Re: [PATCH 1/2] power_supply: Fix Oops from NULL pointer dereference from wakeup_source_activate

[Shuah Khan <shuah.kh@samsung.com>]

On 11/19/2013 04:13 PM, Greg KH wrote:
> On Tue, Nov 19, 2013 at 08:59:35AM -0700, Shuah Khan wrote:
>> 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 dereferences 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.
>>
>> [  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>
>
> Care to add a:
> 	Cc: stable <stable@vger.kernel.org>
> to this so that it gets backported to the older kernels that have this
> problem?

Yes this should be in stable as well. However, this patch failed to 
apply to 3.10 and 3.11 (the two releases I spot checked while I was 
contemplating adding cc stable tag.

I plan to back-port and send the stable patch once this gets into the 
mainline. Sounds good?
>
> Oh, and feel free to also add:
> 	Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

thanks,
>
> thanks for the dev_set_name() change,
>
> greg k-h
>


-- 
Shuah Khan
Senior Linux Kernel Developer - Open Source Group
Samsung Research America(Silicon Valley)
shuah.kh@samsung.com | (970) 672-0658