From d71374dafbba7ec3f67371d3b7e9f6310a588808 Mon Sep 17 00:00:00 2001 From: Zhang Yanmin Date: Fri, 2 Jun 2006 12:35:43 +0800 Subject: [PATCH] PCI: fix race with pci_walk_bus and pci_destroy_dev pci_walk_bus has a race with pci_destroy_dev. When cb is called in pci_walk_bus, pci_destroy_dev might unlink the dev pointed by next. Later on in the next loop, pointer next becomes NULL and cause kernel panic. Below patch against 2.6.17-rc4 fixes it by changing pci_bus_lock (spin_lock) to pci_bus_sem (rw_semaphore). Signed-off-by: Zhang Yanmin Signed-off-by: Greg Kroah-Hartman --- drivers/pci/probe.c | 17 +++++++++-------- 1 file changed, 9 insertions(+), 8 deletions(-) (limited to 'drivers/pci/probe.c') diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c index 27148db06ba..f89dbc3738b 100644 --- a/drivers/pci/probe.c +++ b/drivers/pci/probe.c @@ -383,9 +383,9 @@ struct pci_bus * __devinit pci_add_new_bus(struct pci_bus *parent, struct pci_de child = pci_alloc_child_bus(parent, dev, busnr); if (child) { - spin_lock(&pci_bus_lock); + down_write(&pci_bus_sem); list_add_tail(&child->node, &parent->children); - spin_unlock(&pci_bus_lock); + up_write(&pci_bus_sem); } return child; } @@ -844,9 +844,9 @@ void __devinit pci_device_add(struct pci_dev *dev, struct pci_bus *bus) * and the bus list for fixup functions, etc. */ INIT_LIST_HEAD(&dev->global_list); - spin_lock(&pci_bus_lock); + down_write(&pci_bus_sem); list_add_tail(&dev->bus_list, &bus->devices); - spin_unlock(&pci_bus_lock); + up_write(&pci_bus_sem); } struct pci_dev * __devinit @@ -981,9 +981,10 @@ struct pci_bus * __devinit pci_create_bus(struct device *parent, pr_debug("PCI: Bus %04x:%02x already known\n", pci_domain_nr(b), bus); goto err_out; } - spin_lock(&pci_bus_lock); + + down_write(&pci_bus_sem); list_add_tail(&b->node, &pci_root_buses); - spin_unlock(&pci_bus_lock); + up_write(&pci_bus_sem); memset(dev, 0, sizeof(*dev)); dev->parent = parent; @@ -1023,9 +1024,9 @@ class_dev_create_file_err: class_dev_reg_err: device_unregister(dev); dev_reg_err: - spin_lock(&pci_bus_lock); + down_write(&pci_bus_sem); list_del(&b->node); - spin_unlock(&pci_bus_lock); + up_write(&pci_bus_sem); err_out: kfree(dev); kfree(b); -- cgit v1.2.3