RE: [RFC][PATCH -next] make pstore/kmsg_dump run after stoppingother cpus in panic path

[Seiji Aguchi]

Don,

>That is part of the wider problem with kmsg_dump that Vivek talks about
>with me, is that it is just a giant hook in the panic path with limited
>auditing.  So we need to explicit set our expectations with BUG_ONs/WARNs
>otherwise we might get bit later by them.

I found an issue while developing a patch v2.

We can't call BUG_ON(in_nmi() && reason != KMSG_DUMP_PANIC)
because kmsg_dump(KMSG_DUMP_EMERG) is called in NMI context if "panic" kernel parameter is set.

I will keep doing research bust_spinlock() or vprintk() so that lockdep checking works and we can avoid any deadlocks.

Seiji
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