| Message ID | 20240916105514.1260506-1-felix.moessbauer@siemens.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | [v2,1/1] io_uring/sqpoll: do not put cpumasks on stack | expand |
On 9/16/24 4:55 AM, Felix Moessbauer wrote: > Putting the cpumask on the stack is deprecated for a long time (since > 2d3854a37e8), as these can be big. Given that, we port-over the stack > allocated mask to the cpumask allocation api. I'd change that last sentence to: Given that, change the on-stack allocation of allowed_mask to be dynamically allocated. > diff --git a/io_uring/sqpoll.c b/io_uring/sqpoll.c > index 7adfcf6818ff..44b9f58e11b6 100644 > --- a/io_uring/sqpoll.c > +++ b/io_uring/sqpoll.c > @@ -461,15 +461,22 @@ __cold int io_sq_offload_create(struct io_ring_ctx *ctx, > return 0; > > if (p->flags & IORING_SETUP_SQ_AFF) { > - struct cpumask allowed_mask; > + cpumask_var_t allowed_mask; > int cpu = p->sq_thread_cpu; > > ret = -EINVAL; > if (cpu >= nr_cpu_ids || !cpu_online(cpu)) > goto err_sqpoll; > - cpuset_cpus_allowed(current, &allowed_mask); > - if (!cpumask_test_cpu(cpu, &allowed_mask)) > + if (!alloc_cpumask_var(&allowed_mask, GFP_KERNEL)) { > + ret = -ENOMEM; > goto err_sqpoll; > + } > + cpuset_cpus_allowed(current, allowed_mask); > + if (!cpumask_test_cpu(cpu, allowed_mask)) { > + free_cpumask_var(allowed_mask); > + goto err_sqpoll; > + } > + free_cpumask_var(allowed_mask); > sqd->sq_cpu = cpu; The kernel generally does: ret = -ESOMEERROR; if (fails_check) goto err_label; and you're now mixing the two here. To keep it consistent, it'd be better to do : ret = -ENOMEM before the alloc, and then re-set it to -EINVAL before the cpumask check.
diff --git a/io_uring/sqpoll.c b/io_uring/sqpoll.c index 7adfcf6818ff..44b9f58e11b6 100644 --- a/io_uring/sqpoll.c +++ b/io_uring/sqpoll.c @@ -461,15 +461,22 @@ __cold int io_sq_offload_create(struct io_ring_ctx *ctx, return 0; if (p->flags & IORING_SETUP_SQ_AFF) { - struct cpumask allowed_mask; + cpumask_var_t allowed_mask; int cpu = p->sq_thread_cpu; ret = -EINVAL; if (cpu >= nr_cpu_ids || !cpu_online(cpu)) goto err_sqpoll; - cpuset_cpus_allowed(current, &allowed_mask); - if (!cpumask_test_cpu(cpu, &allowed_mask)) + if (!alloc_cpumask_var(&allowed_mask, GFP_KERNEL)) { + ret = -ENOMEM; goto err_sqpoll; + } + cpuset_cpus_allowed(current, allowed_mask); + if (!cpumask_test_cpu(cpu, allowed_mask)) { + free_cpumask_var(allowed_mask); + goto err_sqpoll; + } + free_cpumask_var(allowed_mask); sqd->sq_cpu = cpu; } else { sqd->sq_cpu = -1;
Putting the cpumask on the stack is deprecated for a long time (since 2d3854a37e8), as these can be big. Given that, we port-over the stack allocated mask to the cpumask allocation api. Fixes: f011c9cf04c0 ("io_uring/sqpoll: do not allow pinning outside of cpuset") Signed-off-by: Felix Moessbauer <felix.moessbauer@siemens.com> --- Changes since v1: - don't leak mask in case CPU is not online or too big Best regards, Felix io_uring/sqpoll.c | 13 ++++++++++--- 1 file changed, 10 insertions(+), 3 deletions(-)