fs/resctrl: Fix double-add of pseudo-locked region's RMID to free list

A pseudo-locked group's RMID is freed when it is created. On unmount
rmdir_all_sub() unconditionally frees all RMID of all groups, resulting
in a double-free of the pseudo-locked group's RMID. The consequence of this
is that the original free results in the pseudo-locked group's RMID being
added to the rmid_free_lru linked list and the second free then attempts
to add the same RMID entry to the rmid_free_lru again.

Do not double-free a pseudo-locked group's RMID.

Fixes: e0bdfe8e36f3 ("x86/intel_rdt: Support creation/removal of pseudo-locked region")
Signed-off-by: Reinette Chatre <reinette.chatre@intel.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Cc: <stable@kernel.org>
Link: https://patch.msgid.link/551432dd7e624a862b8e58314c38aaba0afff3e9.1783377598.git.reinette.chatre@intel.com

diff --git a/fs/resctrl/rdtgroup.c b/fs/resctrl/rdtgroup.c
index ce277f16ea12b5435c5ad0c5ca776b6036b37b0f..cc9966ff6cdfb67bf90adba2fe26aff6ded4673e 100644 (file)
--- a/fs/resctrl/rdtgroup.c
+++ b/fs/resctrl/rdtgroup.c
@@ -3084,10 +3084,6 @@ static void rmdir_all_sub(void)
                if (rdtgrp == &rdtgroup_default)
                        continue;
 
-               if (rdtgrp->mode == RDT_MODE_PSEUDO_LOCKSETUP ||
-                   rdtgrp->mode == RDT_MODE_PSEUDO_LOCKED)
-                       rdtgroup_pseudo_lock_remove(rdtgrp);
-
                /*
                 * Give any CPUs back to the default group. We cannot copy
                 * cpu_online_mask because a CPU might have executed the
@@ -3098,7 +3094,13 @@ static void rmdir_all_sub(void)
 
                rdtgroup_unassign_cntrs(rdtgrp);
 
-               free_rmid(rdtgrp->closid, rdtgrp->mon.rmid);
+               if (rdtgrp->mode == RDT_MODE_PSEUDO_LOCKSETUP ||
+                   rdtgrp->mode == RDT_MODE_PSEUDO_LOCKED) {
+                       rdtgroup_pseudo_lock_remove(rdtgrp);
+               } else {
+                       /* Pseudo-locked group's RMID is freed during setup. */
+                       free_rmid(rdtgrp->closid, rdtgrp->mon.rmid);
+               }
 
                kernfs_remove(rdtgrp->kn);
                list_del(&rdtgrp->rdtgroup_list);