Re: [Crash-utility] Fix pvops Xen detection for kernels >= v4.20

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(a)suse.com&gt;

--- 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. */ -- Crash-utility mailing list Crash-utility(a)redhat.com https://listman.redhat.com/mailman/listinfo/crash-utility