From 09a5336228420af4803c7bbdf91f8f24fc0942bf Mon Sep 17 00:00:00 2001 From: Oscar Salvador Date: Wed, 12 Jun 2024 10:29:36 +0200 Subject: [PATCH] mm/hugetlb: guard dequeue_hugetlb_folio_nodemask against NUMA_NO_NODE uses 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 Reported-by: syzbot+569ed13f4054f271087b@syzkaller.appspotmail.com Tested-by: syzbot+569ed13f4054f271087b@syzkaller.appspotmail.com Reviewed-by: Muchun Song Acked-by: Vivek Kasireddy Cc: Oscar Salvador Signed-off-by: Andrew Morton --- mm/hugetlb.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/mm/hugetlb.c b/mm/hugetlb.c index 3518321f65982..6a5ea898e4dac 100644 --- a/mm/hugetlb.c +++ b/mm/hugetlb.c @@ -1355,6 +1355,10 @@ static struct folio *dequeue_hugetlb_folio_nodemask(struct hstate *h, gfp_t gfp_ 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: -- 2.47.2