mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-10-28 15:20:41 +00:00
blkcg: blkcg_css_alloc() should grab blkcg_pol_mutex while iterating blkcg_policy[]
An entry in blkcg_policy[] is stable while there are non-bypassing
in-flight IOs on a request_queue which has the policy activated. This
is why most derefs of blkcg_policy[] don't need explicit locking;
however, blkcg_css_alloc() isn't invoked from IO path and thus doesn't
have this protection and may race policies being added and removed.
Fix it by adding explicit blkcg_pol_mutex protection around
blkcg_policy[] iteration in blkcg_css_alloc().
Signed-off-by: Tejun Heo <tj@kernel.org>
Fixes: e48453c386
("block, cgroup: implement policy-specific per-blkcg data")
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: Arianna Avanzini <avanzini.arianna@gmail.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
This commit is contained in:
parent
838f13bf4b
commit
144232b342
1 changed files with 4 additions and 0 deletions
|
@ -844,6 +844,8 @@ blkcg_css_alloc(struct cgroup_subsys_state *parent_css)
|
||||||
goto free_blkcg;
|
goto free_blkcg;
|
||||||
}
|
}
|
||||||
|
|
||||||
|
mutex_lock(&blkcg_pol_mutex);
|
||||||
|
|
||||||
for (i = 0; i < BLKCG_MAX_POLS ; i++) {
|
for (i = 0; i < BLKCG_MAX_POLS ; i++) {
|
||||||
struct blkcg_policy *pol = blkcg_policy[i];
|
struct blkcg_policy *pol = blkcg_policy[i];
|
||||||
struct blkcg_policy_data *cpd;
|
struct blkcg_policy_data *cpd;
|
||||||
|
@ -860,6 +862,7 @@ blkcg_css_alloc(struct cgroup_subsys_state *parent_css)
|
||||||
BUG_ON(blkcg->pd[i]);
|
BUG_ON(blkcg->pd[i]);
|
||||||
cpd = kzalloc(pol->cpd_size, GFP_KERNEL);
|
cpd = kzalloc(pol->cpd_size, GFP_KERNEL);
|
||||||
if (!cpd) {
|
if (!cpd) {
|
||||||
|
mutex_unlock(&blkcg_pol_mutex);
|
||||||
ret = ERR_PTR(-ENOMEM);
|
ret = ERR_PTR(-ENOMEM);
|
||||||
goto free_pd_blkcg;
|
goto free_pd_blkcg;
|
||||||
}
|
}
|
||||||
|
@ -868,6 +871,7 @@ blkcg_css_alloc(struct cgroup_subsys_state *parent_css)
|
||||||
pol->cpd_init_fn(blkcg);
|
pol->cpd_init_fn(blkcg);
|
||||||
}
|
}
|
||||||
|
|
||||||
|
mutex_unlock(&blkcg_pol_mutex);
|
||||||
done:
|
done:
|
||||||
spin_lock_init(&blkcg->lock);
|
spin_lock_init(&blkcg->lock);
|
||||||
INIT_RADIX_TREE(&blkcg->blkg_tree, GFP_ATOMIC);
|
INIT_RADIX_TREE(&blkcg->blkg_tree, GFP_ATOMIC);
|
||||||
|
|
Loading…
Reference in a new issue