On Thu, Mar 12, 2015 at 01:04:16PM +0900, Ethan Zhao wrote: > call kobject_get() to kojbect that is not initalized or released will only > leave following like call trace to us: > > -----------[ cut here ]------------ > [ 54.545816] WARNING: CPU: 0 PID: 213 at include/linux/kref.h:47 > kobject_get+0x41/0x50() > [ 54.642595] Modules linked in: i2c_i801(+) mfd_core shpchp(+) > acpi_cpufreq(+) edac_core ioatdma(+) xfs libcrc32c ast syscopyarea ixgbe > sysfillrect sysimgblt sr_mod sd_mod drm_kms_helper igb mdio cdrom e1000e ahci > dca ttm libahci uas drm i2c_algo_bit ptp megaraid_sas libata usb_storage > i2c_core pps_core dm_mirror dm_region_hash dm_log dm_mod > [ 55.007264] CPU: 0 PID: 213 Comm: kworker/0:2 Not tainted > 3.18.5 > [ 55.099970] Hardware name: Oracle Corporation SUN FIRE X4170 M2 SERVER > /ASSY,MOTHERBOARD,X4170, BIOS 08120104 05/08/2012 > [ 55.239736] Workqueue: kacpi_notify acpi_os_execute_deferred > [ 55.308598] 0000000000000000 00000000bd730b61 ffff88046742baf8 > ffffffff816b7edb > [ 55.398305] 0000000000000000 0000000000000000 ffff88046742bb38 > ffffffff81078ae1 > [ 55.488040] ffff88046742bbd8 ffff8806706b3000 0000000000000292 > 0000000000000000 > [ 55.577776] Call Trace: > [ 55.608228] [<ffffffff816b7edb>] dump_stack+0x46/0x58 > [ 55.670895] [<ffffffff81078ae1>] warn_slowpath_common+0x81/0xa0 > [ 55.743952] [<ffffffff81078bfa>] warn_slowpath_null+0x1a/0x20 > [ 55.814929] [<ffffffff8130d0d1>] kobject_get+0x41/0x50 > [ 55.878654] [<ffffffff8153e955>] cpufreq_cpu_get+0x75/0xc0 > [ 55.946528] [<ffffffff8153f37e>] cpufreq_update_policy+0x2e/0x1f0 > > The above issue was casued by a race condition, if there is a WARN in > kobject_get() of the kobject is not initialized, that would save us much > time to debug it. > > Signed-off-by: Ethan Zhao <[email protected]> > --- > lib/kobject.c | 7 ++++++- > 1 file changed, 6 insertions(+), 1 deletion(-) > > diff --git a/lib/kobject.c b/lib/kobject.c > index 03d4ab3..3b841b9 100644 > --- a/lib/kobject.c > +++ b/lib/kobject.c > @@ -576,8 +576,13 @@ void kobject_del(struct kobject *kobj) > */ > struct kobject *kobject_get(struct kobject *kobj) > { > - if (kobj) > + if (kobj) { > + if (!kobj->state_initialized) > + WARN(1, KERN_WARNING "kobject: '%s' (%p): is not " > + "initialized, yet kobject_get() is being " > + "called.\n", kobject_name(kobj), kobj); > kref_get(&kobj->kref); > + } > return kobj; > } >
Have you tried running a system with this patch to see if there are a lot of messages at boot time? I'm a bit worried that the initial kobject init sequence would trigger this, but haven't looked at the full codepath just yet given that I haven't had my morning coffee... thanks, greg k-h -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
