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[PATCH] PCI: fix race with pci_walk_bus and pci_destroy_dev

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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 <yanmin.zhang@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This commit is contained in:
Zhang Yanmin
2006-06-02 12:35:43 +08:00
committed by Greg Kroah-Hartman
parent 733a7fe122
commit d71374dafb
5 changed files with 41 additions and 43 deletions
Download Patch File Download Diff File Expand all files Collapse all files

17
drivers/pci/probe.c
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@@ -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);