From: Zhang Yuchen zhangyuchen.lcr@bytedance.com
commit 6d2555cde2918409b0331560e66f84a0ad4849c6 upstream.
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 Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/char/ipmi/ipmi_ssif.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
--- a/drivers/char/ipmi/ipmi_ssif.c +++ b/drivers/char/ipmi/ipmi_ssif.c @@ -794,9 +794,9 @@ static void msg_done_handler(struct ssif } 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",