Commit 96480d9c authored by Seiji Aguchi's avatar Seiji Aguchi Committed by Tony Luck
Browse files

efi_pstore: Remove a logic erasing entries from a write callback to hold multiple logs 



[Issue]

Currently, efi_pstore driver simply overwrites existing panic messages in NVRAM.
So, in the following scenario, we will lose 1st panic messages.

1. kernel panics.
2. efi_pstore is kicked and writes panic messages to NVRAM.
3. system reboots.
4. kernel panics again before a user checks the 1st panic messages in NVRAM.

[Solution]

A reasonable solution to fix the issue is just holding multiple logs without erasing
existing entries.
This patch removes a logic erasing existing entries in a write callback
because the logic is not needed in the write callback to support holding multiple logs.

Signed-off-by: default avatarSeiji Aguchi <seiji.aguchi@hds.com>
Acked-by: default avatarMike Waychison <mikew@google.com>
Signed-off-by: default avatarTony Luck <tony.luck@intel.com>
parent dd230fec

drivers/firmware/efivars.c

+2 −37
Original line number Diff line number Diff line
@@ -701,18 +701,13 @@ static int efi_pstore_write(enum pstore_type_id type, 
		unsigned int part, size_t size, struct pstore_info *psi)

{

	char name[DUMP_NAME_LEN];

	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, 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);



	/*
@@ -730,35 +725,8 @@ static int efi_pstore_write(enum pstore_type_id type, 
		return -ENOSPC;

	}



	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);

	sprintf(name, "dump-type%u-%u-%lu", type, part,

		get_seconds());



	for (i = 0; i < DUMP_NAME_LEN; i++)

		efi_name[i] = name[i];
@@ -768,9 +736,6 @@ static int efi_pstore_write(enum pstore_type_id type, 


	spin_unlock(&efivars->lock);



	if (found)

		efivar_unregister(found);



	if (size)

		ret = efivar_create_sysfs_entry(efivars,

					  utf16_strsize(efi_name,

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