Hi Petr,
Thank you, while I didn't get to the point of failure I'm please to see
I was not wrong in finding what I thought was evidence the coredump is
not in a format crash is able to read...cause not being the generation
of the coredump but, instead, the rather classic example of a kernel
change that made crash obsolete in the same product.
I expect to be working on all needed crash changes from now.
--
David.
On 6/25/21 9:21 AM, Petr Tesařík wrote:
Kernel commit 5c83511bdb9832c86be20fb86b783356e2f58062 removed
pv_init_ops, and later commit 054ac8ad5ebe4a69e1f0e842483821ddbe560121
removed the Xen-specific paravirt patch function. As a result, pvops Xen
dumps are no longer recognized as Xen dumps, and virtual-to-physical
translation fails.
Use the value of xen_start_info to determine whether the kernel is
running in Xen PV mode. This pointer is set during the initialization of
a PV domain. Kudos to Juergen Gross, who suggested this check.
Signed-off-by: Petr Tesarik <ptesarik@xxxxxxxx>
---
kernel.c | 34 ++++++++++++++++++++++++++++------
1 file changed, 28 insertions(+), 6 deletions(-)
diff --git a/kernel.c b/kernel.c
index e123f76..36fdea2 100644
--- a/kernel.c
+++ b/kernel.c
@@ -95,6 +95,7 @@ static ulong __dump_audit(char *);
static void dump_audit(void);
static char *vmcoreinfo_read_string(const char *);
static void check_vmcoreinfo(void);
+static int is_pvops_xen(void);
/*
@@ -109,7 +110,6 @@ kernel_init()
char *rqstruct;
char *rq_timestamp_name = NULL;
char *irq_desc_type_name;
- ulong pv_init_ops;
struct gnu_request req;
if (pc->flags & KERNEL_DEBUG_QUERY)
@@ -169,11 +169,7 @@ kernel_init()
error(FATAL, "cannot malloc m2p page.");
}
- if (PVOPS() && symbol_exists("pv_init_ops") &&
- readmem(symbol_value("pv_init_ops"), KVADDR, &pv_init_ops,
- sizeof(void *), "pv_init_ops", RETURN_ON_ERROR) &&
- ((p1 = value_symbol(pv_init_ops)) &&
- (STREQ(p1, "xen_patch") || STREQ(p1,
"paravirt_patch_default")))) {
+ if (is_pvops_xen()) {
kt->flags |= ARCH_XEN | ARCH_PVOPS_XEN;
kt->xen_flags |= WRITABLE_PAGE_TABLES;
if (machine_type("X86"))
@@ -10709,6 +10705,32 @@ paravirt_init(void)
}
}
+static int
+is_pvops_xen(void)
+{
+ ulong addr;
+ char *sym;
+
+ if (!PVOPS())
+ return FALSE;
+
+ if (symbol_exists("pv_init_ops") &&
+ readmem(symbol_value("pv_init_ops"), KVADDR, &addr,
+ sizeof(void *), "pv_init_ops", RETURN_ON_ERROR) &&
+ (sym = value_symbol(addr)) &&
+ (STREQ(sym, "xen_patch") ||
+ STREQ(sym, "paravirt_patch_default")))
+ return TRUE;
+
+ if (symbol_exists("xen_start_info") &&
+ readmem(symbol_value("xen_start_info"), KVADDR, &addr,
+ sizeof(void *), "xen_start_info", RETURN_ON_ERROR) &&
+ addr != 0)
+ return TRUE;
+
+ return FALSE;
+}
+
/*
* Get the kernel's xtime timespec from its relevant location.
*/
--
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