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[PATCH] ibmasm driver: fix race in command refcount logic 

This patch fixes a race in the command reference counting logic by putting
spinlocks around kobject_put() in the command_put function.

- Also added debug messages.

- Changed a memcpy to memcpy_fromio since we are reading from io space.

Signed-off-by: Max Asbock <masbock@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
hifive-unleashed-5.1
Max Asbock 2005-06-21 17:16:36 -07:00 committed by Linus Torvalds
parent 278d72ae88
commit 8818760512
6 changed files with 51 additions and 13 deletions
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30
drivers/misc/ibmasm/command.c
View File

@ -23,6 +23,7 @@
*/
#include "ibmasm.h"
#include "lowlevel.h"
static void exec_next_command(struct service_processor *sp);
static void free_command(struct kobject *kobj);
@ -31,8 +32,9 @@ static struct kobj_type ibmasm_cmd_kobj_type = {
.release = free_command,
};
static atomic_t command_count = ATOMIC_INIT(0);
struct command *ibmasm_new_command(size_t buffer_size)
struct command *ibmasm_new_command(struct service_processor *sp, size_t buffer_size)
{
struct command *cmd;
@ -55,11 +57,15 @@ struct command *ibmasm_new_command(size_t buffer_size)
kobject_init(&cmd->kobj);
cmd->kobj.ktype = &ibmasm_cmd_kobj_type;
cmd->lock = &sp->lock;
cmd->status = IBMASM_CMD_PENDING;
init_waitqueue_head(&cmd->wait);
INIT_LIST_HEAD(&cmd->queue_node);
atomic_inc(&command_count);
dbg("command count: %d\n", atomic_read(&command_count));
return cmd;
}
@ -68,6 +74,8 @@ static void free_command(struct kobject *kobj)
struct command *cmd = to_command(kobj);
list_del(&cmd->queue_node);
atomic_dec(&command_count);
dbg("command count: %d\n", atomic_read(&command_count));
kfree(cmd->buffer);
kfree(cmd);
}
@ -94,8 +102,14 @@ static struct command *dequeue_command(struct service_processor *sp)
static inline void do_exec_command(struct service_processor *sp)
{
char tsbuf[32];
dbg("%s:%d at %s\n", __FUNCTION__, __LINE__, get_timestamp(tsbuf));
if (ibmasm_send_i2o_message(sp)) {
sp->current_command->status = IBMASM_CMD_FAILED;
wake_up(&sp->current_command->wait);
command_put(sp->current_command);
exec_next_command(sp);
}
}
@ -111,14 +125,16 @@ static inline void do_exec_command(struct service_processor *sp)
void ibmasm_exec_command(struct service_processor *sp, struct command *cmd)
{
unsigned long flags;
char tsbuf[32];
dbg("%s:%d at %s\n", __FUNCTION__, __LINE__, get_timestamp(tsbuf));
spin_lock_irqsave(&sp->lock, flags);
if (!sp->current_command) {
command_get(cmd);
sp->current_command = cmd;
command_get(sp->current_command);
spin_unlock_irqrestore(&sp->lock, flags);
do_exec_command(sp);
} else {
enqueue_command(sp, cmd);
@ -129,9 +145,9 @@ void ibmasm_exec_command(struct service_processor *sp, struct command *cmd)
static void exec_next_command(struct service_processor *sp)
{
unsigned long flags;
char tsbuf[32];
wake_up(&sp->current_command->wait);
command_put(sp->current_command);
dbg("%s:%d at %s\n", __FUNCTION__, __LINE__, get_timestamp(tsbuf));
spin_lock_irqsave(&sp->lock, flags);
sp->current_command = dequeue_command(sp);
@ -169,7 +185,9 @@ void ibmasm_receive_command_response(struct service_processor *sp, void *respons
if (!sp->current_command)
return;
memcpy(cmd->buffer, response, min(size, cmd->buffer_size));
memcpy_fromio(cmd->buffer, response, min(size, cmd->buffer_size));
cmd->status = IBMASM_CMD_COMPLETE;
wake_up(&sp->current_command->wait);
command_put(sp->current_command);
exec_next_command(sp);
}

10
drivers/misc/ibmasm/dot_command.c
View File

@ -33,7 +33,13 @@ void ibmasm_receive_message(struct service_processor *sp, void *message, int mes
u32 size;
struct dot_command_header *header = (struct dot_command_header *)message;
if (message_size == 0)
return;
size = get_dot_command_size(message);
if (size == 0)
return;
if (size > message_size)
size = message_size;
@ -67,7 +73,7 @@ int ibmasm_send_driver_vpd(struct service_processor *sp)
u8 *vpd_data;
int result = 0;
command = ibmasm_new_command(INIT_BUFFER_SIZE);
command = ibmasm_new_command(sp, INIT_BUFFER_SIZE);
if (command == NULL)
return -ENOMEM;
@ -121,7 +127,7 @@ int ibmasm_send_os_state(struct service_processor *sp, int os_state)
struct os_state_command *os_state_cmd;
int result = 0;
cmd = ibmasm_new_command(sizeof(struct os_state_command));
cmd = ibmasm_new_command(sp, sizeof(struct os_state_command));
if (cmd == NULL)
return -ENOMEM;

13
drivers/misc/ibmasm/heartbeat.c
View File

@ -25,6 +25,7 @@
#include <linux/notifier.h>
#include "ibmasm.h"
#include "dot_command.h"
#include "lowlevel.h"
static int suspend_heartbeats = 0;
@ -62,7 +63,7 @@ void ibmasm_unregister_panic_notifier(void)
int ibmasm_heartbeat_init(struct service_processor *sp)
{
sp->heartbeat = ibmasm_new_command(HEARTBEAT_BUFFER_SIZE);
sp->heartbeat = ibmasm_new_command(sp, HEARTBEAT_BUFFER_SIZE);
if (sp->heartbeat == NULL)
return -ENOMEM;
@ -71,6 +72,12 @@ int ibmasm_heartbeat_init(struct service_processor *sp)
void ibmasm_heartbeat_exit(struct service_processor *sp)
{
char tsbuf[32];
dbg("%s:%d at %s\n", __FUNCTION__, __LINE__, get_timestamp(tsbuf));
ibmasm_wait_for_response(sp->heartbeat, IBMASM_CMD_TIMEOUT_NORMAL);
dbg("%s:%d at %s\n", __FUNCTION__, __LINE__, get_timestamp(tsbuf));
suspend_heartbeats = 1;
command_put(sp->heartbeat);
}
@ -78,14 +85,16 @@ void ibmasm_receive_heartbeat(struct service_processor *sp, void *message, size
{
struct command *cmd = sp->heartbeat;
struct dot_command_header *header = (struct dot_command_header *)cmd->buffer;
char tsbuf[32];
dbg("%s:%d at %s\n", __FUNCTION__, __LINE__, get_timestamp(tsbuf));
if (suspend_heartbeats)
return;
/* return the received dot command to sender */
cmd->status = IBMASM_CMD_PENDING;
size = min(size, cmd->buffer_size);
memcpy(cmd->buffer, message, size);
memcpy_fromio(cmd->buffer, message, size);
header->type = sp_write;
ibmasm_exec_command(sp, cmd);
}

7
drivers/misc/ibmasm/ibmasm.h
View File

@ -95,12 +95,17 @@ struct command {
size_t buffer_size;
int status;
struct kobject kobj;
spinlock_t *lock;
};
#define to_command(c) container_of(c, struct command, kobj)
static inline void command_put(struct command *cmd)
{
unsigned long flags;
spin_lock_irqsave(cmd->lock, flags);
kobject_put(&cmd->kobj);
spin_unlock_irqrestore(cmd->lock, flags);
}
static inline void command_get(struct command *cmd)
@ -159,7 +164,7 @@ struct service_processor {
};
/* command processing */
extern struct command *ibmasm_new_command(size_t buffer_size);
extern struct command *ibmasm_new_command(struct service_processor *sp, size_t buffer_size);
extern void ibmasm_exec_command(struct service_processor *sp, struct command *cmd);
extern void ibmasm_wait_for_response(struct command *cmd, int timeout);
extern void ibmasm_receive_command_response(struct service_processor *sp, void *response, size_t size);

2
drivers/misc/ibmasm/ibmasmfs.c
View File

@ -321,7 +321,7 @@ static ssize_t command_file_write(struct file *file, const char __user *ubuff, s
if (command_data->command)
return -EAGAIN;
cmd = ibmasm_new_command(count);
cmd = ibmasm_new_command(command_data->sp, count);
if (!cmd)
return -ENOMEM;

2
drivers/misc/ibmasm/r_heartbeat.c
View File

@ -63,7 +63,7 @@ int ibmasm_start_reverse_heartbeat(struct service_processor *sp, struct reverse_
int times_failed = 0;
int result = 1;
cmd = ibmasm_new_command(sizeof rhb_dot_cmd);
cmd = ibmasm_new_command(sp, sizeof rhb_dot_cmd);
if (!cmd)
return -ENOMEM;