[Devel] [PATCH vz10 v2] ve: set proper VE state on ve_create() error

[Konstantin Khorenko]

If we fail to alloc ve_struct, we'll crash here on setting VE state.

Moving ve_set_state() earlier makes err_ve: label redundant,
so get rid of it according to coding style rules.

Also let's set VE_STATE_DEAD state right before freeing ve_struct
instead of VE_STATE_STOPPED, it will be more logical to see _DEAD state
in the freed/not used memory and it corresponds to other cases when
VE_STATE_DEAD is set:

ve_start_container()
err handling:
        ve_set_state(ve, VE_STATE_STOPPED);
        ve_drop_context(ve); // not freeing memory

ve_exit_ns
        ve_set_state(ve, VE_STATE_STOPPED);
        put_ve(ve); /* from ve_start_container() */
        // no memory free here, only later in ve_destroy()

ve_destroy
        ve_set_state(ve, VE_STATE_DEAD);
        kmem_cache_free(ve_cachep, ve); // freeing memory

ve_create
err handling:
        ve_set_state(ve, VE_STATE_DEAD); // logical to use _DEAD here
        kmem_cache_free(ve_cachep, ve);  // freeing memory as well

Fixes: 666e40b308457 ("ve/cgroups: Drop lock when stopping workqueue to
avoid dead lock")
Signed-off-by: Konstantin Khorenko <khore...@virtuozzo.com>

Feature: ve: ve generic structures
---
v2:
  * drop err_ve: label

 kernel/ve/ve.c | 8 +++-----
 1 file changed, 3 insertions(+), 5 deletions(-)

diff --git a/kernel/ve/ve.c b/kernel/ve/ve.c
index 146f7922d4856..663c1c2255621 100644
--- a/kernel/ve/ve.c
+++ b/kernel/ve/ve.c
@@ -951,10 +951,9 @@ static struct cgroup_subsys_state *ve_create(struct 
cgroup_subsys_state *parent_
        if (css_to_ve(parent_css) != &ve0)
                return ERR_PTR(-ENOTDIR);
 
-       err = -ENOMEM;
        ve = kmem_cache_zalloc(ve_cachep, GFP_KERNEL);
        if (!ve)
-               goto err_ve;
+               return ERR_PTR(-ENOMEM);
 
        ve->sched_lat_ve.cur = alloc_percpu(struct kstat_lat_pcpu_snap_struct);
        if (!ve->sched_lat_ve.cur)
@@ -1019,7 +1018,6 @@ static struct cgroup_subsys_state *ve_create(struct 
cgroup_subsys_state *parent_
        ve->aio_nr = 0;
        ve->aio_max_nr = AIO_MAX_NR_DEFAULT;
 #endif
-
        return &ve->css;
 
 err_vdso:
@@ -1028,9 +1026,9 @@ static struct cgroup_subsys_state *ve_create(struct 
cgroup_subsys_state *parent_
 err_log:
        free_percpu(ve->sched_lat_ve.cur);
 err_lat:
+       ve_set_state(ve, VE_STATE_DEAD);
        kmem_cache_free(ve_cachep, ve);
-err_ve:
-       ve_set_state(ve, VE_STATE_STOPPED);
+
        return ERR_PTR(err);
 }
 
-- 
2.43.0

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