[PATCH] cpufreq: brcmstb-avs-cpufreq: Fix -Warray-bounds bug

From: Gustavo A. R. Silva
Date: Mon Jul 31 2023 - 16:53:02 EST


Update the iteration conditions in the for() loop to avoid writing in
array `table` beyond its allocated size.

This fixes the following -Warray-bounds warning seen after building
ARM with multi_v7_defconfig (GCC 13):
In function 'brcm_avs_get_freq_table',
inlined from 'brcm_avs_cpufreq_init' at drivers/cpufreq/brcmstb-avs-cpufreq.c:623:15:
drivers/cpufreq/brcmstb-avs-cpufreq.c:449:28: warning: array subscript 5 is outside array bounds of 'void[60]' [-Warray-bounds=]
449 | table[i].frequency = CPUFREQ_TABLE_END;
In file included from include/linux/node.h:18,
from include/linux/cpu.h:17,
from include/linux/cpufreq.h:12,
from drivers/cpufreq/brcmstb-avs-cpufreq.c:44:
In function 'devm_kmalloc_array',
inlined from 'devm_kcalloc' at include/linux/device.h:328:9,
inlined from 'brcm_avs_get_freq_table' at drivers/cpufreq/brcmstb-avs-cpufreq.c:437:10,
inlined from 'brcm_avs_cpufreq_init' at drivers/cpufreq/brcmstb-avs-cpufreq.c:623:15:
include/linux/device.h:323:16: note: at offset 60 into object of size 60 allocated by 'devm_kmalloc'
323 | return devm_kmalloc(dev, bytes, flags);
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

This helps with the ongoing efforts to tighten the FORTIFY_SOURCE
routines on memcpy() and help us make progress towards globally
enabling -Warray-bounds.

Link: https://github.com/KSPP/linux/issues/324
Fixes: de322e085995 ("cpufreq: brcmstb-avs-cpufreq: AVS CPUfreq driver for Broadcom STB SoCs")
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Gustavo A. R. Silva <gustavoars@xxxxxxxxxx>
---
drivers/cpufreq/brcmstb-avs-cpufreq.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/cpufreq/brcmstb-avs-cpufreq.c b/drivers/cpufreq/brcmstb-avs-cpufreq.c
index 1bdd513bcd19..99ba2d707eff 100644
--- a/drivers/cpufreq/brcmstb-avs-cpufreq.c
+++ b/drivers/cpufreq/brcmstb-avs-cpufreq.c
@@ -439,7 +439,7 @@ brcm_avs_get_freq_table(struct device *dev, struct private_data *priv)
if (!table)
return ERR_PTR(-ENOMEM);

- for (i = AVS_PSTATE_P0; i <= AVS_PSTATE_MAX; i++) {
+ for (i = AVS_PSTATE_P0; i < AVS_PSTATE_MAX; i++) {
ret = brcm_avs_set_pstate(priv, i);
if (ret)
return ERR_PTR(ret);
--
2.34.1