Miao Xie
2013-Dec-17 04:01 UTC
[PATCH] Btrfs: fix double initialization of the raid kobject
We met the following oops when doing space balance:
kobject (ffff88081b590278): tried to init an initialized object, something is
seriously wrong.
...
Call Trace:
[<ffffffff81937262>] dump_stack+0x49/0x5f
[<ffffffff8137d259>] kobject_init+0x89/0xa0
[<ffffffff8137d36a>] kobject_init_and_add+0x2a/0x70
[<ffffffffa009bd79>] ? clear_extent_bit+0x199/0x470 [btrfs]
[<ffffffffa005e82c>] __link_block_group+0xfc/0x120 [btrfs]
[<ffffffffa006b9db>] btrfs_make_block_group+0x24b/0x370 [btrfs]
[<ffffffffa00a899b>] __btrfs_alloc_chunk+0x54b/0x7e0 [btrfs]
[<ffffffffa00a8c6f>] btrfs_alloc_chunk+0x3f/0x50 [btrfs]
[<ffffffffa0060123>] do_chunk_alloc+0x363/0x440 [btrfs]
[<ffffffffa00633d4>] btrfs_check_data_free_space+0x104/0x310 [btrfs]
[<ffffffffa0069f4d>] btrfs_write_dirty_block_groups+0x48d/0x600 [btrfs]
[<ffffffffa007aad4>] commit_cowonly_roots+0x184/0x250 [btrfs]
...
Steps to reproduce:
# mkfs.btrfs -f <dev>
# mount -o nospace_cache <dev> <mnt>
# btrfs balance start <mnt>
# dd if=/dev/zero of=<mnt>/tmpfile bs=1M count=1
The reason of this problem is that we initialized the raid kobject when we added
a block group into a empty raid list. As we know, when we mounted a btrfs
filesystem,
the raid list was empty, we would initialize the raid kobject when we added the
first
block group. But if there was not data stored in the block group, the block
group
would be freed when doing balance, and the raid list would be empty. And then if
we
allocated a new block group and added it into the raid list, we would initialize
the raid kobject again, the oops happened.
Fix this problem by initializing the raid kobject just when mounting the fs.
Signed-off-by: Miao Xie <miaox@cn.fujitsu.com>
---
fs/btrfs/extent-tree.c | 9 +++++----
1 file changed, 5 insertions(+), 4 deletions(-)
diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index cd4d9ca..d667aad 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -3464,8 +3464,10 @@ static int update_space_info(struct btrfs_fs_info *info,
u64 flags,
return ret;
}
- for (i = 0; i < BTRFS_NR_RAID_TYPES; i++)
+ for (i = 0; i < BTRFS_NR_RAID_TYPES; i++) {
INIT_LIST_HEAD(&found->block_groups[i]);
+ kobject_init(&found->block_group_kobjs[i], &btrfs_raid_ktype);
+ }
init_rwsem(&found->groups_sem);
spin_lock_init(&found->lock);
found->flags = flags & BTRFS_BLOCK_GROUP_TYPE_MASK;
@@ -8423,9 +8425,8 @@ static void __link_block_group(struct btrfs_space_info
*space_info,
int ret;
kobject_get(&space_info->kobj); /* put in release */
- ret = kobject_init_and_add(kobj, &btrfs_raid_ktype,
- &space_info->kobj, "%s",
- get_raid_name(index));
+ ret = kobject_add(kobj, &space_info->kobj, "%s",
+ get_raid_name(index));
if (ret) {
pr_warn("btrfs: failed to add kobject for block cache.
ignoring.\n");
kobject_put(&space_info->kobj);
--
1.8.3.1
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Miao Xie
2013-Dec-17 09:15 UTC
Re: [PATCH] Btrfs: fix double initialization of the raid kobject
On tue, 17 Dec 2013 12:01:12 +0800, Miao Xie wrote:> We met the following oops when doing space balance: > kobject (ffff88081b590278): tried to init an initialized object, something is seriously wrong. > ... > Call Trace: > [<ffffffff81937262>] dump_stack+0x49/0x5f > [<ffffffff8137d259>] kobject_init+0x89/0xa0 > [<ffffffff8137d36a>] kobject_init_and_add+0x2a/0x70 > [<ffffffffa009bd79>] ? clear_extent_bit+0x199/0x470 [btrfs] > [<ffffffffa005e82c>] __link_block_group+0xfc/0x120 [btrfs] > [<ffffffffa006b9db>] btrfs_make_block_group+0x24b/0x370 [btrfs] > [<ffffffffa00a899b>] __btrfs_alloc_chunk+0x54b/0x7e0 [btrfs] > [<ffffffffa00a8c6f>] btrfs_alloc_chunk+0x3f/0x50 [btrfs] > [<ffffffffa0060123>] do_chunk_alloc+0x363/0x440 [btrfs] > [<ffffffffa00633d4>] btrfs_check_data_free_space+0x104/0x310 [btrfs] > [<ffffffffa0069f4d>] btrfs_write_dirty_block_groups+0x48d/0x600 [btrfs] > [<ffffffffa007aad4>] commit_cowonly_roots+0x184/0x250 [btrfs] > ... > > Steps to reproduce: > # mkfs.btrfs -f <dev> > # mount -o nospace_cache <dev> <mnt> > # btrfs balance start <mnt> > # dd if=/dev/zero of=<mnt>/tmpfile bs=1M count=1 > > The reason of this problem is that we initialized the raid kobject when we added > a block group into a empty raid list. As we know, when we mounted a btrfs filesystem, > the raid list was empty, we would initialize the raid kobject when we added the first > block group. But if there was not data stored in the block group, the block group > would be freed when doing balance, and the raid list would be empty. And then if we > allocated a new block group and added it into the raid list, we would initialize > the raid kobject again, the oops happened. > > Fix this problem by initializing the raid kobject just when mounting the fs. > > Signed-off-by: Miao Xie <miaox@cn.fujitsu.com>This bug was reported by Wang Shilong, so add Reported-by: Wang Shilong <wangsl.fnst@cn.fujitsu.com> Thanks Miao> --- > fs/btrfs/extent-tree.c | 9 +++++---- > 1 file changed, 5 insertions(+), 4 deletions(-) > > diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c > index cd4d9ca..d667aad 100644 > --- a/fs/btrfs/extent-tree.c > +++ b/fs/btrfs/extent-tree.c > @@ -3464,8 +3464,10 @@ static int update_space_info(struct btrfs_fs_info *info, u64 flags, > return ret; > } > > - for (i = 0; i < BTRFS_NR_RAID_TYPES; i++) > + for (i = 0; i < BTRFS_NR_RAID_TYPES; i++) { > INIT_LIST_HEAD(&found->block_groups[i]); > + kobject_init(&found->block_group_kobjs[i], &btrfs_raid_ktype); > + } > init_rwsem(&found->groups_sem); > spin_lock_init(&found->lock); > found->flags = flags & BTRFS_BLOCK_GROUP_TYPE_MASK; > @@ -8423,9 +8425,8 @@ static void __link_block_group(struct btrfs_space_info *space_info, > int ret; > > kobject_get(&space_info->kobj); /* put in release */ > - ret = kobject_init_and_add(kobj, &btrfs_raid_ktype, > - &space_info->kobj, "%s", > - get_raid_name(index)); > + ret = kobject_add(kobj, &space_info->kobj, "%s", > + get_raid_name(index)); > if (ret) { > pr_warn("btrfs: failed to add kobject for block cache. ignoring.\n"); > kobject_put(&space_info->kobj); >-- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html