[Crash-utility] Crash problems with Xen

[Dave Anderson]

----- Original Message -----
> Hi,
> 
> for me crash failed to debug xen environments with:
> 
> crash: invalid structure member offset: domain_is_paused_by_controller
>        FILE: xen_hyper.c  LINE: 1255  FUNCTION:
>        xen_hyper_store_domain_context()
> 
> [/usr/bin/crash] error trace: 546170 => 545bc9 => 545a81 => 510fd0
> 
>   510fd0: OFFSET_verify+224
>   545a81: xen_hyper_store_domain_context+1265
>   545bc9: xen_hyper_refresh_domain_context_space+153
>   546170: xen_hyper_domain_init+864
> 
> The problem is a change of an item in struct domain in xen version 4.2
> I tried to fix the problem for me so I can debug the old and the newer
> xen versions. I'm not sure this was the right way to fix this.
> Thanks.
> 
> Dietmar.

Your patch looks reasonable.  I have two *very* minor nits:

(1) Put the new domain_controller_pause_count at the end of the xen_hyper_offset_table.
    In the fairly unlikely event that somebody has an extension module for xen
    debugging, it will break unless recompiled.
(2) In xen_hyper_dump_xen_hyper_offset_table(), display both the old and new offsets.
    That fact that one or the other shows -1 would be more helpful than not showing it.

Note that these suggestions apply to the mainline offset[] table and the dump_offset_table()
function.

Thanks,
  Dave

 
> 
> diff -pNaur crash-7.1.0-org/xen_hyper.c crash-7.1.0/xen_hyper.c
> --- crash-7.1.0-org/xen_hyper.c	2015-02-06 19:44:11.000000000 +0100
> +++ crash-7.1.0/xen_hyper.c	2015-03-10 13:57:48.000000000 +0100
> @@ -218,7 +218,12 @@ xen_hyper_domain_init(void)
>  	XEN_HYPER_MEMBER_OFFSET_INIT(domain_is_polling, "domain", "is_polling");
>  
>  	XEN_HYPER_MEMBER_OFFSET_INIT(domain_is_dying, "domain", "is_dying");
> +	/*
> +	 * In Xen 4.2 is_paused_by_controller changed to
> +	 * controller_pause_count.
> +	 */
>  	XEN_HYPER_MEMBER_OFFSET_INIT(domain_is_paused_by_controller, "domain",
>  	"is_paused_by_controller");
> +	XEN_HYPER_MEMBER_OFFSET_INIT(domain_controller_pause_count, "domain",
> "controller_pause_count");
>  	XEN_HYPER_MEMBER_OFFSET_INIT(domain_is_shutting_down, "domain",
>  	"is_shutting_down");
>  	XEN_HYPER_MEMBER_OFFSET_INIT(domain_is_shut_down, "domain",
>  	"is_shut_down");
>  	XEN_HYPER_MEMBER_OFFSET_INIT(domain_vcpu, "domain", "vcpu");
> @@ -1269,9 +1274,15 @@ xen_hyper_store_domain_context(struct xe
>  				*(dp + XEN_HYPER_OFFSET(domain_is_polling))) {
>  			dc->domain_flags |= XEN_HYPER_DOMS_polling;
>  		}
> -		if (*(dp + XEN_HYPER_OFFSET(domain_is_paused_by_controller))) {
> +		if (XEN_HYPER_VALID_MEMBER(domain_is_paused_by_controller) &&
> +			*(dp + XEN_HYPER_OFFSET(domain_is_paused_by_controller))) {
>  			dc->domain_flags |= XEN_HYPER_DOMS_ctrl_pause;
>  		}
> +		if (XEN_HYPER_VALID_MEMBER(domain_controller_pause_count) &&
> +			*(dp + XEN_HYPER_OFFSET(domain_controller_pause_count))) {
> +			dc->domain_flags |= XEN_HYPER_DOMS_ctrl_pause;
> +		}
> +
>  		if (*(dp + XEN_HYPER_OFFSET(domain_is_dying))) {
>  			dc->domain_flags |= XEN_HYPER_DOMS_dying;
>  		}
> diff -pNaur crash-7.1.0-org/xen_hyper_defs.h crash-7.1.0/xen_hyper_defs.h
> --- crash-7.1.0-org/xen_hyper_defs.h	2015-02-06 19:44:11.000000000 +0100
> +++ crash-7.1.0/xen_hyper_defs.h	2015-03-10 13:52:37.000000000 +0100
> @@ -679,6 +679,7 @@ struct xen_hyper_offset_table {
>  	long domain_is_polling;
>  	long domain_is_dying;
>  	long domain_is_paused_by_controller;
> +	long domain_controller_pause_count;
>  	long domain_is_shutting_down;
>  	long domain_is_shut_down;
>  	long domain_vcpu;
> diff -pNaur crash-7.1.0-org/xen_hyper_dump_tables.c
> crash-7.1.0/xen_hyper_dump_tables.c
> --- crash-7.1.0-org/xen_hyper_dump_tables.c	2015-02-06 19:44:11.000000000
> +0100
> +++ crash-7.1.0/xen_hyper_dump_tables.c	2015-03-10 14:00:20.000000000 +0100
> @@ -784,8 +784,14 @@ xen_hyper_dump_xen_hyper_offset_table(ch
>  	}
>  	XEN_HYPER_PRI(fp, len, "domain_is_dying: ", buf, flag,
>  		(buf, "%ld\n", xen_hyper_offset_table.domain_is_dying));
> -	XEN_HYPER_PRI(fp, len, "domain_is_paused_by_controller: ", buf, flag,
> -		(buf, "%ld\n", xen_hyper_offset_table.domain_is_paused_by_controller));
> +	if (XEN_HYPER_VALID_MEMBER(domain_is_paused_by_controller)) {
> +		XEN_HYPER_PRI(fp, len, "domain_is_paused_by_controller: ", buf, flag,
> +			(buf, "%ld\n", xen_hyper_offset_table.domain_is_paused_by_controller));
> +	}
> +	if (XEN_HYPER_VALID_MEMBER(domain_controller_pause_count)) {
> +		XEN_HYPER_PRI(fp, len, "domain_controller_pause_count: ", buf, flag,
> +			(buf, "%ld\n", xen_hyper_offset_table.domain_controller_pause_count));
> +	}
>  	XEN_HYPER_PRI(fp, len, "domain_is_shutting_down: ", buf, flag,
>  		(buf, "%ld\n", xen_hyper_offset_table.domain_is_shutting_down));
>  	XEN_HYPER_PRI(fp, len, "domain_is_shut_down: ", buf, flag,
> 
> 
> 
> 
> 
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