Committed to rh10-6.12.0-211.30.1.14.3.vz10. On 7/8/26 12:56, Vladimir Riabchun wrote: > When creating a container with a lockdep enabled, there is a warning: > [ 177.055606] WARNING: CPU: 2 PID: 6013 at kernel/cgroup/cgroup.c:3050 > cgroup_migrate_add_src+0xe4/0x4d0 > [ 177.057199] Modules linked in: ... > [ 177.069734] CPU: 2 UID: 0 PID: 6013 Comm: vzctl ve: 123 Kdump: loaded Not > tainted 6.12.0-211.16.1.12.10.ovz10-v2 #2 12.10.ovz10 PREEMPT(voluntary) > [ 177.071838] Hardware name: Acronis OpenStack Compute/Virtuozzo, BIOS > 1.16.1-1.vz9.2 04/01/2014 > [ 177.073190] RIP: 0010:cgroup_migrate_add_src+0xe4/0x4d0 > [ 177.074016] Code: 00 00 48 83 c4 10 5b 5d 41 5c 41 5d 41 5e 41 5f e9 11 ba > 61 02 be ff ff ff ff 48 c7 c7 10 c5 47 9e e8 f0 23 5f 02 85 c0 75 02 <0f> 0b > 48 b8 00 00 00 00 00 fc ff df 48 89 ea 83 e5 07 48 c1 ea 03 > [ 177.076731] RSP: 0018:ffffc900054777f8 EFLAGS: 00010046 > [ 177.077560] RAX: 0000000000000000 RBX: ffff88813ad28800 RCX: > 0000000000000001 > [ 177.078736] RDX: 0000000000000046 RSI: ffffffff9d4f3310 RDI: > ffffffff9cbd1440 > [ 177.079831] RBP: ffffffff9ed162b4 R08: 0000000000000000 R09: > 0000000000000006 > [ 177.080969] R10: 0000000000000000 R11: 0000000000000001 R12: > ffffc900054778b0 > [ 177.082029] R13: ffff88819b2e6000 R14: ffff88819b2e6000 R15: > ffff88858f118000 > [ 177.083078] FS: 00007f0172bdc600(0000) GS:ffff88875e400000(0000) > knlGS:0000000000000000 > [ 177.084316] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > [ 177.085204] CR2: 00007ffe60f65cc8 CR3: 00000001b52ae006 CR4: > 00000000003726f0 > [ 177.086271] Call Trace: > [ 177.086735] <TASK> > [ 177.096467] ? cgroup_migrate_add_src+0xe0/0x4d0 > [ 177.097217] cgroup_attach_task+0x1a0/0x560 > [ 177.100947] ve_start_container+0x7f8/0xbd0 > [ 177.101731] ve_state_write+0x5b/0x80 > [ 177.102369] cgroup_file_write+0x2c6/0x740 > [ 177.106910] kernfs_fop_write_iter+0x3df/0x5f0 > [ 177.107638] vfs_write+0x5fd/0xe90 > [ 177.112378] ksys_write+0xfb/0x1d0 > [ 177.114393] do_syscall_64+0x92/0x180 > [ 177.123132] entry_SYSCALL_64_after_hwframe+0x76/0x7e > [ 177.123955] RIP: 0033:0x7f01737d7954 > [ 177.124604] Code: c7 00 16 00 00 00 b8 ff ff ff ff c3 66 2e 0f 1f 84 00 00 > 00 00 00 f3 0f 1e fa 80 3d 75 d7 0d 00 00 74 13 b8 01 00 00 00 0f 05 <48> 3d > 00 f0 ff ff 77 54 c3 0f 1f 00 48 83 ec 28 48 89 54 24 18 48 > [ 177.127297] RSP: 002b:00007ffe60f67da8 EFLAGS: 00000202 ORIG_RAX: > 0000000000000001 > [ 177.128471] RAX: ffffffffffffffda RBX: 0000000000000005 RCX: > 00007f01737d7954 > [ 177.129527] RDX: 0000000000000005 RSI: 00007f0173916081 RDI: > 000000000000000b > [ 177.130579] RBP: 000000000000000b R08: 0000000000000073 R09: > 00000000ffffffff > [ 177.131636] R10: 0000000000000000 R11: 0000000000000202 R12: > 00007f0173916081 > [ 177.132756] R13: 00007ffe60f67e10 R14: 00007ffe60f68ea0 R15: > 0000556be8eeb1b0 > [ 177.133851] </TASK> > [ 177.134301] irq event stamp: 2964 > [ 177.134903] hardirqs last enabled at (2963): [<ffffffff9c4dd717>] > _raw_spin_unlock_irqrestore+0x57/0x80 > [ 177.136366] hardirqs last disabled at (2964): [<ffffffff9c4dd310>] > _raw_spin_lock_irq+0x60/0x90 > [ 177.137686] softirqs last enabled at (2916): [<ffffffff99b16a07>] > handle_softirqs+0x397/0x540 > [ 177.138987] softirqs last disabled at (2907): [<ffffffff99b16d3d>] > __irq_exit_rcu+0xfd/0x250 > [ 177.140263] ---[ end trace 0000000000000000 ]--- > > This is caused by cgroup_leave_vz_slice calling cgroup_attach_task > without cgroup_lock. cgroup_join_vz_slice doesn't have this issue > because cgroup_kn_lock_live implicitly takes cgroup_lock. > Protect cgroup_attach_task call in cgroup_leave_vz_slice with the > same mutex. > > One more issue, found by Pavel Tikhomirov, is missing > cgroup_attach_lock. > cgroup_attach_task requires cgroup_threadgroup_rwsem being held, which > is not done in both cgroup_join_vz_slice and cgroup_leave_vz_slice. > > This requirement is described in cgroup_attach_lock comment, and > in kernel code all calls to cgroup_attach_task are protected by > cgroup_attach_lock: > - __cgroup[1]_procs_write: lock taken by cgroup_procs_write_start > - cgroup_attach_task_all: explicit lock > > Do it in our code as well. > > https://virtuozzo.atlassian.net/browse/VSTOR-136835 > > Feature: debug kernel > Fixes: 20a5affcf263 ("ve/cgroup: add vz.slice cgroup to put kernel threads > to") > Signed-off-by: Vladimir Riabchun <[email protected]> > --- > Changes since v1: > - Protected both vz-related cgroup_attach_task calls with > cgroup_attach_lock. > > kernel/cgroup/cgroup.c | 10 +++++++++- > 1 file changed, 9 insertions(+), 1 deletion(-) > > diff --git a/kernel/cgroup/cgroup.c b/kernel/cgroup/cgroup.c > index 5585545304a3..4db77090f1be 100644 > --- a/kernel/cgroup/cgroup.c > +++ b/kernel/cgroup/cgroup.c > @@ -2276,7 +2276,9 @@ int cgroup_join_vz_slice(struct ve_struct *ve) > return -ENODEV; > } > > + cgroup_attach_lock(true); > ret = cgroup_attach_task(cgrp, current, true); > + cgroup_attach_unlock(true); > cgroup_kn_unlock(kn); > kernfs_put(kn); > return ret; > @@ -2286,6 +2288,7 @@ int cgroup_leave_vz_slice(struct ve_struct *ve) > { > struct css_set *cset; > struct cgroup *cgrp; > + int ret; > > cset = rcu_dereference_protected(ve->ve_nsproxy, > 1)->cgroup_ns->root_cset; > cgrp = __cset_cgroup_from_root(cset, &cgrp_dfl_root); > @@ -2294,7 +2297,12 @@ int cgroup_leave_vz_slice(struct ve_struct *ve) > !test_bit(CGRP_VE_ROOT, &cgrp->flags)) > return 0; > > - return cgroup_attach_task(cgrp, current, true); > + cgroup_lock(); > + cgroup_attach_lock(true); > + ret = cgroup_attach_task(cgrp, current, true); > + cgroup_attach_unlock(true); > + cgroup_unlock(); > + return ret; > } > > struct cgroup_subsys_state *css_ve_root1(struct cgroup_subsys_state *css)
-- Best regards, Pavel Tikhomirov Senior Software Developer, Virtuozzo. _______________________________________________ Devel mailing list [email protected] https://lists.openvz.org/mailman/listinfo/devel
