From: Ian Jackson <ian.jackson@eu.citrix.com>
Date: Mon, 7 Dec 2009 12:25:54 +0000 (+0000)
Subject: passthrough: Fix no_wb not to crash on unknown registers
X-Git-Tag: xen-4.0.0-rc1~7
X-Git-Url: http://xenbits.xensource.com/gitweb?a=commitdiff_plain;h=9297e6402f6aa1b52e5577edc875eb2d2163baeb;p=qemu-xen-4.6-testing.git

passthrough: Fix no_wb not to crash on unknown registers

e2b98415256cb264bc25e6df539ec0dc9d1b85b0 broke things sometimes:

 If pt_find_reg_grp() fails and returns NULL, it will jump to out:,
 but at this time reg is still NULL (pt_find_reg() is not reached)
 which leads to a NULL dereference.

This patch fixes it.

Submitted-By: Qing He <qing.he@intel.com>
Signed-off-by: Ian Jackson <ian.jackson@eu.citrix.com>
---

diff --git a/hw/pass-through.c b/hw/pass-through.c
index b125d7222..e7bd38602 100644
--- a/hw/pass-through.c
+++ b/hw/pass-through.c
@@ -1556,7 +1556,7 @@ static void pt_pci_write_config(PCIDevice *d, uint32_t address, uint32_t val,
     val >>= ((address & 3) << 3);
 
 out:
-    if (!reg->no_wb) {
+    if (!(reg && reg->no_wb)) {  /* unknown regs are passed through */
         ret = pci_write_block(pci_dev, address, (uint8_t *)&val, len);
 
         if (!ret)