IPMI driver can be unloaded when being accessed by user space

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Environment

SUSE Linux Enterprise Server 15 Support Pack 1

Situation

The ipmi_si driver can be unloaded when /dev/ipmi is opened by user space utilities.

On Dell EMC PowerEdge systems with SLES 15 SP1 installed, this could lead to side effects such as the following message below being logged in iDRAC System Event Log when iSM (iDRAC Service Module) is running.

iSM uses /dev/ipmi device to communicate with iDRAC and the communication may break if ipmi_si driver is unloaded and following message is logged.

The watchdog timer expired

Resolution

The issue is addressed in the following upstream commit :

ipmi: Don't allow device module unload when in use
https://github.com/torvalds/linux/commit/cbb79863fc3175ed5ac506465948b02a893a8235

This is resolved in SUSE Linux Enterprise Server 15 SP1 Maintenance Update Kernel version 4.12.14-197.34.1 and later (04 Mar 2020 - the Linux Kernel 560)

Cause

Currently, it is possible to unload the driver when in use.

Disclaimer

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