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| author | Zhang Yanmin <yanmin.zhang@intel.com> | 2006-06-02 12:35:43 +0800 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@suse.de> | 2006-06-21 12:00:01 -0700 |
| commit | d71374dafbba7ec3f67371d3b7e9f6310a588808 (patch) | |
| tree | 116dcd65fde3701d10fea954cdbd5bb063182b2c /drivers/pci/bus.c | |
| parent | 733a7fe12248072e1bca729c88a26298666f1956 (diff) | |
| download | linux-d71374dafbba7ec3f67371d3b7e9f6310a588808.tar.gz linux-d71374dafbba7ec3f67371d3b7e9f6310a588808.tar.bz2 linux-d71374dafbba7ec3f67371d3b7e9f6310a588808.zip | |
[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 <yanmin.zhang@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Diffstat (limited to 'drivers/pci/bus.c')
| -rw-r--r-- | drivers/pci/bus.c | 21 |
1 files changed, 9 insertions, 12 deletions
diff --git a/drivers/pci/bus.c b/drivers/pci/bus.c index eed67d9e73bc..723092682023 100644 --- a/drivers/pci/bus.c +++ b/drivers/pci/bus.c @@ -81,9 +81,9 @@ void __devinit pci_bus_add_device(struct pci_dev *dev) { device_add(&dev->dev); - spin_lock(&pci_bus_lock); + down_write(&pci_bus_sem); list_add_tail(&dev->global_list, &pci_devices); - spin_unlock(&pci_bus_lock); + up_write(&pci_bus_sem); pci_proc_attach_device(dev); pci_create_sysfs_dev_files(dev); @@ -125,10 +125,10 @@ void __devinit pci_bus_add_devices(struct pci_bus *bus) */ if (dev->subordinate) { if (list_empty(&dev->subordinate->node)) { - spin_lock(&pci_bus_lock); + down_write(&pci_bus_sem); list_add_tail(&dev->subordinate->node, &dev->bus->children); - spin_unlock(&pci_bus_lock); + up_write(&pci_bus_sem); } pci_bus_add_devices(dev->subordinate); @@ -168,7 +168,7 @@ void pci_walk_bus(struct pci_bus *top, void (*cb)(struct pci_dev *, void *), struct list_head *next; bus = top; - spin_lock(&pci_bus_lock); + down_read(&pci_bus_sem); next = top->devices.next; for (;;) { if (next == &bus->devices) { @@ -180,22 +180,19 @@ void pci_walk_bus(struct pci_bus *top, void (*cb)(struct pci_dev *, void *), continue; } dev = list_entry(next, struct pci_dev, bus_list); - pci_dev_get(dev); if (dev->subordinate) { /* this is a pci-pci bridge, do its devices next */ next = dev->subordinate->devices.next; bus = dev->subordinate; } else next = dev->bus_list.next; - spin_unlock(&pci_bus_lock); - /* Run device routines with the bus unlocked */ + /* Run device routines with the device locked */ + down(&dev->dev.sem); cb(dev, userdata); - - spin_lock(&pci_bus_lock); - pci_dev_put(dev); + up(&dev->dev.sem); } - spin_unlock(&pci_bus_lock); + up_read(&pci_bus_sem); } EXPORT_SYMBOL_GPL(pci_walk_bus); |