[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [Xen-changelog] [xen stable-4.10] xen/sched: fix csched2_deinit_pdata()
commit d93beccffe155737574e2f0ecea5ddb6ed795ead Author: Juergen Gross <jgross@xxxxxxxx> AuthorDate: Tue Jun 4 15:53:50 2019 +0200 Commit: Jan Beulich <jbeulich@xxxxxxxx> CommitDate: Tue Jun 4 15:53:50 2019 +0200 xen/sched: fix csched2_deinit_pdata() Commit 753ba43d6d16e688 ("xen/sched: fix credit2 smt idle handling") introduced a regression when switching cpus between cpupools. When assigning a cpu to a cpupool with credit2 being the default scheduler csched2_deinit_pdata() is called for the credit2 private data after the new scheduler's private data has been hooked to the per-cpu scheduler data. Unfortunately csched2_deinit_pdata() will cycle through all per-cpu scheduler areas it knows of for removing the cpu from the respective sibling masks including the area of the just moved cpu. This will (depending on the new scheduler) either clobber the data of the new scheduler or in case of sched_rt lead to a crash. Avoid that by removing the cpu from the list of active cpus in credit2 data first. The opposite problem is occurring when removing a cpu from a cpupool: init_pdata() of credit2 will access the per-cpu data of the old scheduler. Signed-off-by: Juergen Gross <jgross@xxxxxxxx> Reviewed-by: Dario Faggioli <dfaggioli@xxxxxxxx> master commit: ffd3367ed682b6ac6f57fcb151921054dd4cce7e master date: 2019-05-17 15:41:17 +0200 --- xen/common/sched_credit2.c | 23 +++++++++++------------ 1 file changed, 11 insertions(+), 12 deletions(-) diff --git a/xen/common/sched_credit2.c b/xen/common/sched_credit2.c index 0f4137ba86..8270dae666 100644 --- a/xen/common/sched_credit2.c +++ b/xen/common/sched_credit2.c @@ -3814,22 +3814,21 @@ init_pdata(struct csched2_private *prv, struct csched2_pcpu *spc, activate_runqueue(prv, spc->runq_id); } - __cpumask_set_cpu(cpu, &rqd->idle); - __cpumask_set_cpu(cpu, &rqd->active); - __cpumask_set_cpu(cpu, &prv->initialized); - __cpumask_set_cpu(cpu, &rqd->smt_idle); + __cpumask_set_cpu(cpu, &spc->sibling_mask); - /* On the boot cpu we are called before cpu_sibling_mask has been set up. */ - if ( cpu == 0 && system_state < SYS_STATE_active ) - __cpumask_set_cpu(cpu, &csched2_pcpu(cpu)->sibling_mask); - else + if ( cpumask_weight(&rqd->active) > 0 ) for_each_cpu ( rcpu, per_cpu(cpu_sibling_mask, cpu) ) if ( cpumask_test_cpu(rcpu, &rqd->active) ) { __cpumask_set_cpu(cpu, &csched2_pcpu(rcpu)->sibling_mask); - __cpumask_set_cpu(rcpu, &csched2_pcpu(cpu)->sibling_mask); + __cpumask_set_cpu(rcpu, &spc->sibling_mask); } + __cpumask_set_cpu(cpu, &rqd->idle); + __cpumask_set_cpu(cpu, &rqd->active); + __cpumask_set_cpu(cpu, &prv->initialized); + __cpumask_set_cpu(cpu, &rqd->smt_idle); + if ( cpumask_weight(&rqd->active) == 1 ) rqd->pick_bias = cpu; @@ -3938,13 +3937,13 @@ csched2_deinit_pdata(const struct scheduler *ops, void *pcpu, int cpu) printk(XENLOG_INFO "Removing cpu %d from runqueue %d\n", cpu, spc->runq_id); - for_each_cpu ( rcpu, &rqd->active ) - __cpumask_clear_cpu(cpu, &csched2_pcpu(rcpu)->sibling_mask); - __cpumask_clear_cpu(cpu, &rqd->idle); __cpumask_clear_cpu(cpu, &rqd->smt_idle); __cpumask_clear_cpu(cpu, &rqd->active); + for_each_cpu ( rcpu, &rqd->active ) + __cpumask_clear_cpu(cpu, &csched2_pcpu(rcpu)->sibling_mask); + if ( cpumask_empty(&rqd->active) ) { printk(XENLOG_INFO " No cpus left on runqueue, disabling\n"); -- generated by git-patchbot for /home/xen/git/xen.git#stable-4.10 _______________________________________________ Xen-changelog mailing list Xen-changelog@xxxxxxxxxxxxxxxxxxxx https://lists.xenproject.org/xen-changelog
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