From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754099Ab3KPAJU (ORCPT ); Fri, 15 Nov 2013 19:09:20 -0500 Received: from v094114.home.net.pl ([79.96.170.134]:51680 "HELO v094114.home.net.pl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1752354Ab3KPAJK (ORCPT ); Fri, 15 Nov 2013 19:09:10 -0500 From: "Rafael J. Wysocki" To: Shuah Khan Cc: len.brown@intel.com, pavel@ucw.cz, gregkh@linuxfoundation.org, linux-pm@vger.kernel.org, linux-kernel@vger.kernel.org, shuahkhan@gmail.com, anton@enomsg.org, dwmw2@infradead.org, stable@vger.kernel.org Subject: Re: [PATCH] power: Change device_wakeup_enable() to check for null dev_name(dev) Date: Sat, 16 Nov 2013 01:21:43 +0100 Message-ID: <4035469.UfR6Rto3I2@vostro.rjw.lan> User-Agent: KMail/4.10.5 (Linux/3.12.0-rc6+; KDE/4.10.5; x86_64; ; ) In-Reply-To: <1384560238-10708-1-git-send-email-shuah.kh@samsung.com> References: <1384560238-10708-1-git-send-email-shuah.kh@samsung.com> MIME-Version: 1.0 Content-Transfer-Encoding: 7Bit Content-Type: text/plain; charset="utf-8" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Friday, November 15, 2013 05:03:57 PM Shuah Khan wrote: > device_wakeup_enable() uses dev_name(dev) as the wakeup source name. > When it gets called with a device with its name not yet set, ws structure > with ws->name = NULL gets created. > > When kernel is booted with wakeup_source_activate enabled, it will panic > when the trace point code tries to derefernces ws->name. > > Change device_wakeup_enable() to check for dev_name(dev) null condition > and return -EINVAL to avoid panics when device_wakeup_enable() gets called > before device is fully initialized with its name. > > The following panic resulted from power_supply_register() registering > wakeup source with a null device name. > > [ 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: [] 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:[] [] 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] [] ? ftrace_raw_event_wakeup_source+0x43/0xe0 > [ 819.773520] [] wakeup_source_report_event+0xb8/0xd0 > [ 819.773595] [] __pm_stay_awake+0x2d/0x50 > [ 819.773724] [] power_supply_changed+0x3c/0x90 > [ 819.773795] [] power_supply_register+0x18c/0x250 > [ 819.773869] [] sysfs_add_battery+0x61/0x7b > [ 819.773935] [] battery_notify+0x37/0x3f > [ 819.774001] [] notifier_call_chain+0x4c/0x70 > [ 819.774071] [] __blocking_notifier_call_chain+0x4d/0x70 > [ 819.774149] [] blocking_notifier_call_chain+0x16/0x20 > [ 819.774227] [] pm_notifier_call_chain+0x1a/0x40 > [ 819.774316] [] hibernate+0x66/0x1c0 > [ 819.774407] [] state_store+0x71/0xa0 > [ 819.774507] [] kobj_attr_store+0xf/0x20 > [ 819.774613] [] sysfs_write_file+0x128/0x1c0 > [ 819.774735] [] vfs_write+0xbd/0x1e0 > [ 819.774841] [] SyS_write+0x49/0xa0 > [ 819.774939] [] 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 [] skip_spaces+0x30/0x30 > [ 819.775881] RSP > [ 819.775949] CR2: 0000000000000000 > [ 819.794175] ---[ end trace c4ef25127039952e ]--- > > Signed-off-by: Shuah Khan > Cc: stable@vger.kernel.org > --- > drivers/base/power/wakeup.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/base/power/wakeup.c b/drivers/base/power/wakeup.c > index 2d56f41..e086f12 100644 > --- a/drivers/base/power/wakeup.c > +++ b/drivers/base/power/wakeup.c > @@ -220,7 +220,7 @@ int device_wakeup_enable(struct device *dev) > struct wakeup_source *ws; > int ret; > > - if (!dev || !dev->power.can_wakeup) > + if (!dev || !dev->power.can_wakeup || !dev_name(dev)) > return -EINVAL; Can you please use WARN_ON(!dev_name(dev)) here? While I agree that it is a bad idea to crash the kernel because dev has no name, that indicates a driver bug that shouldn't be too easy to ignore. Thanks! -- I speak only for myself. Rafael J. Wysocki, Intel Open Source Technology Center.