[PATCH 5.6 056/167] net: stmmac: dwmac-meson8b: Add missing boundary to RGMII TX clock array

From: Greg Kroah-Hartman
Date: Tue Apr 28 2020 - 15:00:08 EST


From: Marc Zyngier <maz@xxxxxxxxxx>

[ Upstream commit f0212a5ebfa6cd789ab47666b9cc169e6e688732 ]

Running with KASAN on a VIM3L systems leads to the following splat
when probing the Ethernet device:

==================================================================
BUG: KASAN: global-out-of-bounds in _get_maxdiv+0x74/0xd8
Read of size 4 at addr ffffa000090615f4 by task systemd-udevd/139
CPU: 1 PID: 139 Comm: systemd-udevd Tainted: G E 5.7.0-rc1-00101-g8624b7577b9c #781
Hardware name: amlogic w400/w400, BIOS 2020.01-rc5 03/12/2020
Call trace:
dump_backtrace+0x0/0x2a0
show_stack+0x20/0x30
dump_stack+0xec/0x148
print_address_description.isra.12+0x70/0x35c
__kasan_report+0xfc/0x1d4
kasan_report+0x4c/0x68
__asan_load4+0x9c/0xd8
_get_maxdiv+0x74/0xd8
clk_divider_bestdiv+0x74/0x5e0
clk_divider_round_rate+0x80/0x1a8
clk_core_determine_round_nolock.part.9+0x9c/0xd0
clk_core_round_rate_nolock+0xf0/0x108
clk_hw_round_rate+0xac/0xf0
clk_factor_round_rate+0xb8/0xd0
clk_core_determine_round_nolock.part.9+0x9c/0xd0
clk_core_round_rate_nolock+0xf0/0x108
clk_core_round_rate_nolock+0xbc/0x108
clk_core_set_rate_nolock+0xc4/0x2e8
clk_set_rate+0x58/0xe0
meson8b_dwmac_probe+0x588/0x72c [dwmac_meson8b]
platform_drv_probe+0x78/0xd8
really_probe+0x158/0x610
driver_probe_device+0x140/0x1b0
device_driver_attach+0xa4/0xb0
__driver_attach+0xcc/0x1c8
bus_for_each_dev+0xf4/0x168
driver_attach+0x3c/0x50
bus_add_driver+0x238/0x2e8
driver_register+0xc8/0x1e8
__platform_driver_register+0x88/0x98
meson8b_dwmac_driver_init+0x28/0x1000 [dwmac_meson8b]
do_one_initcall+0xa8/0x328
do_init_module+0xe8/0x368
load_module+0x3300/0x36b0
__do_sys_finit_module+0x120/0x1a8
__arm64_sys_finit_module+0x4c/0x60
el0_svc_common.constprop.2+0xe4/0x268
do_el0_svc+0x98/0xa8
el0_svc+0x24/0x68
el0_sync_handler+0x12c/0x318
el0_sync+0x158/0x180

The buggy address belongs to the variable:
div_table.63646+0x34/0xfffffffffffffa40 [dwmac_meson8b]

Memory state around the buggy address:
ffffa00009061480: fa fa fa fa 00 00 00 01 fa fa fa fa 00 00 00 00
ffffa00009061500: 05 fa fa fa fa fa fa fa 00 04 fa fa fa fa fa fa
>ffffa00009061580: 00 03 fa fa fa fa fa fa 00 00 00 00 00 00 fa fa
^
ffffa00009061600: fa fa fa fa 00 01 fa fa fa fa fa fa 01 fa fa fa
ffffa00009061680: fa fa fa fa 00 01 fa fa fa fa fa fa 04 fa fa fa
==================================================================

Digging into this indeed shows that the clock divider array is
lacking a final fence, and that the clock subsystems goes in the
weeds. Oh well.

Let's add the empty structure that indicates the end of the array.

Fixes: bd6f48546b9c ("net: stmmac: dwmac-meson8b: Fix the RGMII TX delay on Meson8b/8m2 SoCs")
Signed-off-by: Marc Zyngier <maz@xxxxxxxxxx>
Cc: Martin Blumenstingl <martin.blumenstingl@xxxxxxxxxxxxxx>
Reviewed-by: Martin Blumenstingl <martin.blumenstingl@xxxxxxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/net/ethernet/stmicro/stmmac/dwmac-meson8b.c | 1 +
1 file changed, 1 insertion(+)

--- a/drivers/net/ethernet/stmicro/stmmac/dwmac-meson8b.c
+++ b/drivers/net/ethernet/stmicro/stmmac/dwmac-meson8b.c
@@ -119,6 +119,7 @@ static int meson8b_init_rgmii_tx_clk(str
{ .div = 5, .val = 5, },
{ .div = 6, .val = 6, },
{ .div = 7, .val = 7, },
+ { /* end of array */ }
};

clk_configs = devm_kzalloc(dev, sizeof(*clk_configs), GFP_KERNEL);