--- /dev/null
+From a09c17240bdf2e9fa6d0591afa9448b59785f7d4 Mon Sep 17 00:00:00 2001
+From: Jens Axboe <axboe@kernel.dk>
+Date: Mon, 16 Sep 2024 02:58:06 -0600
+Subject: io_uring/sqpoll: retain test for whether the CPU is valid
+
+From: Jens Axboe <axboe@kernel.dk>
+
+commit a09c17240bdf2e9fa6d0591afa9448b59785f7d4 upstream.
+
+A recent commit ensured that SQPOLL cannot be setup with a CPU that
+isn't in the current tasks cpuset, but it also dropped testing whether
+the CPU is valid in the first place. Without that, if a task passes in
+a CPU value that is too high, the following KASAN splat can get
+triggered:
+
+BUG: KASAN: stack-out-of-bounds in io_sq_offload_create+0x858/0xaa4
+Read of size 8 at addr ffff800089bc7b90 by task wq-aff.t/1391
+
+CPU: 4 UID: 1000 PID: 1391 Comm: wq-aff.t Not tainted 6.11.0-rc7-00227-g371c468f4db6 #7080
+Hardware name: linux,dummy-virt (DT)
+Call trace:
+ dump_backtrace.part.0+0xcc/0xe0
+ show_stack+0x14/0x1c
+ dump_stack_lvl+0x58/0x74
+ print_report+0x16c/0x4c8
+ kasan_report+0x9c/0xe4
+ __asan_report_load8_noabort+0x1c/0x24
+ io_sq_offload_create+0x858/0xaa4
+ io_uring_setup+0x1394/0x17c4
+ __arm64_sys_io_uring_setup+0x6c/0x180
+ invoke_syscall+0x6c/0x260
+ el0_svc_common.constprop.0+0x158/0x224
+ do_el0_svc+0x3c/0x5c
+ el0_svc+0x34/0x70
+ el0t_64_sync_handler+0x118/0x124
+ el0t_64_sync+0x168/0x16c
+
+The buggy address belongs to stack of task wq-aff.t/1391
+ and is located at offset 48 in frame:
+ io_sq_offload_create+0x0/0xaa4
+
+This frame has 1 object:
+ [32, 40) 'allowed_mask'
+
+The buggy address belongs to the virtual mapping at
+ [ffff800089bc0000, ffff800089bc9000) created by:
+ kernel_clone+0x124/0x7e0
+
+The buggy address belongs to the physical page:
+page: refcount:1 mapcount:0 mapping:0000000000000000 index:0xffff0000d740af80 pfn:0x11740a
+memcg:ffff0000c2706f02
+flags: 0xbffe00000000000(node=0|zone=2|lastcpupid=0x1fff)
+raw: 0bffe00000000000 0000000000000000 dead000000000122 0000000000000000
+raw: ffff0000d740af80 0000000000000000 00000001ffffffff ffff0000c2706f02
+page dumped because: kasan: bad access detected
+
+Memory state around the buggy address:
+ ffff800089bc7a80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
+ ffff800089bc7b00: 00 00 00 00 00 00 00 00 00 00 00 00 f1 f1 f1 f1
+>ffff800089bc7b80: 00 f3 f3 f3 00 00 00 00 00 00 00 00 00 00 00 00
+ ^
+ ffff800089bc7c00: 00 00 00 00 00 00 00 00 00 00 00 00 f1 f1 f1 f1
+ ffff800089bc7c80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 f3
+
+Reported-by: kernel test robot <oliver.sang@intel.com>
+Closes: https://lore.kernel.org/oe-lkp/202409161632.cbeeca0d-lkp@intel.com
+Fixes: f011c9cf04c0 ("io_uring/sqpoll: do not allow pinning outside of cpuset")
+Tested-by: Felix Moessbauer <felix.moessbauer@siemens.com>
+Signed-off-by: Jens Axboe <axboe@kernel.dk>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+---
+ io_uring/sqpoll.c | 2 ++
+ 1 file changed, 2 insertions(+)
+
+--- a/io_uring/sqpoll.c
++++ b/io_uring/sqpoll.c
+@@ -465,6 +465,8 @@ __cold int io_sq_offload_create(struct i
+ 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))
+ goto err_sqpoll;