ACK: [SRU][J:linux-bluefield][PATCH v1 0/1] UBUNTU: SAUCE: ipmb_host: IPMI panic event causes hang

[Thibault Ferrante]

Acked-by: Thibault Ferrante <thibault.ferrante at canonical.com>


On 13/05/2025 14:36, Chris Babroski wrote:
> BugLink: https://bugs.launchpad.net/bugs/2110498
> 
> SRU Justification:
> 
> [Impact]
> 
> When the kernel configs CONFIG_IPMI_PANIC_EVENT or CONFIG_IPMI_PANIC_STRING
> are enabled the ipmi_msghandler driver will attempt to send the kernel
> panic event to the BMC to record in the SEL. It was found that this causes
> a hang on BlueField which can block kdump from running and rebooting the
> system after a kernel panic occurs.
> 
> [Fix]
> 
> The ipmi_msghandler driver requires the ipmi_smi_handlers "poll" and
> "set_run_to_completion" callbacks to be implemented in order to send the
> panic event. If those functions are not registered then panic eventing will
> be skipped.
> 
> In the BlueField ipmb_host driver these callbacks are registered, but are
> not implemented to do anything. When the IPMI panic handler runs it
> attempts to send the panic request and waits for the operation to be
> completed by polling. Because the poll handler is not fully implemented,
> this causes an infinite loop.
> 
> The fix is to remove unimplemented ipmi_smi handlers because IPMI panic
> eventing is not supported on BlueField.
> 
> [Test Case]
> 
> * Boot image on BF3 platform with updated ipmb_host driver
> * Verify no error messages or failures when loading ipmb_host driver.
> * Verify IPMI communication with BMC using "ipmitool mc info"
>    and "ipmitool lan print"
> * Enable NMI watchdog, trigger CPU hard lockup, verify BF3 saves crash
>    information and reboots automatically instead of hanging.
> 
> [Regression Potential]
> 
> Low potential for creating regression because the callback functions that
> were removed were not implemented to do anything and the ipmi_msghandler
> driver checks if the callbacks are NULL before calling them.
>