+ mm-hugetlb-guard-dequeue_hugetlb_folio_nodemask-against-numa_no_node-uses.patch added to mm-unstable branch

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

The patch titled
     Subject: mm/hugetlb: guard dequeue_hugetlb_folio_nodemask against NUMA_NO_NODE uses
has been added to the -mm mm-unstable branch.  Its filename is
     mm-hugetlb-guard-dequeue_hugetlb_folio_nodemask-against-numa_no_node-uses.patch

This patch will shortly appear at
     https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-hugetlb-guard-dequeue_hugetlb_folio_nodemask-against-numa_no_node-uses.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: Oscar Salvador <osalvador@suse.de>
Subject: mm/hugetlb: guard dequeue_hugetlb_folio_nodemask against NUMA_NO_NODE uses
Date: Wed, 12 Jun 2024 10:29:36 +0200

dequeue_hugetlb_folio_nodemask() expects a preferred node where to get the
hugetlb page from.  It does not expect, though, users to pass
NUMA_NO_NODE, otherwise we will get trash when trying to get the zonelist
from that node.  All current users are careful enough to not pass
NUMA_NO_NODE, but it opens the door for new users to get this wrong since
it is not documented [0].

Guard against this by getting the local nid if NUMA_NO_NODE was passed.

[0] https://lore.kernel.org/linux-mm/0000000000004f12bb061a9acf07@google.com/

Closes: https://lore.kernel.org/linux-mm/0000000000004f12bb061a9acf07@google.com/
Link: https://lkml.kernel.org/r/20240612082936.10867-1-osalvador@suse.de
Signed-off-by: Oscar Salvador <osalvador@suse.de>
Reported-by: syzbot+569ed13f4054f271087b@syzkaller.appspotmail.com
Tested-by: syzbot+569ed13f4054f271087b@syzkaller.appspotmail.com
Reviewed-by: Muchun Song <muchun.song@linux.dev>
Acked-by: Vivek Kasireddy <vivek.kasireddy@intel.com>
Cc: Oscar Salvador <osalvador@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 mm/hugetlb.c |    4 ++++
 1 file changed, 4 insertions(+)

--- a/mm/hugetlb.c~mm-hugetlb-guard-dequeue_hugetlb_folio_nodemask-against-numa_no_node-uses
+++ a/mm/hugetlb.c
@@ -1355,6 +1355,10 @@ static struct folio *dequeue_hugetlb_fol
 	struct zoneref *z;
 	int node = NUMA_NO_NODE;
 
+	/* 'nid' should not be NUMA_NO_NODE. Try to catch any misuse of it and rectifiy. */
+	if (nid == NUMA_NO_NODE)
+		nid = numa_node_id();
+
 	zonelist = node_zonelist(nid, gfp_mask);
 
 retry_cpuset:
_

Patches currently in -mm which might be from osalvador@suse.de are

mm-hugetlb-drop-node_alloc_noretry-from-alloc_fresh_hugetlb_folio.patch
arch-x86-do-not-explicitly-clear-reserved-flag-in-free_pagetable.patch
mm-hugetlb-guard-dequeue_hugetlb_folio_nodemask-against-numa_no_node-uses.patch