linux

iv/linux

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Zhang Yuchen ba81099935 ipmi: fix SSIF not responding under certain cond.

[ Upstream commit 6d2555cde2918409b0331560e66f84a0ad4849c6 ]

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: Sasha Levin <sashal@kernel.org>

2023-05-17 11:13:22 +02:00

bt-bmc.c

ipmi: Add or fix SPDX-License-Identifier in all files

2018-02-27 07:42:51 -06:00

ipmi_bt_sm.c

ipmi: Move BT capabilities detection to the detect call

2018-08-31 08:42:59 -05:00

ipmi_devintf.c

ipmi_devintf: Add an error return on invalid ioctls

2018-04-18 10:23:04 -05:00

ipmi_dmi.c

ipmi:dmi: Ignore IPMI SMBIOS entries with a zero base address