[PATCH 5.10.y] ipmi:ssif: Clean up kthread on errors

[Corey Minyard <corey@minyard.net>]

If an error occurs after the ssif kthread is created, but before the
main IPMI code starts the ssif interface, the ssif kthread will not
be stopped.

So make sure the kthread is stopped on an error condition if it is
running.

Fixes: 259307074bfc ("ipmi: Add SMBus interface driver (SSIF)")
Reported-by: Li Xiao <<252270051@hdu.edu.cn>
Cc: stable@vger.kernel.org
Reviewed-by: Li Xiao <252270051@hdu.edu.cn>
[Adjusted for stopping flag and complete operation still being present.]
Signed-off-by: Corey Minyard <corey@minyard.net>
(cherry picked from commit 75c486cb1bcaa1a3ec3a6438498176a3a4998ae4)
---
Version 2 of this patch, not taking a patch and then doing the fix
for it later, but just doing the patch.  The fix for setting the
thread to NULL on an ERR_PTR() error return is already in the main
kernel and should be coming to stable.

 drivers/char/ipmi/ipmi_ssif.c | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/drivers/char/ipmi/ipmi_ssif.c b/drivers/char/ipmi/ipmi_ssif.c
index 430302d2da6e..b884bfae7fa6 100644
--- a/drivers/char/ipmi/ipmi_ssif.c
+++ b/drivers/char/ipmi/ipmi_ssif.c
@@ -1292,6 +1292,7 @@ static void shutdown_ssif(void *send_info)
 	if (ssif_info->thread) {
 		complete(&ssif_info->wake_thread);
 		kthread_stop(ssif_info->thread);
+		ssif_info->thread = NULL;
 	}
 }
 
@@ -1922,6 +1923,17 @@ static int ssif_probe(struct i2c_client *client, const struct i2c_device_id *id)
 
  out:
 	if (rv) {
+		/*
+		 * If ipmi_register_smi() starts the interface, it will
+		 * call shutdown and that will free the thread and set
+		 * it to NULL.  Otherwise it must be freed here.
+		 */
+		if (ssif_info->thread) {
+			ssif_info->stopping = true;
+			complete(&ssif_info->wake_thread);
+			kthread_stop(ssif_info->thread);
+			ssif_info->thread = NULL;
+		}
 		if (addr_info)
 			addr_info->client = NULL;
 
-- 
2.43.0