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| author | Tejun Heo <tj@kernel.org> | 2022-08-16 01:27:38 +0200 |
|---|---|---|
| committer | Tejun Heo <tj@kernel.org> | 2022-08-17 19:36:05 +0200 |
| commit | 4f7e7236435ca0abe005c674ebd6892c6e83aeb3 (patch) | |
| tree | 35e9a5ce25341e6348141027edc1b4bfa141802c /kernel/padata.c | |
| parent | sched/psi: Remove redundant cgroup_psi() when !CONFIG_CGROUPS (diff) | |
| download | linux-4f7e7236435ca0abe005c674ebd6892c6e83aeb3.tar.xz linux-4f7e7236435ca0abe005c674ebd6892c6e83aeb3.zip | |
cgroup: Fix threadgroup_rwsem <-> cpus_read_lock() deadlock
Bringing up a CPU may involve creating and destroying tasks which requires
read-locking threadgroup_rwsem, so threadgroup_rwsem nests inside
cpus_read_lock(). However, cpuset's ->attach(), which may be called with
thredagroup_rwsem write-locked, also wants to disable CPU hotplug and
acquires cpus_read_lock(), leading to a deadlock.
Fix it by guaranteeing that ->attach() is always called with CPU hotplug
disabled and removing cpus_read_lock() call from cpuset_attach().
Signed-off-by: Tejun Heo <tj@kernel.org>
Reviewed-and-tested-by: Imran Khan <imran.f.khan@oracle.com>
Reported-and-tested-by: Xuewen Yan <xuewen.yan@unisoc.com>
Fixes: 05c7b7a92cc8 ("cgroup/cpuset: Fix a race between cpuset_attach() and cpu hotplug")
Cc: stable@vger.kernel.org # v5.17+
Diffstat (limited to 'kernel/padata.c')
0 files changed, 0 insertions, 0 deletions