Commit 501302d5 authored by Xiao Liang's avatar Xiao Liang Committed by Herbert Xu
Browse files

padata: Reset next CPU when reorder sequence wraps around 



When seq_nr wraps around, the next reorder job with seq 0 is hashed to
the first CPU in padata_do_serial(). Correspondingly, need reset pd->cpu
to the first one when pd->processed wraps around. Otherwise, if the
number of used CPUs is not a power of 2, padata_find_next() will be
checking a wrong list, hence deadlock.

Fixes: 6fc4dbcf ("padata: Replace delayed timer with immediate workqueue in padata_reorder")
Cc: <stable@vger.kernel.org>
Signed-off-by: default avatarXiao Liang <shaw.leon@gmail.com>
Signed-off-by: default avatarHerbert Xu <herbert@gondor.apana.org.au>
parent 56a50e37

kernel/padata.c

+5 −1
Original line number Diff line number Diff line
@@ -291,8 +291,12 @@ static void padata_reorder(struct padata_priv *padata) 
		struct padata_serial_queue *squeue;

		int cb_cpu;



		cpu = cpumask_next_wrap(cpu, pd->cpumask.pcpu);

		processed++;

		/* When sequence wraps around, reset to the first CPU. */

		if (unlikely(processed == 0))

			cpu = cpumask_first(pd->cpumask.pcpu);

		else

			cpu = cpumask_next_wrap(cpu, pd->cpumask.pcpu);



		cb_cpu = padata->cb_cpu;

		squeue = per_cpu_ptr(pd->squeue, cb_cpu);