On 2024/2/16 19:15, Byungchul Park wrote:
With numa balancing on, when a numa system is running where a numa node
doesn't have its local memory so it has no managed zones, the following
oops has been observed. It's because wakeup_kswapd() is called with a
wrong zone index, -1. Fixed it by checking the index before calling
wakeup_kswapd().
BUG: unable to handle page fault for address: 00000000000033f3
#PF: supervisor read access in kernel mode
#PF: error_code(0x0000) - not-present page
PGD 0 P4D 0
Oops: 0000 [#1] PREEMPT SMP NOPTI
CPU: 2 PID: 895 Comm: masim Not tainted 6.6.0-dirty #255
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS
rel-1.16.0-0-gd239552ce722-prebuilt.qemu.org 04/01/2014
RIP: 0010:wakeup_kswapd (./linux/mm/vmscan.c:7812)
Code: (omitted)
RSP: 0000:ffffc90004257d58 EFLAGS: 00010286
RAX: ffffffffffffffff RBX: ffff88883fff0480 RCX: 0000000000000003
RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffff88883fff0480
RBP: ffffffffffffffff R08: ff0003ffffffffff R09: ffffffffffffffff
R10: ffff888106c95540 R11: 0000000055555554 R12: 0000000000000003
R13: 0000000000000000 R14: 0000000000000000 R15: ffff88883fff0940
FS: 00007fc4b8124740(0000) GS:ffff888827c00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00000000000033f3 CR3: 000000026cc08004 CR4: 0000000000770ee0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
PKRU: 55555554
Call Trace:
<TASK>
? __die
? page_fault_oops
? __pte_offset_map_lock
? exc_page_fault
? asm_exc_page_fault
? wakeup_kswapd
migrate_misplaced_page
__handle_mm_fault
handle_mm_fault
do_user_addr_fault
exc_page_fault
asm_exc_page_fault
RIP: 0033:0x55b897ba0808
Code: (omitted)
RSP: 002b:00007ffeefa821a0 EFLAGS: 00010287
RAX: 000055b89983acd0 RBX: 00007ffeefa823f8 RCX: 000055b89983acd0
RDX: 00007fc2f8122010 RSI: 0000000000020000 RDI: 000055b89983acd0
RBP: 00007ffeefa821a0 R08: 0000000000000037 R09: 0000000000000075
R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000000000
R13: 00007ffeefa82410 R14: 000055b897ba5dd8 R15: 00007fc4b8340000
</TASK>
Signed-off-by: Byungchul Park <byungchul@xxxxxx>
Reported-by: Hyeongtak Ji <hyeongtak.ji@xxxxxx>
Cc: stable@xxxxxxxxxxxxxxx
Fixes: c574bbe917036 ("NUMA balancing: optimize page placement for memory tiering system")
This means that there is no memory on the target node？ if so, we can add
a check at the beginning to avoid calling unnecessary
migrate_misplaced_folio().
diff --git a/mm/memory.c b/mm/memory.c
index e95503d7544e..a64a1aac463f 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -5182,7 +5182,7 @@ static vm_fault_t do_numa_page(struct vm_fault *vmf)
else
last_cpupid = folio_last_cpupid(folio);
target_nid = numa_migrate_prep(folio, vma, vmf->address, nid,
&flags);
- if (target_nid == NUMA_NO_NODE) {
+ if (target_nid == NUMA_NO_NODE || !node_state(target_nid,
N_MEMORY)) {
folio_put(folio);
goto out_map;
}
(similar changes for do_huge_pmd_numa_page())
---
mm/migrate.c | 8 ++++++++
1 file changed, 8 insertions(+)
diff --git a/mm/migrate.c b/mm/migrate.c
index fbc8586ed735..51ee6865b0f6 100644
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -2825,6 +2825,14 @@ static int numamigrate_isolate_folio(pg_data_t *pgdat, struct folio *folio)
if (managed_zone(pgdat->node_zones + z))
break;
}
+
+ /*
+ * If there are no managed zones, it should not proceed
+ * further.
+ */
+ if (z < 0)
+ return 0;
+
wakeup_kswapd(pgdat->node_zones + z, 0,
folio_order(folio), ZONE_MOVABLE);
return 0;
