On 8/21/19 11:51 PM, Herbert Xu wrote:
On Mon, Aug 12, 2019 at 05:02:00PM -0400, Daniel Jordan wrote:__padata_remove_cpu clears the offlined CPU from the usable masks after padata_alloc_pd has initialized pd->cpu, which means pd->cpu could be initialized to this CPU, causing padata to wait indefinitely for the next job in padata_get_next. Make the usable masks reflect the offline CPU when they're established in padata_setup_cpumasks so pd->cpu is initialized properly. Fixes: 6fc4dbcf0276 ("padata: Replace delayed timer with immediate workqueue in padata_reorder") Signed-off-by: Daniel Jordan <daniel.m.jordan@xxxxxxxxxx> Cc: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx> Cc: Steffen Klassert <steffen.klassert@xxxxxxxxxxx> Cc: linux-crypto@xxxxxxxxxxxxxxx Cc: linux-kernel@xxxxxxxxxxxxxxx --- Hi, one more edge case. All combinations of CPUs among parallel_cpumask, serial_cpumask, and CPU hotplug have now been tested in a 4-CPU VM, and an 8-CPU VM has run with random combinations of these settings for over an hour. kernel/padata.c | 18 ++++++++++++++---- 1 file changed, 14 insertions(+), 4 deletions(-)If we modify patch 2/2 by calling this after cpu_online_mask has been updated then this problem should go away because we can then remove the cpumask_clear_cpu calls.
Yep, agreed.
