FAILED: patch "[PATCH] mm/page_alloc: don't spin_trylock() when disallowed in" failed to apply to 6.18-stable tree

The patch below does not apply to the 6.18-stable tree.
If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <[email protected]>.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.18.y
git checkout FETCH_HEAD
git cherry-pick -x 52dcc33881e55189650404f833c0e6b7913d6c16
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<[email protected]>' --in-reply-to '2026090357-enjoying-caption-48e1@gregkh' --subject-prefix 'PATCH 6.18.y' 'HEAD^..'

Possible dependencies:

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 52dcc33881e55189650404f833c0e6b7913d6c16 Mon Sep 17 00:00:00 2001
From: Brendan Jackman <[email protected]>
Date: Wed, 15 Jul 2026 09:03:59 +0000
Subject: [PATCH] mm/page_alloc: don't spin_trylock() when disallowed in
free_one_page()

__free_frozen_pages() checks can_spin_trylock() before entering into the main free_frozen_page_commit()/free_one_page() path, but before this it can get to free_one_page() via the !pcp_allowed_order() and MIGRATE_ISOLATE paths.

The !pcp_allowed_order() path depends on usage by callers so might not be possible in practice. The MIGRATE_ISOLATE path probably means kernel crashes and privilege escalation if anyone ever did memory hotplug and BPF tracing on a PREEMPT_RT or !SMP build.

index b3487c00971e..891f687e622c 100644
@@ -1559,7 +1559,7 @@ static void free_one_page(struct zone *zone, struct page *page,
 	unsigned long flags;
 
 	if (unlikely(fpi_flags & FPI_TRYLOCK)) {
-		if (!spin_trylock_irqsave(&zone->lock, flags)) {
+		if (!can_spin_trylock() || !spin_trylock_irqsave(&zone->lock, flags)) {
 			add_page_to_zone_llist(zone, page, order);
 			return;
 		}