linux/kernel/cgroup
Michal Koutný ab3e3b23d8 cgroup: Iterate tasks that did not finish do_exit()
commit 9c974c7724 upstream.

PF_EXITING is set earlier than actual removal from css_set when a task
is exitting. This can confuse cgroup.procs readers who see no PF_EXITING
tasks, however, rmdir is checking against css_set membership so it can
transitionally fail with EBUSY.

Fix this by listing tasks that weren't unlinked from css_set active
lists.
It may happen that other users of the task iterator (without
CSS_TASK_ITER_PROCS) spot a PF_EXITING task before cgroup_exit(). This
is equal to the state before commit c03cd7738a ("cgroup: Include dying
leaders with live threads in PROCS iterations") but it may be reviewed
later.

Reported-by: Suren Baghdasaryan <surenb@google.com>
Fixes: c03cd7738a ("cgroup: Include dying leaders with live threads in PROCS iterations")
Signed-off-by: Michal Koutný <mkoutny@suse.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-03-18 07:14:19 +01:00
..
cgroup-internal.h cgroup/tracing: Move taking of spin lock out of trace event handlers 2018-07-11 10:48:47 -07:00
cgroup-v1.c cgroup/tracing: Move taking of spin lock out of trace event handlers 2018-07-11 10:48:47 -07:00
cgroup.c cgroup: Iterate tasks that did not finish do_exit() 2020-03-18 07:14:19 +01:00
cpuset.c cpuset: restore sanity to cpuset_cpus_allowed_fallback() 2019-07-10 09:53:39 +02:00
debug.c debug cgroup: use task_css_set instead of rcu_dereference 2017-11-27 11:37:33 -08:00
freezer.c cgroup: add @flags to css_task_iter_start() and implement CSS_TASK_ITER_PROCS 2017-07-21 11:14:51 -04:00
Makefile cgroup: Rename kernel/cgroup/stat.c to kernel/cgroup/rstat.c 2018-04-26 14:29:04 -07:00
namespace.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
pids.c cgroup: pids: use atomic64_t for pids->limit 2019-12-17 20:34:56 +01:00
rdma.c rdmacg: Convert to use match_string() helper 2018-05-07 09:27:26 -07:00
rstat.c cgroup, rstat: Don't flush subtree root unless necessary 2019-04-05 22:33:06 +02:00