Re: [PATCH] padata: use smp_mb in padata_reorder to avoid orphaned padata jobs

From: Herbert Xu
Date: Sat Jul 13 2019 - 01:03:50 EST


On Fri, Jul 12, 2019 at 12:07:37PM -0400, Daniel Jordan wrote:
>
> modprobe (CPU2) kworker/21:1-293 (CPU21) kworker/5:2-276 (CPU5)
> -------------------------- ------------------------ ----------------------
> <submit job, seq_nr=16581>
> ...
> padata_do_parallel
> queue_work_on(21, ...)
> <sleeps>
> padata_parallel_worker
> pcrypt_aead_dec
> padata_do_serial
> padata_reorder

This can't happen because if the job started on CPU2 then it must
go back to CPU2 for completion. IOW padata_do_serial should be
punting this to a work queue for CPU2 rather than calling
padata_reorder on CPU21.

Cheers,
--
Email: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx>
Home Page: http://gondor.apana.org.au/~herbert/
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