Re: [PATCH v4 2/5] kexec: do not special-case the -s option

["Michal Suchánek" <msuchanek@suse.de>]

On Thu, 15 Mar 2018 11:38:30 +0100
Simon Horman <horms@verge.net.au> wrote:

> On Tue, Mar 06, 2018 at 02:15:53PM +0100, Michal Suchanek wrote:
> > It is parsed separately to save a few CPU cycles when setting up
> > other options but it just complicates the code. So fold it back and
> > set up all flags both for KEXEC_LOAD and KEXEC_FILE_LOAD
> > 
> > Signed-off-by: Michal Suchanek <msuchanek@suse.de>
> > ---
> >  kexec/kexec.c | 25 ++++---------------------
> >  1 file changed, 4 insertions(+), 21 deletions(-)
> > 
> > diff --git a/kexec/kexec.c b/kexec/kexec.c
> > index ab8cff7fe083..9ea102e1565a 100644
> > --- a/kexec/kexec.c
> > +++ b/kexec/kexec.c
> > @@ -1256,19 +1256,6 @@ int main(int argc, char *argv[])
> >  	};
> >  	static const char short_options[] = KEXEC_ALL_OPT_STR;
> >  
> > -	/*
> > -	 * First check if --use-kexec-file-syscall is set. That
> > changes lot of
> > -	 * things
> > -	 */
> > -	while ((opt = getopt_long(argc, argv, short_options,
> > -				  options, 0)) != -1) {
> > -		switch(opt) {
> > -		case OPT_KEXEC_FILE_SYSCALL:
> > -			do_kexec_file_syscall = 1;
> > -			break;
> > -		}
> > -	}
> > -
> >  	/* Reset getopt for the next pass. */
> >  	opterr = 1;
> >  	optind = 1;
> > @@ -1310,8 +1297,7 @@ int main(int argc, char *argv[])
> >  			do_shutdown = 0;
> >  			do_sync = 0;
> >  			do_unload = 1;
> > -			if (do_kexec_file_syscall)
> > -				kexec_file_flags |=
> > KEXEC_FILE_UNLOAD;
> > +			kexec_file_flags |= KEXEC_FILE_UNLOAD;
> >  			break;
> >  		case OPT_EXEC:
> >  			do_load = 0;  
>  @@ -1354,11 +1340,8 @@ int main(int argc, char *argv[])
> 
>  The existing code has the following above the context shown in the
> patch:
> 
> 			do_load = 1;
> 
> 
> >  			do_exec = 0;
> >  			do_shutdown = 0;
> >  			do_sync = 0;
> > -			if (do_kexec_file_syscall)
> > -				kexec_file_flags |=
> > KEXEC_FILE_ON_CRASH;
> > -			else
> > -				kexec_flags = KEXEC_ON_CRASH;
> > -			break;
> > +			kexec_file_flags |= KEXEC_FILE_ON_CRASH;
> > +			kexec_flags = KEXEC_ON_CRASH;  
> 
> kexec_flags is now set regardless of the value of
> do_kexec_file_syscall, which was not the case prior to this patch.
> That seems to affect the following which appears later in the
> function. Is that ok?
> 
> 
>         if (do_load && (kexec_flags & KEXEC_ON_CRASH) &&
>             !is_crashkernel_mem_reserved()) {
>                 die("Memory for crashkernel is not reserved\n"
>                     "Please reserve memory by passing"
>                     "\"crashkernel=X@Y\" parameter to kernel\n"
>                     "Then try to loading kdump kernel\n");
>         }

Do you not need memory for kexec -s? This looks broken to start with.
> 
> 	...
> 
>         if ((result == 0) && do_load_jump_back_helper) {

And yes, this should not be allowed with -s

Thanks

Michal

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