power_supply: Fix Oops from NULL pointer dereference from wakeup_source_activate

power_supply_register() calls device_init_wakeup() to register a wakeup
source before initializing dev_name. As a result, device_wakeup_enable()
end up registering wakeup source with a null name when
wakeup_source_register() gets called with dev_name(dev) which is null at
the time.

When kernel is booted with wakeup_source_activate enabled, it will panic
when the trace point code tries to dereference ws->name.

Fixed the problem by moving up the kobject_set_name() call prior to
accesses to dev_name(). Replaced kobject_set_name() with dev_set_name()
which is the right interface to be called from drivers. Fixed the call to
device_del() prior to device_add() in for wakeup_init_failed error
handling code.

Trace after the change:

            bash-2143  [003] d...   132.280697: wakeup_source_activate: BAT1 state=0x20001
     kworker/3:2-1169  [003] d...   132.281305: wakeup_source_deactivate: BAT1 state=0x30000

Oops message:

[  819.769934] device: 'BAT1': device_add
[  819.770078] PM: Adding info for No Bus:BAT1
[  819.770235] BUG: unable to handle kernel NULL pointer dereference at           (null)
[  819.770435] IP: [<ffffffff813381c0>] skip_spaces+0x30/0x30
[  819.770572] PGD 3efd90067 PUD 3eff61067 PMD 0
[  819.770716] Oops: 0000 [#1] SMP
[  819.770829] Modules linked in: arc4 iwldvm mac80211 x86_pkg_temp_thermal coretemp kvm_intel joydev i915 kvm uvcvideo ghash_clmulni_intel videobuf2_vmalloc aesni_intel videobuf2_memops videobuf2_core aes_x86_64 ablk_helper cryptd videodev iwlwifi lrw rfcomm gf128mul glue_helper bnep btusb media bluetooth parport_pc hid_generic ppdev snd_hda_codec_hdmi drm_kms_helper snd_hda_codec_realtek cfg80211 drm tpm_infineon samsung_laptop snd_hda_intel usbhid snd_hda_codec hid snd_hwdep snd_pcm microcode snd_page_alloc snd_timer psmouse i2c_algo_bit lpc_ich tpm_tis video wmi mac_hid serio_raw ext2 lp parport r8169 mii
[  819.771802] CPU: 0 PID: 2167 Comm: bash Not tainted 3.12.0+ #25
[  819.771876] Hardware name: SAMSUNG ELECTRONICS CO., LTD. 900X3C/900X3D/900X4C/900X4D/SAMSUNG_NP1234567890, BIOS P03AAC 07/12/2012
[  819.772022] task: ffff88002e6ddcc0 ti: ffff8804015ca000 task.ti: ffff8804015ca000
[  819.772119] RIP: 0010:[<ffffffff813381c0>]  [<ffffffff813381c0>] skip_spaces+0x30/0x30
[  819.772242] RSP: 0018:ffff8804015cbc70  EFLAGS: 00010046
[  819.772310] RAX: 0000000000000003 RBX: ffff88040cfd6d40 RCX: 0000000000000018
[  819.772397] RDX: 0000000000020001 RSI: 0000000000000000 RDI: 0000000000000000
[  819.772484] RBP: ffff8804015cbcc0 R08: 0000000000000000 R09: ffff8803f0768d40
[  819.772570] R10: ffffea001033b800 R11: 0000000000000000 R12: ffffffff81c519c0
[  819.772656] R13: 0000000000020001 R14: 0000000000000000 R15: 0000000000020001
[  819.772744] FS:  00007ff98309b740(0000) GS:ffff88041f200000(0000) knlGS:0000000000000000
[  819.772845] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[  819.772917] CR2: 0000000000000000 CR3: 00000003f59dc000 CR4: 00000000001407f0
[  819.773001] Stack:
[  819.773030]  ffffffff81114003 ffff8804015cbcb0 0000000000000000 0000000000000046
[  819.773146]  ffff880409757a18 ffff8803f065a160 0000000000000000 0000000000020001
[  819.773273]  0000000000000000 0000000000000000 ffff8804015cbce8 ffffffff8143e388
[  819.773387] Call Trace:
[  819.773434]  [<ffffffff81114003>] ? ftrace_raw_event_wakeup_source+0x43/0xe0
[  819.773520]  [<ffffffff8143e388>] wakeup_source_report_event+0xb8/0xd0
[  819.773595]  [<ffffffff8143e3cd>] __pm_stay_awake+0x2d/0x50
[  819.773724]  [<ffffffff8153395c>] power_supply_changed+0x3c/0x90
[  819.773795]  [<ffffffff8153407c>] power_supply_register+0x18c/0x250
[  819.773869]  [<ffffffff813d8d18>] sysfs_add_battery+0x61/0x7b
[  819.773935]  [<ffffffff813d8d69>] battery_notify+0x37/0x3f
[  819.774001]  [<ffffffff816ccb7c>] notifier_call_chain+0x4c/0x70
[  819.774071]  [<ffffffff81073ded>] __blocking_notifier_call_chain+0x4d/0x70
[  819.774149]  [<ffffffff81073e26>] blocking_notifier_call_chain+0x16/0x20
[  819.774227]  [<ffffffff8109397a>] pm_notifier_call_chain+0x1a/0x40
[  819.774316]  [<ffffffff81095b66>] hibernate+0x66/0x1c0
[  819.774407]  [<ffffffff81093931>] state_store+0x71/0xa0
[  819.774507]  [<ffffffff81331d8f>] kobj_attr_store+0xf/0x20
[  819.774613]  [<ffffffff811f8618>] sysfs_write_file+0x128/0x1c0
[  819.774735]  [<ffffffff8118579d>] vfs_write+0xbd/0x1e0
[  819.774841]  [<ffffffff811861d9>] SyS_write+0x49/0xa0
[  819.774939]  [<ffffffff816d1052>] system_call_fastpath+0x16/0x1b
[  819.775055] Code: 89 f8 48 89 e5 f6 82 c0 a6 84 81 20 74 15 0f 1f 44 00 00 48 83 c0 01 0f b6 10 f6 82 c0 a6 84 81 20 75 f0 5d c3 66 0f 1f 44 00 00 <80> 3f 00 55 48 89 e5 74 15 48 89 f8 0f 1f 40 00 48 83 c0 01 80
[  819.775760] RIP  [<ffffffff813381c0>] skip_spaces+0x30/0x30
[  819.775881]  RSP <ffff8804015cbc70>
[  819.775949] CR2: 0000000000000000
[  819.794175] ---[ end trace c4ef25127039952e ]---
Signed-off-by: Shuah Khan <shuah.kh@samsung.com>
Acked-by: Anton Vorontsov <anton@enomsg.org>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: stable@vger.kernel.org
Signed-off-by: Anton Vorontsov <anton@enomsg.org>

drivers/power/power_supply_core.c

@@ -511,6 +511,10 @@ int power_supply_register(struct device *parent, struct power_supply *psy)
 	dev_set_drvdata(dev, psy);
 	psy->dev = dev;
 
+	rc = dev_set_name(dev, "%s", psy->name);
+	if (rc)
+		goto dev_set_name_failed;
+
 	INIT_WORK(&psy->changed_work, power_supply_changed_work);
 
 	rc = power_supply_check_supplies(psy);
@@ -524,10 +528,6 @@ int power_supply_register(struct device *parent, struct power_supply *psy)
 	if (rc)
 		goto wakeup_init_failed;
 
-	rc = kobject_set_name(&dev->kobj, "%s", psy->name);
-	if (rc)
-		goto kobject_set_name_failed;
-
 	rc = device_add(dev);
 	if (rc)
 		goto device_add_failed;
@@ -553,11 +553,11 @@ int power_supply_register(struct device *parent, struct power_supply *psy)
 register_cooler_failed:
 	psy_unregister_thermal(psy);
 register_thermal_failed:
-wakeup_init_failed:
 	device_del(dev);
-kobject_set_name_failed:
 device_add_failed:
+wakeup_init_failed:
 check_supplies_failed:
+dev_set_name_failed:
 	put_device(dev);
 success:
 	return rc;