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| author | Anand Jain <anand.jain@oracle.com> | 2018-08-06 18:12:37 +0800 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2018-10-10 08:54:19 +0200 |
| commit | 4e380c50cf12f07d01262b81f5c61249503d2ce3 (patch) | |
| tree | 9e77ed05a870506313eb01f22967d4ea79517e7f /fs/btrfs/volumes.c | |
| parent | 9e685bec07ae0348a895c777d593c3a1b1954745 (diff) | |
btrfs: btrfs_shrink_device should call commit transaction at the end
[ Upstream commit 801660b040d132f67fac6a95910ad307c5929b49 ]
Test case btrfs/164 reports use-after-free:
[ 6712.084324] general protection fault: 0000 [#1] PREEMPT SMP
..
[ 6712.195423] btrfs_update_commit_device_size+0x75/0xf0 [btrfs]
[ 6712.201424] btrfs_commit_transaction+0x57d/0xa90 [btrfs]
[ 6712.206999] btrfs_rm_device+0x627/0x850 [btrfs]
[ 6712.211800] btrfs_ioctl+0x2b03/0x3120 [btrfs]
Reason for this is that btrfs_shrink_device adds the resized device to
the fs_devices::resized_devices after it has called the last commit
transaction.
So the list fs_devices::resized_devices is not empty when
btrfs_shrink_device returns. Now the parent function
btrfs_rm_device calls:
btrfs_close_bdev(device);
call_rcu(&device->rcu, free_device_rcu);
and then does the transactio ncommit. It goes through the
fs_devices::resized_devices in btrfs_update_commit_device_size and
leads to use-after-free.
Fix this by making sure btrfs_shrink_device calls the last needed
btrfs_commit_transaction before the return. This is consistent with what
the grow counterpart does and this makes sure the on-disk state is
persistent when the function returns.
Reported-by: Lu Fengqi <lufq.fnst@cn.fujitsu.com>
Tested-by: Lu Fengqi <lufq.fnst@cn.fujitsu.com>
Signed-off-by: Anand Jain <anand.jain@oracle.com>
Reviewed-by: David Sterba <dsterba@suse.com>
[ update changelog ]
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'fs/btrfs/volumes.c')
| -rw-r--r-- | fs/btrfs/volumes.c | 7 |
1 files changed, 6 insertions, 1 deletions
diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c index a39b1f0b0606..a0947f4a3e87 100644 --- a/fs/btrfs/volumes.c +++ b/fs/btrfs/volumes.c @@ -4517,7 +4517,12 @@ again: /* Now btrfs_update_device() will change the on-disk size. */ ret = btrfs_update_device(trans, device); - btrfs_end_transaction(trans); + if (ret < 0) { + btrfs_abort_transaction(trans, ret); + btrfs_end_transaction(trans); + } else { + ret = btrfs_commit_transaction(trans); + } done: btrfs_free_path(path); if (ret) { |