fs/bcachefs/btree_update_interior.c:1582 btree_split() warn: variable dereferenced before check 'path1' (see line 1483)
From: Dan Carpenter
Date: Tue Nov 07 2023 - 12:08:15 EST
tree: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
head: be3ca57cfb777ad820c6659d52e60bbdd36bf5ff
commit: e4215d0fec777e6516306f5f1b69a45a4205dce0 bcachefs: All held locks must be in a btree path
config: x86_64-randconfig-161-20231107 (https://download.01.org/0day-ci/archive/20231107/202311072233.KsJQSI13-lkp@xxxxxxxxx/config)
compiler: gcc-12 (Debian 12.2.0-14) 12.2.0
reproduce: (https://download.01.org/0day-ci/archive/20231107/202311072233.KsJQSI13-lkp@xxxxxxxxx/reproduce)
If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@xxxxxxxxx>
| Reported-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
| Closes: https://lore.kernel.org/r/202311072233.KsJQSI13-lkp@xxxxxxxxx/
smatch warnings:
fs/bcachefs/btree_update_interior.c:1582 btree_split() warn: variable dereferenced before check 'path1' (see line 1483)
vim +/path1 +1582 fs/bcachefs/btree_update_interior.c
67e0dd8f0d8b4bf Kent Overstreet 2021-08-30 1451 static void btree_split(struct btree_update *as, struct btree_trans *trans,
67e0dd8f0d8b4bf Kent Overstreet 2021-08-30 1452 struct btree_path *path, struct btree *b,
67e0dd8f0d8b4bf Kent Overstreet 2021-08-30 1453 struct keylist *keys, unsigned flags)
1c6fdbd8f2465dd Kent Overstreet 2017-03-16 1454 {
1c6fdbd8f2465dd Kent Overstreet 2017-03-16 1455 struct bch_fs *c = as->c;
67e0dd8f0d8b4bf Kent Overstreet 2021-08-30 1456 struct btree *parent = btree_node_parent(path, b);
1c6fdbd8f2465dd Kent Overstreet 2017-03-16 1457 struct btree *n1, *n2 = NULL, *n3 = NULL;
e4215d0fec777e6 Kent Overstreet 2022-09-16 1458 struct btree_path *path1 = NULL, *path2 = NULL;
1c6fdbd8f2465dd Kent Overstreet 2017-03-16 1459 u64 start_time = local_clock();
1c6fdbd8f2465dd Kent Overstreet 2017-03-16 1460
1c6fdbd8f2465dd Kent Overstreet 2017-03-16 1461 BUG_ON(!parent && (b != btree_node_root(c, b)));
67e0dd8f0d8b4bf Kent Overstreet 2021-08-30 1462 BUG_ON(!btree_node_intent_locked(path, btree_node_root(c, b)->c.level));
1c6fdbd8f2465dd Kent Overstreet 2017-03-16 1463
1c6fdbd8f2465dd Kent Overstreet 2017-03-16 1464 bch2_btree_interior_update_will_free_node(as, b);
1c6fdbd8f2465dd Kent Overstreet 2017-03-16 1465
ca7d8fcabf29fae Kent Overstreet 2022-08-21 1466 n1 = bch2_btree_node_alloc_replacement(as, trans, b);
1c6fdbd8f2465dd Kent Overstreet 2017-03-16 1467
1c6fdbd8f2465dd Kent Overstreet 2017-03-16 1468 if (keys)
67e0dd8f0d8b4bf Kent Overstreet 2021-08-30 1469 btree_split_insert_keys(as, trans, path, n1, keys);
1c6fdbd8f2465dd Kent Overstreet 2017-03-16 1470
5525f632dc123ed Kent Overstreet 2020-01-15 1471 if (bset_u64s(&n1->set[0]) > BTREE_SPLIT_THRESHOLD(c)) {
674cfc26240b780 Kent Overstreet 2022-08-27 1472 trace_and_count(c, btree_node_split, c, b);
1c6fdbd8f2465dd Kent Overstreet 2017-03-16 1473
ca7d8fcabf29fae Kent Overstreet 2022-08-21 1474 n2 = __btree_split_node(as, trans, n1);
1c6fdbd8f2465dd Kent Overstreet 2017-03-16 1475
1c6fdbd8f2465dd Kent Overstreet 2017-03-16 1476 bch2_btree_build_aux_trees(n2);
1c6fdbd8f2465dd Kent Overstreet 2017-03-16 1477 bch2_btree_build_aux_trees(n1);
c43a6ef9a0747ef Kent Overstreet 2020-06-06 1478 six_unlock_write(&n2->c.lock);
c43a6ef9a0747ef Kent Overstreet 2020-06-06 1479 six_unlock_write(&n1->c.lock);
1c6fdbd8f2465dd Kent Overstreet 2017-03-16 1480
e4215d0fec777e6 Kent Overstreet 2022-09-16 1481 path1 = get_unlocked_mut_path(trans, path->btree_id, n1->c.level, n1->key.k.p);
e4215d0fec777e6 Kent Overstreet 2022-09-16 1482 six_lock_increment(&n1->c.lock, SIX_LOCK_intent);
e4215d0fec777e6 Kent Overstreet 2022-09-16 @1483 mark_btree_node_locked(trans, path1, n1->c.level, SIX_LOCK_intent);
path1 dereferenced without checking.
e4215d0fec777e6 Kent Overstreet 2022-09-16 1484 bch2_btree_path_level_init(trans, path1, n1);
e4215d0fec777e6 Kent Overstreet 2022-09-16 1485
e4215d0fec777e6 Kent Overstreet 2022-09-16 1486 path2 = get_unlocked_mut_path(trans, path->btree_id, n2->c.level, n2->key.k.p);
e4215d0fec777e6 Kent Overstreet 2022-09-16 1487 six_lock_increment(&n2->c.lock, SIX_LOCK_intent);
e4215d0fec777e6 Kent Overstreet 2022-09-16 1488 mark_btree_node_locked(trans, path2, n2->c.level, SIX_LOCK_intent);
e4215d0fec777e6 Kent Overstreet 2022-09-16 1489 bch2_btree_path_level_init(trans, path2, n2);
e4215d0fec777e6 Kent Overstreet 2022-09-16 1490
7419646b254a599 Kent Overstreet 2022-04-14 1491 bch2_btree_update_add_new_node(as, n1);
7419646b254a599 Kent Overstreet 2022-04-14 1492
82732ef510b8455 Kent Overstreet 2022-02-26 1493 bch2_btree_node_write(c, n1, SIX_LOCK_intent, 0);
82732ef510b8455 Kent Overstreet 2022-02-26 1494 bch2_btree_node_write(c, n2, SIX_LOCK_intent, 0);
1c6fdbd8f2465dd Kent Overstreet 2017-03-16 1495
1c6fdbd8f2465dd Kent Overstreet 2017-03-16 1496 /*
1c6fdbd8f2465dd Kent Overstreet 2017-03-16 1497 * Note that on recursive parent_keys == keys, so we
1c6fdbd8f2465dd Kent Overstreet 2017-03-16 1498 * can't start adding new keys to parent_keys before emptying it
1c6fdbd8f2465dd Kent Overstreet 2017-03-16 1499 * out (which we did with btree_split_insert_keys() above)
1c6fdbd8f2465dd Kent Overstreet 2017-03-16 1500 */
1c6fdbd8f2465dd Kent Overstreet 2017-03-16 1501 bch2_keylist_add(&as->parent_keys, &n1->key);
1c6fdbd8f2465dd Kent Overstreet 2017-03-16 1502 bch2_keylist_add(&as->parent_keys, &n2->key);
1c6fdbd8f2465dd Kent Overstreet 2017-03-16 1503
1c6fdbd8f2465dd Kent Overstreet 2017-03-16 1504 if (!parent) {
1c6fdbd8f2465dd Kent Overstreet 2017-03-16 1505 /* Depth increases, make a new root */
ca7d8fcabf29fae Kent Overstreet 2022-08-21 1506 n3 = __btree_root_alloc(as, trans, b->c.level + 1);
1c6fdbd8f2465dd Kent Overstreet 2017-03-16 1507
e4215d0fec777e6 Kent Overstreet 2022-09-16 1508 path2->locks_want++;
e4215d0fec777e6 Kent Overstreet 2022-09-16 1509 BUG_ON(btree_node_locked(path2, n3->c.level));
e4215d0fec777e6 Kent Overstreet 2022-09-16 1510 six_lock_increment(&n3->c.lock, SIX_LOCK_intent);
e4215d0fec777e6 Kent Overstreet 2022-09-16 1511 mark_btree_node_locked(trans, path2, n3->c.level, SIX_LOCK_intent);
e4215d0fec777e6 Kent Overstreet 2022-09-16 1512 bch2_btree_path_level_init(trans, path2, n3);
e4215d0fec777e6 Kent Overstreet 2022-09-16 1513
1c6fdbd8f2465dd Kent Overstreet 2017-03-16 1514 n3->sib_u64s[0] = U16_MAX;
1c6fdbd8f2465dd Kent Overstreet 2017-03-16 1515 n3->sib_u64s[1] = U16_MAX;
1c6fdbd8f2465dd Kent Overstreet 2017-03-16 1516
67e0dd8f0d8b4bf Kent Overstreet 2021-08-30 1517 btree_split_insert_keys(as, trans, path, n3, &as->parent_keys);
1c6fdbd8f2465dd Kent Overstreet 2017-03-16 1518
82732ef510b8455 Kent Overstreet 2022-02-26 1519 bch2_btree_node_write(c, n3, SIX_LOCK_intent, 0);
1c6fdbd8f2465dd Kent Overstreet 2017-03-16 1520 }
1c6fdbd8f2465dd Kent Overstreet 2017-03-16 1521 } else {
674cfc26240b780 Kent Overstreet 2022-08-27 1522 trace_and_count(c, btree_node_compact, c, b);
1c6fdbd8f2465dd Kent Overstreet 2017-03-16 1523
1c6fdbd8f2465dd Kent Overstreet 2017-03-16 1524 bch2_btree_build_aux_trees(n1);
c43a6ef9a0747ef Kent Overstreet 2020-06-06 1525 six_unlock_write(&n1->c.lock);
1c6fdbd8f2465dd Kent Overstreet 2017-03-16 1526
e4215d0fec777e6 Kent Overstreet 2022-09-16 1527 path1 = get_unlocked_mut_path(trans, path->btree_id, n1->c.level, n1->key.k.p);
e4215d0fec777e6 Kent Overstreet 2022-09-16 1528 six_lock_increment(&n1->c.lock, SIX_LOCK_intent);
e4215d0fec777e6 Kent Overstreet 2022-09-16 1529 mark_btree_node_locked(trans, path1, n1->c.level, SIX_LOCK_intent);
path1 dereferenced here.
e4215d0fec777e6 Kent Overstreet 2022-09-16 1530 bch2_btree_path_level_init(trans, path1, n1);
e4215d0fec777e6 Kent Overstreet 2022-09-16 1531
7419646b254a599 Kent Overstreet 2022-04-14 1532 bch2_btree_update_add_new_node(as, n1);
7419646b254a599 Kent Overstreet 2022-04-14 1533
82732ef510b8455 Kent Overstreet 2022-02-26 1534 bch2_btree_node_write(c, n1, SIX_LOCK_intent, 0);
9f1833cadda7bb4 Kent Overstreet 2021-07-10 1535
6357d6071fccb5c Kent Overstreet 2020-02-08 1536 if (parent)
1c6fdbd8f2465dd Kent Overstreet 2017-03-16 1537 bch2_keylist_add(&as->parent_keys, &n1->key);
1c6fdbd8f2465dd Kent Overstreet 2017-03-16 1538 }
1c6fdbd8f2465dd Kent Overstreet 2017-03-16 1539
1c6fdbd8f2465dd Kent Overstreet 2017-03-16 1540 /* New nodes all written, now make them visible: */
1c6fdbd8f2465dd Kent Overstreet 2017-03-16 1541
1c6fdbd8f2465dd Kent Overstreet 2017-03-16 1542 if (parent) {
1c6fdbd8f2465dd Kent Overstreet 2017-03-16 1543 /* Split a non root node */
67e0dd8f0d8b4bf Kent Overstreet 2021-08-30 1544 bch2_btree_insert_node(as, trans, path, parent, &as->parent_keys, flags);
1c6fdbd8f2465dd Kent Overstreet 2017-03-16 1545 } else if (n3) {
67e0dd8f0d8b4bf Kent Overstreet 2021-08-30 1546 bch2_btree_set_root(as, trans, path, n3);
1c6fdbd8f2465dd Kent Overstreet 2017-03-16 1547 } else {
1c6fdbd8f2465dd Kent Overstreet 2017-03-16 1548 /* Root filled up but didn't need to be split */
67e0dd8f0d8b4bf Kent Overstreet 2021-08-30 1549 bch2_btree_set_root(as, trans, path, n1);
1c6fdbd8f2465dd Kent Overstreet 2017-03-16 1550 }
1c6fdbd8f2465dd Kent Overstreet 2017-03-16 1551
00b8ccf7074fddb Kent Overstreet 2020-05-25 1552 bch2_btree_update_get_open_buckets(as, n1);
1c6fdbd8f2465dd Kent Overstreet 2017-03-16 1553 if (n2)
00b8ccf7074fddb Kent Overstreet 2020-05-25 1554 bch2_btree_update_get_open_buckets(as, n2);
1c6fdbd8f2465dd Kent Overstreet 2017-03-16 1555 if (n3)
00b8ccf7074fddb Kent Overstreet 2020-05-25 1556 bch2_btree_update_get_open_buckets(as, n3);
1c6fdbd8f2465dd Kent Overstreet 2017-03-16 1557
ea3532cbf7fdbb9 Kent Overstreet 2019-10-11 1558 /*
ea3532cbf7fdbb9 Kent Overstreet 2019-10-11 1559 * The old node must be freed (in memory) _before_ unlocking the new
ea3532cbf7fdbb9 Kent Overstreet 2019-10-11 1560 * nodes - else another thread could re-acquire a read lock on the old
ea3532cbf7fdbb9 Kent Overstreet 2019-10-11 1561 * node after another thread has locked and updated the new node, thus
ea3532cbf7fdbb9 Kent Overstreet 2019-10-11 1562 * seeing stale data:
ea3532cbf7fdbb9 Kent Overstreet 2019-10-11 1563 */
38474c264252475 Kent Overstreet 2022-09-02 1564 bch2_btree_node_free_inmem(trans, path, b);
38474c264252475 Kent Overstreet 2022-09-02 1565
38474c264252475 Kent Overstreet 2022-09-02 1566 if (n3)
38474c264252475 Kent Overstreet 2022-09-02 1567 bch2_trans_node_add(trans, n3);
38474c264252475 Kent Overstreet 2022-09-02 1568 if (n2)
38474c264252475 Kent Overstreet 2022-09-02 1569 bch2_trans_node_add(trans, n2);
38474c264252475 Kent Overstreet 2022-09-02 1570 bch2_trans_node_add(trans, n1);
ad7ae8d63fa82e5 Kent Overstreet 2018-11-23 1571
ea3532cbf7fdbb9 Kent Overstreet 2019-10-11 1572 if (n3)
ea3532cbf7fdbb9 Kent Overstreet 2019-10-11 1573 six_unlock_intent(&n3->c.lock);
ea3532cbf7fdbb9 Kent Overstreet 2019-10-11 1574 if (n2)
ea3532cbf7fdbb9 Kent Overstreet 2019-10-11 1575 six_unlock_intent(&n2->c.lock);
ea3532cbf7fdbb9 Kent Overstreet 2019-10-11 1576 six_unlock_intent(&n1->c.lock);
ea3532cbf7fdbb9 Kent Overstreet 2019-10-11 1577
e4215d0fec777e6 Kent Overstreet 2022-09-16 1578 if (path2) {
e4215d0fec777e6 Kent Overstreet 2022-09-16 1579 __bch2_btree_path_unlock(trans, path2);
e4215d0fec777e6 Kent Overstreet 2022-09-16 1580 bch2_path_put(trans, path2, true);
e4215d0fec777e6 Kent Overstreet 2022-09-16 1581 }
e4215d0fec777e6 Kent Overstreet 2022-09-16 @1582 if (path1) {
path1 was already dereferenced.
e4215d0fec777e6 Kent Overstreet 2022-09-16 1583 __bch2_btree_path_unlock(trans, path1);
e4215d0fec777e6 Kent Overstreet 2022-09-16 1584 bch2_path_put(trans, path1, true);
e4215d0fec777e6 Kent Overstreet 2022-09-16 1585 }
e4215d0fec777e6 Kent Overstreet 2022-09-16 1586
a0a568794d09a20 Kent Overstreet 2021-08-30 1587 bch2_trans_verify_locks(trans);
ad7ae8d63fa82e5 Kent Overstreet 2018-11-23 1588
991ba0211290884 Kent Overstreet 2021-12-10 1589 bch2_time_stats_update(&c->times[n2
991ba0211290884 Kent Overstreet 2021-12-10 1590 ? BCH_TIME_btree_node_split
991ba0211290884 Kent Overstreet 2021-12-10 1591 : BCH_TIME_btree_node_compact],
dc3b63dc33e1b65 Kent Overstreet 2019-03-21 1592 start_time);
1c6fdbd8f2465dd Kent Overstreet 2017-03-16 1593 }
--
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