Messages in this thread Patch in this message | | | From | Phil Auld <> | Subject | [PATCH] sched: use rq_lock/unlock in online_fair_sched_group | Date | Thu, 1 Aug 2019 09:37:49 -0400 |
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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.
[472978.683085] rq->clock_update_flags & RQCF_UPDATED [472978.683100] WARNING: CPU: 5 PID: 54385 at kernel/sched/core.c:210 update_rq_clock+0xec/0x150 [472978.758465] Modules linked in: fuse vfat msdos fat ext4 mbcache jbd2 sunrpc iTCO_wdt gpio_ich iTCO_vendor_support intel_powerclamp coretemp kvm_intel kvm ipmi_ssif irqbypass ipmi_si crct10dif_pclmul crc32_pclmul ghash_clmulni_intel joydev pcspkr intel_cstate acpi_power_meter ipmi_devintf sg intel_uncore i7core_edac hpilo hpwdt lpc_ich ipmi_msghandler acpi_cpufreq ip_tables xfs libcrc32c sr_mod sd_mod cdrom ata_generic radeon i2c_algo_bit drm_kms_helper syscopyarea sysfillrect sysimgblt fb_sys_fops ttm ata_piix drm myri10ge hpsa libata serio_raw crc32c_intel scsi_transport_sas netxen_nic dca dm_mirror dm_region_hash dm_log dm_mod [472979.050101] CPU: 5 PID: 54385 Comm: cgcreate Not tainted 5.2.0-rc6+ #135 [472979.089586] Hardware name: HP ProLiant DL580 G7, BIOS P65 08/16/2015 [472979.123638] RIP: 0010:update_rq_clock+0xec/0x150 [472979.146435] Code: a8 04 0f 84 55 ff ff ff 80 3d 93 34 2c 01 00 0f 85 48 ff ff ff 48 c7 c7 08 b9 a8 b7 31 c0 c6 05 7d 34 2c 01 01 e8 04 21 fd ff <0f> 0b 8b 83 b0 09 00 00 e9 26 ff ff ff e8 72 c3 f5 ff 66 90 4c 8b [472979.247671] RSP: 0018:ffffa9addac67d48 EFLAGS: 00010086 [472979.277071] RAX: 0000000000000000 RBX: ffff9db3ff62a380 RCX: 0000000000000000 [472979.314842] RDX: 0000000000000005 RSI: ffffffffb8434a45 RDI: ffffffffb84325ec [472979.352189] RBP: 0000000000000000 R08: ffffffffb8434a20 R09: ffffffb27562d751 [472979.389326] R10: 000000000000d471 R11: ffffa9addac67a58 R12: ffff9d8a1c9d5a00 [472979.425255] R13: ffff9db3fbbed400 R14: 000000000002a380 R15: 0000000000000000 [472979.462417] FS: 00007f6a8218cb80(0000) GS:ffff9db3ff740000(0000) knlGS:0000000000000000 [472979.511306] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [472979.543386] CR2: 00007f6a82198000 CR3: 0000003f33f16005 CR4: 00000000000206e0 [472979.578646] Call Trace: [472979.591702] online_fair_sched_group+0x53/0x100 [472979.618172] cpu_cgroup_css_online+0x16/0x20 [472979.640264] online_css+0x1c/0x60 [472979.657648] cgroup_apply_control_enable+0x231/0x3b0 [472979.684979] cgroup_mkdir+0x41b/0x530 [472979.704845] kernfs_iop_mkdir+0x61/0xa0 [472979.726278] vfs_mkdir+0x108/0x1a0 [472979.745665] do_mkdirat+0x77/0xe0 [472979.764981] do_syscall_64+0x55/0x1d0 [472979.785990] entry_SYSCALL_64_after_hwframe+0x44/0xa9
Using the wrappers in online_fair_sched_group instead of the raw locking removes this warning.
Signed-off-by: Phil Auld <pauld@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Ingo Molnar <mingo@kernel.org> Cc: Vincent Guittot <vincent.guittot@linaro.org> --- Resend with PATCH instead of CHANGE in subject, and more recent upstream x86 backtrace.
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
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