[PATCH] ipmi: code cleanup and prevent potential issue.

From: wu000273
Date: Tue Jun 09 2020 - 02:04:27 EST


From: Qiushi Wu <wu000273@xxxxxxx>

All the previous get/put operations against intf->refcount are
inside the mutex. Thus, put the last kref_put() also inside mutex
to make sure get/put functions execute in order and prevent the
potential race condition.

Signed-off-by: Qiushi Wu <wu000273@xxxxxxx>
---
drivers/char/ipmi/ipmi_msghandler.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/char/ipmi/ipmi_msghandler.c b/drivers/char/ipmi/ipmi_msghandler.c
index e1b22fe0916c..d34343e34272 100644
--- a/drivers/char/ipmi/ipmi_msghandler.c
+++ b/drivers/char/ipmi/ipmi_msghandler.c
@@ -2583,10 +2583,11 @@ static int __bmc_get_device_id(struct ipmi_smi *intf, struct bmc_device *bmc,
*guid = bmc->guid;
}

+ kref_put(&intf->refcount, intf_free);
+
mutex_unlock(&bmc->dyn_mutex);
mutex_unlock(&intf->bmc_reg_mutex);

- kref_put(&intf->refcount, intf_free);
return rv;
}

--
2.17.1