io_uring/sqpoll: do not put cpumask on stack

Putting the cpumask on the stack is deprecated for a long time (since
2d3854a37e8), as these can be big. Given that, change the on-stack
allocation of allowed_mask to be dynamically allocated.

Fixes: f011c9cf04c0 ("io_uring/sqpoll: do not allow pinning outside of cpuset")
Signed-off-by: Felix Moessbauer <felix.moessbauer@siemens.com>
Link: https://lore.kernel.org/r/20240916111150.1266191-1-felix.moessbauer@siemens.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/io_uring/sqpoll.c b/io_uring/sqpoll.c
index 7adfcf6818ff25076c8d03738e62989816ca20f5..7c79685baeb1aa375a2de128da245f62fe0b17ba 100644 (file)
--- 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))
+                       ret = -ENOMEM;
+                       if (!alloc_cpumask_var(&allowed_mask, GFP_KERNEL))
                                goto err_sqpoll;
+                       ret = -EINVAL;
+                       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;