Ksawlii/kernel_samsung_a53x
1
0
Fork 0
Code Issues Pull requests Projects Releases Packages Wiki Activity Actions
kernel_samsung_a53x/drivers/md
History
Mingzhe Zou 3ebbf81da0 bcache: fixup lock c->root error 
commit e34820f984512b433ee1fc291417e60c47d56727 upstream.

We had a problem with io hung because it was waiting for c->root to
release the lock.

crash> cache_set.root -l cache_set.list ffffa03fde4c0050
  root = 0xffff802ef454c800
crash> btree -o 0xffff802ef454c800 | grep rw_semaphore
  [ffff802ef454c858] struct rw_semaphore lock;
crash> struct rw_semaphore ffff802ef454c858
struct rw_semaphore {
  count = {
    counter = -4294967297
  },
  wait_list = {
    next = 0xffff00006786fc28,
    prev = 0xffff00005d0efac8
  },
  wait_lock = {
    raw_lock = {
      {
        val = {
          counter = 0
        },
        {
          locked = 0 '\000',
          pending = 0 '\000'
        },
        {
          locked_pending = 0,
          tail = 0
        }
      }
    }
  },
  osq = {
    tail = {
      counter = 0
    }
  },
  owner = 0xffffa03fdc586603
}

The "counter = -4294967297" means that lock count is -1 and a write lock
is being attempted. Then, we found that there is a btree with a counter
of 1 in btree_cache_freeable.

crash> cache_set -l cache_set.list ffffa03fde4c0050 -o|grep btree_cache
  [ffffa03fde4c1140] struct list_head btree_cache;
  [ffffa03fde4c1150] struct list_head btree_cache_freeable;
  [ffffa03fde4c1160] struct list_head btree_cache_freed;
  [ffffa03fde4c1170] unsigned int btree_cache_used;
  [ffffa03fde4c1178] wait_queue_head_t btree_cache_wait;
  [ffffa03fde4c1190] struct task_struct *btree_cache_alloc_lock;
crash> list -H ffffa03fde4c1140|wc -l
973
crash> list -H ffffa03fde4c1150|wc -l
1123
crash> cache_set.btree_cache_used -l cache_set.list ffffa03fde4c0050
  btree_cache_used = 2097
crash> list -s btree -l btree.list -H ffffa03fde4c1140|grep -E -A2 "^  lock = {" > btree_cache.txt
crash> list -s btree -l btree.list -H ffffa03fde4c1150|grep -E -A2 "^  lock = {" > btree_cache_freeable.txt
[root@node-3 127.0.0.1-2023-08-04-16:40:28]# pwd
/var/crash/127.0.0.1-2023-08-04-16:40:28
[root@node-3 127.0.0.1-2023-08-04-16:40:28]# cat btree_cache.txt|grep counter|grep -v "counter = 0"
[root@node-3 127.0.0.1-2023-08-04-16:40:28]# cat btree_cache_freeable.txt|grep counter|grep -v "counter = 0"
      counter = 1

We found that this is a bug in bch_sectors_dirty_init() when locking c->root:
    (1). Thread X has locked c->root(A) write.
    (2). Thread Y failed to lock c->root(A), waiting for the lock(c->root A).
    (3). Thread X bch_btree_set_root() changes c->root from A to B.
    (4). Thread X releases the lock(c->root A).
    (5). Thread Y successfully locks c->root(A).
    (6). Thread Y releases the lock(c->root B).

        down_write locked ---(1)----------------------┐
                |                                     |
                |   down_read waiting ---(2)----┐     |
                |           |               ┌-------------┐ ┌-------------┐
        bch_btree_set_root ===(3)========>> | c->root   A | | c->root   B |
                |           |               └-------------┘ └-------------┘
            up_write ---(4)---------------------┘     |            |
                            |                         |            |
                    down_read locked ---(5)-----------┘            |
                            |                                      |
                        up_read ---(6)-----------------------------┘

Since c->root may change, the correct steps to lock c->root should be
the same as bch_root_usage(), compare after locking.

static unsigned int bch_root_usage(struct cache_set *c)
{
        unsigned int bytes = 0;
        struct bkey *k;
        struct btree *b;
        struct btree_iter iter;

        goto lock_root;

        do {
                rw_unlock(false, b);
lock_root:
                b = c->root;
                rw_lock(false, b, b->level);
        } while (b != c->root);

        for_each_key_filter(&b->keys, k, &iter, bch_ptr_bad)
                bytes += bkey_bytes(k);

        rw_unlock(false, b);

        return (bytes * 100) / btree_bytes(c);
}

Fixes: b144e45fc576 ("bcache: make bch_sectors_dirty_init() to be multithreaded")
Signed-off-by: Mingzhe Zou <mingzhe.zou@easystack.cn>
Cc:  <stable@vger.kernel.org>
Signed-off-by: Coly Li <colyli@suse.de>
Link: https://lore.kernel.org/r/20231120052503.6122-7-colyli@suse.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-11-18 12:10:57 +01:00
..
bcache bcache: fixup lock c->root error 2024-11-18 12:10:57 +01:00
persistent-data Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
alta_bigdata.c Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
dm-bio-prison-v1.c Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
dm-bio-prison-v1.h Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
dm-bio-prison-v2.c Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
dm-bio-prison-v2.h Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
dm-bio-record.h Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
dm-bow.c Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
dm-bufio.c Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
dm-builtin.c Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
dm-cache-background-tracker.c Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
dm-cache-background-tracker.h Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
dm-cache-block-types.h Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
dm-cache-metadata.c Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
dm-cache-metadata.h Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
dm-cache-policy-internal.h Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
dm-cache-policy-smq.c Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
dm-cache-policy.c Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
dm-cache-policy.h Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
dm-cache-target.c Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
dm-clone-metadata.c Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
dm-clone-metadata.h Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
dm-clone-target.c Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
dm-core.h Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
dm-crypt.c Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
dm-default-key.c Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
dm-delay.c dm-delay: fix a race between delay_presuspend and delay_bio 2024-11-18 12:10:57 +01:00
dm-dust.c Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
dm-ebs-target.c Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
dm-era-target.c Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
dm-exception-store.c Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
dm-exception-store.h Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
dm-flakey.c Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
dm-historical-service-time.c Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
dm-init.c Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
dm-integrity.c Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
dm-io.c Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
dm-ioctl.c Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
dm-kcopyd.c Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
dm-linear.c Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
dm-log-userspace-base.c Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
dm-log-userspace-transfer.c Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
dm-log-userspace-transfer.h Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
dm-log-writes.c Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
dm-log.c Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
dm-mpath.c Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
dm-mpath.h Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
dm-path-selector.c Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
dm-path-selector.h Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
dm-queue-length.c Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
dm-raid.c Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
dm-raid1.c Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
dm-region-hash.c Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
dm-round-robin.c Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
dm-rq.c Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
dm-rq.h Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
dm-service-time.c Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
dm-snap-persistent.c Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
dm-snap-transient.c Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
dm-snap.c Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
dm-stats.c Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
dm-stats.h Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
dm-stripe.c Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
dm-switch.c Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
dm-sysfs.c Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
dm-table.c Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
dm-target.c Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
dm-thin-metadata.c Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
dm-thin-metadata.h Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
dm-thin.c Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
dm-uevent.c Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
dm-uevent.h Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
dm-unstripe.c Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
dm-user.c Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
dm-verity-debug.c Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
dm-verity-debug.h Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
dm-verity-fec.c Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
dm-verity-fec.h Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
dm-verity-target.c Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
dm-verity-verify-sig.c Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
dm-verity-verify-sig.h Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
dm-verity.h Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
dm-writecache.c Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
dm-zero.c Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
dm-zoned-metadata.c Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
dm-zoned-reclaim.c Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
dm-zoned-target.c Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
dm-zoned.h Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
dm.c Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
dm.h Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
Kconfig Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
Makefile Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
md-autodetect.c Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
md-bitmap.c Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
md-bitmap.h Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
md-cluster.c Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
md-cluster.h Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
md-faulty.c Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
md-linear.c Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
md-linear.h Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
md-multipath.c Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
md-multipath.h Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
md.c Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
md.h Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
raid0.c Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
raid0.h Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
raid1-10.c Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
raid1.c Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
raid1.h Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
raid5-cache.c Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
raid5-log.h Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
raid5-ppl.c Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
raid5.c Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
raid5.h Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
raid10.c Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
raid10.h Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00