On 04/29/2013 02:48 AM, Laine Stump wrote:
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@xxxxxxxxxx> --- 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
Yes, I just noticed this, it should be different code path.
virPCIDeviceAddressIsEqual() (but *does* call the function that actually has the bug).
Yes, another 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=9579b6bc209b46a0f079b21455b598c817925b48
It should be okay if the patch is backported into rhel.
(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
Yes, the function interface will be more complex and return value should be tri-state not simple true/false.
check all three possibilities). I think in this case it's better for the caller to make sure the pointers it sends are valid.)
Yes, a simple way is the caller makes sure pointers is Non-NULL, maybe, we need also to add comment "The caller should make sure the pointers it sends are valid" into the virPCIDeviceAddressIsEqual(). However, in order to avoid the caller missing argument judgement, I think we should also fix virPCIDeviceAddressIsEqual(). Thanks for your comments, Alex
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