[PATCH v2] clk: meson: align gxbb_32k_clk_sel number of parents with actual count

[Martin Blumenstingl]

The following out-of-bounds read has been observed by Christian on a
GXBB WeTek Hub:
==================================================================
BUG: KASAN: global-out-of-bounds in __clk_register+0x1b70/0x2418
Read of size 8 at addr ffffd66320cf88e0 by task swapper/0/1

CPU: 0 UID: 0 PID: 1 Comm: swapper/0 Not tainted 7.0.0-rc5 #1 PREEMPT
Hardware name: WeTek Hub (DT)
Call trace:
 show_stack+0x14/0x20 (C)
 dump_stack_lvl+0x74/0x94
 print_report+0x164/0x4b0
 kasan_report+0x98/0xd8
 __asan_report_load8_noabort+0x1c/0x24
 __clk_register+0x1b70/0x2418
 devm_clk_hw_register+0x74/0x15c
 meson_clkc_init+0xd4/0x20c
 meson_clkc_syscon_probe+0x5c/0x94
 platform_probe+0xbc/0x17c
 really_probe+0x184/0x844
 __driver_probe_device+0x154/0x35c
 driver_probe_device+0x60/0x188
 __driver_attach+0x168/0x4a0
 bus_for_each_dev+0xec/0x180
 driver_attach+0x38/0x58
 bus_add_driver+0x238/0x4c0
 driver_register+0x150/0x388
 __platform_driver_register+0x54/0x7c
 gxbb_clkc_driver_init+0x18/0x20
 do_one_initcall+0xb8/0x340
 kernel_init_freeable+0x49c/0x52c
 kernel_init+0x24/0x148
 ret_from_fork+0x10/0x20

The buggy address belongs to the variable:
 gxbb_32k_clk_parents+0x60/0x400

The buggy address belongs to a vmalloc virtual mapping
The buggy address belongs to the physical page:

Memory state around the buggy address:
 ffffd66320cf8780: 00 00 00 00 f9 f9 f9 f9 00 f9 f9 f9 f9 f9 f9 f9
 ffffd66320cf8800: 00 04 f9 f9 f9 f9 f9 f9 00 04 f9 f9 f9 f9 f9 f9
>ffffd66320cf8880: 00 00 00 00 00 00 00 00 00 00 00 00 f9 f9 f9 f9
                                                       ^
 ffffd66320cf8900: 00 01 f9 f9 f9 f9 f9 f9 00 06 f9 f9 f9 f9 f9 f9
 ffffd66320cf8980: 00 00 02 f9 f9 f9 f9 f9 00 00 02 f9 f9 f9 f9 f9
==================================================================

Commit 7915d7d5407c ("clk: amlogic: gxbb: drop non existing 32k clock
parent") dropped a non-existing clock parent from the gxbb_32k_clk_sel
mux but didn't adjust the hard-coded num_parents field. Fix the actual
number of parents of that mux by using ARRAY_SIZE instead (avoiding
similar problems in future).

Fixes: 7915d7d5407c ("clk: amlogic: gxbb: drop non existing 32k clock parent")
Reported-by: Christian Hewitt <christianshewitt@xxxxxxxxx>
Cc: stable@xxxxxxxxxxxxxxx
Tested-by: Christian Hewitt <christianshewitt@xxxxxxxxx>
Signed-off-by: Martin Blumenstingl <martin.blumenstingl@xxxxxxxxxxxxxx>
---
Changes since v1 at [0]:
- fix typo in my own email address (apologies for the noise)


[0] https://lore.kernel.org/linux-amlogic/20260623201522.1322463-1-martin.blumenstingl@xxxxxxxxxxxxxx/T/#u


 drivers/clk/meson/gxbb.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/clk/meson/gxbb.c b/drivers/clk/meson/gxbb.c
index f9131d014ef4..d432e08d1777 100644
--- a/drivers/clk/meson/gxbb.c
+++ b/drivers/clk/meson/gxbb.c
@@ -1394,7 +1394,7 @@ static struct clk_regmap gxbb_32k_clk_sel = {
 		.name = "32k_clk_sel",
 		.ops = &clk_regmap_mux_ops,
 		.parent_data = gxbb_32k_clk_parents,
-		.num_parents = 4,
+		.num_parents = ARRAY_SIZE(gxbb_32k_clk_parents),
 		.flags = CLK_SET_RATE_PARENT,
 	},
 };
-- 
2.54.0