Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752612AbbFCD2h (ORCPT ); Tue, 2 Jun 2015 23:28:37 -0400 Received: from mga03.intel.com ([134.134.136.65]:37944 "EHLO mga03.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751673AbbFCD23 (ORCPT ); Tue, 2 Jun 2015 23:28:29 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.13,544,1427785200"; d="scan'208";a="501896642" Message-ID: <556E7319.9020006@intel.com> Date: Wed, 03 Jun 2015 11:23:05 +0800 From: Lan Tianyu User-Agent: Mozilla/5.0 (X11; Linux i686 on x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.0 MIME-Version: 1.0 To: "Pan, XinhuiX" , "linux-acpi@vger.kernel.org" , "linux-kernel@vger.kernel.org" CC: "rjw@rjwysocki.net" , "lenb@kernel.org" , "yanmin_zhang@linux.intel.com" , "mnipxh@163.com" Subject: Re: [PATCH] ACPI / osl: add acpi_os_down_wait to avoid a schedule BUG References: <5566B6BE.3050303@intel.com> In-Reply-To: <5566B6BE.3050303@intel.com> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 6195 Lines: 127 On 2015年05月28日 14:33, Pan, XinhuiX wrote: > acpi_os_wait_semaphore can be called in local/hard irq disabled path. like in cpu up/down callback. > So when dirver try to acquire the semaphore, current code may call down_wait which might sleep. > Then hit panic as we can't schedule here. So introduce acpi_os_down_wait to cover such case. > acpi_os_down_wait use down_trylock, and use cpu_relax to wait the semaphore signalled if preempt is disabled. > > below is the panic. Hi Xinhui: Does this issue happen in the latest upstream kernel? In the latest code, acpi_cpu_soft_notify() doesn't detail with CPU_DYING event and return directly. The issue should not take place. > > [ 1148.230132, 1]smpboot: CPU 3 is now offline > [ 1148.277288, 0]smpboot: CPU 2 is now offline > [ 1148.322385, 1]BUG: scheduling while atomic: migration/1/13/0x00000002 > [ 1148.329604, 1]Modules linked in: hid_sensor_hub sens_col_core hid_heci_ish heci_ish heci vidt_driver atomisp_css2401a0_v21 lm3642 8723bs(O) cfg80211 gc2235 bt_lpm videobuf_vmalloc 6lowpan_iphc i p6table_raw iptable_raw videobuf_core rfkill_gpio atmel_mxt_ts > [ 1148.355276, 1]CPU: 1 PID: 13 Comm: migration/1 Tainted: G W O 3.14.37-x86_64-L1-R409-g73e8207 #25 > [ 1148.365983, 1]Hardware name: Intel Corporation CHERRYVIEW C0 PLATFORM/Cherry Trail CR, BIOS CH2TCR.X64.0004.R48.1504211851 04/21/2015 > [ 1148.379397, 1] ffff880077801140 ffff880073233a58 ffffffff819eec6c ffff8800732303d0 > [ 1148.387914, 1] ffff880073233a70 ffffffff819eb0e0 ffff88007ac92240 ffff880073233ad0 > [ 1148.396430, 1] ffffffff819f790a ffff8800732303d0 ffff880073233fd8 0000000000012240 > [ 1148.404948, 1]Call Trace: > [ 1148.407912, 1] [] dump_stack+0x4e/0x7a > [ 1148.413872, 1] [] __schedule_bug+0x58/0x67 > [ 1148.420219, 1] [] __schedule+0x67a/0x7b0 > [ 1148.426369, 1] [] schedule+0x29/0x70 > [ 1148.432123, 1] [] schedule_timeout+0x269/0x310 > [ 1148.438860, 1] [] ? update_group_power+0x16c/0x260 > [ 1148.445988, 1] [] __down_common+0x91/0xd6 > [ 1148.452236, 1] [] ? update_cfs_rq_blocked_load+0xc0/0x130 > [ 1148.460036, 1] [] __down_timeout+0x16/0x18 > [ 1148.466380, 1] [] down_timeout+0x4c/0x60 > [ 1148.472534, 1] [] acpi_os_wait_semaphore+0x43/0x57 > [ 1148.479658, 1] [] acpi_ut_acquire_mutex+0x48/0x88 > [ 1148.486683, 1] [] ? acpi_match_device+0x4d/0x4d > [ 1148.493516, 1] [] acpi_get_data+0x35/0x77 > [ 1148.499761, 1] [] acpi_bus_get_device+0x21/0x3e > [ 1148.506593, 1] [] acpi_cpu_soft_notify+0x3d/0xd3 > [ 1148.513522, 1] [] notifier_call_chain+0x53/0xa0 > [ 1148.520356, 1] [] ? cpu_stop_park+0x51/0x70 > [ 1148.526801, 1] [] __raw_notifier_call_chain+0xe/0x10 > [ 1148.534118, 1] [] cpu_notify+0x23/0x50 > [ 1148.540075, 1] [] take_cpu_down+0x27/0x40 > [ 1148.546322, 1] [] multi_cpu_stop+0xc1/0x110 > [ 1148.552763, 1] [] ? cpu_stop_should_run+0x50/0x50 > [ 1148.559776, 1] [] cpu_stopper_thread+0x78/0x150 > [ 1148.566608, 1] [] ? _raw_spin_unlock_irq+0x1e/0x40 > [ 1148.573730, 1] [] ? finish_task_switch+0x57/0xd0 > [ 1148.580646, 1] [] ? __schedule+0x37e/0x7b0 > [ 1148.586991, 1] [] smpboot_thread_fn+0x17d/0x2b0 > [ 1148.593819, 1] [] ? SyS_setgroups+0x160/0x160 > [ 1148.600455, 1] [] kthread+0xe4/0x100 > [ 1148.606208, 1] [] ? kthread_create_on_node+0x190/0x190 > [ 1148.613721, 1] [] ret_from_fork+0x58/0x90 > [ 1148.619967, 1] [] ? kthread_create_on_node+0x190/0x190 > > Signed-off-by: Pan Xinhui > --- > drivers/acpi/osl.c | 28 +++++++++++++++++++++++++++- > 1 file changed, 27 insertions(+), 1 deletion(-) > > diff --git a/drivers/acpi/osl.c b/drivers/acpi/osl.c > index 7ccba39..57a1812 100644 > --- a/drivers/acpi/osl.c > +++ b/drivers/acpi/osl.c > @@ -1195,6 +1195,32 @@ void acpi_os_wait_events_complete(void) > flush_workqueue(kacpi_notify_wq); > } > > +static int acpi_os_down_wait(struct semaphore *sem, long jiffies_timeout) > +{ > + unsigned long deadline_time; > + int ret = 0; > + > + if (down_trylock(sem)) { > + if (unlikely(preempt_count())) { > + deadline_time = jiffies + jiffies_timeout; > + while (true) { > + cpu_relax(); > + > + if (!down_trylock(sem)) > + break; > + > + if (time_after(jiffies, deadline_time)) { > + ret = -ETIME; > + break; > + } > + } > + } else > + ret = down_timeout(sem, jiffies_timeout); > + } > + > + return ret; > +} > + > struct acpi_hp_work { > struct work_struct work; > struct acpi_device *adev; > @@ -1309,7 +1335,7 @@ acpi_status acpi_os_wait_semaphore(acpi_handle handle, u32 units, u16 timeout) > else > jiffies = msecs_to_jiffies(timeout); > > - ret = down_timeout(sem, jiffies); > + ret = acpi_os_down_wait(sem, jiffies); > if (ret) > status = AE_TIME; > > -- > 1.9.1 > -- > To unsubscribe from this list: send the line "unsubscribe linux-acpi" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > -- Best regards Tianyu Lan -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/