On Thu, 30 Mar 2023 09:38:22 -0400 Mathieu Desnoyers <mathieu.desnoyers@xxxxxxxxxxxx> wrote: > commit f1a7941243c1 ("mm: convert mm's rss stats into percpu_counter") > introduces a memory leak by missing a call to destroy_context() when a > percpu_counter fails to allocate. > > Before introducing the per-cpu counter allocations, init_new_context() > was the last call that could fail in mm_init(), and thus there was no > need to ever invoke destroy_context() in the error paths. Adding the > following percpu counter allocations adds error paths after > init_new_context(), which means its associated destroy_context() needs > to be called when percpu counters fail to allocate. > > ... > > --- a/kernel/fork.c > +++ b/kernel/fork.c > @@ -1171,6 +1171,7 @@ static struct mm_struct *mm_init(struct mm_struct *mm, struct task_struct *p, > fail_pcpu: > while (i > 0) > percpu_counter_destroy(&mm->rss_stat[--i]); > + destroy_context(mm); > fail_nocontext: > mm_free_pgd(mm); > fail_nopgd: Is there really a leak? I wasn't able to find a version of init_new_context() which performs allocation.