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 <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>

diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index 3518321f659827fef668315418a0c1ec507a19c3..6a5ea898e4dac3eab5e3304cdb5e2c251461c05d 100644 (file)
--- 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: