* [PATCH 1/2] kselftests: cgroup: add freezer mkdir test
@ 2019-09-12 17:56 Roman Gushchin
2019-09-12 17:56 ` [PATCH 2/2] cgroup: freezer: fix frozen state inheritance Roman Gushchin
0 siblings, 1 reply; 3+ messages in thread
From: Roman Gushchin @ 2019-09-12 17:56 UTC (permalink / raw)
To: Tejun Heo, cgroups
Cc: linux-kernel, kernel-team, Mark Crossen, Roman Gushchin, Shuah Khan
Add a new cgroup freezer selftest, which checks that if a cgroup is
frozen, their new child cgroups will properly inherit the frozen
state.
It creates a parent cgroup, freezes it, creates a child cgroup
and populates it with a dummy process. Then it checks that both
parent and child cgroup are frozen.
Signed-off-by: Roman Gushchin <guro@fb.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Shuah Khan <shuah@kernel.org>
---
tools/testing/selftests/cgroup/test_freezer.c | 54 +++++++++++++++++++
1 file changed, 54 insertions(+)
diff --git a/tools/testing/selftests/cgroup/test_freezer.c b/tools/testing/selftests/cgroup/test_freezer.c
index 8219a30853d2..0fc1b6d4b0f9 100644
--- a/tools/testing/selftests/cgroup/test_freezer.c
+++ b/tools/testing/selftests/cgroup/test_freezer.c
@@ -447,6 +447,59 @@ static int test_cgfreezer_forkbomb(const char *root)
return ret;
}
+/*
+ * The test creates a cgroups and freezes it. Then it creates a child cgroup
+ * and populates it with a task. After that it checks that the child cgroup
+ * is frozen and the parent cgroup remains frozen too.
+ */
+static int test_cgfreezer_mkdir(const char *root)
+{
+ int ret = KSFT_FAIL;
+ char *parent, *child = NULL;
+ int pid;
+
+ parent = cg_name(root, "cg_test_mkdir_A");
+ if (!parent)
+ goto cleanup;
+
+ child = cg_name(parent, "cg_test_mkdir_B");
+ if (!child)
+ goto cleanup;
+
+ if (cg_create(parent))
+ goto cleanup;
+
+ if (cg_freeze_wait(parent, true))
+ goto cleanup;
+
+ if (cg_create(child))
+ goto cleanup;
+
+ pid = cg_run_nowait(child, child_fn, NULL);
+ if (pid < 0)
+ goto cleanup;
+
+ if (cg_wait_for_proc_count(child, 1))
+ goto cleanup;
+
+ if (cg_check_frozen(child, true))
+ goto cleanup;
+
+ if (cg_check_frozen(parent, true))
+ goto cleanup;
+
+ ret = KSFT_PASS;
+
+cleanup:
+ if (child)
+ cg_destroy(child);
+ free(child);
+ if (parent)
+ cg_destroy(parent);
+ free(parent);
+ return ret;
+}
+
/*
* The test creates two nested cgroups, freezes the parent
* and removes the child. Then it checks that the parent cgroup
@@ -815,6 +868,7 @@ struct cgfreezer_test {
T(test_cgfreezer_simple),
T(test_cgfreezer_tree),
T(test_cgfreezer_forkbomb),
+ T(test_cgfreezer_mkdir),
T(test_cgfreezer_rmdir),
T(test_cgfreezer_migrate),
T(test_cgfreezer_ptrace),
--
2.21.0
^ permalink raw reply related [flat|nested] 3+ messages in thread
* [PATCH 2/2] cgroup: freezer: fix frozen state inheritance
2019-09-12 17:56 [PATCH 1/2] kselftests: cgroup: add freezer mkdir test Roman Gushchin
@ 2019-09-12 17:56 ` Roman Gushchin
2019-09-12 21:07 ` Tejun Heo
0 siblings, 1 reply; 3+ messages in thread
From: Roman Gushchin @ 2019-09-12 17:56 UTC (permalink / raw)
To: Tejun Heo, cgroups
Cc: linux-kernel, kernel-team, Mark Crossen, Roman Gushchin, stable
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>
Cc: Tejun Heo <tj@kernel.org>
Cc: stable@vger.kernel.org
---
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 753afbca549f..8be1da1ebd9a 100644
--- a/kernel/cgroup/cgroup.c
+++ b/kernel/cgroup/cgroup.c
@@ -5255,8 +5255,16 @@ 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)) {
--
2.21.0
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH 2/2] cgroup: freezer: fix frozen state inheritance
2019-09-12 17:56 ` [PATCH 2/2] cgroup: freezer: fix frozen state inheritance Roman Gushchin
@ 2019-09-12 21:07 ` Tejun Heo
0 siblings, 0 replies; 3+ messages in thread
From: Tejun Heo @ 2019-09-12 21:07 UTC (permalink / raw)
To: Roman Gushchin; +Cc: cgroups, linux-kernel, kernel-team, Mark Crossen, stable
Applied 1-2 to cgroup/for-5.3-fixes.
Thanks.
--
tejun
^ permalink raw reply [flat|nested] 3+ messages in thread
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2019-09-12 21:07 ` Tejun Heo
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