FAILED: patch "[PATCH] ipmi: fix SSIF not responding under certain cond." failed to apply to 4.19-stable tree

[<gregkh@linuxfoundation.org>]

The patch below does not apply to the 4.19-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@vger.kernel.org>.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-4.19.y
git checkout FETCH_HEAD
git cherry-pick -x 6d2555cde2918409b0331560e66f84a0ad4849c6
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable@vger.kernel.org>' --in-reply-to '2023050637-exposure-stoke-eef2@gregkh' --subject-prefix 'PATCH 4.19.y' HEAD^..

Possible dependencies:

6d2555cde291 ("ipmi: fix SSIF not responding under certain cond.")

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 6d2555cde2918409b0331560e66f84a0ad4849c6 Mon Sep 17 00:00:00 2001
From: Zhang Yuchen <zhangyuchen.lcr@bytedance.com>
Date: Wed, 12 Apr 2023 15:49:07 +0800
Subject: [PATCH] ipmi: fix SSIF not responding under certain cond.

The ipmi communication is not restored after a specific version of BMC is
upgraded on our server.
The ipmi driver does not respond after printing the following log:

    ipmi_ssif: Invalid response getting flags: 1c 1

I found that after entering this branch, ssif_info->ssif_state always
holds SSIF_GETTING_FLAGS and never return to IDLE.

As a result, the driver cannot be loaded, because the driver status is
checked during the unload process and must be IDLE in shutdown_ssif():

        while (ssif_info->ssif_state != SSIF_IDLE)
                schedule_timeout(1);

The process trigger this problem is:

1. One msg timeout and next msg start send, and call
ssif_set_need_watch().

2. ssif_set_need_watch()->watch_timeout()->start_flag_fetch() change
ssif_state to SSIF_GETTING_FLAGS.

3. In msg_done_handler() ssif_state == SSIF_GETTING_FLAGS, if an error
message is received, the second branch does not modify the ssif_state.

4. All retry action need IS_SSIF_IDLE() == True. Include retry action in
watch_timeout(), msg_done_handler(). Sending msg does not work either.
SSIF_IDLE is also checked in start_next_msg().

5. The only thing that can be triggered in the SSIF driver is
watch_timeout(), after destory_user(), this timer will stop too.

So, if enter this branch, the ssif_state will remain SSIF_GETTING_FLAGS
and can't send msg, no timer started, can't unload.

We did a comparative test before and after adding this patch, and the
result is effective.

Fixes: 259307074bfc ("ipmi: Add SMBus interface driver (SSIF)")

Cc: stable@vger.kernel.org
Signed-off-by: Zhang Yuchen <zhangyuchen.lcr@bytedance.com>
Message-Id: <20230412074907.80046-1-zhangyuchen.lcr@bytedance.com>
Signed-off-by: Corey Minyard <minyard@acm.org>

diff --git a/drivers/char/ipmi/ipmi_ssif.c b/drivers/char/ipmi/ipmi_ssif.c
index e4f6ecc12ed7..0eca46eea35c 100644
--- a/drivers/char/ipmi/ipmi_ssif.c
+++ b/drivers/char/ipmi/ipmi_ssif.c
@@ -786,9 +786,9 @@ static void msg_done_handler(struct ssif_info *ssif_info, int result,
 		} else if (data[0] != (IPMI_NETFN_APP_REQUEST | 1) << 2
 			   || data[1] != IPMI_GET_MSG_FLAGS_CMD) {
 			/*
-			 * Don't abort here, maybe it was a queued
-			 * response to a previous command.
+			 * Recv error response, give up.
 			 */
+			ssif_info->ssif_state = SSIF_IDLE;
 			ipmi_ssif_unlock_cond(ssif_info, flags);
 			dev_warn(&ssif_info->client->dev,
 				 "Invalid response getting flags: %x %x\n",