Enabling WARN_DOUBLE_CLOCK in /sys/kernel/debug/sched_features causes warning to fire in update_rq_clock. This seems to be caused by onlining a new fair sched group not using the rq lock wrappers.
[ 612.379993] rq->clock_update_flags & RQCF_UPDATED [ 612.380007] WARNING: CPU: 6 PID: 21426 at kernel/sched/core.c:225 update_rq_clock+0x90/0x130 [ 612.393082] Modules linked in: binfmt_misc rpcsec_gss_krb5 auth_rpcgss nfsv4 dns_resolver nfs lockd grace fscache sunrpc vfat fat sg xgene_hwmon gpio_xgene_sb gpio_dwapb gpio_generic xgene_edac mailbox_xgene_slimpro xgene_rng uio_pdrv_genirq uio sch_fq_codel xfs libcrc32c xgene_enet i2c_xgene_slimpro at803x realtek ahci_xgene libahci_platform mdio_xgene dm_mirror dm_region_hash dm_log dm_mod [ 612.427615] CPU: 6 PID: 21426 Comm: (dnf) Not tainted 4.16.0-10.el8+5.aarch64 #1 [ 612.434973] Hardware name: AppliedMicro X-Gene Mustang Board/X-Gene Mustang Board, BIOS 3.06.25 Oct 17 2016 [ 612.444667] pstate: 60000085 (nZCv daIf -PAN -UAO) [ 612.449434] pc : update_rq_clock+0x90/0x130 [ 612.453595] lr : update_rq_clock+0x90/0x130 [ 612.457754] sp : ffff00000efefd60 [ 612.461050] x29: ffff00000efefd60 x28: ffff8003c23d5400 [ 612.466335] x27: ffff8003ca119c00 x26: ffff0000090bc000 [ 612.471620] x25: ffff0000090bc090 x24: ffff0000090b3c68 [ 612.476905] x23: ffff8003cefe1500 x22: ffff000008dbd280 [ 612.482192] x21: 0000000000000000 x20: 0000000000000000 [ 612.487478] x19: ffff8003ffddd280 x18: ffffffffffffffff [ 612.492763] x17: 0000000000000000 x16: 0000000000000000 [ 612.498049] x15: ffff0000090b3c08 x14: ffff0000897a5a17 [ 612.503334] x13: ffff0000097a5a25 x12: ffff0000090ff000 [ 612.508620] x11: ffff0000090bbc90 x10: ffff000008548a78 [ 612.513906] x9 : 00000000ffffffd0 x8 : 50555f4643515220 [ 612.519191] x7 : 26207367616c665f x6 : 00000000000001cd [ 612.524477] x5 : 00ffffffffffffff x4 : 0000000000000000 [ 612.529761] x3 : 0000000000000000 x2 : ffffffffffffffff [ 612.535047] x1 : 1f9a6a58385a9900 x0 : 0000000000000000 [ 612.540333] Call trace: [ 612.542767] update_rq_clock+0x90/0x130 [ 612.546585] online_fair_sched_group+0x70/0x140 [ 612.551092] sched_online_group+0xd0/0xf0 [ 612.555082] sched_autogroup_create_attach+0xd0/0x198 [ 612.560108] sys_setsid+0x140/0x160 [ 612.563579] el0_svc_naked+0x44/0x48 Signed-off-by: Phil Auld <pa...@redhat.com> Cc: Peter Zijlstra <pet...@infradead.org> Cc: Ingo Molnar <mi...@kernel.org> Cc: Vincent Guittot <vincent.guit...@linaro.org> --- kernel/sched/fair.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index 036be95a87e9..5c1299a5675c 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -10242,17 +10242,17 @@ void online_fair_sched_group(struct task_group *tg) { struct sched_entity *se; struct rq *rq; + struct rq_flags rf; int i; for_each_possible_cpu(i) { rq = cpu_rq(i); se = tg->se[i]; - - raw_spin_lock_irq(&rq->lock); + rq_lock(rq, &rf); update_rq_clock(rq); attach_entity_cfs_rq(se); sync_throttle(tg, i); - raw_spin_unlock_irq(&rq->lock); + rq_unlock(rq, &rf); } } -- 2.18.0