Skip to contentSkip to conversation

cpufreq: brcmstb-avs-cpufreq: Fix -Warray-bounds bug

PATCH Applied Gustavo A. R. Silva 4 participants 4 messages Aug 1, 2023 – Aug 4, 2023

Subsystems (3)
CPU frequency scaling framework Broadcom BCM7XXX Arm architecture Broadcom stb avs cpufreq driver
lore
Share & tools
lore

Gustavo A. R. Silva

author
#0 lore raw

PATCH v3 1/1 cpufreq: brcmstb-avs-cpufreq: Fix -Warray-bounds bug

Allocate extra space for terminating element at:

drivers/cpufreq/brcmstb-avs-cpufreq.c:
449 table[i].frequency = CPUFREQ_TABLE_END;

and add code comment to make this clear.

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 [email protected]
Signed-off-by Gustavo A. R. Silva <[email protected]>

---
Changes in v3:
- Allocate extra space for a terminating element. (Kees Cook)
- Update changelog text.

Changes in v2:
- Update changelog text. Add more details.
- Link: https://lore.kernel.org/linux-hardening/202307311610.B1EB796684@keescook/

v1:
- Link: https://lore.kernel.org/linux-hardening/ZMgfWEA0GAN%2FRog8@work/

 drivers/cpufreq/brcmstb-avs-cpufreq.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)
drivers/cpufreq/brcmstb-avs-cpufreq.c +5 -1
index ffea6402189d..3052949aebbc 100644
@@ -434,7 +434,11 @@ brcm_avs_get_freq_table(struct device *dev, struct private_data *priv)
 	if (ret)
 		return ERR_PTR(ret);
 
-	table = devm_kcalloc(dev, AVS_PSTATE_MAX + 1, sizeof(*table),
+	/*
+	 * We allocate space for the 5 different P-STATES AVS,
+	 * plus extra space for a terminating element.
+	 */
+	table = devm_kcalloc(dev, AVS_PSTATE_MAX + 1 + 1, sizeof(*table),
 			     GFP_KERNEL);
 	if (!table)
 		return ERR_PTR(-ENOMEM);
Signature · 1 line
2.34.1
maintainer Reviewed-by on v3 1/1
#1 lore raw
Quoted 25 lines · Gustavo A. R. Silva

Allocate extra space for terminating element at:

drivers/cpufreq/brcmstb-avs-cpufreq.c:
449 table[i].frequency = CPUFREQ_TABLE_END;

and add code comment to make this clear.

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);
       |                ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Quoted 8 lines

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 [email protected]
Signed-off-by Gustavo A. R. Silva <[email protected]>
Reviewed-by Florian Fainelli <[email protected]>
Signature · 1 line
Florian

_______________________________________________
linux-arm-kernel mailing list
[email protected]
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

maintainer Applied
#2 lore raw
Quoted 30 lines · Florian Fainelli
Quoted 29 lines · Gustavo A. R. Silva

Allocate extra space for terminating element at:

drivers/cpufreq/brcmstb-avs-cpufreq.c:
449 table[i].frequency = CPUFREQ_TABLE_END;

and add code comment to make this clear.

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.

Quoted 6 lines
Quoted 4 lines
Link https://github.com/KSPP/linux/issues/324
Fixes de322e085995 ("cpufreq: brcmstb-avs-cpufreq: AVS CPUfreq driver for Broadcom STB SoCs")
Cc [email protected]
Signed-off-by Gustavo A. R. Silva <[email protected]>
Reviewed-by Florian Fainelli <[email protected]>

Applied. Thanks.

Signature · 1 line
viresh