Thanks for the patch Johannes! I tried tried it immediately, but it still hangs. But this time the worker threads have a slightly different call stack. Most of them are now waiting in css_killed_work_fn: [ffff880c31a33e18] mutex_lock at ffffffff813c1bb4 [ffff880c31a33e30] css_killed_work_fn at ffffffff81080eba [ffff880c31a33e50] process_one_work at ffffffff8103f7db [ffff880c31a33e90] worker_thread at ffffffff8103fc7d [ffff880c31a33eb0] worker_thread at ffffffff8103fb39 [ffff880c31a33ec8] kthread at ffffffff8104479c [ffff880c31a33f28] kthread at ffffffff81044714 [ffff880c31a33f50] ret_from_fork at ffffffff813c503c [ffff880c31a33f80] kthread at ffffffff81044714 The other few workers hang at the beginning of proc_cgroupstats_show and one in cgroup_rmdir: [ffff8800b7825e40] mutex_lock at ffffffff813c1bb4 [ffff8800b7825e58] proc_cgroupstats_show at ffffffff8107f5f0 [ffff8800b7825e78] seq_read at ffffffff81107953 [ffff8800b7825ee0] proc_reg_read at ffffffff81135f73 [ffff8800b7825f18] vfs_read at ffffffff810ed3ea [ffff8800b7825f48] sys_read at ffffffff810edad6 [ffff8800b7825f80] tracesys at ffffffff813c52db [ffff880c308e1e40] mutex_lock at ffffffff813c1bb4 [ffff880c308e1e58] cgroup_rmdir at ffffffff81081d25 [ffff880c308e1e78] vfs_rmdir at ffffffff810f8bed [ffff880c308e1ea0] do_rmdir at ffffffff810f8d02 [ffff880c308e1f18] user_exit at ffffffff8100aed1 [ffff880c308e1f28] syscall_trace_enter at ffffffff8100c356 [ffff880c308e1f70] sys_rmdir at ffffffff810f9a95 [ffff880c308e1f80] tracesys at ffffffff813c52db The looping thread is still this one: [ffff880c30049d50] mem_cgroup_reparent_charges at ffffffff810e637b [ffff880c30049de0] mem_cgroup_css_offline at ffffffff810e679d [ffff880c30049e10] offline_css at ffffffff8107f02f [ffff880c30049e30] css_killed_work_fn at ffffffff81080ec2 [ffff880c30049e50] process_one_work at ffffffff8103f7db [ffff880c30049e90] worker_thread at ffffffff8103fc7d [ffff880c30049eb0] worker_thread at ffffffff8103fb39 [ffff880c30049ec8] kthread at ffffffff8104479c [ffff880c30049f28] kthread at ffffffff81044714 [ffff880c30049f50] ret_from_fork at ffffffff813c503c [ffff880c30049f80] kthread at ffffffff81044714 -- To unsubscribe from this list: send the line "unsubscribe cgroups" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
