[Crash-utility] faulty use of "set" command when running against the xen hypervisor

[Dave Anderson]

I suppose it should also require an error-catcher if you actually try to
set some bogus "context" value:

@@ -2144,6 +2153,8 @@ cmd_set(void)
                                         "on" : "off");
                         return;

+               } else if (XEN_HYPER_MODE()) {
+                       error(FATAL, "invalid argument for the Xen hypervisor\n");
                 } else if (runtime) {
                         ulong pid, task;

to change the behavior from this:

   crash> set 1
   set: invalid task or pid value: 1
   crash

to this:

   crash> set 1
   set: invalid argument for the Xen hypervisor
   crash>

Dave



Dave Anderson wrote:
> 
> Cai Quan bumped into another problem when running against the xen 
> hypervisor,
> where entering the "set" command alone with no arguments generates a 
> SIGSEGV.
> 
> I also note that "set -c #" and "set -p" options make no sense either:
> 
>   # crash --xen_phys_start 3ee00000 xen-syms-2.6.18-92.el5 vmcore
> 
>   crash 4.0-7.2
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>   Copyright (C) 2006, 2007  VA Linux Systems Japan K.K.
>   Copyright (C) 2005  NEC Corporation
>   Copyright (C) 1999, 2002, 2007  Silicon Graphics, Inc.
>   Copyright (C) 1999, 2000, 2001, 2002  Mission Critical Linux, Inc.
>   This program is free software, covered by the GNU General Public License,
>   and you are welcome to change it and/or distribute copies of it under
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> details.
> 
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> 
>      KERNEL: xen-syms-2.6.18-92.el5
>   DEBUGINFO: ./xen-syms-2.6.18-92.el5.debug
>    DUMPFILE: vmcore
>        CPUS: 2
>     DOMAINS: 4
>      UPTIME: 00:34:18
>     MACHINE: Intel(R) Pentium(R) 4 CPU 3.40GHz  (3400 Mhz)
>      MEMORY: 1 GB
>     PCPU-ID: 1
>        PCPU: ffff83003f05ff28
>     VCPU-ID: 1
>        VCPU: ffff83003eef6080  (VCPU_RUNNING)
>   DOMAIN-ID: 0
>      DOMAIN: ffff83003eef8080  (DOMAIN_RUNNING)
>       STATE: CRASH
> 
>   crash> set -c 0
>   set: invalid cpu number: system has only 0 cpu
>   crash> set -p
>   set: no panic task found!
>   crash> set
>   Segmentation fault
> 
>   #
> 
> Admittedly it's a nonsensical usages of "set", since there's no concept of
> a PID "context" in the hypervisor.
> 
> The attached patch changes the behavior to:
> 
>   crash> set -c 0
>   set: -c option not supported on this architecture or kernel
>   crash> set -p
>   set: -p option not supported on this architecture or kernel
>   crash> set
>   set: requires an option with the Xen hypervisor
>   crash>
> 
> Itsura, are you OK with the attached patch?
> 
> Thanks,
>   Dave
> 
> 
> 
> ------------------------------------------------------------------------
> 
> --- crash/tools.c.orig
> +++ crash/tools.c
> @@ -1673,6 +1673,9 @@ cmd_set(void)
>                  switch(c)
>  		{
>  		case 'c':
> +			if (XEN_HYPER_MODE())
> +				option_not_supported(c);
> +
>  			if (!runtime) {
>  				error(INFO, 
>  				    "cpu setting not allowed from .%src\n",
> @@ -1689,6 +1692,9 @@ cmd_set(void)
>  			return;
>  
>  		case 'p':
> +			if (XEN_HYPER_MODE())
> +				option_not_supported(c);
> +
>  			if (!runtime)
>  				return;
>  
> @@ -1723,7 +1729,10 @@ cmd_set(void)
>  	}
>  
>  	if (!args[optind]) {
> -		if (runtime)
> +		if (XEN_HYPER_MODE())
> +			error(INFO, 
> +			    "requires an option with the Xen hypervisor\n");
> +		else if (runtime)
>  			show_context(CURRENT_CONTEXT());
>  		return;
>  	}
> 
> 
> ------------------------------------------------------------------------
> 
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