* [RFC PATCH linux dev-5.4 1/4] ARM: configs: aspeed-g5: Disable netfilter
2020-05-14 13:26 [RFC PATCH linux dev-5.4 0/4] Enable kprobes on AST2500 and later Andrew Jeffery
@ 2020-05-14 13:27 ` Andrew Jeffery
2020-05-14 13:27 ` [RFC PATCH linux dev-5.4 2/4] ARM: configs: aspeed-g5: Enable modules Andrew Jeffery
` (2 subsequent siblings)
3 siblings, 0 replies; 11+ messages in thread
From: Andrew Jeffery @ 2020-05-14 13:27 UTC (permalink / raw)
To: joel; +Cc: openbmc
Enabling modules with CONFIG_NETFILTER=y and CONFIG_NETFILTER_ADVANCED=n
results in a diverse set of netfilter functions being built as modules.
These functions were not previously enabled in any way because modules
were disabled, therefore we can't have been using them. Given that we
aren't using them, disable netfilter as well to prevent them from being
built.
CONFIG_NETFILTER=y was introduced in 20c90af9ea6a ("ARM: config: aspeed:
Update defconfig") with little fanfare in the commit message, which
makes me wonder whether it was enabled because we needed it or whether
its addition slipped through the cracks.
Signed-off-by: Andrew Jeffery <andrew@aj.id.au>
---
arch/arm/configs/aspeed_g5_defconfig | 2 --
1 file changed, 2 deletions(-)
diff --git a/arch/arm/configs/aspeed_g5_defconfig b/arch/arm/configs/aspeed_g5_defconfig
index cdf30fbe613e..e124b4ddd442 100644
--- a/arch/arm/configs/aspeed_g5_defconfig
+++ b/arch/arm/configs/aspeed_g5_defconfig
@@ -69,8 +69,6 @@ CONFIG_IPV6_ROUTER_PREF=y
CONFIG_IPV6_ROUTE_INFO=y
CONFIG_IPV6_OPTIMISTIC_DAD=y
CONFIG_IPV6_MULTIPLE_TABLES=y
-CONFIG_NETFILTER=y
-# CONFIG_NETFILTER_ADVANCED is not set
CONFIG_VLAN_8021Q=y
CONFIG_NET_NCSI=y
# CONFIG_WIRELESS is not set
--
2.25.1
^ permalink raw reply related [flat|nested] 11+ messages in thread* [RFC PATCH linux dev-5.4 2/4] ARM: configs: aspeed-g5: Enable modules
2020-05-14 13:26 [RFC PATCH linux dev-5.4 0/4] Enable kprobes on AST2500 and later Andrew Jeffery
2020-05-14 13:27 ` [RFC PATCH linux dev-5.4 1/4] ARM: configs: aspeed-g5: Disable netfilter Andrew Jeffery
@ 2020-05-14 13:27 ` Andrew Jeffery
2020-05-14 13:52 ` Patrick Williams
2020-05-14 17:51 ` Milton Miller II
2020-05-14 13:27 ` [RFC PATCH linux dev-5.4 3/4] ARM: configs: aspeed-g5: Enable kprobes Andrew Jeffery
2020-05-14 13:27 ` [RFC PATCH linux dev-5.4 4/4] ARM: configs: aspeed-g5: Set CONFIG_FORTIFY_SOURCE=n to appease kprobes Andrew Jeffery
3 siblings, 2 replies; 11+ messages in thread
From: Andrew Jeffery @ 2020-05-14 13:27 UTC (permalink / raw)
To: joel; +Cc: openbmc
This is a step on the path to enabling kprobes, which depend on
CONFIG_MODULES=y.
Setting CONFIG_MODULES=y results in the following change in kernel size:
Before:
$ size vmlinux
text data bss dec hex filename
8140500 2440582 178904 10759986 a42f32 vmlinux
$ stat --printf '%s\n' arch/arm/boot/zImage
3445200
After:
$ size vmlinux
text data bss dec hex filename
8240349 2388862 172304 10801515 a4d16b vmlinux
$ stat --printf '%s\n' arch/arm/boot/zImage
3458368
This gives a 41,529 byte increase to vmlinux and a 13,168 byte increase
to the size of the compressed kernel image. In the most constrained BMC
flash layout (arch/arm/boot/dts/openbmc-flash-layout.dtsi) this change
decreases the free space in the kernel partition from 1,011,248 bytes to
998,080 bytes.
CONFIG_HW_RANDOM=y seems to come along for the ride with the
`./scripts/config -e modules && make olddefconfig && make
savedefconfig`. The measurements above include it, I haven't
investigated why it gets enabled or what effect disabling it might have
on the numbers.
Signed-off-by: Andrew Jeffery <andrew@aj.id.au>
---
arch/arm/configs/aspeed_g5_defconfig | 2 ++
1 file changed, 2 insertions(+)
diff --git a/arch/arm/configs/aspeed_g5_defconfig b/arch/arm/configs/aspeed_g5_defconfig
index e124b4ddd442..e30f27a413f4 100644
--- a/arch/arm/configs/aspeed_g5_defconfig
+++ b/arch/arm/configs/aspeed_g5_defconfig
@@ -46,6 +46,7 @@ CONFIG_NEON=y
CONFIG_KERNEL_MODE_NEON=y
CONFIG_FIRMWARE_MEMMAP=y
CONFIG_JUMP_LABEL=y
+CONFIG_MODULES=y
# CONFIG_BLK_DEV_BSG is not set
# CONFIG_BLK_DEBUG_FS is not set
# CONFIG_MQ_IOSCHED_DEADLINE is not set
@@ -152,6 +153,7 @@ CONFIG_SERIAL_8250_DW=y
CONFIG_SERIAL_OF_PLATFORM=y
CONFIG_ASPEED_KCS_IPMI_BMC=y
CONFIG_ASPEED_BT_IPMI_BMC=y
+CONFIG_HW_RANDOM=y
CONFIG_HW_RANDOM_TIMERIOMEM=y
# CONFIG_I2C_COMPAT is not set
CONFIG_I2C_CHARDEV=y
--
2.25.1
^ permalink raw reply related [flat|nested] 11+ messages in thread* Re: [RFC PATCH linux dev-5.4 2/4] ARM: configs: aspeed-g5: Enable modules
2020-05-14 13:27 ` [RFC PATCH linux dev-5.4 2/4] ARM: configs: aspeed-g5: Enable modules Andrew Jeffery
@ 2020-05-14 13:52 ` Patrick Williams
2020-05-14 17:51 ` Milton Miller II
1 sibling, 0 replies; 11+ messages in thread
From: Patrick Williams @ 2020-05-14 13:52 UTC (permalink / raw)
To: Andrew Jeffery; +Cc: joel, openbmc
[-- Attachment #1: Type: text/plain, Size: 2770 bytes --]
On Thu, May 14, 2020 at 10:57:01PM +0930, Andrew Jeffery wrote:
> This is a step on the path to enabling kprobes, which depend on
> CONFIG_MODULES=y.
>
> Setting CONFIG_MODULES=y results in the following change in kernel size:
>
> Before:
> $ size vmlinux
> text data bss dec hex filename
> 8140500 2440582 178904 10759986 a42f32 vmlinux
> $ stat --printf '%s\n' arch/arm/boot/zImage
> 3445200
>
> After:
> $ size vmlinux
> text data bss dec hex filename
> 8240349 2388862 172304 10801515 a4d16b vmlinux
> $ stat --printf '%s\n' arch/arm/boot/zImage
> 3458368
>
> This gives a 41,529 byte increase to vmlinux and a 13,168 byte increase
> to the size of the compressed kernel image. In the most constrained BMC
> flash layout (arch/arm/boot/dts/openbmc-flash-layout.dtsi) this change
> decreases the free space in the kernel partition from 1,011,248 bytes to
> 998,080 bytes.
>
> CONFIG_HW_RANDOM=y seems to come along for the ride with the
> `./scripts/config -e modules && make olddefconfig && make
> savedefconfig`. The measurements above include it, I haven't
> investigated why it gets enabled or what effect disabling it might have
> on the numbers.
>
> Signed-off-by: Andrew Jeffery <andrew@aj.id.au>
> ---
> arch/arm/configs/aspeed_g5_defconfig | 2 ++
> 1 file changed, 2 insertions(+)
>
> diff --git a/arch/arm/configs/aspeed_g5_defconfig b/arch/arm/configs/aspeed_g5_defconfig
> index e124b4ddd442..e30f27a413f4 100644
> --- a/arch/arm/configs/aspeed_g5_defconfig
> +++ b/arch/arm/configs/aspeed_g5_defconfig
> @@ -46,6 +46,7 @@ CONFIG_NEON=y
> CONFIG_KERNEL_MODE_NEON=y
> CONFIG_FIRMWARE_MEMMAP=y
> CONFIG_JUMP_LABEL=y
> +CONFIG_MODULES=y
> # CONFIG_BLK_DEV_BSG is not set
> # CONFIG_BLK_DEBUG_FS is not set
> # CONFIG_MQ_IOSCHED_DEADLINE is not set
> @@ -152,6 +153,7 @@ CONFIG_SERIAL_8250_DW=y
> CONFIG_SERIAL_OF_PLATFORM=y
> CONFIG_ASPEED_KCS_IPMI_BMC=y
> CONFIG_ASPEED_BT_IPMI_BMC=y
> +CONFIG_HW_RANDOM=y
> CONFIG_HW_RANDOM_TIMERIOMEM=y
> # CONFIG_I2C_COMPAT is not set
> CONFIG_I2C_CHARDEV=y
> --
> 2.25.1
>
We're already using modules on the facebook/openbmc kernels and it
hasn't seemed to cause any issues. Is there any argument why we
shouldn't begin moving some of the drivers to be modules? Any easy
change would be to make all the hwmon content as modules and load them
based on the device tree.
I think there is a DISTRO_FEATURE we should enable for userspace support
of modules. Let me know if you want me to investigate that.
Reviewed-by: Patrick Williams <patrick@stwcx.xyz>
--
Patrick Williams
[-- Attachment #2: signature.asc --]
[-- Type: application/pgp-signature, Size: 833 bytes --]
^ permalink raw reply [flat|nested] 11+ messages in thread
* RE: [RFC PATCH linux dev-5.4 2/4] ARM: configs: aspeed-g5: Enable modules
2020-05-14 13:27 ` [RFC PATCH linux dev-5.4 2/4] ARM: configs: aspeed-g5: Enable modules Andrew Jeffery
2020-05-14 13:52 ` Patrick Williams
@ 2020-05-14 17:51 ` Milton Miller II
1 sibling, 0 replies; 11+ messages in thread
From: Milton Miller II @ 2020-05-14 17:51 UTC (permalink / raw)
To: Patrick Williams; +Cc: Andrew Jeffery, openbmc
On May 14, 2020 around 8:53AM in some timezone, Patrick Williams wrote:
>On Thu, May 14, 2020 at 10:57:01PM +0930, Andrew Jeffery wrote:>> This is a step on the path to enabling kprobes, which depend on
>> CONFIG_MODULES=y.
>>
>> Setting CONFIG_MODULES=y results in the following change in kernel
>size:
>>
>> Before:
>> $ size vmlinux
>> text data bss dec hex filename
>> 8140500 2440582 178904 10759986 a42f32 vmlinux
>> $ stat --printf '%s\n' arch/arm/boot/zImage
>> 3445200
>>
>> After:
>> $ size vmlinux
>> text data bss dec hex filename
>> 8240349 2388862 172304 10801515 a4d16b vmlinux
>> $ stat --printf '%s\n' arch/arm/boot/zImage
>> 3458368
>>
>> This gives a 41,529 byte increase to vmlinux and a 13,168 byte
>increase
>> to the size of the compressed kernel image. In the most constrained
>BMC
>> flash layout (arch/arm/boot/dts/openbmc-flash-layout.dtsi) this
>change
>> decreases the free space in the kernel partition from 1,011,248
>bytes to
>> 998,080 bytes.
>>
>> CONFIG_HW_RANDOM=y seems to come along for the ride with the
>> `./scripts/config -e modules && make olddefconfig && make
>> savedefconfig`. The measurements above include it, I haven't
>> investigated why it gets enabled or what effect disabling it might
>have
>> on the numbers.
>>
>> Signed-off-by: Andrew Jeffery <andrew@aj.id.au>
>> ---
>> arch/arm/configs/aspeed_g5_defconfig | 2 ++
>> 1 file changed, 2 insertions(+)
>>
>> diff --git a/arch/arm/configs/aspeed_g5_defconfig
>b/arch/arm/configs/aspeed_g5_defconfig
>> index e124b4ddd442..e30f27a413f4 100644
>> --- a/arch/arm/configs/aspeed_g5_defconfig
>> +++ b/arch/arm/configs/aspeed_g5_defconfig
>> @@ -46,6 +46,7 @@ CONFIG_NEON=y
>> CONFIG_KERNEL_MODE_NEON=y
>> CONFIG_FIRMWARE_MEMMAP=y
>> CONFIG_JUMP_LABEL=y
>> +CONFIG_MODULES=y
>> # CONFIG_BLK_DEV_BSG is not set
>> # CONFIG_BLK_DEBUG_FS is not set
>> # CONFIG_MQ_IOSCHED_DEADLINE is not set
>> @@ -152,6 +153,7 @@ CONFIG_SERIAL_8250_DW=y
>> CONFIG_SERIAL_OF_PLATFORM=y
>> CONFIG_ASPEED_KCS_IPMI_BMC=y
>> CONFIG_ASPEED_BT_IPMI_BMC=y
>> +CONFIG_HW_RANDOM=y
>> CONFIG_HW_RANDOM_TIMERIOMEM=y
>> # CONFIG_I2C_COMPAT is not set
>> CONFIG_I2C_CHARDEV=y
>> --
>> 2.25.1
>>
>
>We're already using modules on the facebook/openbmc kernels and it
>hasn't seemed to cause any issues. Is there any argument why we
>shouldn't begin moving some of the drivers to be modules? Any easy
>change would be to make all the hwmon content as modules and load
>them
>based on the device tree.
>
>I think there is a DISTRO_FEATURE we should enable for userspace
>support
>of modules. Let me know if you want me to investigate that.
This gerrit is still open. It also adds content to the rootfs b
ecause it tries to pull in vmlinux into the root fs as part of the
base kernel recipie:
https://gerrit.openbmc-project.xyz/c/openbmc/meta-phosphor/+/26092
actually this one that has failed since September:
https://gerrit.openbmc-project.xyz/c/openbmc/meta-phosphor/+/25536/2
milton
^ permalink raw reply [flat|nested] 11+ messages in thread
* [RFC PATCH linux dev-5.4 3/4] ARM: configs: aspeed-g5: Enable kprobes
2020-05-14 13:26 [RFC PATCH linux dev-5.4 0/4] Enable kprobes on AST2500 and later Andrew Jeffery
2020-05-14 13:27 ` [RFC PATCH linux dev-5.4 1/4] ARM: configs: aspeed-g5: Disable netfilter Andrew Jeffery
2020-05-14 13:27 ` [RFC PATCH linux dev-5.4 2/4] ARM: configs: aspeed-g5: Enable modules Andrew Jeffery
@ 2020-05-14 13:27 ` Andrew Jeffery
2020-05-14 23:58 ` Andrew Jeffery
2020-05-14 13:27 ` [RFC PATCH linux dev-5.4 4/4] ARM: configs: aspeed-g5: Set CONFIG_FORTIFY_SOURCE=n to appease kprobes Andrew Jeffery
3 siblings, 1 reply; 11+ messages in thread
From: Andrew Jeffery @ 2020-05-14 13:27 UTC (permalink / raw)
To: joel; +Cc: openbmc
Enable kprobes to improve the debugging experience on the AST2500 and
later.
Setting CONFIG_KPROBES=y results in the following change in kernel size:
Before:
$ size vmlinux
text data bss dec hex filename
8240349 2388862 172304 10801515 a4d16b vmlinux
$ stat --printf '%s\n' *.zImage
3458368
After:
$ size vmlinux
text data bss dec hex filename
8279214 2399530 176912 10855656 a5a4e8 vmlinux
$ stat --printf '%s\n' *.zImage
3471880
This gives a 54,141 byte increase to vmlinux and a 13,512 byte increase
to the size of the compressed kernel image. In the most constrained BMC
flash layout (arch/arm/boot/dts/openbmc-flash-layout.dtsi) this change
decreases the free space in the kernel partition from 998,080 bytes to
984,568 bytes.
Signed-off-by: Andrew Jeffery <andrew@aj.id.au>
---
arch/arm/configs/aspeed_g5_defconfig | 1 +
1 file changed, 1 insertion(+)
diff --git a/arch/arm/configs/aspeed_g5_defconfig b/arch/arm/configs/aspeed_g5_defconfig
index e30f27a413f4..254fb7562738 100644
--- a/arch/arm/configs/aspeed_g5_defconfig
+++ b/arch/arm/configs/aspeed_g5_defconfig
@@ -45,6 +45,7 @@ CONFIG_VFP=y
CONFIG_NEON=y
CONFIG_KERNEL_MODE_NEON=y
CONFIG_FIRMWARE_MEMMAP=y
+CONFIG_KPROBES=y
CONFIG_JUMP_LABEL=y
CONFIG_MODULES=y
# CONFIG_BLK_DEV_BSG is not set
--
2.25.1
^ permalink raw reply related [flat|nested] 11+ messages in thread* Re: [RFC PATCH linux dev-5.4 3/4] ARM: configs: aspeed-g5: Enable kprobes
2020-05-14 13:27 ` [RFC PATCH linux dev-5.4 3/4] ARM: configs: aspeed-g5: Enable kprobes Andrew Jeffery
@ 2020-05-14 23:58 ` Andrew Jeffery
0 siblings, 0 replies; 11+ messages in thread
From: Andrew Jeffery @ 2020-05-14 23:58 UTC (permalink / raw)
To: Joel Stanley; +Cc: openbmc
On Thu, 14 May 2020, at 22:57, Andrew Jeffery wrote:
> Enable kprobes to improve the debugging experience on the AST2500 and
> later.
>
> Setting CONFIG_KPROBES=y results in the following change in kernel size:
>
> Before:
> $ size vmlinux
> text data bss dec hex filename
> 8240349 2388862 172304 10801515 a4d16b vmlinux
> $ stat --printf '%s\n' *.zImage
> 3458368
>
> After:
> $ size vmlinux
> text data bss dec hex filename
> 8279214 2399530 176912 10855656 a5a4e8 vmlinux
> $ stat --printf '%s\n' *.zImage
> 3471880
>
> This gives a 54,141 byte increase to vmlinux and a 13,512 byte increase
> to the size of the compressed kernel image. In the most constrained BMC
> flash layout (arch/arm/boot/dts/openbmc-flash-layout.dtsi) this change
> decreases the free space in the kernel partition from 998,080 bytes to
> 984,568 bytes.
Just realised I should be measuring the FIT not the zImage so ignore the
free-space numbers for the moment.
Andrew
^ permalink raw reply [flat|nested] 11+ messages in thread
* [RFC PATCH linux dev-5.4 4/4] ARM: configs: aspeed-g5: Set CONFIG_FORTIFY_SOURCE=n to appease kprobes
2020-05-14 13:26 [RFC PATCH linux dev-5.4 0/4] Enable kprobes on AST2500 and later Andrew Jeffery
` (2 preceding siblings ...)
2020-05-14 13:27 ` [RFC PATCH linux dev-5.4 3/4] ARM: configs: aspeed-g5: Enable kprobes Andrew Jeffery
@ 2020-05-14 13:27 ` Andrew Jeffery
2020-05-14 13:54 ` Patrick Williams
3 siblings, 1 reply; 11+ messages in thread
From: Andrew Jeffery @ 2020-05-14 13:27 UTC (permalink / raw)
To: joel; +Cc: openbmc
Setting CONFIG_FORTIFY_SOURCE=y and CONFIG_KPROBES=y on arm gives a panic when
trying to insert a new probe:
$ echo r:myretprobe do_sys_open '$retval' >> /sys/kernel/debug/tracing/kprobe_events
[ 51.688589] detected buffer overflow in memcpy
[ 51.689430] ------------[ cut here ]------------
[ 51.689627] kernel BUG at lib/string.c:1096!
[ 51.689800] Internal error: Oops - BUG: 0 [#1] SMP ARM
[ 51.690107] Modules linked in:
[ 51.690442] CPU: 0 PID: 107 Comm: sh Not tainted 5.4.39-00272-ga1ee7c973659 #6
[ 51.690674] Hardware name: Generic DT based system
[ 51.691184] PC is at fortify_panic+0x18/0x20
[ 51.691371] LR is at __irq_work_queue_local+0x40/0x7c
[ 51.691575] pc : [<8083eaa4>] lr : [<8020e0ec>] psr: 60000013
[ 51.691812] sp : bd237cb0 ip : bd237bc0 fp : bd237cbc
[ 51.692129] r10: 00000007 r9 : 00000000 r8 : 00000060
[ 51.692395] r7 : 8011f2f0 r6 : b5092480 r5 : 7f000000 r4 : b4c53b4c
[ 51.692723] r3 : 80c04c48 r2 : 00000000 r1 : bd7c5448 r0 : 00000022
[ 51.693088] Flags: nZCv IRQs on FIQs on Mode SVC_32 ISA ARM Segment none
[ 51.693449] Control: 10c5387d Table: b50f406a DAC: 00000051
[ 51.693769] Process sh (pid: 107, stack limit = 0x4e9b7225)
[ 51.694126] Stack: (0xbd237cb0 to 0xbd238000)
YOLO it and disable fortified source.
Signed-off-by: Andrew Jeffery <andrew@aj.id.au>
---
arch/arm/configs/aspeed_g5_defconfig | 1 -
1 file changed, 1 deletion(-)
diff --git a/arch/arm/configs/aspeed_g5_defconfig b/arch/arm/configs/aspeed_g5_defconfig
index 254fb7562738..b7f8ccc99000 100644
--- a/arch/arm/configs/aspeed_g5_defconfig
+++ b/arch/arm/configs/aspeed_g5_defconfig
@@ -269,7 +269,6 @@ CONFIG_SQUASHFS_XZ=y
CONFIG_SQUASHFS_ZSTD=y
# CONFIG_NETWORK_FILESYSTEMS is not set
CONFIG_HARDENED_USERCOPY=y
-CONFIG_FORTIFY_SOURCE=y
CONFIG_CRYPTO_HMAC=y
CONFIG_CRYPTO_SHA256=y
CONFIG_CRYPTO_USER_API_HASH=y
--
2.25.1
^ permalink raw reply related [flat|nested] 11+ messages in thread* Re: [RFC PATCH linux dev-5.4 4/4] ARM: configs: aspeed-g5: Set CONFIG_FORTIFY_SOURCE=n to appease kprobes
2020-05-14 13:27 ` [RFC PATCH linux dev-5.4 4/4] ARM: configs: aspeed-g5: Set CONFIG_FORTIFY_SOURCE=n to appease kprobes Andrew Jeffery
@ 2020-05-14 13:54 ` Patrick Williams
2020-05-14 22:10 ` Andrew Jeffery
0 siblings, 1 reply; 11+ messages in thread
From: Patrick Williams @ 2020-05-14 13:54 UTC (permalink / raw)
To: Andrew Jeffery; +Cc: joel, openbmc
[-- Attachment #1: Type: text/plain, Size: 1733 bytes --]
On Thu, May 14, 2020 at 10:57:03PM +0930, Andrew Jeffery wrote:
> Setting CONFIG_FORTIFY_SOURCE=y and CONFIG_KPROBES=y on arm gives a panic when
> trying to insert a new probe:
>
> $ echo r:myretprobe do_sys_open '$retval' >> /sys/kernel/debug/tracing/kprobe_events
> [ 51.688589] detected buffer overflow in memcpy
> [ 51.689430] ------------[ cut here ]------------
> [ 51.689627] kernel BUG at lib/string.c:1096!
> [ 51.689800] Internal error: Oops - BUG: 0 [#1] SMP ARM
> [ 51.690107] Modules linked in:
> [ 51.690442] CPU: 0 PID: 107 Comm: sh Not tainted 5.4.39-00272-ga1ee7c973659 #6
> [ 51.690674] Hardware name: Generic DT based system
> [ 51.691184] PC is at fortify_panic+0x18/0x20
> [ 51.691371] LR is at __irq_work_queue_local+0x40/0x7c
> [ 51.691575] pc : [<8083eaa4>] lr : [<8020e0ec>] psr: 60000013
> [ 51.691812] sp : bd237cb0 ip : bd237bc0 fp : bd237cbc
> [ 51.692129] r10: 00000007 r9 : 00000000 r8 : 00000060
> [ 51.692395] r7 : 8011f2f0 r6 : b5092480 r5 : 7f000000 r4 : b4c53b4c
> [ 51.692723] r3 : 80c04c48 r2 : 00000000 r1 : bd7c5448 r0 : 00000022
> [ 51.693088] Flags: nZCv IRQs on FIQs on Mode SVC_32 ISA ARM Segment none
> [ 51.693449] Control: 10c5387d Table: b50f406a DAC: 00000051
> [ 51.693769] Process sh (pid: 107, stack limit = 0x4e9b7225)
> [ 51.694126] Stack: (0xbd237cb0 to 0xbd238000)
>
> YOLO it and disable fortified source.
>
> Signed-off-by: Andrew Jeffery <andrew@aj.id.au>
> ---
> arch/arm/configs/aspeed_g5_defconfig | 1 -
> 1 file changed, 1 deletion(-)
Doesn't this mean we're just hiding a bug with KPROBE code and
potentially hiding more bugs with other drivers?
--
Patrick Williams
[-- Attachment #2: signature.asc --]
[-- Type: application/pgp-signature, Size: 833 bytes --]
^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: [RFC PATCH linux dev-5.4 4/4] ARM: configs: aspeed-g5: Set CONFIG_FORTIFY_SOURCE=n to appease kprobes
2020-05-14 13:54 ` Patrick Williams
@ 2020-05-14 22:10 ` Andrew Jeffery
2020-05-18 0:58 ` Andrew Jeffery
0 siblings, 1 reply; 11+ messages in thread
From: Andrew Jeffery @ 2020-05-14 22:10 UTC (permalink / raw)
To: Patrick Williams; +Cc: Joel Stanley, openbmc
On Thu, 14 May 2020, at 23:24, Patrick Williams wrote:
> On Thu, May 14, 2020 at 10:57:03PM +0930, Andrew Jeffery wrote:
> > Setting CONFIG_FORTIFY_SOURCE=y and CONFIG_KPROBES=y on arm gives a panic when
> > trying to insert a new probe:
> >
> > $ echo r:myretprobe do_sys_open '$retval' >> /sys/kernel/debug/tracing/kprobe_events
> > [ 51.688589] detected buffer overflow in memcpy
> > [ 51.689430] ------------[ cut here ]------------
> > [ 51.689627] kernel BUG at lib/string.c:1096!
> > [ 51.689800] Internal error: Oops - BUG: 0 [#1] SMP ARM
> > [ 51.690107] Modules linked in:
> > [ 51.690442] CPU: 0 PID: 107 Comm: sh Not tainted 5.4.39-00272-ga1ee7c973659 #6
> > [ 51.690674] Hardware name: Generic DT based system
> > [ 51.691184] PC is at fortify_panic+0x18/0x20
> > [ 51.691371] LR is at __irq_work_queue_local+0x40/0x7c
> > [ 51.691575] pc : [<8083eaa4>] lr : [<8020e0ec>] psr: 60000013
> > [ 51.691812] sp : bd237cb0 ip : bd237bc0 fp : bd237cbc
> > [ 51.692129] r10: 00000007 r9 : 00000000 r8 : 00000060
> > [ 51.692395] r7 : 8011f2f0 r6 : b5092480 r5 : 7f000000 r4 : b4c53b4c
> > [ 51.692723] r3 : 80c04c48 r2 : 00000000 r1 : bd7c5448 r0 : 00000022
> > [ 51.693088] Flags: nZCv IRQs on FIQs on Mode SVC_32 ISA ARM Segment none
> > [ 51.693449] Control: 10c5387d Table: b50f406a DAC: 00000051
> > [ 51.693769] Process sh (pid: 107, stack limit = 0x4e9b7225)
> > [ 51.694126] Stack: (0xbd237cb0 to 0xbd238000)
> >
> > YOLO it and disable fortified source.
> >
> > Signed-off-by: Andrew Jeffery <andrew@aj.id.au>
> > ---
> > arch/arm/configs/aspeed_g5_defconfig | 1 -
> > 1 file changed, 1 deletion(-)
>
> Doesn't this mean we're just hiding a bug with KPROBE code
Possibly.
> and
> potentially hiding more bugs with other drivers?
Yes.
You should view this series as "things I did to get kprobes 'working'" and not
"patches we should apply to the kernel tree". This one in particular was a
low-key troll patch to flush out any information on why
CONFIG_FORTIFY_SOURCE=y breaks kprobes in particular. I mean, it even
features "YOLO" in the commit mesage, so don't take it too seriously :)
Andrew
^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: [RFC PATCH linux dev-5.4 4/4] ARM: configs: aspeed-g5: Set CONFIG_FORTIFY_SOURCE=n to appease kprobes
2020-05-14 22:10 ` Andrew Jeffery
@ 2020-05-18 0:58 ` Andrew Jeffery
0 siblings, 0 replies; 11+ messages in thread
From: Andrew Jeffery @ 2020-05-18 0:58 UTC (permalink / raw)
To: Patrick Williams; +Cc: openbmc
On Fri, 15 May 2020, at 07:40, Andrew Jeffery wrote:
>
>
> On Thu, 14 May 2020, at 23:24, Patrick Williams wrote:
> > On Thu, May 14, 2020 at 10:57:03PM +0930, Andrew Jeffery wrote:
> > > Setting CONFIG_FORTIFY_SOURCE=y and CONFIG_KPROBES=y on arm gives a panic when
> > > trying to insert a new probe:
> > >
> > > $ echo r:myretprobe do_sys_open '$retval' >> /sys/kernel/debug/tracing/kprobe_events
> > > [ 51.688589] detected buffer overflow in memcpy
> > > [ 51.689430] ------------[ cut here ]------------
> > > [ 51.689627] kernel BUG at lib/string.c:1096!
> > > [ 51.689800] Internal error: Oops - BUG: 0 [#1] SMP ARM
> > > [ 51.690107] Modules linked in:
> > > [ 51.690442] CPU: 0 PID: 107 Comm: sh Not tainted 5.4.39-00272-ga1ee7c973659 #6
> > > [ 51.690674] Hardware name: Generic DT based system
> > > [ 51.691184] PC is at fortify_panic+0x18/0x20
> > > [ 51.691371] LR is at __irq_work_queue_local+0x40/0x7c
> > > [ 51.691575] pc : [<8083eaa4>] lr : [<8020e0ec>] psr: 60000013
> > > [ 51.691812] sp : bd237cb0 ip : bd237bc0 fp : bd237cbc
> > > [ 51.692129] r10: 00000007 r9 : 00000000 r8 : 00000060
> > > [ 51.692395] r7 : 8011f2f0 r6 : b5092480 r5 : 7f000000 r4 : b4c53b4c
> > > [ 51.692723] r3 : 80c04c48 r2 : 00000000 r1 : bd7c5448 r0 : 00000022
> > > [ 51.693088] Flags: nZCv IRQs on FIQs on Mode SVC_32 ISA ARM Segment none
> > > [ 51.693449] Control: 10c5387d Table: b50f406a DAC: 00000051
> > > [ 51.693769] Process sh (pid: 107, stack limit = 0x4e9b7225)
> > > [ 51.694126] Stack: (0xbd237cb0 to 0xbd238000)
> > >
> > > YOLO it and disable fortified source.
> > >
> > > Signed-off-by: Andrew Jeffery <andrew@aj.id.au>
> > > ---
> > > arch/arm/configs/aspeed_g5_defconfig | 1 -
> > > 1 file changed, 1 deletion(-)
> >
> > Doesn't this mean we're just hiding a bug with KPROBE code
>
> Possibly.
>
> > and
> > potentially hiding more bugs with other drivers?
>
> Yes.
>
> You should view this series as "things I did to get kprobes 'working'" and not
> "patches we should apply to the kernel tree". This one in particular was a
> low-key troll patch to flush out any information on why
> CONFIG_FORTIFY_SOURCE=y breaks kprobes in particular.
In [1] Kees Cook suggests it's a false-positive and provides a potential fix. This
was submitted at [2]. [3] then fixes the fix. Turns out the issue needs fixing
again due to compiler advances, so I sent [4] but it looks like we might instead
resolve it by [5].
[1] https://bugzilla.redhat.com/show_bug.cgi?id=1639397
[2] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=e46daee53bb5
[3] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=0ac569bf6a798
[4] https://lore.kernel.org/linux-arm-kernel/20200517153959.293224-1-andrew@aj.id.au/
[5] https://lore.kernel.org/linux-arm-kernel/202005171447.00CFE0C@keescook/
Andrew
^ permalink raw reply [flat|nested] 11+ messages in thread