[Problem]
efi_pstore creates sysfs files when logging kernel messages to NVRAM.
Currently, the sysfs files are updated in a workqueue which is registered in a
write callback.
On the other hand, a situation which users need the sysfs files is just oops
case because a system will
be down and they can't access to sysfs files in other cases like panic, reboot
or emergency_restart.
Also, if kernel panics due to a bug of workqueue operations and a write
callback of efi_pstore is called in
panic case, efi_pstore may fail due to a failure of schedule_work().
And panic_notifier_chain()/emergency_restart() is not kicked if efi_pstore
fails.
This may cause user's unwanted result.
[Patch Description]
This patch skips a registration of a workqueue in a write callback in cases
other than oops.
Also, a logic of erase callback is freshly created instead of sharing with a
write callback because the sysfs
operation is kicked in just oops case in a write callback and an erase callback
doesn't work without any change.
By separating a logic to a write callback, an erase callback works correctly.
Signed-off-by: Seiji Aguchi <seiji.agu...@hds.com>
---
drivers/firmware/efivars.c | 53 ++++++++++++++++++++++++++++++++++++++++++-
1 files changed, 51 insertions(+), 2 deletions(-)
diff --git a/drivers/firmware/efivars.c b/drivers/firmware/efivars.c
index 8717ea9..4811abb 100644
--- a/drivers/firmware/efivars.c
+++ b/drivers/firmware/efivars.c
@@ -747,7 +747,11 @@ static int efi_pstore_write(enum pstore_type_id type,
spin_unlock_irqrestore(&efivars->lock, flags);
- schedule_work(&efivar_work);
+ /*
+ * The user may want to see an entry for this write in sysfs.
+ */
+ if (reason == KMSG_DUMP_OOPS)
+ schedule_work(&efivar_work);
*id = part;
return ret;
@@ -756,7 +760,52 @@ static int efi_pstore_write(enum pstore_type_id type,
static int efi_pstore_erase(enum pstore_type_id type, u64 id,
struct pstore_info *psi)
{
- efi_pstore_write(type, 0, &id, (unsigned int)id, 0, psi);
+ char stub_name[DUMP_NAME_LEN];
+ efi_char16_t efi_name[DUMP_NAME_LEN];
+ efi_guid_t vendor = LINUX_EFI_CRASH_GUID;
+ struct efivars *efivars = psi->data;
+ struct efivar_entry *entry, *found = NULL;
+ int i;
+ unsigned long flags;
+
+ sprintf(stub_name, "dump-type%u-%llu-", type, id);
+
+ spin_lock_irqsave(&efivars->lock, flags);
+
+ for (i = 0; i < DUMP_NAME_LEN; i++)
+ efi_name[i] = stub_name[i];
+
+ /*
+ * Clean up any entries with the same name
+ */
+
+ list_for_each_entry(entry, &efivars->list, list) {
+ get_var_data_locked(efivars, &entry->var);
+
+ if (efi_guidcmp(entry->var.VendorGuid, vendor))
+ continue;
+ if (utf16_strncmp(entry->var.VariableName, efi_name,
+ utf16_strlen(efi_name)))
+ continue;
+ /* Needs to be a prefix */
+ if (entry->var.VariableName[utf16_strlen(efi_name)] == 0)
+ continue;
+
+ /* found */
+ found = entry;
+ efivars->ops->set_variable(entry->var.VariableName,
+ &entry->var.VendorGuid,
+ PSTORE_EFI_ATTRIBUTES,
+ 0, NULL);
+ }
+
+ if (found)
+ list_del(&found->list);
+
+ spin_unlock_irqrestore(&efivars->lock, flags);
+
+ if (found)
+ efivar_unregister(found);
return 0;
}
-- 1.7.1
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