On Wed, Jun 25, 2025 at 5:30 AM Lorenzo Stoakes lorenzo.stoakes@oracle.com wrote:
This patch results in some spam :) there's a stray mmap_assert_locked() in anon_vma_name() that triggers constantly.
Ah, damn! This was triggered before and I completely forgot to fix it. Thanks for reporting it!
Andrew - I attach a fix-patch for this, could you apply as at least a temporary fix? As mm-new is broken at the moment with this patch.
Yes please.Andrew, if you would prefer me to respin the series please let me know.
Suren - could you check and obviously suggest something more sensible if you feel this isn't right.
This is exactly what I was planning to do but it slipped from my mind.
I'm not actually sure if we'd always have the VMA read lock here, maybe we need an 'assert mmap lock or vma lock' predicate?
For now this is the only place that needs it. Maybe we can wait until there is more demand for it?
Worth auditing other mmap lock asserts that might have been missed with this change also.
I'll go over it once more but this was the only reported issue with the previous version. Thanks, Suren.
Cheers, Lorenzo
----8<---- From 1ed3bd12d43be1f8303fd6b7b714f5ef7e60728a Mon Sep 17 00:00:00 2001 From: Lorenzo Stoakes lorenzo.stoakes@oracle.com Date: Wed, 25 Jun 2025 13:28:36 +0100 Subject: [PATCH] mm/madvise: fixup stray mmap lock assert in anon_vma_name()
anon_vma_name() is being called under VMA lock, but is assert mmap lock which won't necessarily be held.
This results in the kernel spamming warnings about this on startup.
Replace this with an open-coded 'mmap or VMA lock' assert to resolve.
Signed-off-by: Lorenzo Stoakes lorenzo.stoakes@oracle.com
Acked-by: Suren Baghdasaryan surenb@google.com
mm/madvise.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/mm/madvise.c b/mm/madvise.c index c467ee42596f..0530d033b3dd 100644 --- a/mm/madvise.c +++ b/mm/madvise.c @@ -108,7 +108,8 @@ void anon_vma_name_free(struct kref *kref)
struct anon_vma_name *anon_vma_name(struct vm_area_struct *vma) {
mmap_assert_locked(vma->vm_mm);
if (!rwsem_is_locked(&vma->vm_mm->mmap_lock))vma_assert_locked(vma); return vma->anon_name;}
2.50.0