From: Ethan Zhao Date: Thu, 12 Mar 2015 04:04:16 +0000 (+0900) Subject: kobject: WARN as tip when call kobject_get() to a kobject not initialized X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=d82d54af7b14092dc5934a8ce09170789c9ddb57;p=GitHub%2Fmoto-9609%2Fandroid_kernel_motorola_exynos9610.git kobject: WARN as tip when call kobject_get() to a kobject not initialized 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] [] dump_stack+0x46/0x58 [ 55.670895] [] warn_slowpath_common+0x81/0xa0 [ 55.743952] [] warn_slowpath_null+0x1a/0x20 [ 55.814929] [] kobject_get+0x41/0x50 [ 55.878654] [] cpufreq_cpu_get+0x75/0xc0 [ 55.946528] [] 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 Signed-off-by: Greg Kroah-Hartman --- diff --git a/lib/kobject.c b/lib/kobject.c index 03d4ab349fa7..3b841b97fccd 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; }