pstore updates for v6.9-rc1

- Make PSTORE_RAM available by default on arm64 (Nícolas F. R. A. Prado)
 
 - Allow for dynamic initialization in modular build (Guilherme G. Piccoli)
 
 - Add missing allocation failure check (Kunwu Chan)
 
 - Avoid duplicate memory zeroing (Christophe JAILLET)
 
 - Avoid potential double-free during pstorefs umount
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Merge tag 'pstore-v6.9-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux

Pull pstore updates from Kees Cook:

 - Make PSTORE_RAM available by default on arm64 (Nícolas F R A Prado)

 - Allow for dynamic initialization in modular build (Guilherme G
   Piccoli)

 - Add missing allocation failure check (Kunwu Chan)

 - Avoid duplicate memory zeroing (Christophe JAILLET)

 - Avoid potential double-free during pstorefs umount

* tag 'pstore-v6.9-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux:
  pstore/zone: Don't clear memory twice
  pstore/zone: Add a null pointer check to the psz_kmsg_read
  efi: pstore: Allow dynamic initialization based on module parameter
  arm64: defconfig: Enable PSTORE_RAM
  pstore/ram: Register to module device table
  pstore: inode: Only d_invalidate() is needed

arch/arm64/configs/defconfig

@@ -1616,6 +1616,7 @@ CONFIG_CONFIGFS_FS=y
 CONFIG_EFIVAR_FS=y
 CONFIG_UBIFS_FS=m
 CONFIG_SQUASHFS=y
+CONFIG_PSTORE_RAM=m
 CONFIG_NFS_FS=y
 CONFIG_NFS_V4=y
 CONFIG_NFS_V4_1=y

drivers/firmware/efi/efi-pstore.c

@@ -14,16 +14,43 @@ static unsigned int record_size = 1024;
 module_param(record_size, uint, 0444);
 MODULE_PARM_DESC(record_size, "size of each pstore UEFI var (in bytes, min/default=1024)");
 
-static bool efivars_pstore_disable =
-	IS_ENABLED(CONFIG_EFI_VARS_PSTORE_DEFAULT_DISABLE);
-
-module_param_named(pstore_disable, efivars_pstore_disable, bool, 0644);
-
 #define PSTORE_EFI_ATTRIBUTES \
 	(EFI_VARIABLE_NON_VOLATILE | \
 	 EFI_VARIABLE_BOOTSERVICE_ACCESS | \
 	 EFI_VARIABLE_RUNTIME_ACCESS)
 
+static bool pstore_disable = IS_ENABLED(CONFIG_EFI_VARS_PSTORE_DEFAULT_DISABLE);
+
+static int efivars_pstore_init(void);
+static void efivars_pstore_exit(void);
+
+static int efi_pstore_disable_set(const char *val, const struct kernel_param *kp)
+{
+	int err;
+	bool old_pstore_disable = pstore_disable;
+
+	err = param_set_bool(val, kp);
+	if (err)
+		return err;
+
+	if (old_pstore_disable != pstore_disable) {
+		if (pstore_disable)
+			efivars_pstore_exit();
+		else
+			efivars_pstore_init();
+	}
+
+	return 0;
+}
+
+static const struct kernel_param_ops pstore_disable_ops = {
+	.set	= efi_pstore_disable_set,
+	.get	= param_get_bool,
+};
+
+module_param_cb(pstore_disable, &pstore_disable_ops, &pstore_disable, 0644);
+__MODULE_PARM_TYPE(pstore_disable, "bool");
+
 static int efi_pstore_open(struct pstore_info *psi)
 {
 	int err;
@@ -218,12 +245,12 @@ static struct pstore_info efi_pstore_info = {
 	.erase		= efi_pstore_erase,
 };
 
-static __init int efivars_pstore_init(void)
+static int efivars_pstore_init(void)
 {
 	if (!efivar_supports_writes())
 		return 0;
 
-	if (efivars_pstore_disable)
+	if (pstore_disable)
 		return 0;
 
 	/*
@@ -250,7 +277,7 @@ static __init int efivars_pstore_init(void)
 	return 0;
 }
 
-static __exit void efivars_pstore_exit(void)
+static void efivars_pstore_exit(void)
 {
 	if (!efi_pstore_info.bufsize)
 		return;

fs/pstore/inode.c

@@ -307,7 +307,6 @@ int pstore_put_backend_records(struct pstore_info *psi)
 {
 	struct pstore_private *pos, *tmp;
 	struct dentry *root;
-	int rc = 0;
 
 	root = psinfo_lock_root();
 	if (!root)
@@ -317,11 +316,8 @@ int pstore_put_backend_records(struct pstore_info *psi)
 		list_for_each_entry_safe(pos, tmp, &records_list, list) {
 			if (pos->record->psi == psi) {
 				list_del_init(&pos->list);
-				rc = simple_unlink(d_inode(root), pos->dentry);
-				if (WARN_ON(rc))
-					break;
-				d_drop(pos->dentry);
-				dput(pos->dentry);
+				d_invalidate(pos->dentry);
+				simple_unlink(d_inode(root), pos->dentry);
 				pos->dentry = NULL;
 			}
 		}
@@ -329,7 +325,7 @@ int pstore_put_backend_records(struct pstore_info *psi)
 
 	inode_unlock(d_inode(root));
 
-	return rc;
+	return 0;
 }
 
 /*

fs/pstore/ram.c

@@ -893,6 +893,7 @@ static const struct of_device_id dt_match[] = {
 	{ .compatible = "ramoops" },
 	{}
 };
+MODULE_DEVICE_TABLE(of, dt_match);
 
 static struct platform_driver ramoops_driver = {
 	.probe		= ramoops_probe,

fs/pstore/zone.c

@@ -973,6 +973,8 @@ static ssize_t psz_kmsg_read(struct pstore_zone *zone,
 		char *buf = kasprintf(GFP_KERNEL, "%s: Total %d times\n",
 				      kmsg_dump_reason_str(record->reason),
 				      record->count);
+		if (!buf)
+			return -ENOMEM;
 		hlen = strlen(buf);
 		record->buf = krealloc(buf, hlen + size, GFP_KERNEL);
 		if (!record->buf) {
@@ -1215,7 +1217,6 @@ static struct pstore_zone **psz_init_zones(enum pstore_type_id type,
 		pr_err("allocate for zones %s failed\n", name);
 		return ERR_PTR(-ENOMEM);
 	}
-	memset(zones, 0, c * sizeof(*zones));
 
 	for (i = 0; i < c; i++) {
 		zone = psz_init_zone(type, off, record_size);