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ACPI / IPMI: Fix race caused by the timed out ACPI IPMI transfers

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This patch fixes races caused by timed out ACPI IPMI transfers.

This patch uses timeout mechanism provided by ipmi_si to avoid the race
that the msg_done flag is set but without any protection, its content can
be invalid.  Thanks for the suggestion of Corey Minyard.

Signed-off-by: Lv Zheng <lv.zheng@intel.com>
Reviewed-by: Huang Ying <ying.huang@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
This commit is contained in:
Lv Zheng 2013-09-13 13:13:47 +08:00 committed by Rafael J. Wysocki
parent 5ac557ef49
commit 8584ec6ae9
1 changed files with 27 additions and 22 deletions
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49
drivers/acpi/acpi_ipmi.c
View file

@ -51,7 +51,7 @@ MODULE_LICENSE("GPL");
#define ACPI_IPMI_TIMEOUT 0x10
#define ACPI_IPMI_UNKNOWN 0x07
/* the IPMI timeout is 5s */
#define IPMI_TIMEOUT (5 * HZ)
#define IPMI_TIMEOUT (5000)
#define ACPI_IPMI_MAX_MSG_LENGTH 64
struct acpi_ipmi_device {
@ -135,6 +135,7 @@ static struct acpi_ipmi_msg *acpi_alloc_ipmi_msg(struct acpi_ipmi_device *ipmi)
init_completion(&ipmi_msg->tx_complete);
INIT_LIST_HEAD(&ipmi_msg->head);
ipmi_msg->device = ipmi;
ipmi_msg->msg_done = ACPI_IPMI_UNKNOWN;
return ipmi_msg;
}
@ -192,7 +193,7 @@ static int acpi_format_ipmi_request(struct acpi_ipmi_msg *tx_msg,
}
static void acpi_format_ipmi_response(struct acpi_ipmi_msg *msg,
acpi_integer *value, int rem_time)
acpi_integer *value)
{
struct acpi_ipmi_buffer *buffer;
@ -201,24 +202,17 @@ static void acpi_format_ipmi_response(struct acpi_ipmi_msg *msg,
* IPMI message returned by IPMI command.
*/
buffer = (struct acpi_ipmi_buffer *)value;
if (!rem_time && !msg->msg_done) {
buffer->status = ACPI_IPMI_TIMEOUT;
return;
}
/*
* If the flag of msg_done is not set or the recv length is zero, it
* means that the IPMI command is not executed correctly.
* The status code will be ACPI_IPMI_UNKNOWN.
* If the flag of msg_done is not set, it means that the IPMI command is
* not executed correctly.
*/
if (!msg->msg_done || !msg->rx_len) {
buffer->status = ACPI_IPMI_UNKNOWN;
buffer->status = msg->msg_done;
if (msg->msg_done != ACPI_IPMI_OK)
return;
}
/*
* If the IPMI response message is obtained correctly, the status code
* will be ACPI_IPMI_OK
*/
buffer->status = ACPI_IPMI_OK;
buffer->length = msg->rx_len;
memcpy(buffer->data, msg->data, msg->rx_len);
}
@ -280,11 +274,23 @@ static void ipmi_msg_handler(struct ipmi_recv_msg *msg, void *user_msg_data)
dev_WARN_ONCE(&pnp_dev->dev, true,
"Unexpected response (msg len %d).\n",
msg->msg.data_len);
} else {
tx_msg->rx_len = msg->msg.data_len;
memcpy(tx_msg->data, msg->msg.data, tx_msg->rx_len);
tx_msg->msg_done = 1;
goto out_comp;
}
/* response msg is an error msg */
msg->recv_type = IPMI_RESPONSE_RECV_TYPE;
if (msg->recv_type == IPMI_RESPONSE_RECV_TYPE &&
msg->msg.data_len == 1) {
if (msg->msg.data[0] == IPMI_TIMEOUT_COMPLETION_CODE) {
dev_WARN_ONCE(&pnp_dev->dev, true,
"Unexpected response (timeout).\n");
tx_msg->msg_done = ACPI_IPMI_TIMEOUT;
}
goto out_comp;
}
tx_msg->rx_len = msg->msg.data_len;
memcpy(tx_msg->data, msg->msg.data, tx_msg->rx_len);
tx_msg->msg_done = ACPI_IPMI_OK;
out_comp:
complete(&tx_msg->tx_complete);
out_lock:
spin_unlock_irqrestore(&ipmi_device->tx_msg_lock, flags);
@ -392,7 +398,7 @@ acpi_ipmi_space_handler(u32 function, acpi_physical_address address,
{
struct acpi_ipmi_msg *tx_msg;
struct acpi_ipmi_device *ipmi_device = handler_context;
int err, rem_time;
int err;
acpi_status status;
unsigned long flags;
/*
@ -422,14 +428,13 @@ acpi_ipmi_space_handler(u32 function, acpi_physical_address address,
&tx_msg->addr,
tx_msg->tx_msgid,
&tx_msg->tx_message,
NULL, 0, 0, 0);
NULL, 0, 0, IPMI_TIMEOUT);
if (err) {
status = AE_ERROR;
goto out_list;
}
rem_time = wait_for_completion_timeout(&tx_msg->tx_complete,
IPMI_TIMEOUT);
acpi_format_ipmi_response(tx_msg, value, rem_time);
wait_for_completion(&tx_msg->tx_complete);
acpi_format_ipmi_response(tx_msg, value);
status = AE_OK;
out_list: