pidns: find_new_reaper() can no longer switch to init_pid_ns.child_reaper

find_new_reaper() changes pid_ns->child_reaper, see add0d4df ("pid_ns:
zap_pid_ns_processes: fix the ->child_reaper changing").

The original reason has gone away after the previous patch, ->children
list must be empty after zap_pid_ns_processes().

However now we can not switch to init_pid_ns.child_reaper.
__unhash_process() relies on the "->child_reaper == parent" check, but
this check does not work if the last exiting task is also the child
reaper.

As Eric sugested, we can change __unhash_process() to use the parent's
pid_ns and remove this code.

Also, with this change we can move detach_pid(PIDTYPE_PID) back, where it
was before the previous fix.

Signed-off-by: Oleg Nesterov <[email protected]>
Acked-by: "Eric W. Biederman" <[email protected]>
Cc: Louis Rilling <[email protected]>
Cc: Mike Galbraith <[email protected]>
Acked-by: Pavel Emelyanov <[email protected]>
Tested-by: Andrew Wagin <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

0 files changed, 0 insertions, 0 deletions