Re: [PATCH v2 1/5] tracefs: Reset permissions on remount if permissions are options

On Thu, 02 May 2024 11:15:48 -0400 Steven Rostedt rostedt@goodmis.org wrote:

+/*

• • On a remount of tracefs, if UID or GID options are set, then
• • the mount point inode permissions should be used.
• • Reset the saved permission flags appropriately.
• */

+void eventfs_remount(struct tracefs_inode *ti, bool update_uid, bool update_gid) +{

• struct eventfs_inode *ei = ti->private;

And I just realized there's a race here too :-p

I need to set ti->private = NULL before freeing the ei, and probably free the ei via RCU.

-- Steve

• if (!ei)

• return;
  

• if (update_uid)

• ei->attr.mode &= ~EVENTFS_SAVE_UID;
  

• if (update_gid)

• ei->attr.mode &= ~EVENTFS_SAVE_GID;
  

• if (!ei->entry_attrs)

• return;
  

• for (int i = 0; i < ei->nr_entries; i++) {

• if (update_uid)
  

• 	ei->entry_attrs[i].mode &= ~EVENTFS_SAVE_UID;
  

• if (update_gid)
  

• 	ei->entry_attrs[i].mode &= ~EVENTFS_SAVE_GID;
  

• }

+}