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

[Brian Mak]

On Aug 20, 2025, at 9:47 PM, Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> wrote:

> On Tue, 5 Aug 2025 14:15:26 -0700 Brian Mak <makb@xxxxxxxxxxx> 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"!

Hi Andrew,

Thanks for your comment. The userspace-visible runtime effect of this
bug is that kexec_file_load returns EINVAL when attempting to use the
KEXEC_FILE_NO_CMA flag. This is stated in the sentence following the
"this flag is broken" statement.

Is there something else that you wanted me to add here?

Thanks,
Brian