Hello Shakeel Butt,
Commit ad80273d43b7 ("memcg: replace memcg ID idr with xarray") from
Aug 9, 2024 (linux-next), leads to the following Smatch static
checker warning:
mm/memcontrol.c:3592 mem_cgroup_alloc()
warn: passing zero to 'ERR_PTR'
mm/memcontrol.c
3525 static struct mem_cgroup *mem_cgroup_alloc(struct mem_cgroup *parent)
3526 {
3527 struct memcg_vmstats_percpu *statc, *pstatc;
3528 struct mem_cgroup *memcg;
3529 int node, cpu;
3530 int __maybe_unused i;
3531 long error = -ENOMEM;
3532
3533 memcg = kzalloc(struct_size(memcg, nodeinfo, nr_node_ids), GFP_KERNEL);
3534 if (!memcg)
3535 return ERR_PTR(error);
3536
3537 error = xa_alloc(&mem_cgroup_ids, &memcg->id.id, NULL,
3538 XA_LIMIT(1, MEM_CGROUP_ID_MAX), GFP_KERNEL);
3539 if (error)
3540 goto fail;
3541
3542 memcg->vmstats = kzalloc(sizeof(struct memcg_vmstats),
3543 GFP_KERNEL_ACCOUNT);
3544 if (!memcg->vmstats)
3545 goto fail;
These error paths should all return -ENOMEM.
3546
3547 memcg->vmstats_percpu = alloc_percpu_gfp(struct memcg_vmstats_percpu,
3548 GFP_KERNEL_ACCOUNT);
3549 if (!memcg->vmstats_percpu)
3550 goto fail;
^^^^^^^^^
3551
3552 for_each_possible_cpu(cpu) {
3553 if (parent)
3554 pstatc = per_cpu_ptr(parent->vmstats_percpu, cpu);
3555 statc = per_cpu_ptr(memcg->vmstats_percpu, cpu);
3556 statc->parent = parent ? pstatc : NULL;
3557 statc->vmstats = memcg->vmstats;
3558 }
3559
3560 for_each_node(node)
3561 if (!alloc_mem_cgroup_per_node_info(memcg, node))
3562 goto fail;
^^^^^^^^^^
3563
3564 if (memcg_wb_domain_init(memcg, GFP_KERNEL))
3565 goto fail;
^^^^^^^^^^
It might be nice to propogate the error code from memcg_wb_domain_init()
3566
3567 INIT_WORK(&memcg->high_work, high_work_func);
3568 vmpressure_init(&memcg->vmpressure);
3569 INIT_LIST_HEAD(&memcg->memory_peaks);
3570 INIT_LIST_HEAD(&memcg->swap_peaks);
3571 spin_lock_init(&memcg->peaks_lock);
3572 memcg->socket_pressure = jiffies;
3573 memcg1_memcg_init(memcg);
3574 memcg->kmemcg_id = -1;
3575 INIT_LIST_HEAD(&memcg->objcg_list);
3576 #ifdef CONFIG_CGROUP_WRITEBACK
3577 INIT_LIST_HEAD(&memcg->cgwb_list);
3578 for (i = 0; i < MEMCG_CGWB_FRN_CNT; i++)
3579 memcg->cgwb_frn[i].done =
3580 __WB_COMPLETION_INIT(&memcg_cgwb_frn_waitq);
3581 #endif
3582 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
3583 spin_lock_init(&memcg->deferred_split_queue.split_queue_lock);
3584 INIT_LIST_HEAD(&memcg->deferred_split_queue.split_queue);
3585 memcg->deferred_split_queue.split_queue_len = 0;
3586 #endif
3587 lru_gen_init_memcg(memcg);
3588 return memcg;
3589 fail:
3590 mem_cgroup_id_remove(memcg);
3591 __mem_cgroup_free(memcg);
--> 3592 return ERR_PTR(error);
3593 }
regards,
dan carpenter
