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JP Kobryn
eea51c6e3f
css_rstat_exit() may be called asynchronously in scenarios where preceding
calls to css_rstat_init() have not completed. One such example is this
sequence below:
css_create(...)
{
...
init_and_link_css(css, ...);
err = percpu_ref_init(...);
if (err)
goto err_free_css;
err = cgroup_idr_alloc(...);
if (err)
goto err_free_css;
err = css_rstat_init(css, ...);
if (err)
goto err_free_css;
...
err_free_css:
INIT_RCU_WORK(&css->destroy_rwork, css_free_rwork_fn);
queue_rcu_work(cgroup_destroy_wq, &css->destroy_rwork);
return ERR_PTR(err);
}
If any of the three goto jumps are taken, async cleanup will begin and
css_rstat_exit() will be invoked on an uninitialized css->rstat_cpu.
Avoid accessing the unitialized field by returning early in
css_rstat_exit() if this is the case.
Signed-off-by: JP Kobryn <[email protected]>
Suggested-by: Michal Koutný <[email protected]>
Fixes: 5da3bfa029 ("cgroup: use separate rstat trees for each subsystem")
Cc: [email protected] # v6.16
Reported-by: [email protected]
Acked-by: Shakeel Butt <[email protected]>
Signed-off-by: Tejun Heo <[email protected]>