On 2025-03-30 19:27, Stephen Rothwell wrote:

Hi all,

On Tue, 11 Mar 2025 12:04:22 +1100 Stephen Rothwell [off-list ref] wrote:

quoted

Today's linux-next merge of the bpf-next tree got a conflict in:

   mm/page_owner.c

between commit:

   a5bc091881fd ("mm: page_owner: use new iteration API")

from the mm-unstable branch of the mm tree and commit:

   8c57b687e833 ("mm, bpf: Introduce free_pages_nolock()")

from the bpf-next tree.

I fixed it up (see below) and can carry the fix as necessary. This
is now fixed as far as linux-next is concerned, but any non trivial
conflicts should be mentioned to your upstream maintainer when your tree
is submitted for merging.  You may also want to consider cooperating
with the maintainer of the conflicting tree to minimise any particularly
complex conflicts.


diff --cc mm/page_owner.c
index 849d4a471b6c,90e31d0e3ed7..000000000000

--- a/mm/page_owner.c
+++ b/mm/page_owner.c

@@@ -297,11 -293,17 +297,17 @@@ void __reset_page_owner(struct page *pa
   
   	page_owner = get_page_owner(page_ext);
   	alloc_handle = page_owner->handle;
  +	page_ext_put(page_ext);
   
- 	handle = save_stack(GFP_NOWAIT | __GFP_NOWARN);
+ 	/*
+ 	 * Do not specify GFP_NOWAIT to make gfpflags_allow_spinning() == false
+ 	 * to prevent issues in stack_depot_save().
+ 	 * This is similar to try_alloc_pages() gfp flags, but only used
+ 	 * to signal stack_depot to avoid spin_locks.
+ 	 */
+ 	handle = save_stack(__GFP_NOWARN);
  -	__update_page_owner_free_handle(page_ext, handle, order, current->pid,
  +	__update_page_owner_free_handle(page, handle, order, current->pid,
   					current->tgid, free_ts_nsec);
  -	page_ext_put(page_ext);
   
   	if (alloc_handle != early_handle)
   		/*

This is now a conflict between the mm-stable tree and Linus' tree.

What's the best way to resolve this? Should I post again or can we just use your fix?