PCI: fix nested spinlock hang in aer_inject

The aer_inject module hangs in aer_inject() when checking the device's
error masks.  The hang is due to a recursive use of the aer_inject lock.
The aer_inject() routine grabs the lock while processing the error and then
calls pci_read_config_dword to read the masks. The pci_read_config_dword
routine is earlier overridden by pci_read_aer, which among other things,
grabs the aer_inject lock.

Fixed by moving the pci_read_config_dword calls to read the masks to before
the lock is taken.

Acked-by: Huang Ying <ying.huang@intel.com>
Signed-off-by: Andrew Patterson <andrew.patterson@hp.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>

1 files changed, 6 insertions, 6 deletions

diff --git a/drivers/pci/pcie/aer/aer_inject.c b/drivers/pci/pcie/aer/aer_inject.c
index 8c30a9544d61..223052b73563 100644
--- a/drivers/pci/pcie/aer/aer_inject.c
+++ b/drivers/pci/pcie/aer/aer_inject.c
@@ -321,7 +321,7 @@ static int aer_inject(struct aer_error_inj *einj)
         unsigned long flags;
         unsigned int devfn = PCI_DEVFN(einj->dev, einj->fn);
         int pos_cap_err, rp_pos_cap_err;
-        u32 sever, mask;
+        u32 sever, cor_mask, uncor_mask;
         int ret = 0;
 
         dev = pci_get_domain_bus_and_slot((int)einj->domain, einj->bus, devfn);
@@ -339,6 +339,9 @@ static int aer_inject(struct aer_error_inj *einj)
                 goto out_put;
         }
         pci_read_config_dword(dev, pos_cap_err + PCI_ERR_UNCOR_SEVER, &sever);
+        pci_read_config_dword(dev, pos_cap_err + PCI_ERR_COR_MASK, &cor_mask);
+        pci_read_config_dword(dev, pos_cap_err + PCI_ERR_UNCOR_MASK,
+                              &uncor_mask);
 
         rp_pos_cap_err = pci_find_ext_capability(rpdev, PCI_EXT_CAP_ID_ERR);
         if (!rp_pos_cap_err) {
@@ -374,17 +377,14 @@ static int aer_inject(struct aer_error_inj *einj)
         err->header_log2 = einj->header_log2;
         err->header_log3 = einj->header_log3;
 
-        pci_read_config_dword(dev, pos_cap_err + PCI_ERR_COR_MASK, &mask);
-        if (einj->cor_status && !(einj->cor_status & ~mask)) {
+        if (einj->cor_status && !(einj->cor_status & ~cor_mask)) {
                 ret = -EINVAL;
                 printk(KERN_WARNING "The correctable error(s) is masked "
                                 "by device\n");
                 spin_unlock_irqrestore(&inject_lock, flags);
                 goto out_put;
         }
-
-        pci_read_config_dword(dev, pos_cap_err + PCI_ERR_UNCOR_MASK, &mask);
-        if (einj->uncor_status && !(einj->uncor_status & ~mask)) {
+        if (einj->uncor_status && !(einj->uncor_status & ~uncor_mask)) {
                 ret = -EINVAL;
                 printk(KERN_WARNING "The uncorrectable error(s) is masked "
                                 "by device\n");