On Wed, Feb 13, 2013 at 5:59 AM, Rafael J. Wysocki <rjw@xxxxxxx> wrote: > On Tuesday, February 12, 2013 05:54:08 PM Yinghai Lu wrote: >> On Tue, Feb 12, 2013 at 4:16 PM, Rafael J. Wysocki <rjw@xxxxxxx> wrote: >> > From: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx> >> > >> > After commit 1aeae82 (ACPI / PCI: avoid building pci_slot as module) >> > the pci_slot driver's .add() callback routine, acpi_pci_slot_add(), >> > is executed from within acpi_pci_root_add() before the PCI devices on >> > the bus are enumerated and that triggers the WARN_ON() in >> > kobject_get(): >> > >> > WARNING: at /scratch/rafael/work/test/include/linux/kref.h:42 kobject_get+0x33/0x40() >> > Hardware name: PORTEGE R500 >> > Modules linked in: >> > Pid: 1, comm: swapper/0 Not tainted 3.8.0-rc7+ #160 >> > Call Trace: >> > [<ffffffff8103d38a>] warn_slowpath_common+0x7a/0xb0 >> > [<ffffffff8103d3d5>] warn_slowpath_null+0x15/0x20 >> > [<ffffffff812f99b3>] kobject_get+0x33/0x40 >> > [<ffffffff81452b82>] get_device+0x12/0x30 >> > [<ffffffff8138df7b>] register_slot+0x243/0x295 >> > [<ffffffff810a7b6d>] ? trace_hardirqs_on+0xd/0x10 >> > [<ffffffff8137b7b9>] acpi_ns_walk_namespace+0x10f/0x24a >> > [<ffffffff8138dd38>] ? walk_p2p_bridge+0x13b/0x13b >> > [<ffffffff8138dd38>] ? walk_p2p_bridge+0x13b/0x13b >> > [<ffffffff8137bdc3>] acpi_walk_namespace+0xe9/0x132 >> > [<ffffffff8138dd38>] ? walk_p2p_bridge+0x13b/0x13b >> > [<ffffffff8138dcf5>] walk_p2p_bridge+0xf8/0x13b >> > [<ffffffff8134d606>] ? acpi_os_signal_semaphore+0x76/0x87 >> > [<ffffffff8138dd38>] ? walk_p2p_bridge+0x13b/0x13b >> > [<ffffffff8137b7b9>] acpi_ns_walk_namespace+0x10f/0x24a >> > [<ffffffff8138dbfd>] ? do_sta_before_sun+0x2b/0x2b >> > [<ffffffff8138dbfd>] ? do_sta_before_sun+0x2b/0x2b >> > [<ffffffff8137bdc3>] acpi_walk_namespace+0xe9/0x132 >> > [<ffffffff81356071>] ? acpi_pci_root_add+0x3e7/0x49a >> > [<ffffffff8138e07f>] acpi_pci_slot_add+0xb2/0x103 >> > [<ffffffff8138dd38>] ? walk_p2p_bridge+0x13b/0x13b >> > [<ffffffff81356089>] acpi_pci_root_add+0x3ff/0x49a >> > >> > which means that pci_bus->dev used in register_slot() has not been >> > registered yet at that point. >> > >> > To fix this use the observation that before commit 1aeae82 >> > acpi_pci_slot_add() was always run after pci_bus_add_devices() >> > and that happened to the acpiphp's .add() callback routine too. >> > Thus it is safe to reorder acpi_pci_root_add() to make the PCI root >> > drivers' .add() callbacks be run after pci_bus_add_devices(), so do >> > that. >> > >> > This approach was previously proposed by Myron Stowe. >> > >> > References: https://patchwork.kernel.org/patch/1848781/ >> > Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx> >> > --- >> > >> > The commit mentioned in the changelog above is in linux-pm.git/linux-next. >> > >> > Thanks, >> > Rafael >> > >> > --- >> > drivers/acpi/pci_root.c | 13 ++++++++----- >> > 1 file changed, 8 insertions(+), 5 deletions(-) >> > >> > Index: test/drivers/acpi/pci_root.c >> > =================================================================== >> > --- test.orig/drivers/acpi/pci_root.c >> > +++ test/drivers/acpi/pci_root.c >> > @@ -600,17 +600,20 @@ static int acpi_pci_root_add(struct acpi >> > if (system_state != SYSTEM_BOOTING) >> > pci_assign_unassigned_bus_resources(root->bus); >> > >> > + /* need to after hot-added ioapic is registered */ >> > + if (system_state != SYSTEM_BOOTING) >> > + pci_enable_bridges(root->bus); >> > + >> > + pci_bus_add_devices(root->bus); >> > + >> > mutex_lock(&acpi_pci_root_lock); >> > + >> > list_for_each_entry(driver, &acpi_pci_drivers, node) >> > if (driver->add) >> > driver->add(root); >> > - mutex_unlock(&acpi_pci_root_lock); >> > >> > - /* need to after hot-added ioapic is registered */ >> > - if (system_state != SYSTEM_BOOTING) >> > - pci_enable_bridges(root->bus); >> > + mutex_unlock(&acpi_pci_root_lock); >> > >> > - pci_bus_add_devices(root->bus); >> > return 1; >> > >> > out_del_root: >> > >> >> No, we don't need this after >> >> | commit 4f535093cf8f6da8cfda7c36c2c1ecd2e9586ee4 >> | PCI: Put pci_dev in device tree as early as possible >> >> in pci/next. >> >> So we can move that Jiang's patch from your tree to Bjorn's tree? > > OK, I'm dropping that patch from my tree, then (hopefully, no one has merged > my acpi-cleanup branch yet). > > Bjorn, could you pick up https://patchwork.kernel.org/patch/2003771/ please? I applied this to my next branch for v3.9: commit ab1a2e038ff2336502e95ec6492c0364a9fc70d0 Author: Jiang Liu <liuj97@xxxxxxxxx> Date: Sat Jan 19 00:07:42 2013 +0800 ACPI / PCI: Make pci_slot built-in only, not a module As discussed in thread at https://patchwork.kernel.org/patch/1946851/, there's no value in supporting CONFIG_ACPI_PCI_SLOT=m any more. So change Kconfig and code to only support building pci_slot as built-in driver. Thanks! Bjorn -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
