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efi_pstore: Check remaining space with QueryVariableInfo() before writing data 

[Issue]

As discussed in a thread below, Running out of space in EFI isn't a well-tested scenario.
And we wouldn't expect all firmware to handle it gracefully.
http://marc.info/?l=linux-kernel&m=134305325801789&w=2

On the other hand, current efi_pstore doesn't check a remaining space of storage at writing time.
Therefore, efi_pstore may not work if it tries to write a large amount of data.

[Patch Description]

To avoid handling the situation above, this patch checks if there is a space enough to log with
QueryVariableInfo() before writing data.

Signed-off-by: Seiji Aguchi <seiji.aguchi@hds.com>
Acked-by: Mike Waychison <mikew@google.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
This commit is contained in:
Seiji Aguchi 2012-11-14 20:25:37 +00:00 committed by Tony Luck
parent 9489e9dcae
commit d80a361d77
2 changed files with 19 additions and 0 deletions
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18
drivers/firmware/efivars.c
View File

@ -707,12 +707,29 @@ static int efi_pstore_write(enum pstore_type_id type,
struct efivars *efivars = psi->data;
struct efivar_entry *entry, *found = NULL;
int i, ret = 0;
u64 storage_space, remaining_space, max_variable_size;
efi_status_t status = EFI_NOT_FOUND;
sprintf(stub_name, "dump-type%u-%u-", type, part);
sprintf(name, "%s%lu", stub_name, get_seconds());
spin_lock(&efivars->lock);
/*
* Check if there is a space enough to log.
* size: a size of logging data
* DUMP_NAME_LEN * 2: a maximum size of variable name
*/
status = efivars->ops->query_variable_info(PSTORE_EFI_ATTRIBUTES,
&storage_space,
&remaining_space,
&max_variable_size);
if (status || remaining_space < size + DUMP_NAME_LEN * 2) {
spin_unlock(&efivars->lock);
*id = part;
return -ENOSPC;
}
for (i = 0; i < DUMP_NAME_LEN; i++)
efi_name[i] = stub_name[i];
@ -1237,6 +1254,7 @@ efivars_init(void)
ops.get_variable = efi.get_variable;
ops.set_variable = efi.set_variable;
ops.get_next_variable = efi.get_next_variable;
ops.query_variable_info = efi.query_variable_info;
error = register_efivars(&__efivars, &ops, efi_kobj);
if (error)
goto err_put;

1
include/linux/efi.h
View File

@ -643,6 +643,7 @@ struct efivar_operations {
efi_get_variable_t *get_variable;
efi_get_next_variable_t *get_next_variable;
efi_set_variable_t *set_variable;
efi_query_variable_info_t *query_variable_info;
};
struct efivars {