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| author | Linus Torvalds <torvalds@linux-foundation.org> | 2017-04-11 23:38:16 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2017-04-11 23:38:16 -0700 |
| commit | 06ea4c38bce80f3eb99b01d7c17419eb1a49fec2 (patch) | |
| tree | 2af3797bce33f38ecfe39aa34ecec01e8ccd4b9c /kernel/cgroup/cgroup-v1.c | |
| parent | af94bdfa798b7da92cc82609acca61a287a004a4 (diff) | |
| parent | bfb0b80db5f9dca5ac0a5fd0edb765ee555e5a8e (diff) | |
Merge branch 'for-4.11-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup
Pull cgroup fixes from Tejun Heo:
"This contains fixes for two long standing subtle bugs:
- kthread_bind() on a new kthread binds it to specific CPUs and
prevents userland from messing with the affinity or cgroup
membership. Unfortunately, for cgroup membership, there's a window
between kthread creation and kthread_bind*() invocation where the
kthread can be moved into a non-root cgroup by userland.
Depending on what controllers are in effect, this can assign the
kthread unexpected attributes. For example, in the reported case,
workqueue workers ended up in a non-root cpuset cgroups and had
their CPU affinities overridden. This broke workqueue invariants
and led to workqueue stalls.
Fixed by closing the window between kthread creation and
kthread_bind() as suggested by Oleg.
- There was a bug in cgroup mount path which could allow two
competing mount attempts to attach the same cgroup_root to two
different superblocks.
This was caused by mishandling return value from kernfs_pin_sb().
Fixed"
* 'for-4.11-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup:
cgroup: avoid attaching a cgroup root to two different superblocks
cgroup, kthread: close race window where new kthreads can be migrated to non-root cgroups
Diffstat (limited to 'kernel/cgroup/cgroup-v1.c')
| -rw-r--r-- | kernel/cgroup/cgroup-v1.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/kernel/cgroup/cgroup-v1.c b/kernel/cgroup/cgroup-v1.c index 1dc22f6b49f5..12e19f0636ea 100644 --- a/kernel/cgroup/cgroup-v1.c +++ b/kernel/cgroup/cgroup-v1.c @@ -1146,7 +1146,7 @@ struct dentry *cgroup1_mount(struct file_system_type *fs_type, int flags, * path is super cold. Let's just sleep a bit and retry. */ pinned_sb = kernfs_pin_sb(root->kf_root, NULL); - if (IS_ERR(pinned_sb) || + if (IS_ERR_OR_NULL(pinned_sb) || !percpu_ref_tryget_live(&root->cgrp.self.refcnt)) { mutex_unlock(&cgroup_mutex); if (!IS_ERR_OR_NULL(pinned_sb)) |