Hi Dave,
when trying to debug the xen hypervisor on a vmcore file it doesn't work for me.
xen_version: 4.11.0_08-1
...
This GDB was configured as "x86_64-unknown-linux-gnu"...
crash: invalid kernel virtual address: bf45ffa0001ef8 type:
"fill_pcpu_struct"
WARNING: cannot fill pcpu_struct.
crash: cannot read cpu_info.
I had a look at this and found a change in the struct tss_struct when trying
to read the rsp0. The change in the xen-git-tree was done with commit 98dffb05ce4.
Old:
struct tss_struct {
unsigned short back_link,__blh;
union { u64 rsp0, esp0; };
...
New:
struct __packed __cacheline_aligned tss_struct {
uint32_t :32;
uint64_t rsp0, rsp1, rsp2;
After fixing this in the crash command I got:
...
This GDB was configured as "x86_64-unknown-linux-gnu"...
KERNEL: xen-syms
DUMPFILE: vmcore
CPUS: 4
DOMAINS: 3
UPTIME: --:--:--
MACHINE: Intel(R) Xeon(R) CPU E5520 @ 2.27GHz (2266 Mhz)
MEMORY: 12 GB
Segmentation fault (core dumped)
It seems that the commit 4e1dca21 in xen_hyper.c isn't sufficient
anymore.
Because reading the symbol "dom0" is successful but the address is zero.
My suggestion now is simply to switch the if statement.
First ask for the symbol "hardware_domain" (introduced in xen version 4.5.0)
and if it isn't found use the symbol "dom0".
This works for me with vmcore's with xen-4.4.4.
Dietmar.
---
x86_64.c | 6 +++++-
xen_hyper.c | 8 ++++----
2 files changed, 9 insertions(+), 5 deletions(-)
diff --git a/x86_64.c b/x86_64.c
index 0f6c584..26eb286 100644
--- a/x86_64.c
+++ b/x86_64.c
@@ -7903,7 +7903,11 @@ x86_64_init_hyper(int when)
case POST_GDB:
XEN_HYPER_STRUCT_SIZE_INIT(cpuinfo_x86, "cpuinfo_x86");
XEN_HYPER_STRUCT_SIZE_INIT(tss_struct, "tss_struct");
- XEN_HYPER_ASSIGN_OFFSET(tss_struct_rsp0) = MEMBER_OFFSET("tss_struct", "__blh") + sizeof(short unsigned int);
+ if (MEMBER_EXISTS("tss_struct", "__blh")) {
+ XEN_HYPER_ASSIGN_OFFSET(tss_struct_rsp0) = MEMBER_OFFSET("tss_struct", "__blh") + sizeof(short unsigned int);
+ } else {
+ XEN_HYPER_ASSIGN_OFFSET(tss_struct_rsp0) = MEMBER_OFFSET("tss_struct", "rsp0");
+ }
XEN_HYPER_MEMBER_OFFSET_INIT(tss_struct_ist, "tss_struct", "ist");
if (symbol_exists("cpu_data")) {
xht->cpu_data_address = symbol_value("cpu_data");
diff --git a/xen_hyper.c b/xen_hyper.c
index 20072e9..f2f00e6 100644
--- a/xen_hyper.c
+++ b/xen_hyper.c
@@ -1060,8 +1060,8 @@ xen_hyper_get_domains(void)
long domain_next_in_list;
int i, j;
- if (!try_get_symbol_data("dom0", sizeof(void *), &domain))
- get_symbol_data("hardware_domain", sizeof(void *), &domain);
+ if (!try_get_symbol_data("hardware_domain", sizeof(void *), &domain))
+ get_symbol_data("dom0", sizeof(void *), &domain);
domain_next_in_list = MEMBER_OFFSET("domain", "next_in_list");
i = 0;
@@ -1103,8 +1103,8 @@ xen_hyper_get_domain_next(int mod, ulong *next)
if (xhdt->dom0) {
*next = xhdt->dom0->domain;
} else {
- if (!try_get_symbol_data("dom0", sizeof(void *), next))
- get_symbol_data("hardware_domain", sizeof(void *), next);
+ if (!try_get_symbol_data("hardware_domain", sizeof(void *), next))
+ get_symbol_data("dom0", sizeof(void *), next);
}
return xhdt->domain_struct;
break;
--
2.12.3
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