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| author | Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> | 2022-08-25 11:38:38 +0300 |
|---|---|---|
| committer | Tejun Heo <tj@kernel.org> | 2022-08-25 20:36:30 +0300 |
| commit | 43626dade36fa74d3329046f4ae2d7fdefe401c6 (patch) | |
| tree | 06f2784c54257714e1576003999fae747af04df7 | |
| parent | 763f4fb76e24959c370cdaa889b2492ba6175580 (diff) | |
| download | linux-43626dade36fa74d3329046f4ae2d7fdefe401c6.tar.xz | |
cgroup: Add missing cpus_read_lock() to cgroup_attach_task_all()
syzbot is hitting percpu_rwsem_assert_held(&cpu_hotplug_lock) warning at
cpuset_attach() [1], for commit 4f7e7236435ca0ab ("cgroup: Fix
threadgroup_rwsem <-> cpus_read_lock() deadlock") missed that
cpuset_attach() is also called from cgroup_attach_task_all().
Add cpus_read_lock() like what cgroup_procs_write_start() does.
Link: https://syzkaller.appspot.com/bug?extid=29d3a3b4d86c8136ad9e [1]
Reported-by: syzbot <syzbot+29d3a3b4d86c8136ad9e@syzkaller.appspotmail.com>
Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Fixes: 4f7e7236435ca0ab ("cgroup: Fix threadgroup_rwsem <-> cpus_read_lock() deadlock")
Signed-off-by: Tejun Heo <tj@kernel.org>
| -rw-r--r-- | kernel/cgroup/cgroup-v1.c | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/kernel/cgroup/cgroup-v1.c b/kernel/cgroup/cgroup-v1.c index 2ade21b54dc4..ff6a8099eb2a 100644 --- a/kernel/cgroup/cgroup-v1.c +++ b/kernel/cgroup/cgroup-v1.c @@ -59,6 +59,7 @@ int cgroup_attach_task_all(struct task_struct *from, struct task_struct *tsk) int retval = 0; mutex_lock(&cgroup_mutex); + cpus_read_lock(); percpu_down_write(&cgroup_threadgroup_rwsem); for_each_root(root) { struct cgroup *from_cgrp; @@ -72,6 +73,7 @@ int cgroup_attach_task_all(struct task_struct *from, struct task_struct *tsk) break; } percpu_up_write(&cgroup_threadgroup_rwsem); + cpus_read_unlock(); mutex_unlock(&cgroup_mutex); return retval; |