+ mm-page_alloc-pass-zone-pointer-to-trace_reclaim_retry_zone.patch added to mm-unstable branch

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

The patch titled
     Subject: mm, page_alloc: pass zone pointer to trace_reclaim_retry_zone
has been added to the -mm mm-unstable branch.  Its filename is
     mm-page_alloc-pass-zone-pointer-to-trace_reclaim_retry_zone.patch

This patch will shortly appear at
     https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-page_alloc-pass-zone-pointer-to-trace_reclaim_retry_zone.patch

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

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------------------------------------------------------
From: Josef Bacik <josef@toxicpanda.com>
Subject: mm, page_alloc: pass zone pointer to trace_reclaim_retry_zone
Date: Tue, 27 Oct 2026 16:46:31 +0100

should_reclaim_retry() walks a zonelist and passes the zoneref pointer
to the reclaim_retry_zone tracepoint, which loads the zone from the
entry again to find the node.

Memory hotplug rebuilds the zonelists in place while allocations are
under way. When a zone in front of the zoneref entry has become empty,
the entries move up, and this one can be the end marker by the time the
tracepoint looks at it. zonelist_node_idx() then dereferences a NULL
zone. Short of that, the event can name another zone than the one its
numbers belong to.

Pass the zone pointer instead of the zoneref pointer.

Link: https://lore.kernel.org/20261027-pgalloc-ai-hotfixes-v1-5-9c7d1aca801e@kernel.org
Fixes: d379f01de095 ("oom, trace: add oom detection tracepoints")
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Vlastimil Babka (SUSE) <vbabka@kernel.org>
Signed-off-by: David Hildenbrand (Arm) <david@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Gregory Price (Meta) <gourry@gourry.net>
Tested-by: Gregory Price (Meta) <gourry@gourry.net>
Acked-by: Zi Yan <ziy@nvidia.com>
Assisted-by: LLM
Cc: Shakeel Butt <shakeel.butt@linux.dev>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Brendan Jackman <brendan.jackman@linux.dev>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: <stable@vger.kernel.org>
---

 include/trace/events/oom.h |    8 ++++----
 mm/page_alloc.c            |    2 +-
 2 files changed, 5 insertions(+), 5 deletions(-)

--- a/include/trace/events/oom.h~mm-page_alloc-pass-zone-pointer-to-trace_reclaim_retry_zone
+++ a/include/trace/events/oom.h
@@ -33,7 +33,7 @@ TRACE_EVENT(oom_score_adj_update,
 
 TRACE_EVENT(reclaim_retry_zone,
 
-	TP_PROTO(struct zoneref *zoneref,
+	TP_PROTO(struct zone *zone,
 		int order,
 		unsigned long reclaimable,
 		unsigned long available,
@@ -41,7 +41,7 @@ TRACE_EVENT(reclaim_retry_zone,
 		int no_progress_loops,
 		bool wmark_check),
 
-	TP_ARGS(zoneref, order, reclaimable, available, min_wmark, no_progress_loops, wmark_check),
+	TP_ARGS(zone, order, reclaimable, available, min_wmark, no_progress_loops, wmark_check),
 
 	TP_STRUCT__entry(
 		__field(	int, node)
@@ -55,8 +55,8 @@ TRACE_EVENT(reclaim_retry_zone,
 	),
 
 	TP_fast_assign(
-		__entry->node = zonelist_node_idx(zoneref);
-		__entry->zone_idx = zonelist_zone_idx(zoneref);
+		__entry->node = zone_to_nid(zone);
+		__entry->zone_idx = zone_idx(zone);
 		__entry->order = order;
 		__entry->reclaimable = reclaimable;
 		__entry->available = available;
--- a/mm/page_alloc.c~mm-page_alloc-pass-zone-pointer-to-trace_reclaim_retry_zone
+++ a/mm/page_alloc.c
@@ -4675,7 +4675,7 @@ should_reclaim_retry(gfp_t gfp_mask, uns
 		 */
 		wmark = __zone_watermark_ok(zone, order, min_wmark,
 				ac->highest_zoneidx, alloc_flags, available);
-		trace_reclaim_retry_zone(z, order, reclaimable,
+		trace_reclaim_retry_zone(zone, order, reclaimable,
 				available, min_wmark, *no_progress_loops, wmark);
 		if (wmark) {
 			ret = true;
_

Patches currently in -mm which might be from josef@toxicpanda.com are

mm-page_alloc-dont-undo-a-racing-start_isolate_page_range.patch
mm-page_alloc-clear-private-of-deferred-free-pages.patch
mm-page_frag-refill-the-cache-for-large-fragments.patch
mm-page_alloc-keep-the-pagesets-of-an-empty-zone.patch
mm-page_alloc-pass-zone-pointer-to-trace_reclaim_retry_zone.patch
mm-compaction-trust-zone-contiguous-only-in-the-span.patch
mm-page_isolation-do-not-take-slab-pages-for-free.patch
mm-memory_hotplug-resize-zones-under-their-seqlock.patch
mm-page_alloc-check-pageblock-pfns-under-span-seqlock.patch