[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [PATCH v2] xen/sched: fix sched_move_domain()
When moving a domain out of a cpupool running with the credit2 scheduler and having multiple run-queues, the following ASSERT() can be observed: (XEN) Xen call trace: (XEN) [<ffff82d04023a700>] R credit2.c#csched2_unit_remove+0xe3/0xe7 (XEN) [<ffff82d040246adb>] S sched_move_domain+0x2f3/0x5b1 (XEN) [<ffff82d040234cf7>] S cpupool.c#cpupool_move_domain_locked+0x1d/0x3b (XEN) [<ffff82d040236025>] S cpupool_move_domain+0x24/0x35 (XEN) [<ffff82d040206513>] S domain_kill+0xa5/0x116 (XEN) [<ffff82d040232b12>] S do_domctl+0xe5f/0x1951 (XEN) [<ffff82d0402276ba>] S timer.c#timer_lock+0x69/0x143 (XEN) [<ffff82d0402dc71b>] S pv_hypercall+0x44e/0x4a9 (XEN) [<ffff82d0402012b7>] S lstar_enter+0x137/0x140 (XEN) (XEN) (XEN) **************************************** (XEN) Panic on CPU 1: (XEN) Assertion 'svc->rqd == c2rqd(sched_unit_master(unit))' failed at common/sched/credit2.c:1159 (XEN) **************************************** This is happening as sched_move_domain() is setting a different cpu for a scheduling unit without telling the scheduler. When this unit is removed from the scheduler, the ASSERT() will trigger. In non-debug builds the result is usually a clobbered pointer, leading to another crash a short time later. Fix that by swapping the two involved actions (setting another cpu and removing the unit from the scheduler). Cc: Henry Wang <Henry.Wang@xxxxxxx> Link: https://github.com/Dasharo/dasharo-issues/issues/488 Fixes: 70fadc41635b ("xen/cpupool: support moving domain between cpupools with different granularity") Signed-off-by: Juergen Gross <jgross@xxxxxxxx> --- V2: - added Link: (reporter didn't want to be added by name) --- xen/common/sched/core.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) diff --git a/xen/common/sched/core.c b/xen/common/sched/core.c index 12deefa745..e9f7486197 100644 --- a/xen/common/sched/core.c +++ b/xen/common/sched/core.c @@ -738,12 +738,13 @@ int sched_move_domain(struct domain *d, struct cpupool *c) new_p = cpumask_first(d->cpupool->cpu_valid); for_each_sched_unit ( d, unit ) { - spinlock_t *lock = unit_schedule_lock_irq(unit); + spinlock_t *lock; + + sched_remove_unit(old_ops, unit); + lock = unit_schedule_lock_irq(unit); sched_set_res(unit, get_sched_res(new_p)); spin_unlock_irq(lock); - - sched_remove_unit(old_ops, unit); } old_units = d->sched_unit_list; -- 2.35.3
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