7.2-stable review patch. If anyone has any objections, please let me know. ------------------ From: Igor Paunovic commit 6eff1d69dae808a1518aee5a58d0853a8db3f1be upstream. rocket_remove() decrements rdev->num_cores for each core it removes, while find_core_for_dev() searches slots 0 to num_cores - 1. Unbinding the cores in the order they were bound therefore loses the last one: by the time it is removed the search range has already shrunk past its slot, so find_core_for_dev() returns -1 and rocket_remove() gives up without doing anything. num_cores never reaches zero, rocket_device_fini() never runs, and the file-scoped rdev keeps pointing at a device that is going away. Binding the cores again starts from that stale count, because rocket_probe() takes rdev->num_cores as the slot to fill. On an RK3588, which describes three cores, the second round lands on slots 1, 2 and 3 while rdev->cores was allocated with room for three: rocket fdab0000.npu: Rockchip NPU core 1 version: 1179210309 rocket fdac0000.npu: Rockchip NPU core 2 version: 1179210309 rocket fdad0000.npu: Rockchip NPU core 3 version: 1179210309 The write to rdev->cores[3] is past the end of the array. Nothing in tree reads the core array often enough to notice, so the overrun is silent today. It turned up while testing a devfreq series on top of this, where a worker walks every core a few times a second, and UBSAN caught the first bool it read out of the overrun entry: UBSAN: invalid-load in drivers/accel/rocket/rocket_devfreq.c:47:10 load of value 5 is not a valid value for type '_Bool' Workqueue: devfreq_wq devfreq_monitor Record how many slots were allocated and search all of them. Every core is then found on removal, num_cores reaches zero, the device is torn down and a later bind starts from a clean rdev. This does not make unbinding a single core out of several work. probe still takes num_cores as the slot to fill, so rebinding one core while its siblings stay bound would write over a slot that is already in use, and rocket_open() still reaches for cores[0] whether or not anything is there. Both of those want more thought than a fix should carry. Found by unbinding and rebinding all three cores on an Orange Pi 5 Plus. With this applied, 25 unbind/rebind rounds and 5 module unload/reload rounds run clean there: the cores land in slots 0, 1 and 2 every time, whichever order they are bound in, and the shared supply goes back to a single user after each round. Fixes: ed98261b4168 ("accel/rocket: Add a new driver for Rockchip's NPU") Cc: stable@vger.kernel.org Signed-off-by: Igor Paunovic Assisted-by: LLM sparse checkpatch Tested-by: Jiaxing Hu # RK3576, two cores Tested-by: Sidong Yang # RK3588, 3 cores Signed-off-by: Heiko Stuebner Link: https://patch.msgid.link/20260904125936.26234-1-royalnet026@gmail.com Signed-off-by: Greg Kroah-Hartman --- drivers/accel/rocket/rocket_device.c | 2 ++ drivers/accel/rocket/rocket_device.h | 1 + drivers/accel/rocket/rocket_drv.c | 2 +- 3 files changed, 4 insertions(+), 1 deletion(-) --- a/drivers/accel/rocket/rocket_device.c +++ b/drivers/accel/rocket/rocket_device.c @@ -31,6 +31,8 @@ struct rocket_device *rocket_device_init if (of_device_is_available(core_node)) num_cores++; + rdev->max_cores = num_cores; + rdev->cores = devm_kcalloc(dev, num_cores, sizeof(*rdev->cores), GFP_KERNEL); if (!rdev->cores) return ERR_PTR(-ENOMEM); --- a/drivers/accel/rocket/rocket_device.h +++ b/drivers/accel/rocket/rocket_device.h @@ -19,6 +19,7 @@ struct rocket_device { struct rocket_core *cores; unsigned int num_cores; + unsigned int max_cores; }; struct rocket_device *rocket_device_init(struct platform_device *pdev, --- a/drivers/accel/rocket/rocket_drv.c +++ b/drivers/accel/rocket/rocket_drv.c @@ -226,7 +226,7 @@ static int find_core_for_dev(struct devi { struct rocket_device *rdev = dev_get_drvdata(dev); - for (unsigned int core = 0; core < rdev->num_cores; core++) { + for (unsigned int core = 0; core < rdev->max_cores; core++) { if (dev == rdev->cores[core].dev) return core; }