Re: [PATCH 6/8] cgroup: mount cgroupns-root when inside non-init cgroupns
From: Sergey Senozhatsky <hidden>
Date: 2015-12-31 13:40:04
Also in:
cgroups, linux-next, lkml
On (12/22/15 22:23), serge.hallyn-GeWIH/nMZzLQT0dZR+AlfA@public.gmane.org wrote: [..]
quoted hunk ↗ jump to hunk
root = kzalloc(sizeof(*root), GFP_KERNEL); if (!root) { ret = -ENOMEM;@@ -2124,12 +2143,30 @@ out_free: kfree(opts.release_agent); kfree(opts.name); - if (ret) + if (ret) { + put_cgroup_ns(ns); return ERR_PTR(ret); + } out_mount: dentry = kernfs_mount(fs_type, flags, root->kf_root, is_v2 ? CGROUP2_SUPER_MAGIC : CGROUP_SUPER_MAGIC, &new_sb); + + /* + * In non-init cgroup namespace, instead of root cgroup's + * dentry, we return the dentry corresponding to the + * cgroupns->root_cgrp. + */ + if (!IS_ERR(dentry) && ns != &init_cgroup_ns) { + struct dentry *nsdentry; + struct cgroup *cgrp; + + cgrp = cset_cgroup_from_root(ns->root_cset, root); + nsdentry = kernfs_node_dentry(cgrp->kn, dentry->d_sb); + dput(dentry); + dentry = nsdentry; + } + if (IS_ERR(dentry) || !new_sb) cgroup_put(&root->cgrp);@@ -2142,6 +2179,7 @@ out_mount: deactivate_super(pinned_sb); } + put_cgroup_ns(ns); return dentry; }
Hello, didn't investigate, just let you know that I'm seeing some warning on linux-next 20151231 1159 is lockdep_assert_held(&css_set_lock) [ 2.880978] WARNING: CPU: 1 PID: 198 at kernel/cgroup.c:1159 cset_cgroup_from_root+0xa8/0xaf() [ 2.880981] Modules linked in: mousedev arc4 nls_iso8859_1 nls_cp437 vfat fat serio_raw iwlmvm psmouse i915 atkbd mac80211 libps2 mxm_wmi i2c_algo_bit drm_kms_helper coretemp cfbfillrect iwlwifi syscopyarea hwmon cfbimgblt crc32c_intel sysfillrect sysimgblt fb_sys_fops cfg80211 ie31200_edac cfbcopyarea evdev r8169 lpc_ich drm i2c_i801 mii intel_gtt edac_core i2c_core mfd_core thermal video i8042 wmi serio button acpi_cpufreq ext4 crc16 mbcache jbd2 sd_mod ehci_pci ehci_hcd ahci libahci libata xhci_pci scsi_mod xhci_hcd usbcore usb_common [ 2.881040] CPU: 1 PID: 198 Comm: kworker/1:2 Tainted: G W 4.4.0-rc7-next-20151231-dbg-00012-gc1e64b7-dirty #316 [ 2.881045] Workqueue: events cgroup_release_agent [ 2.881048] 0000000000000000 ffff88041b7f3cb8 ffffffff811e8bc6 0000000000000000 [ 2.881053] ffff88041b7f3cf0 ffffffff81040889 ffffffff810b2d27 ffffffff8163f3c0 [ 2.881057] ffff88041cc84000 ffff88041b7c0000 ffff88042fa58a00 ffff88041b7f3d00 [ 2.881062] Call Trace: [ 2.881068] [<ffffffff811e8bc6>] dump_stack+0x4b/0x63 [ 2.881073] [<ffffffff81040889>] warn_slowpath_common+0x99/0xb2 [ 2.881076] [<ffffffff810b2d27>] ? cset_cgroup_from_root+0xa8/0xaf [ 2.881080] [<ffffffff81040955>] warn_slowpath_null+0x1a/0x1c [ 2.881083] [<ffffffff810b2d27>] cset_cgroup_from_root+0xa8/0xaf [ 2.881086] [<ffffffff810b58a4>] cgroup_path+0x51/0x83 [ 2.881090] [<ffffffff810b59fa>] cgroup_release_agent+0x75/0xed [ 2.881094] [<ffffffff810566ea>] process_one_work+0x292/0x54b [ 2.881098] [<ffffffff81057826>] worker_thread+0x291/0x383 [ 2.881102] [<ffffffff81057595>] ? rescuer_thread+0x2cf/0x2cf [ 2.881105] [<ffffffff8105c603>] kthread+0xf8/0x100 [ 2.881108] [<ffffffff8105c50b>] ? kthread_create_on_node+0x1c7/0x1c7 [ 2.881114] [<ffffffff813b71bf>] ret_from_fork+0x3f/0x70 [ 2.881117] [<ffffffff8105c50b>] ? kthread_create_on_node+0x1c7/0x1c7 [ 2.881119] ---[ end trace aa407df654d6b05d ]--- -ss