On Fri, Aug 1, 2025 at 3:55 AM Vlastimil Babka vbabka@suse.cz wrote:
On 8/1/25 00:00, Suren Baghdasaryan wrote:
Refactor struct proc_maps_private so that the fields used by PROCMAP_QUERY ioctl are moved into a separate structure. In the next patch this allows ioctl to reuse some of the functions used for reading /proc/pid/maps without using file->private_data. This prevents concurrent modification of file->private_data members by ioctl and /proc/pid/maps readers.
The change is pure code refactoring and has no functional changes.
I think you'll need to adjust task_nommu.c as well, minimally I see it also has m_start() acceding priv->mm directly so it won't compile now?
Ugh, yes, you are right. I'll need to adjust NOMMU code as well. And kernel test bot seems to be complaining already :)
Also not sure about the naming, struct is named "proc_maps_query_data" and priv field named "query" but the read() implementation uses it too, via priv->query, although it does no PROCMAP_QUERY.
Seems to me it's actually something like a mm+vma locking context? Which can be either stored in proc_maps_private for read() operations, or local on-stack for ioctl().
Yes, I struggled with the naming of this structure. Any help with this is highly appreciated.