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authorEthan Zhao <ethan.zhao@oracle.com>2015-03-12 13:04:16 +0900
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2015-03-25 15:26:49 +0100
commitd82d54af7b14092dc5934a8ce09170789c9ddb57 (patch)
tree2774e75816e8d97331217a31983d3b930d8f0d15
parentbea2b592fd18eb8ffa3fc4ad380610632d03a38f (diff)
downloadlinux-linaro-stable-d82d54af7b14092dc5934a8ce09170789c9ddb57.tar.gz
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] [<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 <ethan.zhao@oracle.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--lib/kobject.c7
1 files changed, 6 insertions, 1 deletions
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;
}