From mboxrd@z Thu Jan 1 00:00:00 1970 From: Toshi Kani Subject: Re: [PATCH 2/7] ACPI / scan: Introduce common code for ACPI-based device hotplug Date: Wed, 20 Feb 2013 13:23:34 -0700 Message-ID: <1361391814.9542.72.camel@misato.fc.hp.com> References: <3260206.bhaAobGhpZ@vostro.rjw.lan> <2540040.4NPGdn6Df0@vostro.rjw.lan> <51231EFC.5080006@jp.fujitsu.com> <2868646.oscSukR6ks@vostro.rjw.lan> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit Return-path: Received: from g6t0185.atlanta.hp.com ([15.193.32.62]:4761 "EHLO g6t0185.atlanta.hp.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S934126Ab3BTUeX (ORCPT ); Wed, 20 Feb 2013 15:34:23 -0500 In-Reply-To: <2868646.oscSukR6ks@vostro.rjw.lan> Sender: linux-acpi-owner@vger.kernel.org List-Id: linux-acpi@vger.kernel.org To: "Rafael J. Wysocki" Cc: Yasuaki Ishimatsu , ACPI Devel Maling List , Bjorn Helgaas , LKML , Yinghai Lu , Jiang Liu On Wed, 2013-02-20 at 14:23 +0100, Rafael J. Wysocki wrote: > On Tuesday, February 19, 2013 03:43:08 PM Yasuaki Ishimatsu wrote: : > > > > > - status = acpi_os_hotplug_execute(acpi_bus_hot_remove_device, ej_event); > > > - if (ACPI_FAILURE(status)) { > > > - put_device(&acpi_device->dev); > > > - kfree(ej_event); > > > + acpi_evaluate_hotplug_ost(acpi_device->handle, ost_source, > > > + ACPI_OST_SC_EJECT_IN_PROGRESS, NULL); > > > + get_device(&acpi_device->dev); > > > + ret = acpi_scan_hot_remove(acpi_device); > > > > Why don't you use acpi_os_hotplug_execute()? Do you have some reason? > > Yes, I do. acpi_eject_store() is run in a separate thread anyway (started by > user space), so there's no need to use the workqueue for delayed execution here > and we are under acpi_scan_lock anyway, so there shouldn't be any concurrency > issues. Well, there is an issue... I just tested your patchset and hit the following hang when I tried to delete a container through its sysfs eject. This thread got stuck in trying to delete the sysfs eject file of the container. I believe this is because the shell is still opening this sysfs eject file. PID: 1518 TASK: ffff88005f09c950 CPU: 1 COMMAND: "bash" #0 [ffff88003392baf8] __schedule at ffffffff8151ba75 #1 [ffff88003392bb70] schedule at ffffffff8151bdc7 #2 [ffff88003392bb80] schedule_timeout at ffffffff8151aa55 #3 [ffff88003392bc00] wait_for_common at ffffffff8151bc43 #4 [ffff88003392bc70] wait_for_completion at ffffffff8151bd60 #5 [ffff88003392bc80] sysfs_addrm_finish at ffffffff811984ad #6 [ffff88003392bcd0] sysfs_hash_and_remove at ffffffff81196deb #7 [ffff88003392bd10] sysfs_remove_file at ffffffff81197051 #8 [ffff88003392bd40] device_remove_file at ffffffff81332950 #9 [ffff88003392bd50] acpi_device_unregister at ffffffff812a0556 #10 [ffff88003392bd80] acpi_bus_remove at ffffffff812a0658 #11 [ffff88003392bda0] acpi_bus_trim at ffffffff812a090e #12 [ffff88003392bdd0] acpi_scan_hot_remove at ffffffff812a09c9 #13 [ffff88003392be30] acpi_eject_store at ffffffff812a0b45 #14 [ffff88003392be70] dev_attr_store at ffffffff81332038 #15 [ffff88003392be80] sysfs_write_file at ffffffff81197212 #16 [ffff88003392bee0] vfs_write at ffffffff8113a3cb #17 [ffff88003392bf20] sys_write at ffffffff8113a5fd #18 [ffff88003392bf80] system_call_fastpath at ffffffff81523759 RIP: 00000033a16e4950 RSP: 00007fff4a5f5368 RFLAGS: 00000206 RAX: 0000000000000001 RBX: ffffffff81523759 RCX: ffffffffffffffff RDX: 0000000000000002 RSI: 00007f2f8a3d8000 RDI: 0000000000000001 RBP: 00007f2f8a3d8000 R8: 000000000000000a R9: 00007f2f8a3c4740 R10: 00007f2f8a3c4740 R11: 0000000000000246 R12: 00000033a19b1260 R13: 0000000000000002 R14: ffff880000000000 R15: ffff88003395d680 ORIG_RAX: 0000000000000001 CS: 0033 SS: 002b Thanks, -Toshi