Re: [RFC v3 1/9] sysrq: Implement __handle_sysrq_nolock to avoid recursive locking in kdb

[Steven Rostedt]

On Fri, 25 Apr 2014 17:29:22 +0100
Daniel Thompson <daniel.thompson@xxxxxxxxxx> wrote:

> If kdb is triggered using SysRq-g then any use of the sr command results
> in the SysRq key table lock being recursively acquired, killing the debug
> session. That patch resolves the problem by introducing a _nolock
> alternative for __handle_sysrq.
> 
> Strictly speaking this approach risks racing on the key table when kdb is
> triggered by something other than SysRq-g however in that case any other
> CPU involved should release the spin lock before kgdb parks the slave
> CPUs.

Is that case documented somewhere in the code comments?

-- Steve
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