drm/panthor: validate userspace queue count against initialized firmware slot count

In panthor_drv.c:panthor_ioctl_group_create(),
the queue count is validated against the hardcoded maximum:

	if (!args->queues.count || args->queues.count > MAX_CS_PER_CSG)
		return -EINVAL;

However, if the firmware reports fewer slots than MAX_CS_PER_CSG,
panthor_fw_init_ifaces() will only initialize that smaller number of
stream interfaces.

If unprivileged userspace requests more queues than the firmware reported
(but no more than MAX_CS_PER_CSG), cs_slot_prog_locked() fetches an
uninitialized stream interface and may crash when dereferencing
cs_iface->input->ringbuf_base.

Fixes: de85488138 ("drm/panthor: Add the scheduler logical block")
Cc: stable@vger.kernel.org
Reported-by: sashiko-bot@kernel.org
Closes: https://sashiko.dev/#/patchset/20260803141149.68182-1-osama.abdelkader@gmail.com?part=1
Signed-off-by: Osama Abdelkader <osama.abdelkader@gmail.com>
Reviewed-by: Steven Price <steven.price@arm.com>
Reviewed-by: Liviu Dudau <liviu.dudau@arm.com>
Reviewed-by: Boris Brezillon <boris.brezillon@collabora.com>
Link: https://patch.msgid.link/20260804160048.174148-1-osama.abdelkader@gmail.com
Signed-off-by: Steven Price <steven.price@arm.com>
This commit is contained in:
Osama Abdelkader 2026-08-04 18:00:47 +02:00 committed by Steven Price
parent 57889076af
commit ec86c43dcf

View File

@ -3674,6 +3674,9 @@ int panthor_group_create(struct panthor_file *pfile,
hweight64(group_args->tiler_core_mask) < group_args->max_tiler_cores)
return -EINVAL;
if (group_args->queues.count > sched->cs_slot_count)
return -EINVAL;
group = kzalloc_obj(*group);
if (!group)
return -ENOMEM;