Commit 0997aa54 authored by Felix Moessbauer's avatar Felix Moessbauer Committed by Jens Axboe
Browse files

io_uring/io-wq: do not allow pinning outside of cpuset 



The io worker threads are userland threads that just never exit to the
userland. By that, they are also assigned to a cgroup (the group of the
creating task).

When changing the affinity of the io_wq thread via syscall, we must only
allow cpumasks within the limits defined by the cpuset controller of the
cgroup (if enabled).

Fixes: da64d6db ("io_uring: One wqe per wq")
Signed-off-by: default avatarFelix Moessbauer <felix.moessbauer@siemens.com>
Link: https://lore.kernel.org/r/20240910171157.166423-2-felix.moessbauer@siemens.com


Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent 90bfb28d

io_uring/io-wq.c

+18 −5
Original line number Diff line number Diff line
@@ -13,6 +13,7 @@ 
#include <linux/slab.h>

#include <linux/rculist_nulls.h>

#include <linux/cpu.h>

#include <linux/cpuset.h>

#include <linux/task_work.h>

#include <linux/audit.h>

#include <linux/mmu_context.h>
@@ -1322,17 +1323,29 @@ static int io_wq_cpu_offline(unsigned int cpu, struct hlist_node *node) 


int io_wq_cpu_affinity(struct io_uring_task *tctx, cpumask_var_t mask)

{

	cpumask_var_t allowed_mask;

	int ret = 0;



	if (!tctx || !tctx->io_wq)

		return -EINVAL;



	if (!alloc_cpumask_var(&allowed_mask, GFP_KERNEL))

		return -ENOMEM;



	rcu_read_lock();

	if (mask)

	cpuset_cpus_allowed(tctx->io_wq->task, allowed_mask);

	if (mask) {

		if (cpumask_subset(mask, allowed_mask))

			cpumask_copy(tctx->io_wq->cpu_mask, mask);

		else

		cpumask_copy(tctx->io_wq->cpu_mask, cpu_possible_mask);

			ret = -EINVAL;

	} else {

		cpumask_copy(tctx->io_wq->cpu_mask, allowed_mask);

	}

	rcu_read_unlock();



	return 0;

	free_cpumask_var(allowed_mask);

	return ret;

}



/*