btrfs: relocation: Only remove reloc rb_trees if reloc control has been initialized
authorQu Wenruo <wqu@suse.com>
Tue, 3 Jul 2018 09:10:07 +0000 (17:10 +0800)
committerDavid Sterba <dsterba@suse.com>
Mon, 6 Aug 2018 11:12:42 +0000 (13:12 +0200)
commit389305b2aa68723c754f88d9dbd268a400e10664
tree85dd721ee6bc9443517796cfdb208cc6b0e7916c
parentba480dd4db9f1798541eb2d1c423fc95feee8d36
btrfs: relocation: Only remove reloc rb_trees if reloc control has been initialized

Invalid reloc tree can cause kernel NULL pointer dereference when btrfs
does some cleanup of the reloc roots.

It turns out that fs_info::reloc_ctl can be NULL in
btrfs_recover_relocation() as we allocate relocation control after all
reloc roots have been verified.
So when we hit: note, we haven't called set_reloc_control() thus
fs_info::reloc_ctl is still NULL.

Link: https://bugzilla.kernel.org/show_bug.cgi?id=199833
Reported-by: Xu Wen <wen.xu@gatech.edu>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Tested-by: Gu Jinxiang <gujx@cn.fujitsu.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
fs/btrfs/relocation.c