Patchwork [v5,2/5,RESEND] PCI/AER: use list_for_each_entry to avoid a small race condition window

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Submitter Yijing Wang
Date Nov. 14, 2012, 12:27 p.m.
Message ID <1352896042-11832-3-git-send-email-wangyijing@huawei.com>
Download mbox | patch
Permalink /patch/198886/
State Not Applicable
Headers show

Comments

Yijing Wang - Nov. 14, 2012, 12:27 p.m.
When we rmmod aer_inject module, there is a small race condition window between pci_bus_ops_pop()
and pci_bus_set_ops() in aer_inject_exit, eg. pci_read_aer/pci_write_aer was called between
them. So keep pci_bus_ops_list until pci_bus_set_ops complete, use list_for_each_entry() instead of
pci_bus_ops_pop to get bus_ops.

Signed-off-by: Yijing Wang <wangyijing@huawei.com>
---
 drivers/pci/pcie/aer/aer_inject.c |    5 +++--
 1 files changed, 3 insertions(+), 2 deletions(-)

Patch

diff --git a/drivers/pci/pcie/aer/aer_inject.c b/drivers/pci/pcie/aer/aer_inject.c
index fdab3bb..f499f01 100644
--- a/drivers/pci/pcie/aer/aer_inject.c
+++ b/drivers/pci/pcie/aer/aer_inject.c
@@ -543,10 +543,11 @@  static void __exit aer_inject_exit(void)
 
 	misc_deregister(&aer_inject_device);
 
-	while ((bus_ops = pci_bus_ops_pop())) {
+	list_for_each_entry(bus_ops, &pci_bus_ops_list, list)
 		pci_bus_set_ops(bus_ops->bus, bus_ops->ops);
+
+	while ((bus_ops = pci_bus_ops_pop()))
 		kfree(bus_ops);
-	}
 
 	spin_lock_irqsave(&inject_lock, flags);
 	list_for_each_entry_safe(err, err_next, &einjected, list) {