On 07/14/16 at 06:35pm, joeyli wrote: > Hi Baoquan, > > Thanks for your response! > > On Thu, Jul 14, 2016 at 05:51:24PM +0800, Baoquan He wrote: > > On 07/14/16 at 04:45pm, Lee, Chun-Yi wrote: > > > This patch adds a new "--fallback-kexec" option to give a chance to > > > fallback to old kexec syscall when file based kexec syscall operation > > > failed. > > > > > > This option works with --kexec-file-syscall to provide more flexible > > > way to adapt to different kernels that those kernels built with > > > different kexec syscall config or have different verification policy. > > > > Usually distribuition system uses script to build a framework to > > connect the kexec/kdump, makedumpfile utility chain. This can make user > > execute a very simple script command to implement kexec load or kexec > > jumping job. In this case script can do what you are trying to do. > > > > Yes, the fallback function can be implemented by script. But a new kexec > option is useful to the distro that it may not provides help scripts to > user. > > > Besides, have you actually met that kexec-file failed but old kexec > > syscall works? I mean how did you test it? I am wondering when it will > > happen. > > > > Thanks > > Baoquan > > > I understand, thanks for telling, Joey Lee. However it seems not very necessary to me. So leave this to other people, see if you can get support and an Acked-by. Thanks Baoquan > The currently mainline kernel allows to set CONFIG_KEXEC or CONFIG_KEXEC_FILE > individual. So if kexec found that the file based kexec syscall isn't > available then this is a case to fallback to old kexec. > > Another case is when KEXEC_VERIFY_SIG is set, The fallback function is more > convenient to user to build his own kernel for using or testing. The kexec > tool can try old syscall when verification failed.
