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authorLinus Torvalds <torvalds@linux-foundation.org>2019-09-13 09:52:01 +0100
committerLinus Torvalds <torvalds@linux-foundation.org>2019-09-13 09:52:01 +0100
commita7f89616b7376495424f682b6086e0c391a89a1d (patch)
tree55cf3b4ccb41880d6d0282f91370bffddf33c320
parent1b304a1ae45de4df7d773f0a39d1100aabca615b (diff)
parent97a61369830ab085df5aed0ff9256f35b07d425a (diff)
Merge branch 'for-5.3-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup
Pull cgroup fix from Tejun Heo: "Roman found and fixed a bug in the cgroup2 freezer which allows new child cgroup to escape frozen state" * 'for-5.3-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup: cgroup: freezer: fix frozen state inheritance kselftests: cgroup: add freezer mkdir test
-rw-r--r--kernel/cgroup/cgroup.c10
-rw-r--r--tools/testing/selftests/cgroup/test_freezer.c54
2 files changed, 63 insertions, 1 deletions
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)) {
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
@@ -448,6 +448,59 @@ cleanup:
}
/*
+ * 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
* remains frozen and it's possible to create a new child
@@ -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),