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/search.c | 32 ++++++++++++++++---------------- 1 file changed, 16 insertions(+), 16 deletions(-) (limited to 'drivers/pci/search.c') diff --git a/drivers/pci/search.c b/drivers/pci/search.c index ce7dd6e7be60..622b3f8ba820 100644 --- a/drivers/pci/search.c +++ b/drivers/pci/search.c @@ -13,7 +13,7 @@ #include #include "pci.h" -DEFINE_SPINLOCK(pci_bus_lock); +DECLARE_RWSEM(pci_bus_sem); static struct pci_bus * __devinit pci_do_find_bus(struct pci_bus* bus, unsigned char busnr) @@ -72,11 +72,11 @@ pci_find_next_bus(const struct pci_bus *from) struct pci_bus *b = NULL; WARN_ON(in_interrupt()); - spin_lock(&pci_bus_lock); + down_read(&pci_bus_sem); n = from ? from->node.next : pci_root_buses.next; if (n != &pci_root_buses) b = pci_bus_b(n); - spin_unlock(&pci_bus_lock); + up_read(&pci_bus_sem); return b; } @@ -124,7 +124,7 @@ struct pci_dev * pci_get_slot(struct pci_bus *bus, unsigned int devfn) struct pci_dev *dev; WARN_ON(in_interrupt()); - spin_lock(&pci_bus_lock); + down_read(&pci_bus_sem); list_for_each(tmp, &bus->devices) { dev = pci_dev_b(tmp); @@ -135,7 +135,7 @@ struct pci_dev * pci_get_slot(struct pci_bus *bus, unsigned int devfn) dev = NULL; out: pci_dev_get(dev); - spin_unlock(&pci_bus_lock); + up_read(&pci_bus_sem); return dev; } @@ -167,7 +167,7 @@ static struct pci_dev * pci_find_subsys(unsigned int vendor, struct pci_dev *dev; WARN_ON(in_interrupt()); - spin_lock(&pci_bus_lock); + down_read(&pci_bus_sem); n = from ? from->global_list.next : pci_devices.next; while (n && (n != &pci_devices)) { @@ -181,7 +181,7 @@ static struct pci_dev * pci_find_subsys(unsigned int vendor, } dev = NULL; exit: - spin_unlock(&pci_bus_lock); + up_read(&pci_bus_sem); return dev; } @@ -232,7 +232,7 @@ pci_get_subsys(unsigned int vendor, unsigned int device, struct pci_dev *dev; WARN_ON(in_interrupt()); - spin_lock(&pci_bus_lock); + down_read(&pci_bus_sem); n = from ? from->global_list.next : pci_devices.next; while (n && (n != &pci_devices)) { @@ -247,7 +247,7 @@ pci_get_subsys(unsigned int vendor, unsigned int device, dev = NULL; exit: dev = pci_dev_get(dev); - spin_unlock(&pci_bus_lock); + up_read(&pci_bus_sem); pci_dev_put(from); return dev; } @@ -292,7 +292,7 @@ pci_find_device_reverse(unsigned int vendor, unsigned int device, const struct p struct pci_dev *dev; WARN_ON(in_interrupt()); - spin_lock(&pci_bus_lock); + down_read(&pci_bus_sem); n = from ? from->global_list.prev : pci_devices.prev; while (n && (n != &pci_devices)) { @@ -304,7 +304,7 @@ pci_find_device_reverse(unsigned int vendor, unsigned int device, const struct p } dev = NULL; exit: - spin_unlock(&pci_bus_lock); + up_read(&pci_bus_sem); return dev; } @@ -328,7 +328,7 @@ struct pci_dev *pci_get_class(unsigned int class, struct pci_dev *from) struct pci_dev *dev; WARN_ON(in_interrupt()); - spin_lock(&pci_bus_lock); + down_read(&pci_bus_sem); n = from ? from->global_list.next : pci_devices.next; while (n && (n != &pci_devices)) { @@ -340,7 +340,7 @@ struct pci_dev *pci_get_class(unsigned int class, struct pci_dev *from) dev = NULL; exit: dev = pci_dev_get(dev); - spin_unlock(&pci_bus_lock); + up_read(&pci_bus_sem); pci_dev_put(from); return dev; } @@ -362,7 +362,7 @@ int pci_dev_present(const struct pci_device_id *ids) int found = 0; WARN_ON(in_interrupt()); - spin_lock(&pci_bus_lock); + down_read(&pci_bus_sem); while (ids->vendor || ids->subvendor || ids->class_mask) { list_for_each_entry(dev, &pci_devices, global_list) { if (pci_match_one_device(ids, dev)) { @@ -372,8 +372,8 @@ int pci_dev_present(const struct pci_device_id *ids) } ids++; } -exit: - spin_unlock(&pci_bus_lock); +exit: + up_read(&pci_bus_sem); return found; } EXPORT_SYMBOL(pci_dev_present); -- cgit v1.2.3