Hi, thank you for your report. I have some questions. On Fri, 4 Mar 2011 00:03:55 -0800 Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> wrote: > > (switched to email. Please respond via emailed reply-to-all, not via the > bugzilla web interface). > > On Fri, 4 Mar 2011 04:27:26 GMT bugzilla-daemon@xxxxxxxxxxxxxxxxxxx wrote: > > > https://bugzilla.kernel.org/show_bug.cgi?id=30432 > > > > Summary: rmdir on cgroup can cause hang tasks > > Product: Process Management > > Version: 2.5 > > Kernel Version: 2.6.37 > > Platform: All > > OS/Version: Linux > > Tree: Mainline > > Status: NEW > > Severity: high > > Priority: P1 > > Component: Other > > AssignedTo: process_other@xxxxxxxxxxxxxxxxxxxx > > ReportedBy: bugzilla.kernel.org@xxxxxxxxxx > > Regression: No > > > > > > I just got following hang when removing an empty cgroup. I had still a shell in > > the cgroup that got emptied and removed. The shell as well as the release_agent > > and the program managing the cgroup hangs. > > You tried to remove a cgroup directory via release_agent(i.e. you enabled "notify_on_release", and make the release_agent remove the directory)? And can you show your /proc/cgroups ? Thanks, Daisuke Nishimura. > > The directory structure looks like: > > /sys/fs/cgroup/memory/usr_1000/psn_3234 > > > > ls on /sys/fs/cgroup/memory but ls on /sys/fs/cgroup/memory/usr_1000 hangs. > > > > > > [ 5065.280666] SysRq : Changing Loglevel > > [ 5065.282574] Loglevel set to 5 > > [ 5066.139879] SysRq : Show Blocked State > > [ 5066.141848] task PC stack pid father > > [ 5066.141925] zsh D ffff880071520398 0 8719 3589 0x00000084 > > [ 5066.141937] ffff880002059bd8 0000000000000086 ffff880002059bb8 > > ffffffff00000000 > > [ 5066.143971] 00000000000139c0 ffff880071520000 ffff880071520398 > > ffff880002059fd8 > > [ 5066.146049] ffff8800715203a0 00000000000139c0 ffff880002058010 > > 00000000000139c0 > > [ 5066.148183] Call Trace: > > [ 5066.149853] [<ffffffff8158ec97>] __mutex_lock_slowpath+0xf7/0x180 > > [ 5066.149853] [<ffffffff812d74a6>] ? vsnprintf+0x416/0x5a0 > > [ 5066.149853] [<ffffffff8158eb7b>] mutex_lock+0x2b/0x50 > > [ 5066.149853] [<ffffffff81168252>] do_lookup+0x102/0x180 > > [ 5066.149853] [<ffffffff81168dfd>] link_path_walk+0x4dd/0x9e0 > > [ 5066.149853] [<ffffffff81169417>] path_walk+0x67/0xe0 > > [ 5066.149853] [<ffffffff811695eb>] do_path_lookup+0x5b/0xa0 > > [ 5066.149853] [<ffffffff8116a2f7>] user_path_at+0x57/0xa0 > > [ 5066.149853] [<ffffffff815940e0>] ? do_page_fault+0x1f0/0x4f0 > > [ 5066.149853] [<ffffffff81075e6c>] ? kill_pid_info+0x2c/0x60 > > [ 5066.149853] [<ffffffff811604fc>] vfs_fstatat+0x3c/0x80 > > [ 5066.149853] [<ffffffff8116061b>] vfs_stat+0x1b/0x20 > > [ 5066.149853] [<ffffffff81160644>] sys_newstat+0x24/0x50 > > [ 5066.149853] [<ffffffff810bf6ff>] ? audit_syscall_entry+0x1df/0x280 > > [ 5066.149853] [<ffffffff8100c042>] system_call_fastpath+0x16/0x1b > > [ 5066.149853] ulatencyd D ffff88007a0bc7d8 0 9004 4809 0x00000084 > > [ 5066.149853] ffff880070b55cd8 0000000000000082 0000000000000082 > > ffff88002c9d16c0 > > [ 5066.149853] 00000000000139c0 ffff88007a0bc440 ffff88007a0bc7d8 > > ffff880070b55fd8 > > [ 5066.149853] ffff88007a0bc7e0 00000000000139c0 ffff880070b54010 > > 00000000000139c0 > > [ 5066.149853] Call Trace: > > [ 5066.149853] [<ffffffff8158ec97>] __mutex_lock_slowpath+0xf7/0x180 > > [ 5066.149853] [<ffffffff81166124>] ? exec_permission+0x44/0x90 > > [ 5066.149853] [<ffffffff8158eb7b>] mutex_lock+0x2b/0x50 > > [ 5066.149853] [<ffffffff81168418>] do_last+0x148/0x650 > > [ 5066.149853] [<ffffffff8116a6d5>] do_filp_open+0x205/0x5f0 > > [ 5066.149853] [<ffffffff81167281>] ? path_put+0x31/0x40 > > [ 5066.149853] [<ffffffff8117593a>] ? alloc_fd+0x10a/0x150 > > [ 5066.149853] [<ffffffff81159bb9>] do_sys_open+0x69/0x110 > > [ 5066.149853] [<ffffffff81159ca0>] sys_open+0x20/0x30 > > [ 5066.149853] [<ffffffff8100c042>] system_call_fastpath+0x16/0x1b > > [ 5066.149853] lua D ffff88002c91b118 0 9487 1 0x00000080 > > [ 5066.149853] ffff880078f6db08 0000000000000086 ffff88002c91b118 > > ffff880000000000 > > [ 5066.149853] 00000000000139c0 ffff88002c91ad80 ffff88002c91b118 > > ffff880078f6dfd8 > > [ 5066.149853] ffff88002c91b120 00000000000139c0 ffff880078f6c010 > > 00000000000139c0 > > [ 5066.149853] Call Trace: > > [ 5066.149853] [<ffffffff8158e4d5>] schedule_timeout+0x215/0x2f0 > > [ 5066.149853] [<ffffffff8104e4fd>] ? task_rq_lock+0x5d/0xa0 > > [ 5066.149853] [<ffffffff81059c93>] ? try_to_wake_up+0xc3/0x410 > > [ 5066.149853] [<ffffffff8158e0cb>] wait_for_common+0xdb/0x180 > > [ 5066.149853] [<ffffffff81059fe0>] ? default_wake_function+0x0/0x20 > > [ 5066.244366] [<ffffffff8158e24d>] wait_for_completion+0x1d/0x20 > > [ 5066.244366] [<ffffffff810d44f5>] synchronize_sched+0x55/0x60 > > [ 5066.244366] [<ffffffff81080b00>] ? wakeme_after_rcu+0x0/0x20 > > [ 5066.244366] [<ffffffff811526a3>] mem_cgroup_start_move+0x93/0xa0 > > [ 5066.244366] [<ffffffff8115739b>] mem_cgroup_force_empty+0xdb/0x640 > > [ 5066.244366] [<ffffffff81157914>] mem_cgroup_pre_destroy+0x14/0x20 > > [ 5066.244366] [<ffffffff810ae681>] cgroup_rmdir+0xc1/0x560 > > [ 5066.244366] [<ffffffff81083d70>] ? autoremove_wake_function+0x0/0x40 > > [ 5066.244366] [<ffffffff81167cc4>] vfs_rmdir+0xb4/0x110 > > [ 5066.244366] [<ffffffff81169d13>] do_rmdir+0x133/0x140 > > [ 5066.244366] [<ffffffff810d3c85>] ? call_rcu_sched+0x15/0x20 > > [ 5066.244366] [<ffffffff810bf6ff>] ? audit_syscall_entry+0x1df/0x280 > > [ 5066.244366] [<ffffffff81169d76>] sys_rmdir+0x16/0x20 > > [ 5066.244366] [<ffffffff8100c042>] system_call_fastpath+0x16/0x1b > > -- > To unsubscribe, send a message with 'unsubscribe linux-mm' in > the body to majordomo@xxxxxxxxxx For more info on Linux MM, > see: http://www.linux-mm.org/ . > Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ > Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a> -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxxx For more info on Linux MM, see: http://www.linux-mm.org/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>