mm: mark vmas detached upon exit

When exit_mmap() removes vmas belonging to an exiting task, it does not
mark them as detached since they can't be reached by other tasks and they
will be freed shortly.  Once we introduce vma reuse, all vmas will have to
be in detached state before they are freed to ensure vma when reused is in
a consistent state.  Add missing vma_mark_detached() before freeing the
vma.

Link: https://lkml.kernel.org/r/20250213224655.1680278-6-surenb@google.com
Signed-off-by: Suren Baghdasaryan <surenb@google.com>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Tested-by: Shivank Garg <shivankg@amd.com>
Link: https://lkml.kernel.org/r/5e19ec93-8307-47c2-bb13-3ddf7150624e@amd.com
Reviewed-by: Liam R. Howlett <Liam.Howlett@Oracle.com>
Cc: Christian Brauner <brauner@kernel.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Hugh Dickins <hughd@google.com>
Cc: Jann Horn <jannh@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Klara Modin <klarasmodin@gmail.com>
Cc: Lokesh Gidra <lokeshgidra@google.com>
Cc: Mateusz Guzik <mjguzik@gmail.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Minchan Kim <minchan@google.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Pasha Tatashin <pasha.tatashin@soleen.com>
Cc: "Paul E . McKenney" <paulmck@kernel.org>
Cc: Peter Xu <peterx@redhat.com>
Cc: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Shakeel Butt <shakeel.butt@linux.dev>
Cc: Sourav Panda <souravpanda@google.com>
Cc: Wei Yang <richard.weiyang@gmail.com>
Cc: Will Deacon <will@kernel.org>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/mm/vma.c b/mm/vma.c
index f80feccef88e479b4db88901dc20ae7877884f77..6fe6e6831aaeb45494b5e7539c75ea15f6f2a9cf 100644 (file)
--- a/mm/vma.c
+++ b/mm/vma.c
@@ -427,10 +427,12 @@ void remove_vma(struct vm_area_struct *vma, bool unreachable)
        if (vma->vm_file)
                fput(vma->vm_file);
        mpol_put(vma_policy(vma));
-       if (unreachable)
+       if (unreachable) {
+               vma_mark_detached(vma);
                __vm_area_free(vma);
-       else
+       } else {
                vm_area_free(vma);
+       }
 }
 
 /*