On Mon, Jun 14, 2021 at 01:37:06PM +0200, Daniel Wagner wrote:

On Tue, Jun 08, 2021 at 08:33:39PM +0200, Daniel Wagner wrote:

quoted

cpumask_first_and() returns >= nr_cpu_ids if the two provided masks do
not share a common bit. Verify we get a valid value back from
cpumask_first_and().

So I got feedback on this issue (but not on the patch itself yet). The
system starts with 16 virtual CPU cores and during the test 4 cores are
removed[1] and as soon there is an error on the storage side, the reset
code on the host ends up in this path and crashes. I still don't
understand why the CPU removal is not updating the CPU mask correctly
before we hit the reset path. I'll continue to investigate.

We don't update hctx->cpumask when CPU is added/removed, and that is
assigned against cpu_possible_mask from beginning.

It is one long-term issue, which can be triggered when all cpus in
hctx->cpumask become offline. The thing is that only nvmf_connect_io_queue()
allocates request via specified hctx.

thanks,
Ming