On Sat, Aug 08 2020 at 8:10am -0400, kernel test robot <l...@intel.com> wrote:
> tree: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git > master > head: 449dc8c97089a6e09fb2dac4d92b1b7ac0eb7c1e > commit: 374117ad4736c5a4f8012cfe59fc07d9d58191d5 dm mpath: use double checked > locking in fast path > date: 4 weeks ago > config: arm-randconfig-m031-20200808 (attached as .config) > compiler: arm-linux-gnueabi-gcc (GCC) 9.3.0 > > If you fix the issue, kindly add following tag as appropriate > Reported-by: kernel test robot <l...@intel.com> All 3 recent reports about smatch showing "double unlocked 'm->lock'" appear to be bogus. Think smatch is generating false positives (and given "Old smatch warnings" it seems it has been doing so for some time). In addition, does l...@intel.com no longer test linux-next? The dm-mpath locking changes that were just merged into mainline have been in linux-next since July 13. Why were these tests only done against mainline? Mike > New smatch warnings: > drivers/md/dm-mpath.c:524 multipath_clone_and_map() error: double unlocked > 'm->lock' (orig line 516) > > Old smatch warnings: > drivers/md/dm-mpath.c:446 choose_pgpath() error: double unlocked 'm->lock' > (orig line 416) > drivers/md/dm-mpath.c:457 choose_pgpath() error: double unlocked 'm->lock' > (orig line 403) > drivers/md/dm-mpath.c:525 multipath_clone_and_map() error: double unlocked > 'm->lock' (orig line 516) > drivers/md/dm-mpath.c:526 multipath_clone_and_map() error: double unlocked > 'm->lock' (orig line 524) > drivers/md/dm-mpath.c:626 __map_bio() error: double unlocked 'm->lock' (orig > line 615) > drivers/md/dm-mpath.c:627 __map_bio() error: double unlocked 'm->lock' (orig > line 615) > drivers/md/dm-mpath.c:628 __map_bio() error: double unlocked 'm->lock' (orig > line 626) > drivers/md/dm-mpath.c:629 __map_bio() error: double unlocked 'm->lock' (orig > line 628) > drivers/md/dm-mpath.c:1607 pg_init_done() error: double unlocked 'm->lock' > (orig line 1560) > drivers/md/dm-mpath.c:1707 multipath_end_io_bio() error: double unlocked > 'm->lock' (orig line 1704) > drivers/md/dm-mpath.c:1988 multipath_prepare_ioctl() error: double unlocked > 'm->lock' (orig line 1984) > drivers/md/dm-mpath.c:2012 multipath_prepare_ioctl() error: double unlocked > 'm->lock' (orig line 2001) > > vim +524 drivers/md/dm-mpath.c > > 498 > 499 /* > 500 * Map cloned requests (request-based multipath) > 501 */ > 502 static int multipath_clone_and_map(struct dm_target *ti, struct > request *rq, > 503 union map_info *map_context, > 504 struct request **__clone) > 505 { > 506 struct multipath *m = ti->private; > 507 size_t nr_bytes = blk_rq_bytes(rq); > 508 struct pgpath *pgpath; > 509 struct block_device *bdev; > 510 struct dm_mpath_io *mpio = get_mpio(map_context); > 511 struct request_queue *q; > 512 struct request *clone; > 513 > 514 /* Do we need to select a new pgpath? */ > 515 pgpath = READ_ONCE(m->current_pgpath); > > 516 if (!pgpath || > !mpath_double_check_test_bit(MPATHF_QUEUE_IO, m)) > 517 pgpath = choose_pgpath(m, nr_bytes); > 518 > 519 if (!pgpath) { > 520 if (must_push_back_rq(m)) > 521 return DM_MAPIO_DELAY_REQUEUE; > 522 dm_report_EIO(m); /* Failed */ > 523 return DM_MAPIO_KILL; > > 524 } else if (mpath_double_check_test_bit(MPATHF_QUEUE_IO, > m) || > 525 > mpath_double_check_test_bit(MPATHF_PG_INIT_REQUIRED, m)) { > 526 pg_init_all_paths(m); > 527 return DM_MAPIO_DELAY_REQUEUE; > 528 } > 529 > 530 mpio->pgpath = pgpath; > 531 mpio->nr_bytes = nr_bytes; > 532 > 533 bdev = pgpath->path.dev->bdev; > 534 q = bdev_get_queue(bdev); > 535 clone = blk_get_request(q, rq->cmd_flags | REQ_NOMERGE, > 536 BLK_MQ_REQ_NOWAIT); > 537 if (IS_ERR(clone)) { > 538 /* EBUSY, ENODEV or EWOULDBLOCK: requeue */ > 539 if (blk_queue_dying(q)) { > 540 atomic_inc(&m->pg_init_in_progress); > 541 activate_or_offline_path(pgpath); > 542 return DM_MAPIO_DELAY_REQUEUE; > 543 } > 544 > 545 /* > 546 * blk-mq's SCHED_RESTART can cover this > requeue, so we > 547 * needn't deal with it by DELAY_REQUEUE. More > importantly, > 548 * we have to return DM_MAPIO_REQUEUE so that > blk-mq can > 549 * get the queue busy feedback (via > BLK_STS_RESOURCE), > 550 * otherwise I/O merging can suffer. > 551 */ > 552 return DM_MAPIO_REQUEUE; > 553 } > 554 clone->bio = clone->biotail = NULL; > 555 clone->rq_disk = bdev->bd_disk; > 556 clone->cmd_flags |= REQ_FAILFAST_TRANSPORT; > 557 *__clone = clone; > 558 > 559 if (pgpath->pg->ps.type->start_io) > 560 pgpath->pg->ps.type->start_io(&pgpath->pg->ps, > 561 &pgpath->path, > 562 nr_bytes); > 563 return DM_MAPIO_REMAPPED; > 564 } > 565 > > --- > 0-DAY CI Kernel Test Service, Intel Corporation > https://lists.01.org/hyperkitty/list/kbuild-...@lists.01.org
