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commit6d2555cde2upstream. 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:259307074b("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>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.