Gitweb:
http://git.kernel.org/git/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commit;h=496a0fc8c5572a626de41d56d7c7ed005a2c1b48
Commit: 496a0fc8c5572a626de41d56d7c7ed005a2c1b48
Parent: 01f2073411e01777e3c6f45a4bf05ea76493f326
Author: Matt Domsch <[EMAIL PROTECTED]>
AuthorDate: Fri Jan 26 00:57:18 2007 -0800
Committer: Linus Torvalds <[EMAIL PROTECTED]>
CommitDate: Fri Jan 26 13:51:01 2007 -0800
[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 <[EMAIL PROTECTED]>
Signed-off-by: Matt Domsch <[EMAIL PROTECTED]>
Signed-off-by: Andrew Morton <[EMAIL PROTECTED]>
Signed-off-by: Linus Torvalds <[EMAIL PROTECTED]>
---
drivers/firmware/efivars.c | 29 ++++++++++++-----------------
1 files changed, 12 insertions(+), 17 deletions(-)
diff --git a/drivers/firmware/efivars.c b/drivers/firmware/efivars.c
index 5ab5e39..c6281cc 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);
-
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