+ warning-locking-bug-in-__set_page_owner-2.patch added to mm-hotfixes-unstable branch

[Andrew Morton <akpm@linux-foundation.org>]

The patch titled
     Subject: mm: don't spin in add_stack_record when gfp flags don't allow
has been added to the -mm mm-hotfixes-unstable branch.  Its filename is
     warning-locking-bug-in-__set_page_owner-2.patch

This patch will shortly appear at
     https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/warning-locking-bug-in-__set_page_owner-2.patch

This patch will later appear in the mm-hotfixes-unstable branch at
    git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

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------------------------------------------------------
From: Alexei Starovoitov <ast@kernel.org>
Subject: mm: don't spin in add_stack_record when gfp flags don't allow
Date: Thu, 9 Oct 2025 17:15:13 -0700

syzbot was able to find the following path:
  add_stack_record_to_list mm/page_owner.c:182 [inline]
  inc_stack_record_count mm/page_owner.c:214 [inline]
  __set_page_owner+0x2c3/0x4a0 mm/page_owner.c:333
  set_page_owner include/linux/page_owner.h:32 [inline]
  post_alloc_hook+0x240/0x2a0 mm/page_alloc.c:1851
  prep_new_page mm/page_alloc.c:1859 [inline]
  get_page_from_freelist+0x21e4/0x22c0 mm/page_alloc.c:3858
  alloc_pages_nolock_noprof+0x94/0x120 mm/page_alloc.c:7554

Don't spin in add_stack_record_to_list() when it is called
from *_nolock() context.

Link: https://lkml.kernel.org/r/CAADnVQK_8bNYEA7TJYgwTYR57=TTFagsvRxp62pFzS_z129eTg@mail.gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Reported-by: syzbot+8259e1d0e3ae8ed0c490@syzkaller.appspotmail.com
Reported-by: syzbot+665739f456b28f32b23d@syzkaller.appspotmail.com
Cc: Brendan Jackman <jackmanb@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 mm/page_owner.c |    3 +++
 1 file changed, 3 insertions(+)

--- a/mm/page_owner.c~warning-locking-bug-in-__set_page_owner-2
+++ a/mm/page_owner.c
@@ -168,6 +168,9 @@ static void add_stack_record_to_list(str
 	unsigned long flags;
 	struct stack *stack;
 
+	if (!gfpflags_allow_spinning(gfp_mask))
+		return;
+
 	set_current_in_page_owner();
 	stack = kmalloc(sizeof(*stack), gfp_nested_mask(gfp_mask));
 	if (!stack) {
_

Patches currently in -mm which might be from ast@kernel.org are

warning-locking-bug-in-__set_page_owner-2.patch