The H6 main pin controller has four banks of interrupt-triggering pins. The driver as originally submitted only specified three, but had pin descriptions referencing a fourth bank. This results in a out-of-bounds access into .irq_array of struct sunxi_pinctrl. This however did not result in a crash until v4.20, with commit a66d972465d1 ("devres: Align data[] to ARCH_KMALLOC_MINALIGN"), which changed the alignment of memory region returned by devm_kcalloc(). The increase likely moved the out-of-bounds access into the next, unmapped page.

With KASAN on, the bug is quite clear:

BUG: KASAN: slab-out-of-bounds in sunxi_pinctrl_init_with_variant+0x49c/0x12b8 Write of size 4 at addr ffff80002c680280 by task swapper/0/1

CPU: 2 PID: 1 Comm: swapper/0 Not tainted 5.0.0-rc1-00016-gc480a5e6a077 #3 Hardware name: OrangePi Lite2 (DT) Call trace: dump_backtrace+0x0/0x220 show_stack+0x14/0x20 dump_stack+0xac/0xd4 print_address_description+0x60/0x25c kasan_report+0x14c/0x1ac __asan_store4+0x80/0xa0 sunxi_pinctrl_init_with_variant+0x49c/0x12b8 h6_pinctrl_probe+0x18/0x20 platform_drv_probe+0x6c/0xc8 really_probe+0x244/0x4b0 driver_probe_device.part.4+0x11c/0x164 __driver_attach+0x120/0x190 bus_for_each_dev+0xe8/0x158 driver_attach+0x30/0x40 bus_add_driver+0x308/0x318 driver_register+0xbc/0x1d0 __platform_driver_register+0x7c/0x88 h6_pinctrl_driver_init+0x18/0x20 do_one_initcall+0xd4/0x208 kernel_init_freeable+0x230/0x2c8 kernel_init+0x10/0x108 ret_from_fork+0x10/0x1c

Allocated by task 1: kasan_kmalloc.part.0+0x4c/0x100 kasan_kmalloc+0xc4/0xe8 kasan_slab_alloc+0x14/0x20 __kmalloc_track_caller+0x130/0x238 devm_kmalloc+0x34/0xd0 sunxi_pinctrl_init_with_variant+0x1d8/0x12b8 h6_pinctrl_probe+0x18/0x20 platform_drv_probe+0x6c/0xc8 really_probe+0x244/0x4b0 driver_probe_device.part.4+0x11c/0x164 __driver_attach+0x120/0x190 bus_for_each_dev+0xe8/0x158 driver_attach+0x30/0x40 bus_add_driver+0x308/0x318 driver_register+0xbc/0x1d0 __platform_driver_register+0x7c/0x88 h6_pinctrl_driver_init+0x18/0x20 do_one_initcall+0xd4/0x208 kernel_init_freeable+0x230/0x2c8 kernel_init+0x10/0x108 ret_from_fork+0x10/0x1c

Freed by task 0: (stack is not available)

The buggy address belongs to the object at ffff80002c680080 which belongs to the cache kmalloc-512 of size 512 The buggy address is located 0 bytes to the right of 512-byte region [ffff80002c680080, ffff80002c680280) The buggy address belongs to the page: page:ffff7e0000b1a000 count:1 mapcount:0 mapping:ffff80002e00c780 index:0xffff80002c683c80 compound_mapcount: 0 flags: 0x10200(slab|head) raw: 0000000000010200 ffff80002e003a10 ffff80002e003a10 ffff80002e00c780 raw: ffff80002c683c80 0000000000100001 00000001ffffffff 0000000000000000 page dumped because: kasan: bad access detected

Memory state around the buggy address: ffff80002c680180: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ffff80002c680200: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 >ffff80002c680280: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ^ ffff80002c680300: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff80002c680380: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc

Correct the number of IRQ banks so there are no more mismatches.

Fixes: c8a830904991 ("pinctrl: sunxi: add support for the Allwinner H6 main pin controller") Cc: stable@vger.kernel.org Signed-off-by: Chen-Yu Tsai wens@csie.org --- drivers/pinctrl/sunxi/pinctrl-sun50i-h6.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/pinctrl/sunxi/pinctrl-sun50i-h6.c b/drivers/pinctrl/sunxi/pinctrl-sun50i-h6.c index aa8b58125568..ef4268cc6227 100644 --- a/drivers/pinctrl/sunxi/pinctrl-sun50i-h6.c +++ b/drivers/pinctrl/sunxi/pinctrl-sun50i-h6.c @@ -588,7 +588,7 @@ static const unsigned int h6_irq_bank_map[] = { 1, 5, 6, 7 }; static const struct sunxi_pinctrl_desc h6_pinctrl_data = { .pins = h6_pins, .npins = ARRAY_SIZE(h6_pins), - .irq_banks = 3, + .irq_banks = 4, .irq_bank_map = h6_irq_bank_map, .irq_read_needs_mux = true, };