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A few fixes to reduce places where pstore might hang 

a system in the crash path. Plus a new mountpoint
 (/sys/fs/pstore ... makes more sense then /dev/pstore).
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Merge tag 'please-pull-pstore' of git://git.kernel.org/pub/scm/linux/kernel/git/aegl/linux

Pull pstore patches from Tony Luck:
 "A few fixes to reduce places where pstore might hang a system in the
  crash path.  Plus a new mountpoint (/sys/fs/pstore ...  makes more
  sense then /dev/pstore)."

Fix up trivial conflict in drivers/firmware/efivars.c

* tag 'please-pull-pstore' of git://git.kernel.org/pub/scm/linux/kernel/git/aegl/linux:
  pstore: Create a convenient mount point for pstore
  efi_pstore: Introducing workqueue updating sysfs
  efivars: Disable external interrupt while holding efivars->lock
  efi_pstore: Avoid deadlock in non-blocking paths
  pstore: Avoid deadlock in panic and emergency-restart path
This commit is contained in:
Linus Torvalds 2013-02-21 09:38:18 -08:00
Родитель 850cb82b75 fb0af3f2b1
Коммит 024e4ec185
6 изменённых файлов: 191 добавлений и 59 удалений
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10
Documentation/ABI/testing/pstore
Просмотреть файл

@ -1,4 +1,4 @@
Where: /dev/pstore/...
Where: /sys/fs/pstore/... (or /dev/pstore/...)
Date: March 2011
Kernel Version: 2.6.39
Contact: tony.luck@intel.com
@ -11,9 +11,9 @@ Description: Generic interface to platform dependent persistent storage.
of the console log is captured, but other interesting
data can also be saved.
# mount -t pstore -o kmsg_bytes=8000 - /dev/pstore
# mount -t pstore -o kmsg_bytes=8000 - /sys/fs/pstore
$ ls -l /dev/pstore
$ ls -l /sys/fs/pstore/
total 0
-r--r--r-- 1 root root 7896 Nov 30 15:38 dmesg-erst-1
@ -27,9 +27,9 @@ Description: Generic interface to platform dependent persistent storage.
the file will signal to the underlying persistent storage
device that it can reclaim the space for later re-use.
$ rm /dev/pstore/dmesg-erst-1
$ rm /sys/fs/pstore/dmesg-erst-1
The expectation is that all files in /dev/pstore
The expectation is that all files in /sys/fs/pstore/
will be saved elsewhere and erased from persistent store
soon after boot to free up space ready for the next
catastrophe.

178
drivers/firmware/efivars.c
Просмотреть файл

@ -158,6 +158,13 @@ efivar_create_sysfs_entry(struct efivars *efivars,
efi_char16_t *variable_name,
efi_guid_t *vendor_guid);
/*
* Prototype for workqueue functions updating sysfs entry
*/
static void efivar_update_sysfs_entries(struct work_struct *);
static DECLARE_WORK(efivar_work, efivar_update_sysfs_entries);
/* Return the number of unicode characters in data */
static unsigned long
utf16_strnlen(efi_char16_t *s, size_t maxlength)
@ -405,10 +412,11 @@ static efi_status_t
get_var_data(struct efivars *efivars, struct efi_variable *var)
{
efi_status_t status;
unsigned long flags;
spin_lock(&efivars->lock);
spin_lock_irqsave(&efivars->lock, flags);
status = get_var_data_locked(efivars, var);
spin_unlock(&efivars->lock);
spin_unlock_irqrestore(&efivars->lock, flags);
if (status != EFI_SUCCESS) {
printk(KERN_WARNING "efivars: get_variable() failed 0x%lx!\n",
@ -537,14 +545,14 @@ efivar_store_raw(struct efivar_entry *entry, const char *buf, size_t count)
return -EINVAL;
}
spin_lock(&efivars->lock);
spin_lock_irq(&efivars->lock);
status = efivars->ops->set_variable(new_var->VariableName,
&new_var->VendorGuid,
new_var->Attributes,
new_var->DataSize,
new_var->Data);
spin_unlock(&efivars->lock);
spin_unlock_irq(&efivars->lock);
if (status != EFI_SUCCESS) {
printk(KERN_WARNING "efivars: set_variable() failed: status=%lx\n",
@ -713,7 +721,7 @@ static ssize_t efivarfs_file_write(struct file *file,
* amounts of memory. Pick a default size of 64K if
* QueryVariableInfo() isn't supported by the firmware.
*/
spin_lock(&efivars->lock);
spin_lock_irq(&efivars->lock);
if (!efivars->ops->query_variable_info)
status = EFI_UNSUPPORTED;
@ -723,7 +731,7 @@ static ssize_t efivarfs_file_write(struct file *file,
&remaining_size, &max_size);
}
spin_unlock(&efivars->lock);
spin_unlock_irq(&efivars->lock);
if (status != EFI_SUCCESS) {
if (status != EFI_UNSUPPORTED)
@ -754,7 +762,7 @@ static ssize_t efivarfs_file_write(struct file *file,
* set_variable call, and removal of the variable from the efivars
* list (in the case of an authenticated delete).
*/
spin_lock(&efivars->lock);
spin_lock_irq(&efivars->lock);
status = efivars->ops->set_variable(var->var.VariableName,
&var->var.VendorGuid,
@ -762,7 +770,7 @@ static ssize_t efivarfs_file_write(struct file *file,
data);
if (status != EFI_SUCCESS) {
spin_unlock(&efivars->lock);
spin_unlock_irq(&efivars->lock);
kfree(data);
return efi_status_to_err(status);
@ -783,21 +791,21 @@ static ssize_t efivarfs_file_write(struct file *file,
NULL);
if (status == EFI_BUFFER_TOO_SMALL) {
spin_unlock(&efivars->lock);
spin_unlock_irq(&efivars->lock);
mutex_lock(&inode->i_mutex);
i_size_write(inode, newdatasize + sizeof(attributes));
mutex_unlock(&inode->i_mutex);
} else if (status == EFI_NOT_FOUND) {
list_del(&var->list);
spin_unlock(&efivars->lock);
spin_unlock_irq(&efivars->lock);
efivar_unregister(var);
drop_nlink(inode);
d_delete(file->f_dentry);
dput(file->f_dentry);
} else {
spin_unlock(&efivars->lock);
spin_unlock_irq(&efivars->lock);
pr_warn("efivarfs: inconsistent EFI variable implementation? "
"status = %lx\n", status);
}
@ -819,11 +827,11 @@ static ssize_t efivarfs_file_read(struct file *file, char __user *userbuf,
void *data;
ssize_t size = 0;
spin_lock(&efivars->lock);
spin_lock_irq(&efivars->lock);
status = efivars->ops->get_variable(var->var.VariableName,
&var->var.VendorGuid,
&attributes, &datasize, NULL);
spin_unlock(&efivars->lock);
spin_unlock_irq(&efivars->lock);
if (status != EFI_BUFFER_TOO_SMALL)
return efi_status_to_err(status);
@ -833,12 +841,12 @@ static ssize_t efivarfs_file_read(struct file *file, char __user *userbuf,
if (!data)
return -ENOMEM;
spin_lock(&efivars->lock);
spin_lock_irq(&efivars->lock);
status = efivars->ops->get_variable(var->var.VariableName,
&var->var.VendorGuid,
&attributes, &datasize,
(data + sizeof(attributes)));
spin_unlock(&efivars->lock);
spin_unlock_irq(&efivars->lock);
if (status != EFI_SUCCESS) {
size = efi_status_to_err(status);
@ -966,9 +974,9 @@ static int efivarfs_create(struct inode *dir, struct dentry *dentry,
goto out;
kobject_uevent(&var->kobj, KOBJ_ADD);
spin_lock(&efivars->lock);
spin_lock_irq(&efivars->lock);
list_add(&var->list, &efivars->list);
spin_unlock(&efivars->lock);
spin_unlock_irq(&efivars->lock);
d_instantiate(dentry, inode);
dget(dentry);
out:
@ -985,7 +993,7 @@ static int efivarfs_unlink(struct inode *dir, struct dentry *dentry)
struct efivars *efivars = var->efivars;
efi_status_t status;
spin_lock(&efivars->lock);
spin_lock_irq(&efivars->lock);
status = efivars->ops->set_variable(var->var.VariableName,
&var->var.VendorGuid,
@ -993,14 +1001,14 @@ static int efivarfs_unlink(struct inode *dir, struct dentry *dentry)
if (status == EFI_SUCCESS || status == EFI_NOT_FOUND) {
list_del(&var->list);
spin_unlock(&efivars->lock);
spin_unlock_irq(&efivars->lock);
efivar_unregister(var);
drop_nlink(dentry->d_inode);
dput(dentry);
return 0;
}
spin_unlock(&efivars->lock);
spin_unlock_irq(&efivars->lock);
return -EINVAL;
};
@ -1066,13 +1074,13 @@ static int efivarfs_fill_super(struct super_block *sb, void *data, int silent)
/* copied by the above to local storage in the dentry. */
kfree(name);
spin_lock(&efivars->lock);
spin_lock_irq(&efivars->lock);
efivars->ops->get_variable(entry->var.VariableName,
&entry->var.VendorGuid,
&entry->var.Attributes,
&size,
NULL);
spin_unlock(&efivars->lock);
spin_unlock_irq(&efivars->lock);
mutex_lock(&inode->i_mutex);
inode->i_private = entry;
@ -1123,7 +1131,7 @@ static int efi_pstore_open(struct pstore_info *psi)
{
struct efivars *efivars = psi->data;
spin_lock(&efivars->lock);
spin_lock_irq(&efivars->lock);
efivars->walk_entry = list_first_entry(&efivars->list,
struct efivar_entry, list);
return 0;
@ -1133,7 +1141,7 @@ static int efi_pstore_close(struct pstore_info *psi)
{
struct efivars *efivars = psi->data;
spin_unlock(&efivars->lock);
spin_unlock_irq(&efivars->lock);
return 0;
}
@ -1209,8 +1217,18 @@ static int efi_pstore_write(enum pstore_type_id type,
int i, ret = 0;
u64 storage_space, remaining_space, max_variable_size;
efi_status_t status = EFI_NOT_FOUND;
unsigned long flags;
spin_lock(&efivars->lock);
if (pstore_cannot_block_path(reason)) {
/*
* If the lock is taken by another cpu in non-blocking path,
* this driver returns without entering firmware to avoid
* hanging up.
*/
if (!spin_trylock_irqsave(&efivars->lock, flags))
return -EBUSY;
} else
spin_lock_irqsave(&efivars->lock, flags);
/*
* Check if there is a space enough to log.
@ -1222,7 +1240,7 @@ static int efi_pstore_write(enum pstore_type_id type,
&remaining_space,
&max_variable_size);
if (status || remaining_space < size + DUMP_NAME_LEN * 2) {
spin_unlock(&efivars->lock);
spin_unlock_irqrestore(&efivars->lock, flags);
*id = part;
return -ENOSPC;
}
@ -1236,13 +1254,10 @@ static int efi_pstore_write(enum pstore_type_id type,
efivars->ops->set_variable(efi_name, &vendor, PSTORE_EFI_ATTRIBUTES,
size, psi->buf);
spin_unlock(&efivars->lock);
spin_unlock_irqrestore(&efivars->lock, flags);
if (size)
ret = efivar_create_sysfs_entry(efivars,
utf16_strsize(efi_name,
DUMP_NAME_LEN * 2),
efi_name, &vendor);
if (reason == KMSG_DUMP_OOPS)
schedule_work(&efivar_work);
*id = part;
return ret;
@ -1263,7 +1278,7 @@ static int efi_pstore_erase(enum pstore_type_id type, u64 id, int count,
sprintf(name, "dump-type%u-%u-%d-%lu", type, (unsigned int)id, count,
time.tv_sec);
spin_lock(&efivars->lock);
spin_lock_irq(&efivars->lock);
for (i = 0; i < DUMP_NAME_LEN; i++)
efi_name[i] = name[i];
@ -1307,7 +1322,7 @@ static int efi_pstore_erase(enum pstore_type_id type, u64 id, int count,
if (found)
list_del(&found->list);
spin_unlock(&efivars->lock);
spin_unlock_irq(&efivars->lock);
if (found)
efivar_unregister(found);
@ -1377,7 +1392,7 @@ static ssize_t efivar_create(struct file *filp, struct kobject *kobj,
return -EINVAL;
}
spin_lock(&efivars->lock);
spin_lock_irq(&efivars->lock);
/*
* Does this variable already exist?
@ -1395,7 +1410,7 @@ static ssize_t efivar_create(struct file *filp, struct kobject *kobj,
}
}
if (found) {
spin_unlock(&efivars->lock);
spin_unlock_irq(&efivars->lock);
return -EINVAL;
}
@ -1409,10 +1424,10 @@ static ssize_t efivar_create(struct file *filp, struct kobject *kobj,
if (status != EFI_SUCCESS) {
printk(KERN_WARNING "efivars: set_variable() failed: status=%lx\n",
status);
spin_unlock(&efivars->lock);
spin_unlock_irq(&efivars->lock);
return -EIO;
}
spin_unlock(&efivars->lock);
spin_unlock_irq(&efivars->lock);
/* Create the entry in sysfs. Locking is not required here */
status = efivar_create_sysfs_entry(efivars,
@ -1440,7 +1455,7 @@ static ssize_t efivar_delete(struct file *filp, struct kobject *kobj,
if (!capable(CAP_SYS_ADMIN))
return -EACCES;
spin_lock(&efivars->lock);
spin_lock_irq(&efivars->lock);
/*
* Does this variable already exist?
@ -1458,7 +1473,7 @@ static ssize_t efivar_delete(struct file *filp, struct kobject *kobj,
}
}
if (!found) {
spin_unlock(&efivars->lock);
spin_unlock_irq(&efivars->lock);
return -EINVAL;
}
/* force the Attributes/DataSize to 0 to ensure deletion */
@ -1474,18 +1489,87 @@ static ssize_t efivar_delete(struct file *filp, struct kobject *kobj,
if (status != EFI_SUCCESS) {
printk(KERN_WARNING "efivars: set_variable() failed: status=%lx\n",
status);
spin_unlock(&efivars->lock);
spin_unlock_irq(&efivars->lock);
return -EIO;
}
list_del(&search_efivar->list);
/* We need to release this lock before unregistering. */
spin_unlock(&efivars->lock);
spin_unlock_irq(&efivars->lock);
efivar_unregister(search_efivar);
/* It's dead Jim.... */
return count;
}
static bool variable_is_present(efi_char16_t *variable_name, efi_guid_t *vendor)
{
struct efivar_entry *entry, *n;
struct efivars *efivars = &__efivars;
unsigned long strsize1, strsize2;
bool found = false;
strsize1 = utf16_strsize(variable_name, 1024);
list_for_each_entry_safe(entry, n, &efivars->list, list) {
strsize2 = utf16_strsize(entry->var.VariableName, 1024);
if (strsize1 == strsize2 &&
!memcmp(variable_name, &(entry->var.VariableName),
strsize2) &&
!efi_guidcmp(entry->var.VendorGuid,
*vendor)) {
found = true;
break;
}
}
return found;
}
static void efivar_update_sysfs_entries(struct work_struct *work)
{
struct efivars *efivars = &__efivars;
efi_guid_t vendor;
efi_char16_t *variable_name;
unsigned long variable_name_size = 1024;
efi_status_t status = EFI_NOT_FOUND;
bool found;
/* Add new sysfs entries */
while (1) {
variable_name = kzalloc(variable_name_size, GFP_KERNEL);
if (!variable_name) {
pr_err("efivars: Memory allocation failed.\n");
return;
}
spin_lock_irq(&efivars->lock);
found = false;
while (1) {
variable_name_size = 1024;
status = efivars->ops->get_next_variable(
&variable_name_size,
variable_name,
&vendor);
if (status != EFI_SUCCESS) {
break;
} else {
if (!variable_is_present(variable_name,
&vendor)) {
found = true;
break;
}
}
}
spin_unlock_irq(&efivars->lock);
if (!found) {
kfree(variable_name);
break;
} else
efivar_create_sysfs_entry(efivars,
variable_name_size,
variable_name, &vendor);
}
}
/*
* Let's not leave out systab information that snuck into
* the efivars driver
@ -1594,9 +1678,9 @@ efivar_create_sysfs_entry(struct efivars *efivars,
kfree(short_name);
short_name = NULL;
spin_lock(&efivars->lock);
spin_lock_irq(&efivars->lock);
list_add(&new_efivar->list, &efivars->list);
spin_unlock(&efivars->lock);
spin_unlock_irq(&efivars->lock);
return 0;
}
@ -1665,9 +1749,9 @@ void unregister_efivars(struct efivars *efivars)
struct efivar_entry *entry, *n;
list_for_each_entry_safe(entry, n, &efivars->list, list) {
spin_lock(&efivars->lock);
spin_lock_irq(&efivars->lock);
list_del(&entry->list);
spin_unlock(&efivars->lock);
spin_unlock_irq(&efivars->lock);
efivar_unregister(entry);
}
if (efivars->new_var)
@ -1823,6 +1907,8 @@ err_put:
static void __exit
efivars_exit(void)
{
cancel_work_sync(&efivar_work);
if (efi_enabled(EFI_RUNTIME_SERVICES)) {
unregister_efivars(&__efivars);
kobject_put(efi_kobj);

18
fs/pstore/inode.c
Просмотреть файл

@ -418,9 +418,25 @@ static struct file_system_type pstore_fs_type = {
.kill_sb = pstore_kill_sb,
};
static struct kobject *pstore_kobj;
static int __init init_pstore_fs(void)
{
return register_filesystem(&pstore_fs_type);
int err = 0;
/* Create a convenient mount point for people to access pstore */
pstore_kobj = kobject_create_and_add("pstore", fs_kobj);
if (!pstore_kobj) {
err = -ENOMEM;
goto out;
}
err = register_filesystem(&pstore_fs_type);
if (err < 0)
kobject_put(pstore_kobj);
out:
return err;
}
module_init(init_pstore_fs)

35
fs/pstore/platform.c
Просмотреть файл

@ -96,6 +96,27 @@ static const char *get_reason_str(enum kmsg_dump_reason reason)
}
}
bool pstore_cannot_block_path(enum kmsg_dump_reason reason)
{
/*
* In case of NMI path, pstore shouldn't be blocked
* regardless of reason.
*/
if (in_nmi())
return true;
switch (reason) {
/* In panic case, other cpus are stopped by smp_send_stop(). */
case KMSG_DUMP_PANIC:
/* Emergency restart shouldn't be blocked by spin lock. */
case KMSG_DUMP_EMERG:
return true;
default:
return false;
}
}
EXPORT_SYMBOL_GPL(pstore_cannot_block_path);
/*
* callback from kmsg_dump. (s2,l2) has the most recently
* written bytes, older bytes are in (s1,l1). Save as much
@ -114,10 +135,12 @@ static void pstore_dump(struct kmsg_dumper *dumper,
why = get_reason_str(reason);
if (in_nmi()) {
is_locked = spin_trylock(&psinfo->buf_lock);
if (!is_locked)
pr_err("pstore dump routine blocked in NMI, may corrupt error record\n");
if (pstore_cannot_block_path(reason)) {
is_locked = spin_trylock_irqsave(&psinfo->buf_lock, flags);
if (!is_locked) {
pr_err("pstore dump routine blocked in %s path, may corrupt error record\n"
, in_nmi() ? "NMI" : why);
}
} else
spin_lock_irqsave(&psinfo->buf_lock, flags);
oopscount++;
@ -143,9 +166,9 @@ static void pstore_dump(struct kmsg_dumper *dumper,
total += hsize + len;
part++;
}
if (in_nmi()) {
if (pstore_cannot_block_path(reason)) {
if (is_locked)
spin_unlock(&psinfo->buf_lock);
spin_unlock_irqrestore(&psinfo->buf_lock, flags);
} else
spin_unlock_irqrestore(&psinfo->buf_lock, flags);
}

3
include/linux/efi.h
Просмотреть файл

@ -740,7 +740,8 @@ struct efivars {
* 1) ->list - adds, removals, reads, writes
* 2) ops.[gs]et_variable() calls.
* It must not be held when creating sysfs entries or calling kmalloc.
* ops.get_next_variable() is only called from register_efivars(),
* ops.get_next_variable() is only called from register_efivars()
* or efivar_update_sysfs_entries(),
* which is protected by the BKL, so that path is safe.
*/
spinlock_t lock;

6
include/linux/pstore.h
Просмотреть файл

@ -68,12 +68,18 @@ struct pstore_info {
#ifdef CONFIG_PSTORE
extern int pstore_register(struct pstore_info *);
extern bool pstore_cannot_block_path(enum kmsg_dump_reason reason);
#else
static inline int
pstore_register(struct pstore_info *psi)
{
return -ENODEV;
}
static inline bool
pstore_cannot_block_path(enum kmsg_dump_reason reason)
{
return false;
}
#endif
#endif /*_LINUX_PSTORE_H*/