Re: [PATCH -next 2/2] md/raid5-cache: fix null-ptr-deref in r5l_reclaim_thread()
From: kernel test robot
Date: Tue Jun 27 2023 - 11:13:19 EST
Hi Yu,
kernel test robot noticed the following build warnings:
[auto build test WARNING on next-20230626]
url: https://github.com/intel-lab-lkp/linux/commits/Yu-Kuai/md-raid5-cache-Revert-md-raid5-cache-Clear-conf-log-after-finishing-work/20230627-165746
base: next-20230626
patch link: https://lore.kernel.org/r/20230627085611.4186951-3-yukuai1%40huaweicloud.com
patch subject: [PATCH -next 2/2] md/raid5-cache: fix null-ptr-deref in r5l_reclaim_thread()
config: x86_64-buildonly-randconfig-r003-20230627 (https://download.01.org/0day-ci/archive/20230627/202306272247.VWiGIFDe-lkp@xxxxxxxxx/config)
compiler: gcc-12 (Debian 12.2.0-14) 12.2.0
reproduce: (https://download.01.org/0day-ci/archive/20230627/202306272247.VWiGIFDe-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>
| Closes: https://lore.kernel.org/oe-kbuild-all/202306272247.VWiGIFDe-lkp@xxxxxxxxx/
All warnings (new ones prefixed by >>):
drivers/md/raid5-cache.c: In function 'r5l_do_reclaim':
>> drivers/md/raid5-cache.c:1496:24: warning: unused variable 'conf' [-Wunused-variable]
1496 | struct r5conf *conf = log->rdev->mddev->private;
| ^~~~
vim +/conf +1496 drivers/md/raid5-cache.c
a39f7afde358ca Song Liu 2016-11-17 1493
0576b1c618ef22 Shaohua Li 2015-08-13 1494 static void r5l_do_reclaim(struct r5l_log *log)
0576b1c618ef22 Shaohua Li 2015-08-13 1495 {
a39f7afde358ca Song Liu 2016-11-17 @1496 struct r5conf *conf = log->rdev->mddev->private;
0576b1c618ef22 Shaohua Li 2015-08-13 1497 sector_t reclaim_target = xchg(&log->reclaim_target, 0);
170364619ac21c Christoph Hellwig 2015-10-05 1498 sector_t reclaimable;
170364619ac21c Christoph Hellwig 2015-10-05 1499 sector_t next_checkpoint;
a39f7afde358ca Song Liu 2016-11-17 1500 bool write_super;
0576b1c618ef22 Shaohua Li 2015-08-13 1501
0576b1c618ef22 Shaohua Li 2015-08-13 1502 spin_lock_irq(&log->io_list_lock);
a39f7afde358ca Song Liu 2016-11-17 1503 write_super = r5l_reclaimable_space(log) > log->max_free_space ||
a39f7afde358ca Song Liu 2016-11-17 1504 reclaim_target != 0 || !list_empty(&log->no_space_stripes);
0576b1c618ef22 Shaohua Li 2015-08-13 1505 /*
0576b1c618ef22 Shaohua Li 2015-08-13 1506 * move proper io_unit to reclaim list. We should not change the order.
0576b1c618ef22 Shaohua Li 2015-08-13 1507 * reclaimable/unreclaimable io_unit can be mixed in the list, we
0576b1c618ef22 Shaohua Li 2015-08-13 1508 * shouldn't reuse space of an unreclaimable io_unit
0576b1c618ef22 Shaohua Li 2015-08-13 1509 */
0576b1c618ef22 Shaohua Li 2015-08-13 1510 while (1) {
170364619ac21c Christoph Hellwig 2015-10-05 1511 reclaimable = r5l_reclaimable_space(log);
170364619ac21c Christoph Hellwig 2015-10-05 1512 if (reclaimable >= reclaim_target ||
0576b1c618ef22 Shaohua Li 2015-08-13 1513 (list_empty(&log->running_ios) &&
0576b1c618ef22 Shaohua Li 2015-08-13 1514 list_empty(&log->io_end_ios) &&
a8c34f915976e3 Shaohua Li 2015-09-02 1515 list_empty(&log->flushing_ios) &&
04732f741dce5e Christoph Hellwig 2015-10-05 1516 list_empty(&log->finished_ios)))
0576b1c618ef22 Shaohua Li 2015-08-13 1517 break;
0576b1c618ef22 Shaohua Li 2015-08-13 1518
170364619ac21c Christoph Hellwig 2015-10-05 1519 md_wakeup_thread(log->rdev->mddev->thread);
170364619ac21c Christoph Hellwig 2015-10-05 1520 wait_event_lock_irq(log->iounit_wait,
170364619ac21c Christoph Hellwig 2015-10-05 1521 r5l_reclaimable_space(log) > reclaimable,
170364619ac21c Christoph Hellwig 2015-10-05 1522 log->io_list_lock);
0576b1c618ef22 Shaohua Li 2015-08-13 1523 }
170364619ac21c Christoph Hellwig 2015-10-05 1524
f2ca7c4bb59762 Yu Kuai 2023-06-27 1525 next_checkpoint = r5c_calculate_new_cp(log);
0576b1c618ef22 Shaohua Li 2015-08-13 1526 spin_unlock_irq(&log->io_list_lock);
0576b1c618ef22 Shaohua Li 2015-08-13 1527
a39f7afde358ca Song Liu 2016-11-17 1528 if (reclaimable == 0 || !write_super)
0576b1c618ef22 Shaohua Li 2015-08-13 1529 return;
0576b1c618ef22 Shaohua Li 2015-08-13 1530
0576b1c618ef22 Shaohua Li 2015-08-13 1531 /*
0576b1c618ef22 Shaohua Li 2015-08-13 1532 * write_super will flush cache of each raid disk. We must write super
0576b1c618ef22 Shaohua Li 2015-08-13 1533 * here, because the log area might be reused soon and we don't want to
0576b1c618ef22 Shaohua Li 2015-08-13 1534 * confuse recovery
0576b1c618ef22 Shaohua Li 2015-08-13 1535 */
4b482044d24f3d Shaohua Li 2015-10-08 1536 r5l_write_super_and_discard_space(log, next_checkpoint);
0576b1c618ef22 Shaohua Li 2015-08-13 1537
0576b1c618ef22 Shaohua Li 2015-08-13 1538 mutex_lock(&log->io_mutex);
170364619ac21c Christoph Hellwig 2015-10-05 1539 log->last_checkpoint = next_checkpoint;
a39f7afde358ca Song Liu 2016-11-17 1540 r5c_update_log_state(log);
0576b1c618ef22 Shaohua Li 2015-08-13 1541 mutex_unlock(&log->io_mutex);
0576b1c618ef22 Shaohua Li 2015-08-13 1542
170364619ac21c Christoph Hellwig 2015-10-05 1543 r5l_run_no_space_stripes(log);
0576b1c618ef22 Shaohua Li 2015-08-13 1544 }
0576b1c618ef22 Shaohua Li 2015-08-13 1545
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