[PATCH v2 1/2] kexec: Add KEXEC_FILE_NO_CMA as a legal flag

[Baoquan He]

On 08/20/25 at 09:47pm, Andrew Morton wrote:
> On Tue, 5 Aug 2025 14:15:26 -0700 Brian Mak <makb at juniper.net> wrote:
> 
> > Commit 07d24902977e ("kexec: enable CMA based contiguous allocation")
> > introduces logic to use CMA-based allocation in kexec by default. As
> > part of the changes, it introduces a kexec_file_load flag to disable the
> > use of CMA allocations from userspace. However, this flag is broken
> > since it is missing from the list of legal flags for kexec_file_load.
> > kexec_file_load returns EINVAL when attempting to use the flag.
> > 
> > Fix this by adding the KEXEC_FILE_NO_CMA flag to the list of legal flags
> > for kexec_file_load.
> > 
> > Fixes: 07d24902977e ("kexec: enable CMA based contiguous allocation")
> 
> A description of the userspace-visible runtime effects of this bug
> would be very helpful, please.  A lot more than "is broken"!
> 
> Also, could we please have some reviewer input on this change?

I didn't receive this patchset, and kexec mailing list is not in CC.
I don't know what happened.

> 
> 
> > --- a/include/linux/kexec.h
> > +++ b/include/linux/kexec.h
> > @@ -460,7 +460,8 @@ bool kexec_load_permitted(int kexec_image_type);
> >  
> >  /* List of defined/legal kexec file flags */
> >  #define KEXEC_FILE_FLAGS	(KEXEC_FILE_UNLOAD | KEXEC_FILE_ON_CRASH | \
> > -				 KEXEC_FILE_NO_INITRAMFS | KEXEC_FILE_DEBUG)
> > +				 KEXEC_FILE_NO_INITRAMFS | KEXEC_FILE_DEBUG | \
> > +				 KEXEC_FILE_NO_CMA)
> >  
> >  /* flag to track if kexec reboot is in progress */
> >  extern bool kexec_in_progress;
> > -- 
> > 2.25.1
> > 
>