* [patch][4/4] ibmasm driver: fix race in command refcount logic
@ 2005-06-16 20:20 Max Asbock
0 siblings, 0 replies; only message in thread
From: Max Asbock @ 2005-06-16 20:20 UTC (permalink / raw)
To: linux-kernel; +Cc: Vernon Mauery
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>
diff -urN linux-2.6.12-rc6.test/drivers/misc/ibmasm/command.c linux-2.6.12-rc6.ibmasm/drivers/misc/ibmasm/command.c
--- linux-2.6.12-rc6.test/drivers/misc/ibmasm/command.c 2005-06-09 18:02:28.021406968 -0700
+++ linux-2.6.12-rc6.ibmasm/drivers/misc/ibmasm/command.c 2005-06-08 17:54:09.512988256 -0700
@@ -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 @@
.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 @@
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 @@
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 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 @@
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 @@
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 @@
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);
}
--- linux-2.6.12-rc6.test/drivers/misc/ibmasm/dot_command.c 2005-06-09 18:02:28.021406968 -0700
+++ linux-2.6.12-rc6.ibmasm/drivers/misc/ibmasm/dot_command.c 2005-06-08 17:54:09.517987496 -0700
@@ -33,7 +33,13 @@
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 @@
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 @@
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;
--- linux-2.6.12-rc6.test/drivers/misc/ibmasm/heartbeat.c 2005-06-09 18:02:28.022406816 -0700
+++ linux-2.6.12-rc6.ibmasm/drivers/misc/ibmasm/heartbeat.c 2005-06-08 17:54:09.525986280 -0700
@@ -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 @@
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 @@
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 @@
{
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);
}
--- linux-2.6.12-rc6.test/drivers/misc/ibmasm/ibmasmfs.c 2005-06-09 23:01:41.535058032 -0700
+++ linux-2.6.12-rc6.ibmasm/drivers/misc/ibmasm/ibmasmfs.c 2005-06-08 17:54:09.533985064 -0700
@@ -321,7 +321,7 @@
if (command_data->command)
return -EAGAIN;
- cmd = ibmasm_new_command(count);
+ cmd = ibmasm_new_command(command_data->sp, count);
if (!cmd)
return -ENOMEM;
--- linux-2.6.12-rc6.test/drivers/misc/ibmasm/ibmasm.h 2005-06-09 23:01:41.536057880 -0700
+++ linux-2.6.12-rc6.ibmasm/drivers/misc/ibmasm/ibmasm.h 2005-06-08 17:54:09.534984912 -0700
@@ -91,12 +91,17 @@
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)
@@ -155,7 +160,7 @@
};
/* 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);
diff -urN linux-2.6.12-rc6.test/drivers/misc/ibmasm/r_heartbeat.c linux-2.6.12-rc6.ibmasm/drivers/misc/ibmasm/r_heartbeat.c
--- linux-2.6.12-rc6.test/drivers/misc/ibmasm/r_heartbeat.c 2005-06-09 18:02:28.022406816 -0700
+++ linux-2.6.12-rc6.ibmasm/drivers/misc/ibmasm/r_heartbeat.c 2005-06-08 17:54:09.545983240 -0700
@@ -63,7 +63,7 @@
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;
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