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author | Anand Jain <anand.jain@oracle.com> | 2018-08-06 13:12:37 +0300 |
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committer | David Sterba <dsterba@suse.com> | 2018-08-23 18:37:27 +0300 |
commit | 801660b040d132f67fac6a95910ad307c5929b49 (patch) | |
tree | a179695d4720b1f61d2f8f6bb87c7bacaabf81b3 /fs/signalfd.c | |
parent | a5b7f4295eeae8b05ca91f6d145cd8773b08de9e (diff) | |
download | linux-801660b040d132f67fac6a95910ad307c5929b49.tar.xz |
btrfs: btrfs_shrink_device should call commit transaction at the end
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>
Diffstat (limited to 'fs/signalfd.c')
0 files changed, 0 insertions, 0 deletions