On 04/28/2013 06:12 AM, Alex Jia wrote:
GDB backtrace:
Breakpoint 1, virPCIGetVirtualFunctionIndex (pf_sysfs_device_link=0x7fc04400f470 "/sys/bus/pci/devices/0000:03:00.1", vf_sysfs_device_link=<optimized out>, vf_index=vf_index@entry=0x7fc06897b8f4) at util/virpci.c:2107 2107 if (virPCIDeviceAddressIsEqual(vf_bdf, virt_fns[i])) { (gdb) p *vf_bdf $1 = {domain = 0, bus = 3, slot = 16, function = 1} (gdb) l 2102 "virtual_functions"), pf_sysfs_device_link); 2103 goto out; 2104 } 2105 2106 for (i = 0; i < num_virt_fns; i++) { 2107 if (virPCIDeviceAddressIsEqual(vf_bdf, virt_fns[i])) { 2108 *vf_index = i; 2109 ret = 0; 2110 break; 2111 } (gdb) p num_virt_fns $46 = 2 (gdb) p virt_fns[0] $48 = (virPCIDeviceAddressPtr) 0x0 (gdb) s virPCIDeviceAddressIsEqual (bdf2=0x0, bdf1=0x7fc04400f330) at util/virpci.c:1844 1844 (bdf1->slot == bdf2->slot) && (gdb) s
Program received signal SIGSEGV, Segmentation fault.
RHBZ: https://bugzilla.redhat.com/show_bug.cgi?id=957416
Signed-off-by: Alex Jia <ajia@redhat.com> --- src/util/virpci.c | 3 ++- 1 files changed, 2 insertions(+), 1 deletions(-)
diff --git a/src/util/virpci.c b/src/util/virpci.c index 97bba74..dda044c 100644 --- a/src/util/virpci.c +++ b/src/util/virpci.c @@ -1897,7 +1897,8 @@ static bool virPCIDeviceAddressIsEqual(virPCIDeviceAddressPtr bdf1, virPCIDeviceAddressPtr bdf2) { - return ((bdf1->domain == bdf2->domain) && + return (bdf1 && bdf2 && + (bdf1->domain == bdf2->domain) && (bdf1->bus == bdf2->bus) && (bdf1->slot == bdf2->slot) && (bdf1->function == bdf2->function)); NACK.
This patch only fixes the symptom (not the root cause), and only in the case of starting a domain with an <interface type='hostdev'. It doesn't fix the second crash described in the BZ when running virsh nodedev-dumpxml - the code path of that doesn't ever get to virPCIDeviceAddressIsEqual() (but *does* call the function that actually has the bug). The root cause of these crashes was a typo introduced just before the release of 1.0.4. I found that problem and pushed the correct patch on April 9: http://libvirt.org/git/?p=libvirt.git;a=commit;h=9579b6bc209b46a0f079b21455b... (Beyond that, I don't like the idea of ignoring a NULL pointer - virPCIDeviceAddressIsEqual should always be passed non-NULL pointers, and its only current caller does guarantee that (except for when it has a bug). If we want virPCIDeviceAddressIsEqual to do something with NULL pointers, it should be logging an error and failing, but that would complicate the interface to the function beyond just returning a true/false (it would have to be tri-state, and the caller would need to check all three possibilities). I think in this case it's better for the caller to make sure the pointers it sends are valid.)