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| author | Roman Gushchin <guro@fb.com> | 2019-09-12 10:56:45 -0700 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2019-09-19 09:10:54 +0200 |
| commit | c554749c3f7e5dbda85642ffa0122e136c582960 (patch) | |
| tree | 9288171db6b2480af93740b76d940e0535c82607 /kernel | |
| parent | 4fa875f06c4352d0d8c3564b33cf9605bc8d19b8 (diff) | |
| download | linux-stable-c554749c3f7e5dbda85642ffa0122e136c582960.tar.gz linux-stable-c554749c3f7e5dbda85642ffa0122e136c582960.tar.bz2 linux-stable-c554749c3f7e5dbda85642ffa0122e136c582960.zip | |
cgroup: freezer: fix frozen state inheritance
commit 97a61369830ab085df5aed0ff9256f35b07d425a upstream.
If a new child cgroup is created in the frozen cgroup hierarchy
(one or more of ancestor cgroups is frozen), the CGRP_FREEZE cgroup
flag should be set. Otherwise if a process will be attached to the
child cgroup, it won't become frozen.
The problem can be reproduced with the test_cgfreezer_mkdir test.
This is the output before this patch:
~/test_freezer
ok 1 test_cgfreezer_simple
ok 2 test_cgfreezer_tree
ok 3 test_cgfreezer_forkbomb
Cgroup /sys/fs/cgroup/cg_test_mkdir_A/cg_test_mkdir_B isn't frozen
not ok 4 test_cgfreezer_mkdir
ok 5 test_cgfreezer_rmdir
ok 6 test_cgfreezer_migrate
ok 7 test_cgfreezer_ptrace
ok 8 test_cgfreezer_stopped
ok 9 test_cgfreezer_ptraced
ok 10 test_cgfreezer_vfork
And with this patch:
~/test_freezer
ok 1 test_cgfreezer_simple
ok 2 test_cgfreezer_tree
ok 3 test_cgfreezer_forkbomb
ok 4 test_cgfreezer_mkdir
ok 5 test_cgfreezer_rmdir
ok 6 test_cgfreezer_migrate
ok 7 test_cgfreezer_ptrace
ok 8 test_cgfreezer_stopped
ok 9 test_cgfreezer_ptraced
ok 10 test_cgfreezer_vfork
Reported-by: Mark Crossen <mcrossen@fb.com>
Signed-off-by: Roman Gushchin <guro@fb.com>
Fixes: 76f969e8948d ("cgroup: cgroup v2 freezer")
Cc: Tejun Heo <tj@kernel.org>
Cc: stable@vger.kernel.org # v5.2+
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/cgroup/cgroup.c | 10 |
1 files changed, 9 insertions, 1 deletions
diff --git a/kernel/cgroup/cgroup.c b/kernel/cgroup/cgroup.c index bf9dbffd46b1..d2cba714d3ee 100644 --- a/kernel/cgroup/cgroup.c +++ b/kernel/cgroup/cgroup.c @@ -5213,8 +5213,16 @@ static struct cgroup *cgroup_create(struct cgroup *parent) * if the parent has to be frozen, the child has too. */ cgrp->freezer.e_freeze = parent->freezer.e_freeze; - if (cgrp->freezer.e_freeze) + if (cgrp->freezer.e_freeze) { + /* + * Set the CGRP_FREEZE flag, so when a process will be + * attached to the child cgroup, it will become frozen. + * At this point the new cgroup is unpopulated, so we can + * consider it frozen immediately. + */ + set_bit(CGRP_FREEZE, &cgrp->flags); set_bit(CGRP_FROZEN, &cgrp->flags); + } spin_lock_irq(&css_set_lock); for (tcgrp = cgrp; tcgrp; tcgrp = cgroup_parent(tcgrp)) { |