FDT_SESSION_NODE_NAME    "luo-session"
+#define LUO_FDT_SESSION_COMPATIBLE   "luo-session-v1"
+#define LUO_FDT_SESSION_HEAD         "luo-session-head"
+
+/**
+ * struct luo_session_head_ser - Header for the serialized session data block.
+ * @pgcnt: The total size, in pages, of the entire preserved memory block
+ *         that this header describes.
+ * @count: The number of 'struct luo_session_ser' entries that immediately
+ *         follow this header in the memory block.
+ *
+ * This structure is located at the beginning of a contiguous block of
+ * physical memory preserved across the kexec. It provides the necessary
+ * metadata to interpret the array of session entries that follow.
+ */
+struct luo_session_head_ser {
+     u64 pgcnt;
+     u64 count;
+} __packed;
+
+/**
+ * struct luo_session_ser - Represents the serialized metadata for a LUO session.
+ * @name:    The unique name of the session, copied from the `luo_session`
+ *           structure.
+ * @files:   The physical address of a contiguous memory block that holds
+ *           the serialized state of files.
+ * @pgcnt:   The number of pages occupied by the `files` memory block.
+ * @count:   The total number of files that were part of this session during
+ *           serialization. Used for iteration and validation during
+ *           restoration.
+ *
+ * This structure is used to package session-specific metadata for transfer
+ * between kernels via Kexec Handover. An array of these structures (one per
+ * session) is created and passed to the new kernel, allowing it to reconstruct
+ * the session context.
+ *
+ * If this structure is modified, LUO_SESSION_COMPATIBLE must be updated.
+ */
+struct luo_session_ser {
+     char name[LIVEUPDATE_SESSION_NAME_LENGTH];
+     u64 files;
+     u64 pgcnt;
+     u64 count;
+} __packed;
+
 #endif /* _LINUX_LIVEUPDATE_ABI_LUO_H */

diff --git a/include/uapi/linux/liveupdate.h b/include/uapi/linux/liveupdate.h
index df34c1642c4d..d2ef2f7e0dbd 100644
--- a/include/uapi/linux/liveupdate.h
+++ b/include/uapi/linux/liveupdate.h

@@ -43,4 +43,7 @@
 /* The ioctl type, documented in ioctl-number.rst */
 #define LIVEUPDATE_IOCTL_TYPE                0xBA

+/* The maximum length of session name including null termination */
+#define LIVEUPDATE_SESSION_NAME_LENGTH 56

Out of curiosity, why 56? :)

There is no architectural requirement, I picked 56 to be long enough
to contain a meaningful identifier, and also more efficiently fit the
luo_session_ser[] array. However, now thinking about this, I will bump
it up to 64-bytes, just so it does not look strange.

quoted

+
 #endif /* _UAPI_LIVEUPDATE_H */

diff --git a/kernel/liveupdate/Makefile b/kernel/liveupdate/Makefile
index 413722002b7a..83285e7ad726 100644
--- a/kernel/liveupdate/Makefile
+++ b/kernel/liveupdate/Makefile

@@ -2,7 +2,8 @@

 luo-y :=                                                             \
              luo_core.o                                              \
-             luo_ioctl.o
+             luo_ioctl.o                                             \
+             luo_session.o

 obj-$(CONFIG_KEXEC_HANDOVER)         += kexec_handover.o
 obj-$(CONFIG_KEXEC_HANDOVER_DEBUG)   += kexec_handover_debug.o

diff --git a/kernel/liveupdate/luo_core.c b/kernel/liveupdate/luo_core.c
index c1bd236bccb0..83257ab93ebb 100644
--- a/kernel/liveupdate/luo_core.c
+++ b/kernel/liveupdate/luo_core.c

@@ -116,6 +116,10 @@ static int __init luo_early_startup(void)
      pr_info("Retrieved live update data, liveupdate number: %lld\n",
              luo_global.liveupdate_num);

+     err = luo_session_setup_incoming(luo_global.fdt_in);
+     if (err)
+             return err;
+
      return 0;
 }

@@ -149,6 +153,7 @@ static int __init luo_fdt_setup(void)
      err |= fdt_begin_node(fdt_out, "");
      err |= fdt_property_string(fdt_out, "compatible", LUO_FDT_COMPATIBLE);
      err |= fdt_property(fdt_out, LUO_FDT_LIVEUPDATE_NUM, &ln, sizeof(ln));
+     err |= luo_session_setup_outgoing(fdt_out);
      err |= fdt_end_node(fdt_out);
      err |= fdt_finish(fdt_out);
      if (err)

@@ -202,6 +207,10 @@ int liveupdate_reboot(void)
      if (!liveupdate_enabled())
              return 0;

+     err = luo_session_serialize();
+     if (err)
+             return err;
+
      err = kho_finalize();
      if (err) {
              pr_err("kho_finalize failed %d\n", err);

diff --git a/kernel/liveupdate/luo_internal.h b/kernel/liveupdate/luo_internal.h
index 29f47a69be0b..b4f2d1443c76 100644
--- a/kernel/liveupdate/luo_internal.h
+++ b/kernel/liveupdate/luo_internal.h

@@ -14,4 +14,43 @@ void *luo_alloc_preserve(size_t size);
 void luo_free_unpreserve(void *mem, size_t size);
 void luo_free_restore(void *mem, size_t size);

+/**
+ * struct luo_session - Represents an active or incoming Live Update session.
+ * @name:       A unique name for this session, used for identification and
+ *              retrieval.
+ * @files_list: An ordered list of files associated with this session, it is
+ *              ordered by preservation time.
+ * @ser:        Pointer to the serialized data for this session.
+ * @count:      A counter tracking the number of files currently stored in the
+ *              @files_xa for this session.

                   ^@files_list

Sure, thanks

quoted

+ * @list:       A list_head member used to link this session into a global list
+ *              of either outgoing (to be preserved) or incoming (restored from
+ *              previous kernel) sessions.
+ * @retrieved:  A boolean flag indicating whether this session has been
+ *              retrieved by a consumer in the new kernel.
+ * @mutex:      Session lock, protects files_list, and count.
+ * @files:      The physically contiguous memory block that holds the serialized
+ *              state of files.
+ * @pgcnt:      The number of pages files occupy.

                                      ^ @files

Ok

quoted

+ */
+struct luo_session {
+     char name[LIVEUPDATE_SESSION_NAME_LENGTH];
+     struct list_head files_list;
+     struct luo_session_ser *ser;
+     long count;
+     struct list_head list;
+     bool retrieved;
+     struct mutex mutex;
+     struct luo_file_ser *files;
+     u64 pgcnt;
+};
+
+int luo_session_create(const char *name, struct file **filep);
+int luo_session_retrieve(const char *name, struct file **filep);
+int __init luo_session_setup_outgoing(void *fdt);
+int __init luo_session_setup_incoming(void *fdt);
+int luo_session_serialize(void);
+int luo_session_deserialize(void);

The last four deal with all the sessions, maybe use plural in the function
names.

luo_session_* is a common prefix, I would prefer to keep it the same.
These functions are:

luo_session_serialize_sessions()
luo_session_deserialize_sessions()

But, that becomes redundant, so let's keep them as is.

quoted

+bool luo_session_is_deserialized(void);
+
 #endif /* _LINUX_LUO_INTERNAL_H */

diff --git a/kernel/liveupdate/luo_session.c b/kernel/liveupdate/luo_session.c
new file mode 100644
index 000000000000..a3513118aa74
--- /dev/null
+++ b/kernel/liveupdate/luo_session.c

@@ -0,0 +1,405 @@
+// SPDX-License-Identifier: GPL-2.0
+
+/*
+ * Copyright (c) 2025, Google LLC.
+ * Pasha Tatashin <pasha.tatashin@soleen.com>
+ */
+
+/**
+ * DOC: LUO Sessions
+ *
+ * LUO Sessions provide the core mechanism for grouping and managing `struct
+ * file *` instances that need to be preserved across a kexec-based live
+ * update. Each session acts as a named container for a set of file objects,
+ * allowing a userspace agent to manage the lifecycle of resources critical to a
+ * workload.
+ *
+ * Core Concepts:
+ *
+ * - Named Containers: Sessions are identified by a unique, user-provided name,
+ *   which is used for both creation in the current kernel and retrieval in the
+ *   next kernel.
+ *
+ * - Userspace Interface: Session management is driven from userspace via
+ *   ioctls on /dev/liveupdate.
+ *
+ * - Serialization: Session metadata is preserved using the KHO framework. When
+ *   a live update is triggered via kexec, an array of `struct luo_session_ser`
+ *   is populated and placed in a preserved memory region. An FDT node is also
+ *   created, containing the count of sessions and the physical address of this
+ *   array.
+ *
+ * Session Lifecycle:
+ *
+ * 1.  Creation: A userspace agent calls `luo_session_create()` to create a
+ *     new, empty session and receives a file descriptor for it.
+ *
+ * 2.  Serialization: When the `reboot(LINUX_REBOOT_CMD_KEXEC)` syscall is
+ *     made, `luo_session_serialize()` is called. It iterates through all
+ *     active sessions and writes their metadata into a memory area preserved
+ *     by KHO.
+ *
+ * 3.  Deserialization (in new kernel): After kexec, `luo_session_deserialize()`
+ *     runs, reading the serialized data and creating a list of `struct
+ *     luo_session` objects representing the preserved sessions.
+ *
+ * 4.  Retrieval: A userspace agent in the new kernel can then call
+ *     `luo_session_retrieve()` with a session name to get a new file
+ *     descriptor and access the preserved state.
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/anon_inodes.h>
+#include <linux/errno.h>
+#include <linux/file.h>
+#include <linux/fs.h>
+#include <linux/libfdt.h>
+#include <linux/liveupdate.h>
+#include <linux/liveupdate/abi/luo.h>
+#include <uapi/linux/liveupdate.h>
+#include "luo_internal.h"
+
+/* 16 4K pages, give space for 819 sessions */
+#define LUO_SESSION_PGCNT    16ul
+#define LUO_SESSION_MAX              (((LUO_SESSION_PGCNT << PAGE_SHIFT) -   \
+             sizeof(struct luo_session_head_ser)) /                  \
+             sizeof(struct luo_session_ser))
+
+/**
+ * struct luo_session_head - Head struct for managing LUO sessions.

Head of what? ;-)

Head of incoming and outgoing session lists, sounds appropriate, but
if you do not like that how about: luo_session_set ?

Maybe luo_session_list? Or even luo_sessions?

luo_session_list would sound good, but I prefer to use that for
"struct list_head *"  types. Let's keep luo_session

quoted

+ * @count:    The number of sessions currently tracked in the @list.
+ * @list:     The head of the linked list of `struct luo_session` instances.
+ * @rwsem:    A read-write semaphore providing synchronized access to the
+ *            session list and other fields in this structure.
+ * @head_ser: The head data of serialization array.

                    ^ header?

Yes, I am going to re-name all these to header.

quoted

+ * @ser:      The serialized session data (an array of
+ *            `struct luo_session_ser`).
+ * @active:   Set to true when first initialized. If previous kernel did not
+ *            send session data, active stays false for incoming.
+ */
+struct luo_session_head {
+     long count;
+     struct list_head list;
+     struct rw_semaphore rwsem;
+     struct luo_session_head_ser *head_ser;
+     struct luo_session_ser *ser;
+     bool active;
+};
+
+/**
+ * struct luo_session_global - Global container for managing LUO sessions.
+ * @incoming:     The sessions passed from the previous kernel.
+ * @outgoing:     The sessions that are going to be passed to the next kernel.
+ * @deserialized: The sessions have been deserialized once /dev/liveupdate
+ *                has been opened.
+ */
+struct luo_session_global {
+     struct luo_session_head incoming;
+     struct luo_session_head outgoing;
+     bool deserialized;
+} luo_session_global;

Should be static. And frankly, I don't think grouping two global variables
into a struct gains much.

I have sent a separate fix-up patch to make it static.

static struct luo_sessions luo_sessions_incoming;
static struct luo_sessions luo_sessions_outgoing;

 I prefer to group globals in a struct so over time we do not end-up
sprinkling them all over the file.

reads clearer to me.

quoted

+
+static struct luo_session *luo_session_alloc(const char *name)
+{
+     struct luo_session *session = kzalloc(sizeof(*session), GFP_KERNEL);
+
+     if (!session)
+             return NULL;
+
+     strscpy(session->name, name, sizeof(session->name));
+     INIT_LIST_HEAD(&session->files_list);
+     session->count = 0;

I'd move this after mutex_init(), a bit more readable IMHO.

Sure

quoted

+     INIT_LIST_HEAD(&session->list);
+     mutex_init(&session->mutex);
+
+     return session;
+}
+
+static void luo_session_free(struct luo_session *session)
+{
+     WARN_ON(session->count);
+     WARN_ON(!list_empty(&session->files_list));
+     mutex_destroy(&session->mutex);
+     kfree(session);
+}
+
+static int luo_session_insert(struct luo_session_head *sh,
+                           struct luo_session *session)
+{
+     struct luo_session *it;
+
+     guard(rwsem_write)(&sh->rwsem);
+
+     /*
+      * For outgoing we should make sure there is room in serialization array
+      * for new session.
+      */
+     if (sh == &luo_session_global.outgoing) {
+             if (sh->count == LUO_SESSION_MAX)
+                     return -ENOMEM;
+     }

Not a big deal, but this could be outside the guard().

Yes, but then we would still need to check inside... So, since it is
not a performance critical path, let's keep it cleaner and check only
inside.

quoted

+
+     /*
+      * For small number of sessions this loop won't hurt performance
+      * but if we ever start using a lot of sessions, this might
+      * become a bottle neck during deserialization time, as it would
+      * cause O(n*n) complexity.
+      */

The loop is always O(n*n) in the worst case, no matter how many sessions
there are ;-)

Yes, this is what I am stating, just logically the number of sessions
is not in millions, so it should not cause this to be a problem if it
ever does, we can fix it.

quoted

+     list_for_each_entry(it, &sh->list, list) {
+             if (!strncmp(it->name, session->name, sizeof(it->name)))
+                     return -EEXIST;
+     }
+     list_add_tail(&session->list, &sh->list);
+     sh->count++;
+
+     return 0;
+}
+
+static void luo_session_remove(struct luo_session_head *sh,
+                            struct luo_session *session)
+{
+     guard(rwsem_write)(&sh->rwsem);
+     list_del(&session->list);
+     sh->count--;
+}
+
+static int luo_session_release(struct inode *inodep, struct file *filep)
+{
+     struct luo_session *session = filep->private_data;
+     struct luo_session_head *sh;
+
+     /* If retrieved is set, it means this session is from incoming list */
+     if (session->retrieved)
+             sh = &luo_session_global.incoming;
+     else
+             sh = &luo_session_global.outgoing;

Maybe just add a backpointer to the list to struct luo_session?

This is the only place where this is used, I think it is readable
instead of carrying an extra 8-byte state in every session.

quoted

+
+     luo_session_remove(sh, session);
+     luo_session_free(session);
+
+     return 0;
+}
+
+static const struct file_operations luo_session_fops = {
+     .owner = THIS_MODULE,
+     .release = luo_session_release,
+};
+
+/* Create a "struct file" for session */
+static int luo_session_getfile(struct luo_session *session, struct file **filep)
+{
+     char name_buf[128];
+     struct file *file;
+
+     guard(mutex)(&session->mutex);
+     snprintf(name_buf, sizeof(name_buf), "[luo_session] %s", session->name);
+     file = anon_inode_getfile(name_buf, &luo_session_fops, session, O_RDWR);
+     if (IS_ERR(file))
+             return PTR_ERR(file);
+
+     *filep = file;
+
+     return 0;
+}
+
+int luo_session_create(const char *name, struct file **filep)
+{
+     struct luo_session *session;
+     int err;
+
+     session = luo_session_alloc(name);
+     if (!session)
+             return -ENOMEM;
+
+     err = luo_session_insert(&luo_session_global.outgoing, session);
+     if (err) {
+             luo_session_free(session);
+             return err;

Please goto err_free

Sure.

quoted

+     }
+
+     err = luo_session_getfile(session, filep);
+     if (err) {
+             luo_session_remove(&luo_session_global.outgoing, session);
+             luo_session_free(session);

and goto err_remove

Sure.

quoted

+     }
+
+     return err;
+}
+
+int luo_session_retrieve(const char *name, struct file **filep)
+{
+     struct luo_session_head *sh = &luo_session_global.incoming;
+     struct luo_session *session = NULL;
+     struct luo_session *it;
+     int err;
+
+     scoped_guard(rwsem_read, &sh->rwsem) {
+             list_for_each_entry(it, &sh->list, list) {
+                     if (!strncmp(it->name, name, sizeof(it->name))) {
+                             session = it;
+                             break;
+                     }
+             }
+     }
+
+     if (!session)
+             return -ENOENT;
+
+     scoped_guard(mutex, &session->mutex) {
+             if (session->retrieved)
+                     return -EINVAL;
+     }
+
+     err = luo_session_getfile(session, filep);
+     if (!err) {
+             scoped_guard(mutex, &session->mutex)
+                     session->retrieved = true;
+     }
+
+     return err;
+}
+
+int __init luo_session_setup_outgoing(void *fdt_out)
+{
+     struct luo_session_head_ser *head_ser;
+     u64 head_ser_pa;
+     int err;
+
+     head_ser = luo_alloc_preserve(LUO_SESSION_PGCNT << PAGE_SHIFT);
+     if (IS_ERR(head_ser))
+             return PTR_ERR(head_ser);
+     head_ser_pa = __pa(head_ser);

virt_to_phys please

quoted

+
+     err = fdt_begin_node(fdt_out, LUO_FDT_SESSION_NODE_NAME);
+     err |= fdt_property_string(fdt_out, "compatible",
+                                LUO_FDT_SESSION_COMPATIBLE);
+     err |= fdt_property(fdt_out, LUO_FDT_SESSION_HEAD, &head_ser_pa,
+                         sizeof(head_ser_pa));
+     err |= fdt_end_node(fdt_out);
+
+     if (err)
+             goto err_unpreserve;
+
+     head_ser->pgcnt = LUO_SESSION_PGCNT;
+     INIT_LIST_HEAD(&luo_session_global.outgoing.list);
+     init_rwsem(&luo_session_global.outgoing.rwsem);
+     luo_session_global.outgoing.head_ser = head_ser;
+     luo_session_global.outgoing.ser = (void *)(head_ser + 1);
+     luo_session_global.outgoing.active = true;
+
+     return 0;
+
+err_unpreserve:
+     luo_free_unpreserve(head_ser, LUO_SESSION_PGCNT << PAGE_SHIFT);
+     return err;
+}
+
+int __init luo_session_setup_incoming(void *fdt_in)
+{
+     struct luo_session_head_ser *head_ser;
+     int err, head_size, offset;
+     const void *ptr;
+     u64 head_ser_pa;
+
+     offset = fdt_subnode_offset(fdt_in, 0, LUO_FDT_SESSION_NODE_NAME);
+     if (offset < 0) {
+             pr_err("Unable to get session node: [%s]\n",
+                    LUO_FDT_SESSION_NODE_NAME);
+             return -EINVAL;
+     }
+
+     err = fdt_node_check_compatible(fdt_in, offset,
+                                     LUO_FDT_SESSION_COMPATIBLE);
+     if (err) {
+             pr_err("Session node incompatibale [%s]\n",
+                    LUO_FDT_SESSION_COMPATIBLE);
+             return -EINVAL;
+     }
+
+     head_size = 0;
+     ptr = fdt_getprop(fdt_in, offset, LUO_FDT_SESSION_HEAD, &head_size);
+     if (!ptr || head_size != sizeof(u64)) {
+             pr_err("Unable to get session head '%s' [%d]\n",
+                    LUO_FDT_SESSION_HEAD, head_size);
+             return -EINVAL;
+     }
+
+     memcpy(&head_ser_pa, ptr, sizeof(u64));
+     head_ser = __va(head_ser_pa);
+
+     luo_session_global.incoming.head_ser = head_ser;
+     luo_session_global.incoming.ser = (void *)(head_ser + 1);
+     INIT_LIST_HEAD(&luo_session_global.incoming.list);
+     init_rwsem(&luo_session_global.incoming.rwsem);
+     luo_session_global.incoming.active = true;
+
+     return 0;
+}
+
+bool luo_session_is_deserialized(void)
+{
+     return luo_session_global.deserialized;
+}
+
+int luo_session_deserialize(void)
+{
+     struct luo_session_head *sh = &luo_session_global.incoming;
+
+     if (luo_session_is_deserialized())
+             return 0;
+
+     luo_session_global.deserialized = true;

Shouldn't this be set after deserialization succeeded?

We do luo_session_deserialize() only once even if it failed or was not
needed. So, set this flag at the beginning.

quoted

+     if (!sh->active) {
+             INIT_LIST_HEAD(&sh->list);
+             init_rwsem(&sh->rwsem);
+             return 0;
+     }
+
+     for (int i = 0; i < sh->head_ser->count; i++) {
+             struct luo_session *session;
+
+             session = luo_session_alloc(sh->ser[i].name);
+             if (!session) {
+                     pr_warn("Failed to allocate session [%s] during deserialization\n",
+                             sh->ser[i].name);
+                     return -ENOMEM;
+             }
+
+             if (luo_session_insert(sh, session)) {
+                     pr_warn("Failed to insert session due to name conflict [%s]\n",
+                             session->name);
+                     return -EEXIST;

Need to free allocated sessions if an insert fails.

Thanks, I will fix it.

quoted

+             }
+
+             session->count = sh->ser[i].count;
+             session->files = __va(sh->ser[i].files);
+             session->pgcnt = sh->ser[i].pgcnt;
+     }
+
+     luo_free_restore(sh->head_ser, sh->head_ser->pgcnt << PAGE_SHIFT);
+     sh->head_ser = NULL;
+     sh->ser = NULL;
+
+     return 0;
+}
+
+int luo_session_serialize(void)
+{
+     struct luo_session_head *sh = &luo_session_global.outgoing;
+     struct luo_session *session;
+     int i = 0;
+
+     guard(rwsem_write)(&sh->rwsem);
+     list_for_each_entry(session, &sh->list, list) {
+             strscpy(sh->ser[i].name, session->name,
+                     sizeof(sh->ser[i].name));
+             sh->ser[i].count = session->count;
+             sh->ser[i].files = __pa(session->files);
+             sh->ser[i].pgcnt = session->pgcnt;
+             i++;
+     }
+     sh->head_ser->count = sh->count;
+
+     return 0;
+}
--
2.51.2.1041.gc1ab5b90ca-goog

--
Sincerely yours,
Mike.