btrfs: handle chunk tree lookup error in btrfs_relocate_sys_chunks()

stable inclusion
from stable-v5.4.274
commit 576164bd01bd795f8b09fb194b493103506b33c9
category: bugfix
bugzilla: https://gitee.com/src-openeuler/kernel/issues/I9QGIP
CVE: CVE-2024-35936

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=576164bd01bd795f8b09fb194b493103506b33c9



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[ Upstream commit 7411055db5ce64f836aaffd422396af0075fdc99 ]

The unhandled case in btrfs_relocate_sys_chunks() loop is a corruption,
as it could be caused only by two impossible conditions:

- at first the search key is set up to look for a chunk tree item, with
  offset -1, this is an inexact search and the key->offset will contain
  the correct offset upon a successful search, a valid chunk tree item
  cannot have an offset -1

- after first successful search, the found_key corresponds to a chunk
  item, the offset is decremented by 1 before the next loop, it's
  impossible to find a chunk item there due to alignment and size
  constraints

Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Yifan Qiao <qiaoyifan4@huawei.com>