From 496a0fc8c5572a626de41d56d7c7ed005a2c1b48 Mon Sep 17 00:00:00 2001 From: Matt Domsch Date: Fri, 26 Jan 2007 00:57:18 -0800 Subject: [PATCH] Fix race in efi variable delete code Fix race when deleting an EFI variable and issuing another EFI command on the same variable. The removal of the variable from the efivars_list should be done in efivar_delete and not delayed until the kobject release. Furthermore, remove the item from the list at module unload time, and use list_for_each_entry_safe() rather than list_for_each_safe() for readability. Tested on ia64. Signed-off-by: Prarit Bhargava Signed-off-by: Matt Domsch Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- drivers/firmware/efivars.c | 29 ++++++++++++----------------- 1 file changed, 12 insertions(+), 17 deletions(-) (limited to 'drivers/firmware') diff --git a/drivers/firmware/efivars.c b/drivers/firmware/efivars.c index 5ab5e393b882..c6281ccd4fe7 100644 --- a/drivers/firmware/efivars.c +++ b/drivers/firmware/efivars.c @@ -122,8 +122,6 @@ struct efivar_entry { struct kobject kobj; }; -#define get_efivar_entry(n) list_entry(n, struct efivar_entry, list) - struct efivar_attribute { struct attribute attr; ssize_t (*show) (struct efivar_entry *entry, char *buf); @@ -386,9 +384,6 @@ static struct sysfs_ops efivar_attr_ops = { static void efivar_release(struct kobject *kobj) { struct efivar_entry *var = container_of(kobj, struct efivar_entry, kobj); - spin_lock(&efivars_lock); - list_del(&var->list); - spin_unlock(&efivars_lock); kfree(var); } @@ -430,9 +425,8 @@ static ssize_t efivar_create(struct subsystem *sub, const char *buf, size_t count) { struct efi_variable *new_var = (struct efi_variable *)buf; - struct efivar_entry *search_efivar = NULL; + struct efivar_entry *search_efivar, *n; unsigned long strsize1, strsize2; - struct list_head *pos, *n; efi_status_t status = EFI_NOT_FOUND; int found = 0; @@ -444,8 +438,7 @@ efivar_create(struct subsystem *sub, const char *buf, size_t count) /* * Does this variable already exist? */ - list_for_each_safe(pos, n, &efivar_list) { - search_efivar = get_efivar_entry(pos); + list_for_each_entry_safe(search_efivar, n, &efivar_list, list) { strsize1 = utf8_strsize(search_efivar->var.VariableName, 1024); strsize2 = utf8_strsize(new_var->VariableName, 1024); if (strsize1 == strsize2 && @@ -490,9 +483,8 @@ static ssize_t efivar_delete(struct subsystem *sub, const char *buf, size_t count) { struct efi_variable *del_var = (struct efi_variable *)buf; - struct efivar_entry *search_efivar = NULL; + struct efivar_entry *search_efivar, *n; unsigned long strsize1, strsize2; - struct list_head *pos, *n; efi_status_t status = EFI_NOT_FOUND; int found = 0; @@ -504,8 +496,7 @@ efivar_delete(struct subsystem *sub, const char *buf, size_t count) /* * Does this variable already exist? */ - list_for_each_safe(pos, n, &efivar_list) { - search_efivar = get_efivar_entry(pos); + list_for_each_entry_safe(search_efivar, n, &efivar_list, list) { strsize1 = utf8_strsize(search_efivar->var.VariableName, 1024); strsize2 = utf8_strsize(del_var->VariableName, 1024); if (strsize1 == strsize2 && @@ -537,9 +528,9 @@ efivar_delete(struct subsystem *sub, const char *buf, size_t count) spin_unlock(&efivars_lock); return -EIO; } + list_del(&search_efivar->list); /* We need to release this lock before unregistering. */ spin_unlock(&efivars_lock); - efivar_unregister(search_efivar); /* It's dead Jim.... */ @@ -768,10 +759,14 @@ out_free: static void __exit efivars_exit(void) { - struct list_head *pos, *n; + struct efivar_entry *entry, *n; - list_for_each_safe(pos, n, &efivar_list) - efivar_unregister(get_efivar_entry(pos)); + list_for_each_entry_safe(entry, n, &efivar_list, list) { + spin_lock(&efivars_lock); + list_del(&entry->list); + spin_unlock(&efivars_lock); + efivar_unregister(entry); + } subsystem_unregister(&vars_subsys); firmware_unregister(&efi_subsys); -- cgit v1.2.3