[PATCH 4.9 23/25] ipmi: fix unsigned long underflow

Greg Kroah-Hartman
2017-11-22T10:14:57Z

From: Corey Minyard <cminyard@mvista.com>

commit 392a17b10ec4320d3c0e96e2a23ebaad1123b989 upstream.

When I set the timeout to a specific value such as 500ms, the timeout
event will not happen in time due to the overflow in function
check_msg_timeout:
...
ent->timeout -= timeout_period;
if (ent->timeout > 0)
return;
...

The type of timeout_period is long, but ent->timeout is unsigned long.
This patch makes the type consistent.

Reported-by: Weilong Chen <chenweilong@huawei.com>
Signed-off-by: Corey Minyard <cminyard@mvista.com>
Tested-by: Weilong Chen <chenweilong@huawei.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/char/ipmi/ipmi_msghandler.c | 10 ++++++----
1 file changed, 6 insertions(+), 4 deletions(-)

--- a/drivers/char/ipmi/ipmi_msghandler.c
+++ b/drivers/char/ipmi/ipmi_msghandler.c
@@ -4029,7 +4029,8 @@ smi_from_recv_msg(ipmi_smi_t intf, struc
}

static void check_msg_timeout(ipmi_smi_t intf, struct seq_table *ent,
- struct list_head *timeouts, long timeout_period,
+ struct list_head *timeouts,
+ unsigned long timeout_period,
int slot, unsigned long *flags,
unsigned int *waiting_msgs)
{
@@ -4042,8 +4043,8 @@ static void check_msg_timeout(ipmi_smi_t
if (!ent->inuse)
return;

- ent->timeout -= timeout_period;
- if (ent->timeout > 0) {
+ if (timeout_period < ent->timeout) {
+ ent->timeout -= timeout_period;
(*waiting_msgs)++;
return;
}
@@ -4109,7 +4110,8 @@ static void check_msg_timeout(ipmi_smi_t
}
}

-static unsigned int ipmi_timeout_handler(ipmi_smi_t intf, long timeout_period)
+static unsigned int ipmi_timeout_handler(ipmi_smi_t intf,
+ unsigned long timeout_period)
{
struct list_head timeouts;
struct ipmi_recv_msg *msg, *msg2;