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* [dpdk-dev] [RFC 0/2] gcc 10 disable stringop-overflow warning
@ 2020-03-25 14:11 Kevin Traynor
  2020-03-25 14:11 ` [dpdk-dev] [RFC 1/2] meson: gcc 10 disable stringop-overflow warnings Kevin Traynor
                   ` (3 more replies)
  0 siblings, 4 replies; 18+ messages in thread
From: Kevin Traynor @ 2020-03-25 14:11 UTC (permalink / raw)
  To: dev, thomas, bruce.richardson
  Cc: ravi1.kumar, g.singh, hemant.agrawal, akhil.goyal, johndale,
	hyonkim, jingjing.wu, wenzhuo.lu, rmody, shshaikh, matan,
	shahafs, declan.doherty, cristian.dumitrescu, Kevin Traynor

This is a blunt way to remove this warning.

Some alternatives are:
- disable the warning for individual components
- components rework to statically allocate memory for parts of structs impacted

Maybe there's some other solutions?

Impacted components:
../drivers/crypto/caam_jr/caam_jr_pvt.h
../drivers/crypto/ccp/ccp_crypto.h
../drivers/crypto/dpaa_sec/dpaa_sec.h
../drivers/crypto/virtio/virtio_cryptodev.h
../drivers/net/enic/base/vnic_dev.c
../drivers/net/iavf/../../common/iavf/virtchnl.h
../drivers/net/ice/base/ice_adminq_cmd.h
../drivers/net/mlx4/mlx4_rxtx.c
../drivers/net/qede/base/ecore_mcp.c
../lib/librte_cryptodev/rte_cryptodev.h
../lib/librte_pipeline/rte_table_action.c

Full details in the Bugzilla:
https://bugs.dpdk.org/show_bug.cgi?id=421

Kevin Traynor (2):
  meson: gcc 10 disable stringop-overflow warnings
  mk: gcc 10 disable stringop-overflow warnings

 config/meson.build           | 3 ++-
 mk/toolchain/gcc/rte.vars.mk | 3 +++
 2 files changed, 5 insertions(+), 1 deletion(-)

-- 
2.21.1


^ permalink raw reply	[flat|nested] 18+ messages in thread

* [dpdk-dev] [RFC 1/2] meson: gcc 10 disable stringop-overflow warnings
  2020-03-25 14:11 [dpdk-dev] [RFC 0/2] gcc 10 disable stringop-overflow warning Kevin Traynor
@ 2020-03-25 14:11 ` Kevin Traynor
  2020-03-25 14:11 ` [dpdk-dev] [RFC 2/2] mk: " Kevin Traynor
                   ` (2 subsequent siblings)
  3 siblings, 0 replies; 18+ messages in thread
From: Kevin Traynor @ 2020-03-25 14:11 UTC (permalink / raw)
  To: dev, thomas, bruce.richardson
  Cc: ravi1.kumar, g.singh, hemant.agrawal, akhil.goyal, johndale,
	hyonkim, jingjing.wu, wenzhuo.lu, rmody, shshaikh, matan,
	shahafs, declan.doherty, cristian.dumitrescu, Kevin Traynor

Disable this warning at the top level as it is being
raised on several components.

Bugzilla ID: 421

Signed-off-by: Kevin Traynor <ktraynor@redhat.com>
---
 config/meson.build | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/config/meson.build b/config/meson.build
index abedd76f2..522368a29 100644
--- a/config/meson.build
+++ b/config/meson.build
@@ -200,5 +200,6 @@ warning_flags = [
 	'-Wno-address-of-packed-member',
 	'-Wno-packed-not-aligned',
-	'-Wno-missing-field-initializers'
+	'-Wno-missing-field-initializers',
+	'-Wno-stringop-overflow'
 ]
 if not dpdk_conf.get('RTE_ARCH_64')
-- 
2.21.1


^ permalink raw reply	[flat|nested] 18+ messages in thread

* [dpdk-dev] [RFC 2/2] mk: gcc 10 disable stringop-overflow warnings
  2020-03-25 14:11 [dpdk-dev] [RFC 0/2] gcc 10 disable stringop-overflow warning Kevin Traynor
  2020-03-25 14:11 ` [dpdk-dev] [RFC 1/2] meson: gcc 10 disable stringop-overflow warnings Kevin Traynor
@ 2020-03-25 14:11 ` " Kevin Traynor
  2020-03-25 14:18 ` [dpdk-dev] [RFC 0/2] gcc 10 disable stringop-overflow warning Thomas Monjalon
  2020-04-07 16:27 ` [dpdk-dev] [PATCH] build: gcc 10 disable stringop-overflow warnings Kevin Traynor
  3 siblings, 0 replies; 18+ messages in thread
From: Kevin Traynor @ 2020-03-25 14:11 UTC (permalink / raw)
  To: dev, thomas, bruce.richardson
  Cc: ravi1.kumar, g.singh, hemant.agrawal, akhil.goyal, johndale,
	hyonkim, jingjing.wu, wenzhuo.lu, rmody, shshaikh, matan,
	shahafs, declan.doherty, cristian.dumitrescu, Kevin Traynor

Disable this warning at the top level as it is being
raised on several components.

Bugzilla ID: 421

Signed-off-by: Kevin Traynor <ktraynor@redhat.com>
---
 mk/toolchain/gcc/rte.vars.mk | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/mk/toolchain/gcc/rte.vars.mk b/mk/toolchain/gcc/rte.vars.mk
index f19305e49..fe4b8c705 100644
--- a/mk/toolchain/gcc/rte.vars.mk
+++ b/mk/toolchain/gcc/rte.vars.mk
@@ -101,4 +101,7 @@ endif
 WERROR_FLAGS += -Wno-address-of-packed-member
 
+# disable stringop-overflow warnings
+WERROR_FLAGS += -Wno-stringop-overflow
+
 export CC AS AR LD OBJCOPY OBJDUMP STRIP READELF
 export TOOLCHAIN_CFLAGS TOOLCHAIN_LDFLAGS TOOLCHAIN_ASFLAGS
-- 
2.21.1


^ permalink raw reply	[flat|nested] 18+ messages in thread

* Re: [dpdk-dev] [RFC 0/2] gcc 10 disable stringop-overflow warning
  2020-03-25 14:11 [dpdk-dev] [RFC 0/2] gcc 10 disable stringop-overflow warning Kevin Traynor
  2020-03-25 14:11 ` [dpdk-dev] [RFC 1/2] meson: gcc 10 disable stringop-overflow warnings Kevin Traynor
  2020-03-25 14:11 ` [dpdk-dev] [RFC 2/2] mk: " Kevin Traynor
@ 2020-03-25 14:18 ` Thomas Monjalon
  2020-03-31 14:08   ` Kevin Traynor
  2020-04-07 16:27 ` [dpdk-dev] [PATCH] build: gcc 10 disable stringop-overflow warnings Kevin Traynor
  3 siblings, 1 reply; 18+ messages in thread
From: Thomas Monjalon @ 2020-03-25 14:18 UTC (permalink / raw)
  To: Kevin Traynor
  Cc: dev, bruce.richardson, ravi1.kumar, g.singh, hemant.agrawal,
	akhil.goyal, johndale, hyonkim, jingjing.wu, wenzhuo.lu, rmody,
	shshaikh, matan, shahafs, declan.doherty, cristian.dumitrescu,
	Kevin Traynor

25/03/2020 15:11, Kevin Traynor:
> This is a blunt way to remove this warning.
> 
> Some alternatives are:
> - disable the warning for individual components
> - components rework to statically allocate memory for parts of structs impacted
> 
> Maybe there's some other solutions?

In general, I am against disabling warnings, neither globally nor specifically.
Is there a way to hide false positives without disabling the warning?

> Impacted components:
> ../drivers/crypto/caam_jr/caam_jr_pvt.h
> ../drivers/crypto/ccp/ccp_crypto.h
> ../drivers/crypto/dpaa_sec/dpaa_sec.h
> ../drivers/crypto/virtio/virtio_cryptodev.h
> ../drivers/net/enic/base/vnic_dev.c
> ../drivers/net/iavf/../../common/iavf/virtchnl.h
> ../drivers/net/ice/base/ice_adminq_cmd.h
> ../drivers/net/mlx4/mlx4_rxtx.c
> ../drivers/net/qede/base/ecore_mcp.c
> ../lib/librte_cryptodev/rte_cryptodev.h
> ../lib/librte_pipeline/rte_table_action.c
> 
> Full details in the Bugzilla:
> https://bugs.dpdk.org/show_bug.cgi?id=421

Would be easier to provide explanations here.
I think we need at least one false positive example.

> Kevin Traynor (2):
>   meson: gcc 10 disable stringop-overflow warnings
>   mk: gcc 10 disable stringop-overflow warnings

You don't need to split in 2 patches.




^ permalink raw reply	[flat|nested] 18+ messages in thread

* Re: [dpdk-dev] [RFC 0/2] gcc 10 disable stringop-overflow warning
  2020-03-25 14:18 ` [dpdk-dev] [RFC 0/2] gcc 10 disable stringop-overflow warning Thomas Monjalon
@ 2020-03-31 14:08   ` Kevin Traynor
  2020-03-31 14:53     ` Stephen Hemminger
  0 siblings, 1 reply; 18+ messages in thread
From: Kevin Traynor @ 2020-03-31 14:08 UTC (permalink / raw)
  To: Thomas Monjalon
  Cc: dev, bruce.richardson, ravi1.kumar, g.singh, hemant.agrawal,
	akhil.goyal, johndale, hyonkim, jingjing.wu, wenzhuo.lu, rmody,
	shshaikh, matan, shahafs, declan.doherty, cristian.dumitrescu

On 25/03/2020 14:18, Thomas Monjalon wrote:
> 25/03/2020 15:11, Kevin Traynor:
>> This is a blunt way to remove this warning.
>>
>> Some alternatives are:
>> - disable the warning for individual components
>> - components rework to statically allocate memory for parts of structs impacted
>>
>> Maybe there's some other solutions?
> 
> In general, I am against disabling warnings, neither globally nor specifically.

Me too.

> Is there a way to hide false positives without disabling the warning?
> 

I haven't found one. If anyone has ideas it can be tested on Fedora 32
Beta which is available now, or I can try.

>> Impacted components:
>> ../drivers/crypto/caam_jr/caam_jr_pvt.h
>> ../drivers/crypto/ccp/ccp_crypto.h
>> ../drivers/crypto/dpaa_sec/dpaa_sec.h
>> ../drivers/crypto/virtio/virtio_cryptodev.h
>> ../drivers/net/enic/base/vnic_dev.c
>> ../drivers/net/iavf/../../common/iavf/virtchnl.h
>> ../drivers/net/ice/base/ice_adminq_cmd.h
>> ../drivers/net/mlx4/mlx4_rxtx.c
>> ../drivers/net/qede/base/ecore_mcp.c
>> ../lib/librte_cryptodev/rte_cryptodev.h
>> ../lib/librte_pipeline/rte_table_action.c
>>
>> Full details in the Bugzilla:
>> https://bugs.dpdk.org/show_bug.cgi?id=421
> 
> Would be easier to provide explanations here.
> I think we need at least one false positive example.
> 

If we look at the iavf code for rss_key->key:

struct virtchnl_rss_key {
        u16 vsi_id;
        u16 key_len;
        u8 key[1];         /* RSS hash key, packed bytes */
        ^^^^^^^^^
};

Then in iavf_configure_rss_key()

	len = sizeof(*rss_key) + vf->vf_res->rss_key_size - 1;
                                             ^^^^^^^^^^^^
	rss_key = rte_zmalloc("rss_key", len, 0);
                  ^^^ extra space beyond key[1] allocated here

<snip>
	rte_memcpy(rss_key->key, vf->rss_key, vf->vf_res->rss_key_size);
	                    ^^^                           ^^^^^^^^^^^^

At runtime we have allocated extra space at the end of the struct for
key, and the same size used in the malloc is also considered when
finding the right branches in the memcpy fns. But the compiler does not
know value of size and it simply sees there can be casts of a 1 byte key
to 16 or 32 bytes in some branches of the memcpy fns, so gives a warning.

e.g. _mm256_storeu_si256((__m256i *)dst, ymm0);
That is: Store 256-bits of integer data into memory,
where key is dst so leads to: warning: writing 32 bytes into a region of
size 1 [-Wstringop-overflow=]

Full log for warnings on key below.

>> Kevin Traynor (2):
>>   meson: gcc 10 disable stringop-overflow warnings
>>   mk: gcc 10 disable stringop-overflow warnings
> 
> You don't need to split in 2 patches.
> 

ok, will change if it moves to PATCH.

> 
> 

In file included from
/usr/lib/gcc/x86_64-redhat-linux/10/include/immintrin.h:51,
                 from
/usr/lib/gcc/x86_64-redhat-linux/10/include/x86intrin.h:32,
                 from
../lib/librte_eal/common/include/arch/x86/rte_vect.h:30,
                 from
../lib/librte_eal/common/include/arch/x86/rte_memcpy.h:17,
                 from ../lib/librte_net/rte_ether.h:21,
                 from ../drivers/net/iavf/iavf_vchnl.c:18:
In function ‘_mm256_storeu_si256’,
    inlined from ‘rte_memcpy_aligned’ at
../lib/librte_eal/common/include/arch/x86/rte_memcpy.h:315:2,
    inlined from ‘iavf_configure_rss_key’ at
../lib/librte_eal/common/include/arch/x86/rte_memcpy.h:867:10:
/usr/lib/gcc/x86_64-redhat-linux/10/include/avxintrin.h:928:8: warning:
writing 32 bytes into a region of size 1 [-Wstringop-overflow=]
  928 |   *__P = __A;
      |   ~~~~~^~~~~
In file included from
../drivers/net/iavf/../../common/iavf/iavf_prototype.h:10,
                 from ../drivers/net/iavf/iavf.h:9,
                 from ../drivers/net/iavf/iavf_vchnl.c:22:
../drivers/net/iavf/iavf_vchnl.c: In function ‘iavf_configure_rss_key’:
../drivers/net/iavf/../../common/iavf/virtchnl.h:508:5: note: at offset
0 to object ‘key’ with size 1 declared here
  508 |  u8 key[1];         /* RSS hash key, packed bytes */
      |     ^~~
In file included from
../lib/librte_eal/common/include/arch/x86/rte_atomic.h:15,
                 from ../drivers/net/iavf/iavf_vchnl.c:16:
In function ‘_mm_storeu_si128’,
    inlined from ‘rte_memcpy_aligned’ at
../lib/librte_eal/common/include/arch/x86/rte_memcpy.h:302:2,
    inlined from ‘iavf_configure_rss_key’ at
../lib/librte_eal/common/include/arch/x86/rte_memcpy.h:867:10:
/usr/lib/gcc/x86_64-redhat-linux/10/include/emmintrin.h:727:8: warning:
writing 16 bytes into a region of size 1 [-Wstringop-overflow=]
  727 |   *__P = __B;
      |   ~~~~~^~~~~
In file included from
../drivers/net/iavf/../../common/iavf/iavf_prototype.h:10,
                 from ../drivers/net/iavf/iavf.h:9,
                 from ../drivers/net/iavf/iavf_vchnl.c:22:
../drivers/net/iavf/iavf_vchnl.c: In function ‘iavf_configure_rss_key’:
../drivers/net/iavf/../../common/iavf/virtchnl.h:508:5: note: at offset
0 to object ‘key’ with size 1 declared here
  508 |  u8 key[1];         /* RSS hash key, packed bytes */
      |     ^~~


^ permalink raw reply	[flat|nested] 18+ messages in thread

* Re: [dpdk-dev] [RFC 0/2] gcc 10 disable stringop-overflow warning
  2020-03-31 14:08   ` Kevin Traynor
@ 2020-03-31 14:53     ` Stephen Hemminger
  2020-04-01 11:33       ` Kevin Traynor
  0 siblings, 1 reply; 18+ messages in thread
From: Stephen Hemminger @ 2020-03-31 14:53 UTC (permalink / raw)
  To: Kevin Traynor
  Cc: Thomas Monjalon, dev, bruce.richardson, ravi1.kumar, g.singh,
	hemant.agrawal, akhil.goyal, johndale, hyonkim, jingjing.wu,
	wenzhuo.lu, rmody, shshaikh, matan, shahafs, declan.doherty,
	cristian.dumitrescu

On Tue, 31 Mar 2020 15:08:26 +0100
Kevin Traynor <ktraynor@redhat.com> wrote:

> struct virtchnl_rss_key {
>         u16 vsi_id;
>         u16 key_len;
>         u8 key[1];         /* RSS hash key, packed bytes */
>         ^^^^^^^^^
> };
> 
> Then in iavf_configure_rss_key()
> 
> 	len = sizeof(*rss_key) + vf->vf_res->rss_key_size - 1;
>                                              ^^^^^^^^^^^^
> 	rss_key = rte_zmalloc("rss_key", len, 0);
>                   ^^^ extra space beyond key[1] allocated here
> 
> <snip>
> 	rte_memcpy(rss_key->key, vf->rss_key, vf->vf_res->rss_key_size);
> 	                    ^^^                           ^^^^^^^^^^^^
> 
> At runtime we have allocated extra space at the end of the struct for
> key, and the same size used in the malloc is also considered when
> finding the right branches in the memcpy fns. But the compiler does not
> know value of size and it simply sees there can be casts of a 1 byte key
> to 16 or 32 bytes in some branches of the memcpy fns, so gives a warning.

The standard way to do such a thing is to use an empty
array. The Linux kernel has just gone through cleaning up
all these zero length (and it this case one) array at
end of function.

^ permalink raw reply	[flat|nested] 18+ messages in thread

* Re: [dpdk-dev] [RFC 0/2] gcc 10 disable stringop-overflow warning
  2020-03-31 14:53     ` Stephen Hemminger
@ 2020-04-01 11:33       ` Kevin Traynor
  0 siblings, 0 replies; 18+ messages in thread
From: Kevin Traynor @ 2020-04-01 11:33 UTC (permalink / raw)
  To: Stephen Hemminger
  Cc: Thomas Monjalon, dev, bruce.richardson, ravi1.kumar, g.singh,
	hemant.agrawal, akhil.goyal, johndale, hyonkim, jingjing.wu,
	wenzhuo.lu, rmody, shshaikh, matan, shahafs, declan.doherty,
	cristian.dumitrescu

On 31/03/2020 15:53, Stephen Hemminger wrote:
> On Tue, 31 Mar 2020 15:08:26 +0100
> Kevin Traynor <ktraynor@redhat.com> wrote:
> 
>> struct virtchnl_rss_key {
>>         u16 vsi_id;
>>         u16 key_len;
>>         u8 key[1];         /* RSS hash key, packed bytes */
>>         ^^^^^^^^^
>> };
>>
>> Then in iavf_configure_rss_key()
>>
>> 	len = sizeof(*rss_key) + vf->vf_res->rss_key_size - 1;
>>                                              ^^^^^^^^^^^^
>> 	rss_key = rte_zmalloc("rss_key", len, 0);
>>                   ^^^ extra space beyond key[1] allocated here
>>
>> <snip>
>> 	rte_memcpy(rss_key->key, vf->rss_key, vf->vf_res->rss_key_size);
>> 	                    ^^^                           ^^^^^^^^^^^^
>>
>> At runtime we have allocated extra space at the end of the struct for
>> key, and the same size used in the malloc is also considered when
>> finding the right branches in the memcpy fns. But the compiler does not
>> know value of size and it simply sees there can be casts of a 1 byte key
>> to 16 or 32 bytes in some branches of the memcpy fns, so gives a warning.
> 
> The standard way to do such a thing is to use an empty
> array. The Linux kernel has just gone through cleaning up
> all these zero length (and it this case one) array at
> end of function.
> 

Thanks for the tip. There is only one occurrence of a zero-length array
in these warning (sess_data[0] in ice) and changing to [] does indeed
remove the warning for that.

For the others they have a defined length so it cannot just be removed,
some don't have any dynamic allocation at all, sizes are checked etc.

I don't think adding dynamic allocation for those structs just to get
around this warning is the right way to go.

Crypto/iavf/ip_pipeline maintainers - any comment?

../drivers/crypto/caam_jr/caam_jr_pvt.h:187:10: note: at offset 0 to
object ‘digest’ with size 32 declared here
../drivers/crypto/ccp/ccp_crypto.h:272:11: note: at offset 0 to object
‘key’ with size 32 declared here
../drivers/crypto/dpaa_sec/dpaa_sec.h:217:10: note: at offset 0 to
object ‘digest’ with size 32 declared here
../drivers/crypto/virtio/virtio_cryptodev.h:36:10: note: at offset 0 to
object ‘iv’ with size 16 declared here

../drivers/net/iavf/../../common/iavf/virtchnl.h:508:5: note: at offset
0 to object ‘key’ with size 1 declared here
../drivers/net/iavf/../../common/iavf/virtchnl.h:516:5: note: at offset
0 to object ‘lut’ with size 1 declared here

../lib/librte_pipeline/rte_table_action.c:1648:12: note: at offset 0 to
object ‘cipher_iv’ with size 16 declared here
../lib/librte_pipeline/rte_table_action.c:1650:12: note: at offset 0 to
object ‘auth_iv’ with size 16 declared here
../lib/librte_pipeline/rte_table_action.c:1655:12: note: at offset 0 to
object ‘iv’ with size 16 declared here
../lib/librte_pipeline/rte_table_action.c:1656:12: note: at offset 0 to
object ‘aad’ with size 16 declared here
../lib/librte_pipeline/rte_table_action.c:1728:10: note: at offset 0 to
object ‘iv_aad_data’ with size 32 declared here


^ permalink raw reply	[flat|nested] 18+ messages in thread

* [dpdk-dev] [PATCH] build: gcc 10 disable stringop-overflow warnings
  2020-03-25 14:11 [dpdk-dev] [RFC 0/2] gcc 10 disable stringop-overflow warning Kevin Traynor
                   ` (2 preceding siblings ...)
  2020-03-25 14:18 ` [dpdk-dev] [RFC 0/2] gcc 10 disable stringop-overflow warning Thomas Monjalon
@ 2020-04-07 16:27 ` Kevin Traynor
  2020-04-10 10:51   ` Kevin Traynor
  2020-04-16 18:45   ` [dpdk-dev] [PATCH v2] x86/eal: gcc 10 ignore " Kevin Traynor
  3 siblings, 2 replies; 18+ messages in thread
From: Kevin Traynor @ 2020-04-07 16:27 UTC (permalink / raw)
  To: dev, thomas, bruce.richardson
  Cc: ravi1.kumar, g.singh, hemant.agrawal, akhil.goyal, johndale,
	hyonkim, jingjing.wu, wenzhuo.lu, rmody, shshaikh, matan,
	shahafs, declan.doherty, cristian.dumitrescu, Kevin Traynor

stringop-overflow warns when it sees a possible overflow
in a string operation.

In the rte_memcpy functions different implementations are
used depending on the size. stringop-overflow is raised for
the paths in the function where it sees the static size of the
src could be overflowed.

However, in reality a correct size argument and in some cases
dynamic allocation would ensure that this does not happen.

Disable this warning at the top level as it is being raised on
several components.

For example, in the case below for key, the correct path will be
chosen in rte_memcpy_generic at runtime based on the size argument
but as some paths in the function could lead to a cast to 32 bytes
a warning is raised.

In function ‘_mm256_storeu_si256’,
inlined from ‘rte_memcpy_generic’
at ../lib/librte_eal/common/include/arch/x86/rte_memcpy.h:315:2,
inlined from ‘iavf_configure_rss_key’
at ../lib/librte_eal/common/include/arch/x86/rte_memcpy.h:869:10:

/usr/lib/gcc/x86_64-redhat-linux/10/include/avxintrin.h:928:8:
warning: writing 32 bytes into a region of size 1 [-Wstringop-overflow=]
  928 |   *__P = __A;
      |   ~~~~~^~~~~
In file included
from ../drivers/net/iavf/../../common/iavf/iavf_prototype.h:10,
from ../drivers/net/iavf/iavf.h:9,
from ../drivers/net/iavf/iavf_vchnl.c:22:

../drivers/net/iavf/iavf_vchnl.c:
In function ‘iavf_configure_rss_key’:

../drivers/net/iavf/../../common/iavf/virtchnl.h:508:5:
note: at offset 0 to object ‘key’ with size 1 declared here
  508 |  u8 key[1];         /* RSS hash key, packed bytes */
      |     ^~~

Bugzilla ID: 394
Bugzilla ID: 421

Signed-off-by: Kevin Traynor <ktraynor@redhat.com>
---
 config/meson.build           | 3 ++-
 mk/toolchain/gcc/rte.vars.mk | 3 +++
 2 files changed, 5 insertions(+), 1 deletion(-)

diff --git a/config/meson.build b/config/meson.build
index 58421342b..476a667a9 100644
--- a/config/meson.build
+++ b/config/meson.build
@@ -200,5 +200,6 @@ warning_flags = [
 	'-Wno-address-of-packed-member',
 	'-Wno-packed-not-aligned',
-	'-Wno-missing-field-initializers'
+	'-Wno-missing-field-initializers',
+	'-Wno-stringop-overflow'
 ]
 if not dpdk_conf.get('RTE_ARCH_64')
diff --git a/mk/toolchain/gcc/rte.vars.mk b/mk/toolchain/gcc/rte.vars.mk
index f19305e49..fe4b8c705 100644
--- a/mk/toolchain/gcc/rte.vars.mk
+++ b/mk/toolchain/gcc/rte.vars.mk
@@ -101,4 +101,7 @@ endif
 WERROR_FLAGS += -Wno-address-of-packed-member
 
+# disable stringop-overflow warnings
+WERROR_FLAGS += -Wno-stringop-overflow
+
 export CC AS AR LD OBJCOPY OBJDUMP STRIP READELF
 export TOOLCHAIN_CFLAGS TOOLCHAIN_LDFLAGS TOOLCHAIN_ASFLAGS
-- 
2.21.1


^ permalink raw reply	[flat|nested] 18+ messages in thread

* Re: [dpdk-dev] [PATCH] build: gcc 10 disable stringop-overflow warnings
  2020-04-07 16:27 ` [dpdk-dev] [PATCH] build: gcc 10 disable stringop-overflow warnings Kevin Traynor
@ 2020-04-10 10:51   ` Kevin Traynor
  2020-04-10 13:23     ` Bruce Richardson
  2020-04-16 18:45   ` [dpdk-dev] [PATCH v2] x86/eal: gcc 10 ignore " Kevin Traynor
  1 sibling, 1 reply; 18+ messages in thread
From: Kevin Traynor @ 2020-04-10 10:51 UTC (permalink / raw)
  To: dev, thomas, bruce.richardson
  Cc: ravi1.kumar, g.singh, hemant.agrawal, akhil.goyal, johndale,
	hyonkim, jingjing.wu, wenzhuo.lu, rmody, shshaikh, matan,
	shahafs, declan.doherty, cristian.dumitrescu

On 07/04/2020 17:27, Kevin Traynor wrote:
> stringop-overflow warns when it sees a possible overflow
> in a string operation.
> 
> In the rte_memcpy functions different implementations are
> used depending on the size. stringop-overflow is raised for
> the paths in the function where it sees the static size of the
> src could be overflowed.
> 
> However, in reality a correct size argument and in some cases
> dynamic allocation would ensure that this does not happen.
> 
> Disable this warning at the top level as it is being raised on
> several components.
> 
> For example, in the case below for key, the correct path will be
> chosen in rte_memcpy_generic at runtime based on the size argument
> but as some paths in the function could lead to a cast to 32 bytes
> a warning is raised.
> 
> In function ‘_mm256_storeu_si256’,
> inlined from ‘rte_memcpy_generic’
> at ../lib/librte_eal/common/include/arch/x86/rte_memcpy.h:315:2,
> inlined from ‘iavf_configure_rss_key’
> at ../lib/librte_eal/common/include/arch/x86/rte_memcpy.h:869:10:
> 
> /usr/lib/gcc/x86_64-redhat-linux/10/include/avxintrin.h:928:8:
> warning: writing 32 bytes into a region of size 1 [-Wstringop-overflow=]
>   928 |   *__P = __A;
>       |   ~~~~~^~~~~
> In file included
> from ../drivers/net/iavf/../../common/iavf/iavf_prototype.h:10,
> from ../drivers/net/iavf/iavf.h:9,
> from ../drivers/net/iavf/iavf_vchnl.c:22:
> 
> ../drivers/net/iavf/iavf_vchnl.c:
> In function ‘iavf_configure_rss_key’:
> 
> ../drivers/net/iavf/../../common/iavf/virtchnl.h:508:5:
> note: at offset 0 to object ‘key’ with size 1 declared here
>   508 |  u8 key[1];         /* RSS hash key, packed bytes */
>       |     ^~~
> 

As an alternative, we could remove these warnings for rte_memcpy.h(s)
only. WDYT?

diff --git a/lib/librte_eal/x86/include/rte_memcpy.h
b/lib/librte_eal/x86/include/rte_memcpy.h
index ba44c4a32..862e0c402 100644
--- a/lib/librte_eal/x86/include/rte_memcpy.h
+++ b/lib/librte_eal/x86/include/rte_memcpy.h
@@ -19,4 +19,6 @@
 #include <rte_config.h>

+#pragma GCC diagnostic ignored "-Wstringop-overflow"
+
 #ifdef __cplusplus
 extern "C" {

> Bugzilla ID: 394
> Bugzilla ID: 421
> 
> Signed-off-by: Kevin Traynor <ktraynor@redhat.com>
> --->  config/meson.build           | 3 ++-
>  mk/toolchain/gcc/rte.vars.mk | 3 +++
>  2 files changed, 5 insertions(+), 1 deletion(-)
> 
> diff --git a/config/meson.build b/config/meson.build
> index 58421342b..476a667a9 100644
> --- a/config/meson.build
> +++ b/config/meson.build
> @@ -200,5 +200,6 @@ warning_flags = [
>  	'-Wno-address-of-packed-member',
>  	'-Wno-packed-not-aligned',
> -	'-Wno-missing-field-initializers'
> +	'-Wno-missing-field-initializers',
> +	'-Wno-stringop-overflow'
>  ]
>  if not dpdk_conf.get('RTE_ARCH_64')
> diff --git a/mk/toolchain/gcc/rte.vars.mk b/mk/toolchain/gcc/rte.vars.mk
> index f19305e49..fe4b8c705 100644
> --- a/mk/toolchain/gcc/rte.vars.mk
> +++ b/mk/toolchain/gcc/rte.vars.mk
> @@ -101,4 +101,7 @@ endif
>  WERROR_FLAGS += -Wno-address-of-packed-member
>  
> +# disable stringop-overflow warnings
> +WERROR_FLAGS += -Wno-stringop-overflow
> +
>  export CC AS AR LD OBJCOPY OBJDUMP STRIP READELF
>  export TOOLCHAIN_CFLAGS TOOLCHAIN_LDFLAGS TOOLCHAIN_ASFLAGS
> 


^ permalink raw reply	[flat|nested] 18+ messages in thread

* Re: [dpdk-dev] [PATCH] build: gcc 10 disable stringop-overflow warnings
  2020-04-10 10:51   ` Kevin Traynor
@ 2020-04-10 13:23     ` Bruce Richardson
  2020-04-16 18:43       ` Kevin Traynor
  0 siblings, 1 reply; 18+ messages in thread
From: Bruce Richardson @ 2020-04-10 13:23 UTC (permalink / raw)
  To: Kevin Traynor
  Cc: dev, thomas, ravi1.kumar, g.singh, hemant.agrawal, akhil.goyal,
	johndale, hyonkim, jingjing.wu, wenzhuo.lu, rmody, shshaikh,
	matan, shahafs, declan.doherty, cristian.dumitrescu

On Fri, Apr 10, 2020 at 11:51:56AM +0100, Kevin Traynor wrote:
> On 07/04/2020 17:27, Kevin Traynor wrote:
> > stringop-overflow warns when it sees a possible overflow
> > in a string operation.
> > 
> > In the rte_memcpy functions different implementations are
> > used depending on the size. stringop-overflow is raised for
> > the paths in the function where it sees the static size of the
> > src could be overflowed.
> > 
> > However, in reality a correct size argument and in some cases
> > dynamic allocation would ensure that this does not happen.
> > 
> > Disable this warning at the top level as it is being raised on
> > several components.
> > 
> > For example, in the case below for key, the correct path will be
> > chosen in rte_memcpy_generic at runtime based on the size argument
> > but as some paths in the function could lead to a cast to 32 bytes
> > a warning is raised.
> > 
> > In function ‘_mm256_storeu_si256’,
> > inlined from ‘rte_memcpy_generic’
> > at ../lib/librte_eal/common/include/arch/x86/rte_memcpy.h:315:2,
> > inlined from ‘iavf_configure_rss_key’
> > at ../lib/librte_eal/common/include/arch/x86/rte_memcpy.h:869:10:
> > 
> > /usr/lib/gcc/x86_64-redhat-linux/10/include/avxintrin.h:928:8:
> > warning: writing 32 bytes into a region of size 1 [-Wstringop-overflow=]
> >   928 |   *__P = __A;
> >       |   ~~~~~^~~~~
> > In file included
> > from ../drivers/net/iavf/../../common/iavf/iavf_prototype.h:10,
> > from ../drivers/net/iavf/iavf.h:9,
> > from ../drivers/net/iavf/iavf_vchnl.c:22:
> > 
> > ../drivers/net/iavf/iavf_vchnl.c:
> > In function ‘iavf_configure_rss_key’:
> > 
> > ../drivers/net/iavf/../../common/iavf/virtchnl.h:508:5:
> > note: at offset 0 to object ‘key’ with size 1 declared here
> >   508 |  u8 key[1];         /* RSS hash key, packed bytes */
> >       |     ^~~
> > 
> 
> As an alternative, we could remove these warnings for rte_memcpy.h(s)
> only. WDYT?
> 
> diff --git a/lib/librte_eal/x86/include/rte_memcpy.h
> b/lib/librte_eal/x86/include/rte_memcpy.h
> index ba44c4a32..862e0c402 100644
> --- a/lib/librte_eal/x86/include/rte_memcpy.h
> +++ b/lib/librte_eal/x86/include/rte_memcpy.h
> @@ -19,4 +19,6 @@
>  #include <rte_config.h>
> 
> +#pragma GCC diagnostic ignored "-Wstringop-overflow"
> +
>  #ifdef __cplusplus
>  extern "C" {

Limited disabling is always better than global disabling, so given the
choice of the two, +1 for this.

/Bruce

^ permalink raw reply	[flat|nested] 18+ messages in thread

* Re: [dpdk-dev] [PATCH] build: gcc 10 disable stringop-overflow warnings
  2020-04-10 13:23     ` Bruce Richardson
@ 2020-04-16 18:43       ` Kevin Traynor
  0 siblings, 0 replies; 18+ messages in thread
From: Kevin Traynor @ 2020-04-16 18:43 UTC (permalink / raw)
  To: Bruce Richardson, Gavin Hu
  Cc: dev, thomas, ravi1.kumar, g.singh, hemant.agrawal, akhil.goyal,
	johndale, hyonkim, jingjing.wu, wenzhuo.lu, rmody, shshaikh,
	matan, shahafs, declan.doherty, cristian.dumitrescu

On 10/04/2020 14:23, Bruce Richardson wrote:
> On Fri, Apr 10, 2020 at 11:51:56AM +0100, Kevin Traynor wrote:
>> On 07/04/2020 17:27, Kevin Traynor wrote:
>>> stringop-overflow warns when it sees a possible overflow
>>> in a string operation.
>>>
>>> In the rte_memcpy functions different implementations are
>>> used depending on the size. stringop-overflow is raised for
>>> the paths in the function where it sees the static size of the
>>> src could be overflowed.
>>>
>>> However, in reality a correct size argument and in some cases
>>> dynamic allocation would ensure that this does not happen.
>>>
>>> Disable this warning at the top level as it is being raised on
>>> several components.
>>>
>>> For example, in the case below for key, the correct path will be
>>> chosen in rte_memcpy_generic at runtime based on the size argument
>>> but as some paths in the function could lead to a cast to 32 bytes
>>> a warning is raised.
>>>
>>> In function ‘_mm256_storeu_si256’,
>>> inlined from ‘rte_memcpy_generic’
>>> at ../lib/librte_eal/common/include/arch/x86/rte_memcpy.h:315:2,
>>> inlined from ‘iavf_configure_rss_key’
>>> at ../lib/librte_eal/common/include/arch/x86/rte_memcpy.h:869:10:
>>>
>>> /usr/lib/gcc/x86_64-redhat-linux/10/include/avxintrin.h:928:8:
>>> warning: writing 32 bytes into a region of size 1 [-Wstringop-overflow=]
>>>   928 |   *__P = __A;
>>>       |   ~~~~~^~~~~
>>> In file included
>>> from ../drivers/net/iavf/../../common/iavf/iavf_prototype.h:10,
>>> from ../drivers/net/iavf/iavf.h:9,
>>> from ../drivers/net/iavf/iavf_vchnl.c:22:
>>>
>>> ../drivers/net/iavf/iavf_vchnl.c:
>>> In function ‘iavf_configure_rss_key’:
>>>
>>> ../drivers/net/iavf/../../common/iavf/virtchnl.h:508:5:
>>> note: at offset 0 to object ‘key’ with size 1 declared here
>>>   508 |  u8 key[1];         /* RSS hash key, packed bytes */
>>>       |     ^~~
>>>
>>
>> As an alternative, we could remove these warnings for rte_memcpy.h(s)
>> only. WDYT?
>>
>> diff --git a/lib/librte_eal/x86/include/rte_memcpy.h
>> b/lib/librte_eal/x86/include/rte_memcpy.h
>> index ba44c4a32..862e0c402 100644
>> --- a/lib/librte_eal/x86/include/rte_memcpy.h
>> +++ b/lib/librte_eal/x86/include/rte_memcpy.h
>> @@ -19,4 +19,6 @@
>>  #include <rte_config.h>
>>
>> +#pragma GCC diagnostic ignored "-Wstringop-overflow"
>> +
>>  #ifdef __cplusplus
>>  extern "C" {
> 
> Limited disabling is always better than global disabling, so given the
> choice of the two, +1 for this.
> 

Thanks Bruce. The slight disadvantage of this approach in short term is
a similar issue may also occur for gcc10 on ARM, but I don't have a
setup to test that, so an additional arm/eal fix may be required later.
I will limit fixing to what I can test, x86.

Gavin, can you check if a similar change is required for gcc10 on ARM?

> /Bruce
> 


^ permalink raw reply	[flat|nested] 18+ messages in thread

* [dpdk-dev] [PATCH v2] x86/eal: gcc 10 ignore stringop-overflow warnings
  2020-04-07 16:27 ` [dpdk-dev] [PATCH] build: gcc 10 disable stringop-overflow warnings Kevin Traynor
  2020-04-10 10:51   ` Kevin Traynor
@ 2020-04-16 18:45   ` " Kevin Traynor
  2020-04-17  9:33     ` Bruce Richardson
  2020-04-17 15:43     ` [dpdk-dev] [PATCH v3] " Kevin Traynor
  1 sibling, 2 replies; 18+ messages in thread
From: Kevin Traynor @ 2020-04-16 18:45 UTC (permalink / raw)
  To: dev, thomas, bruce.richardson, Gavin.Hu
  Cc: ravi1.kumar, g.singh, hemant.agrawal, akhil.goyal, johndale,
	hyonkim, jingjing.wu, wenzhuo.lu, rmody, shshaikh, matan,
	shahafs, declan.doherty, cristian.dumitrescu, Kevin Traynor

stringop-overflow warns when it sees a possible overflow
in a string operation.

In the rte_memcpy functions different branches are taken
depending on the size. stringop-overflow is raised for the
branches in the function where it sees the static size of the
src could be overflowed.

However, in reality a correct size argument and in some cases
dynamic allocation would ensure that this does not happen.

For example, in the case below for key, the correct path will be
chosen in rte_memcpy_generic at runtime based on the size argument
but as some paths in the function could lead to a cast to 32 bytes
a warning is raised.

In function ‘_mm256_storeu_si256’,
inlined from ‘rte_memcpy_generic’
at ../lib/librte_eal/common/include/arch/x86/rte_memcpy.h:315:2,
inlined from ‘iavf_configure_rss_key’
at ../lib/librte_eal/common/include/arch/x86/rte_memcpy.h:869:10:

/usr/lib/gcc/x86_64-redhat-linux/10/include/avxintrin.h:928:8:
warning: writing 32 bytes into a region of size 1 [-Wstringop-overflow=]
  928 |   *__P = __A;
      |   ~~~~~^~~~~
In file included
from ../drivers/net/iavf/../../common/iavf/iavf_prototype.h:10,
from ../drivers/net/iavf/iavf.h:9,
from ../drivers/net/iavf/iavf_vchnl.c:22:

../drivers/net/iavf/iavf_vchnl.c:
In function ‘iavf_configure_rss_key’:

../drivers/net/iavf/../../common/iavf/virtchnl.h:508:5:
note: at offset 0 to object ‘key’ with size 1 declared here
  508 |  u8 key[1];         /* RSS hash key, packed bytes */
      |     ^~~

Ignore the stringop-overflow warnings for rte_memcpy.h functions.

Bugzilla ID: 394
Bugzilla ID: 421

Signed-off-by: Kevin Traynor <ktraynor@redhat.com>

---

v2: Change from a global disable to just disabling for x86/rte_memcpy.h
---
 lib/librte_eal/x86/include/rte_memcpy.h | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/lib/librte_eal/x86/include/rte_memcpy.h b/lib/librte_eal/x86/include/rte_memcpy.h
index ba44c4a32..283fb79ba 100644
--- a/lib/librte_eal/x86/include/rte_memcpy.h
+++ b/lib/librte_eal/x86/include/rte_memcpy.h
@@ -23,4 +23,8 @@ extern "C" {
 #endif
 
+#if defined(RTE_TOOLCHAIN_GCC) && (GCC_VERSION >= 100000)
+#pragma GCC diagnostic ignored "-Wstringop-overflow"
+#endif
+
 /**
  * Copy bytes from one location to another. The locations must not overlap.
-- 
2.21.1


^ permalink raw reply	[flat|nested] 18+ messages in thread

* Re: [dpdk-dev] [PATCH v2] x86/eal: gcc 10 ignore stringop-overflow warnings
  2020-04-16 18:45   ` [dpdk-dev] [PATCH v2] x86/eal: gcc 10 ignore " Kevin Traynor
@ 2020-04-17  9:33     ` Bruce Richardson
  2020-04-17 10:13       ` Thomas Monjalon
  2020-04-17 12:40       ` Kevin Traynor
  2020-04-17 15:43     ` [dpdk-dev] [PATCH v3] " Kevin Traynor
  1 sibling, 2 replies; 18+ messages in thread
From: Bruce Richardson @ 2020-04-17  9:33 UTC (permalink / raw)
  To: Kevin Traynor
  Cc: dev, thomas, Gavin.Hu, ravi1.kumar, g.singh, hemant.agrawal,
	akhil.goyal, johndale, hyonkim, jingjing.wu, wenzhuo.lu, rmody,
	shshaikh, matan, shahafs, declan.doherty, cristian.dumitrescu

On Thu, Apr 16, 2020 at 07:45:49PM +0100, Kevin Traynor wrote:
> stringop-overflow warns when it sees a possible overflow
> in a string operation.
> 
> In the rte_memcpy functions different branches are taken
> depending on the size. stringop-overflow is raised for the
> branches in the function where it sees the static size of the
> src could be overflowed.
> 
> However, in reality a correct size argument and in some cases
> dynamic allocation would ensure that this does not happen.
> 
> For example, in the case below for key, the correct path will be
> chosen in rte_memcpy_generic at runtime based on the size argument
> but as some paths in the function could lead to a cast to 32 bytes
> a warning is raised.
> 
> In function ‘_mm256_storeu_si256’,
> inlined from ‘rte_memcpy_generic’
> at ../lib/librte_eal/common/include/arch/x86/rte_memcpy.h:315:2,
> inlined from ‘iavf_configure_rss_key’
> at ../lib/librte_eal/common/include/arch/x86/rte_memcpy.h:869:10:
> 
> /usr/lib/gcc/x86_64-redhat-linux/10/include/avxintrin.h:928:8:
> warning: writing 32 bytes into a region of size 1 [-Wstringop-overflow=]
>   928 |   *__P = __A;
>       |   ~~~~~^~~~~
> In file included
> from ../drivers/net/iavf/../../common/iavf/iavf_prototype.h:10,
> from ../drivers/net/iavf/iavf.h:9,
> from ../drivers/net/iavf/iavf_vchnl.c:22:
> 
> ../drivers/net/iavf/iavf_vchnl.c:
> In function ‘iavf_configure_rss_key’:
> 
> ../drivers/net/iavf/../../common/iavf/virtchnl.h:508:5:
> note: at offset 0 to object ‘key’ with size 1 declared here
>   508 |  u8 key[1];         /* RSS hash key, packed bytes */
>       |     ^~~
> 
> Ignore the stringop-overflow warnings for rte_memcpy.h functions.
> 
> Bugzilla ID: 394
> Bugzilla ID: 421
> 
> Signed-off-by: Kevin Traynor <ktraynor@redhat.com>
> 
> ---
> 
> v2: Change from a global disable to just disabling for x86/rte_memcpy.h
> ---
>  lib/librte_eal/x86/include/rte_memcpy.h | 4 ++++
>  1 file changed, 4 insertions(+)
> 
> diff --git a/lib/librte_eal/x86/include/rte_memcpy.h b/lib/librte_eal/x86/include/rte_memcpy.h
> index ba44c4a32..283fb79ba 100644
> --- a/lib/librte_eal/x86/include/rte_memcpy.h
> +++ b/lib/librte_eal/x86/include/rte_memcpy.h
> @@ -23,4 +23,8 @@ extern "C" {
>  #endif
>  
> +#if defined(RTE_TOOLCHAIN_GCC) && (GCC_VERSION >= 100000)
> +#pragma GCC diagnostic ignored "-Wstringop-overflow"
> +#endif
> +
>  /**
>   * Copy bytes from one location to another. The locations must not overlap.

Does this permanently need to be disabled for all compilation units
including rte_memcpy.h, or can it be used with a push/pop set of pragmas to
only disable for the required functions?

^ permalink raw reply	[flat|nested] 18+ messages in thread

* Re: [dpdk-dev] [PATCH v2] x86/eal: gcc 10 ignore stringop-overflow warnings
  2020-04-17  9:33     ` Bruce Richardson
@ 2020-04-17 10:13       ` Thomas Monjalon
  2020-04-17 14:50         ` Kevin Traynor
  2020-04-17 12:40       ` Kevin Traynor
  1 sibling, 1 reply; 18+ messages in thread
From: Thomas Monjalon @ 2020-04-17 10:13 UTC (permalink / raw)
  To: Kevin Traynor, Bruce Richardson
  Cc: dev, Gavin.Hu, ravi1.kumar, g.singh, hemant.agrawal, akhil.goyal,
	johndale, hyonkim, jingjing.wu, wenzhuo.lu, rmody, shshaikh,
	matan, shahafs, declan.doherty, cristian.dumitrescu,
	konstantin.ananyev, zhihong.wang

17/04/2020 11:33, Bruce Richardson:
> On Thu, Apr 16, 2020 at 07:45:49PM +0100, Kevin Traynor wrote:
> > stringop-overflow warns when it sees a possible overflow
> > in a string operation.
> > 
> > In the rte_memcpy functions different branches are taken
> > depending on the size. stringop-overflow is raised for the
> > branches in the function where it sees the static size of the
> > src could be overflowed.
> > 
> > However, in reality a correct size argument and in some cases
> > dynamic allocation would ensure that this does not happen.
> > 
> > For example, in the case below for key, the correct path will be
> > chosen in rte_memcpy_generic at runtime based on the size argument
> > but as some paths in the function could lead to a cast to 32 bytes
> > a warning is raised.
> > 
> > In function ‘_mm256_storeu_si256’,
> > inlined from ‘rte_memcpy_generic’
> > at ../lib/librte_eal/common/include/arch/x86/rte_memcpy.h:315:2,
> > inlined from ‘iavf_configure_rss_key’
> > at ../lib/librte_eal/common/include/arch/x86/rte_memcpy.h:869:10:
> > 
> > /usr/lib/gcc/x86_64-redhat-linux/10/include/avxintrin.h:928:8:
> > warning: writing 32 bytes into a region of size 1 [-Wstringop-overflow=]
> >   928 |   *__P = __A;
> >       |   ~~~~~^~~~~
> > In file included
> > from ../drivers/net/iavf/../../common/iavf/iavf_prototype.h:10,
> > from ../drivers/net/iavf/iavf.h:9,
> > from ../drivers/net/iavf/iavf_vchnl.c:22:
> > 
> > ../drivers/net/iavf/iavf_vchnl.c:
> > In function ‘iavf_configure_rss_key’:
> > 
> > ../drivers/net/iavf/../../common/iavf/virtchnl.h:508:5:
> > note: at offset 0 to object ‘key’ with size 1 declared here
> >   508 |  u8 key[1];         /* RSS hash key, packed bytes */
> >       |     ^~~
> > 
> > Ignore the stringop-overflow warnings for rte_memcpy.h functions.
> > 
> > Bugzilla ID: 394
> > Bugzilla ID: 421
> > 
> > Signed-off-by: Kevin Traynor <ktraynor@redhat.com>
[...]
> > --- a/lib/librte_eal/x86/include/rte_memcpy.h
> > +++ b/lib/librte_eal/x86/include/rte_memcpy.h
> > +#if defined(RTE_TOOLCHAIN_GCC) && (GCC_VERSION >= 100000)
> > +#pragma GCC diagnostic ignored "-Wstringop-overflow"
> > +#endif
> 
> Does this permanently need to be disabled for all compilation units
> including rte_memcpy.h, or can it be used with a push/pop set of pragmas to
> only disable for the required functions?

Even better, isn't there a solution in memcpy code?



^ permalink raw reply	[flat|nested] 18+ messages in thread

* Re: [dpdk-dev] [PATCH v2] x86/eal: gcc 10 ignore stringop-overflow warnings
  2020-04-17  9:33     ` Bruce Richardson
  2020-04-17 10:13       ` Thomas Monjalon
@ 2020-04-17 12:40       ` Kevin Traynor
  1 sibling, 0 replies; 18+ messages in thread
From: Kevin Traynor @ 2020-04-17 12:40 UTC (permalink / raw)
  To: Bruce Richardson
  Cc: dev, thomas, Gavin.Hu, ravi1.kumar, g.singh, hemant.agrawal,
	akhil.goyal, johndale, hyonkim, jingjing.wu, wenzhuo.lu, rmody,
	shshaikh, matan, shahafs, declan.doherty, cristian.dumitrescu

On 17/04/2020 10:33, Bruce Richardson wrote:
> On Thu, Apr 16, 2020 at 07:45:49PM +0100, Kevin Traynor wrote:
>> stringop-overflow warns when it sees a possible overflow
>> in a string operation.
>>
>> In the rte_memcpy functions different branches are taken
>> depending on the size. stringop-overflow is raised for the
>> branches in the function where it sees the static size of the
>> src could be overflowed.
>>
>> However, in reality a correct size argument and in some cases
>> dynamic allocation would ensure that this does not happen.
>>
>> For example, in the case below for key, the correct path will be
>> chosen in rte_memcpy_generic at runtime based on the size argument
>> but as some paths in the function could lead to a cast to 32 bytes
>> a warning is raised.
>>
>> In function ‘_mm256_storeu_si256’,
>> inlined from ‘rte_memcpy_generic’
>> at ../lib/librte_eal/common/include/arch/x86/rte_memcpy.h:315:2,
>> inlined from ‘iavf_configure_rss_key’
>> at ../lib/librte_eal/common/include/arch/x86/rte_memcpy.h:869:10:
>>
>> /usr/lib/gcc/x86_64-redhat-linux/10/include/avxintrin.h:928:8:
>> warning: writing 32 bytes into a region of size 1 [-Wstringop-overflow=]
>>   928 |   *__P = __A;
>>       |   ~~~~~^~~~~
>> In file included
>> from ../drivers/net/iavf/../../common/iavf/iavf_prototype.h:10,
>> from ../drivers/net/iavf/iavf.h:9,
>> from ../drivers/net/iavf/iavf_vchnl.c:22:
>>
>> ../drivers/net/iavf/iavf_vchnl.c:
>> In function ‘iavf_configure_rss_key’:
>>
>> ../drivers/net/iavf/../../common/iavf/virtchnl.h:508:5:
>> note: at offset 0 to object ‘key’ with size 1 declared here
>>   508 |  u8 key[1];         /* RSS hash key, packed bytes */
>>       |     ^~~
>>
>> Ignore the stringop-overflow warnings for rte_memcpy.h functions.
>>
>> Bugzilla ID: 394
>> Bugzilla ID: 421
>>
>> Signed-off-by: Kevin Traynor <ktraynor@redhat.com>
>>
>> ---
>>
>> v2: Change from a global disable to just disabling for x86/rte_memcpy.h
>> ---
>>  lib/librte_eal/x86/include/rte_memcpy.h | 4 ++++
>>  1 file changed, 4 insertions(+)
>>
>> diff --git a/lib/librte_eal/x86/include/rte_memcpy.h b/lib/librte_eal/x86/include/rte_memcpy.h
>> index ba44c4a32..283fb79ba 100644
>> --- a/lib/librte_eal/x86/include/rte_memcpy.h
>> +++ b/lib/librte_eal/x86/include/rte_memcpy.h
>> @@ -23,4 +23,8 @@ extern "C" {
>>  #endif
>>  
>> +#if defined(RTE_TOOLCHAIN_GCC) && (GCC_VERSION >= 100000)
>> +#pragma GCC diagnostic ignored "-Wstringop-overflow"
>> +#endif
>> +
>>  /**
>>   * Copy bytes from one location to another. The locations must not overlap.
> 
> Does this permanently need to be disabled for all compilation units
> including rte_memcpy.h, or can it be used with a push/pop set of pragmas to
> only disable for the required functions?
> 

Good point about compilation units. I'm not sure it makes sense to do
per function as the only ones that won't need it are the mov64/128/256
that are just wrappers for mov16/32 etc. Every function in rte_memcpy.h
that uses intrinsics and the aligned/generic will likely need it, which
is almost all of them.

With the GCC version conditional wrappers along with multiple
implementations depending on CPUFLAGS per function becomes messy and
harder to test. Considering that adding push/pop for the file only
increases the scope to those wrapper functions, I think it is better to
push/pop for the file.


^ permalink raw reply	[flat|nested] 18+ messages in thread

* Re: [dpdk-dev] [PATCH v2] x86/eal: gcc 10 ignore stringop-overflow warnings
  2020-04-17 10:13       ` Thomas Monjalon
@ 2020-04-17 14:50         ` Kevin Traynor
  0 siblings, 0 replies; 18+ messages in thread
From: Kevin Traynor @ 2020-04-17 14:50 UTC (permalink / raw)
  To: Thomas Monjalon, Bruce Richardson, konstantin.ananyev
  Cc: dev, Gavin.Hu, ravi1.kumar, g.singh, hemant.agrawal, akhil.goyal,
	johndale, hyonkim, jingjing.wu, wenzhuo.lu, rmody, shshaikh,
	matan, shahafs, declan.doherty, cristian.dumitrescu,
	zhihong.wang, David Marchand

On 17/04/2020 11:13, Thomas Monjalon wrote:
> 17/04/2020 11:33, Bruce Richardson:
>> On Thu, Apr 16, 2020 at 07:45:49PM +0100, Kevin Traynor wrote:
>>> stringop-overflow warns when it sees a possible overflow
>>> in a string operation.
>>>
>>> In the rte_memcpy functions different branches are taken
>>> depending on the size. stringop-overflow is raised for the
>>> branches in the function where it sees the static size of the
>>> src could be overflowed.
>>>
>>> However, in reality a correct size argument and in some cases
>>> dynamic allocation would ensure that this does not happen.
>>>
>>> For example, in the case below for key, the correct path will be
>>> chosen in rte_memcpy_generic at runtime based on the size argument
>>> but as some paths in the function could lead to a cast to 32 bytes
>>> a warning is raised.
>>>
>>> In function ‘_mm256_storeu_si256’,
>>> inlined from ‘rte_memcpy_generic’
>>> at ../lib/librte_eal/common/include/arch/x86/rte_memcpy.h:315:2,
>>> inlined from ‘iavf_configure_rss_key’
>>> at ../lib/librte_eal/common/include/arch/x86/rte_memcpy.h:869:10:
>>>
>>> /usr/lib/gcc/x86_64-redhat-linux/10/include/avxintrin.h:928:8:
>>> warning: writing 32 bytes into a region of size 1 [-Wstringop-overflow=]
>>>   928 |   *__P = __A;
>>>       |   ~~~~~^~~~~
>>> In file included
>>> from ../drivers/net/iavf/../../common/iavf/iavf_prototype.h:10,
>>> from ../drivers/net/iavf/iavf.h:9,
>>> from ../drivers/net/iavf/iavf_vchnl.c:22:
>>>
>>> ../drivers/net/iavf/iavf_vchnl.c:
>>> In function ‘iavf_configure_rss_key’:
>>>
>>> ../drivers/net/iavf/../../common/iavf/virtchnl.h:508:5:
>>> note: at offset 0 to object ‘key’ with size 1 declared here
>>>   508 |  u8 key[1];         /* RSS hash key, packed bytes */
>>>       |     ^~~
>>>
>>> Ignore the stringop-overflow warnings for rte_memcpy.h functions.
>>>
>>> Bugzilla ID: 394
>>> Bugzilla ID: 421
>>>
>>> Signed-off-by: Kevin Traynor <ktraynor@redhat.com>
> [...]
>>> --- a/lib/librte_eal/x86/include/rte_memcpy.h
>>> +++ b/lib/librte_eal/x86/include/rte_memcpy.h
>>> +#if defined(RTE_TOOLCHAIN_GCC) && (GCC_VERSION >= 100000)
>>> +#pragma GCC diagnostic ignored "-Wstringop-overflow"
>>> +#endif
>>
>> Does this permanently need to be disabled for all compilation units
>> including rte_memcpy.h, or can it be used with a push/pop set of pragmas to
>> only disable for the required functions?
> 
> Even better, isn't there a solution in memcpy code?
> 
> 

There may be, it could do with fresh eyes - Bruce/Konstantin?

In the meantime I will send a v3 with push/pop so it is available as an
option.


^ permalink raw reply	[flat|nested] 18+ messages in thread

* [dpdk-dev] [PATCH v3] x86/eal: gcc 10 ignore stringop-overflow warnings
  2020-04-16 18:45   ` [dpdk-dev] [PATCH v2] x86/eal: gcc 10 ignore " Kevin Traynor
  2020-04-17  9:33     ` Bruce Richardson
@ 2020-04-17 15:43     ` " Kevin Traynor
  2020-05-06  9:20       ` David Marchand
  1 sibling, 1 reply; 18+ messages in thread
From: Kevin Traynor @ 2020-04-17 15:43 UTC (permalink / raw)
  To: dev, thomas, bruce.richardson, Gavin.Hu, konstantin.ananyev
  Cc: ravi1.kumar, g.singh, hemant.agrawal, akhil.goyal, johndale,
	hyonkim, jingjing.wu, wenzhuo.lu, rmody, shshaikh, matan,
	shahafs, declan.doherty, cristian.dumitrescu, Kevin Traynor

stringop-overflow warns when it sees a possible overflow
in a string operation.

In the rte_memcpy functions different branches are taken
depending on the size. stringop-overflow is raised for the
branches in the function where it sees the static size of the
src could be overflowed.

However, in reality a correct size argument and in some cases
dynamic allocation would ensure that this does not happen.

For example, in the case below for key, the correct path will be
chosen in rte_memcpy_generic at runtime based on the size argument
but as some paths in the function could lead to a cast to 32 bytes
a warning is raised.

In function ‘_mm256_storeu_si256’,
inlined from ‘rte_memcpy_generic’
at ../lib/librte_eal/common/include/arch/x86/rte_memcpy.h:315:2,
inlined from ‘iavf_configure_rss_key’
at ../lib/librte_eal/common/include/arch/x86/rte_memcpy.h:869:10:

/usr/lib/gcc/x86_64-redhat-linux/10/include/avxintrin.h:928:8:
warning: writing 32 bytes into a region of size 1 [-Wstringop-overflow=]
  928 |   *__P = __A;
      |   ~~~~~^~~~~
In file included
from ../drivers/net/iavf/../../common/iavf/iavf_prototype.h:10,
from ../drivers/net/iavf/iavf.h:9,
from ../drivers/net/iavf/iavf_vchnl.c:22:

../drivers/net/iavf/iavf_vchnl.c:
In function ‘iavf_configure_rss_key’:

../drivers/net/iavf/../../common/iavf/virtchnl.h:508:5:
note: at offset 0 to object ‘key’ with size 1 declared here
  508 |  u8 key[1];         /* RSS hash key, packed bytes */
      |     ^~~

Ignore the stringop-overflow warnings for rte_memcpy.h functions.

Bugzilla ID: 394
Bugzilla ID: 421

Signed-off-by: Kevin Traynor <ktraynor@redhat.com>

---
v3: Add push/pop to not leak the ignore warning
v2: Change from a global disable to just disabling for x86/rte_memcpy.h
---
 lib/librte_eal/x86/include/rte_memcpy.h | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/lib/librte_eal/x86/include/rte_memcpy.h b/lib/librte_eal/x86/include/rte_memcpy.h
index ba44c4a32..9c67232df 100644
--- a/lib/librte_eal/x86/include/rte_memcpy.h
+++ b/lib/librte_eal/x86/include/rte_memcpy.h
@@ -23,4 +23,9 @@ extern "C" {
 #endif
 
+#if defined(RTE_TOOLCHAIN_GCC) && (GCC_VERSION >= 100000)
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wstringop-overflow"
+#endif
+
 /**
  * Copy bytes from one location to another. The locations must not overlap.
@@ -870,4 +875,8 @@ rte_memcpy(void *dst, const void *src, size_t n)
 }
 
+#if defined(RTE_TOOLCHAIN_GCC) && (GCC_VERSION >= 100000)
+#pragma GCC diagnostic pop
+#endif
+
 #ifdef __cplusplus
 }
-- 
2.21.1


^ permalink raw reply	[flat|nested] 18+ messages in thread

* Re: [dpdk-dev] [PATCH v3] x86/eal: gcc 10 ignore stringop-overflow warnings
  2020-04-17 15:43     ` [dpdk-dev] [PATCH v3] " Kevin Traynor
@ 2020-05-06  9:20       ` David Marchand
  0 siblings, 0 replies; 18+ messages in thread
From: David Marchand @ 2020-05-06  9:20 UTC (permalink / raw)
  To: Kevin Traynor
  Cc: dev, Thomas Monjalon, Bruce Richardson, Gavin Hu, Ananyev,
	Konstantin, Ravi Kumar, Gagandeep Singh, Hemant Agrawal,
	Akhil Goyal, John Daley, Hyong Youb Kim, Jingjing Wu, Wenzhuo Lu,
	Rasesh Mody, Shahed Shaikh, Matan Azrad, Shahaf Shuler,
	Declan Doherty, Cristian Dumitrescu

On Fri, Apr 17, 2020 at 5:44 PM Kevin Traynor <ktraynor@redhat.com> wrote:
>
> stringop-overflow warns when it sees a possible overflow
> in a string operation.
>
> In the rte_memcpy functions different branches are taken
> depending on the size. stringop-overflow is raised for the
> branches in the function where it sees the static size of the
> src could be overflowed.
>
> However, in reality a correct size argument and in some cases
> dynamic allocation would ensure that this does not happen.
>
> For example, in the case below for key, the correct path will be
> chosen in rte_memcpy_generic at runtime based on the size argument
> but as some paths in the function could lead to a cast to 32 bytes
> a warning is raised.
>
> In function ‘_mm256_storeu_si256’,
> inlined from ‘rte_memcpy_generic’
> at ../lib/librte_eal/common/include/arch/x86/rte_memcpy.h:315:2,
> inlined from ‘iavf_configure_rss_key’
> at ../lib/librte_eal/common/include/arch/x86/rte_memcpy.h:869:10:
>
> /usr/lib/gcc/x86_64-redhat-linux/10/include/avxintrin.h:928:8:
> warning: writing 32 bytes into a region of size 1 [-Wstringop-overflow=]
>   928 |   *__P = __A;
>       |   ~~~~~^~~~~
> In file included
> from ../drivers/net/iavf/../../common/iavf/iavf_prototype.h:10,
> from ../drivers/net/iavf/iavf.h:9,
> from ../drivers/net/iavf/iavf_vchnl.c:22:
>
> ../drivers/net/iavf/iavf_vchnl.c:
> In function ‘iavf_configure_rss_key’:
>
> ../drivers/net/iavf/../../common/iavf/virtchnl.h:508:5:
> note: at offset 0 to object ‘key’ with size 1 declared here
>   508 |  u8 key[1];         /* RSS hash key, packed bytes */
>       |     ^~~
>
> Ignore the stringop-overflow warnings for rte_memcpy.h functions.
>
> Bugzilla ID: 394
> Bugzilla ID: 421
>

Cc: stable@dpdk.org

> Signed-off-by: Kevin Traynor <ktraynor@redhat.com>

Acked-by: Bruce Richardson <bruce.richardson@@intel.com>
Acked-by: Konstantin Ananyev <konstantin.ananyev@intel.com>


Applied, thanks.

-- 
David Marchand


^ permalink raw reply	[flat|nested] 18+ messages in thread

end of thread, back to index

Thread overview: 18+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2020-03-25 14:11 [dpdk-dev] [RFC 0/2] gcc 10 disable stringop-overflow warning Kevin Traynor
2020-03-25 14:11 ` [dpdk-dev] [RFC 1/2] meson: gcc 10 disable stringop-overflow warnings Kevin Traynor
2020-03-25 14:11 ` [dpdk-dev] [RFC 2/2] mk: " Kevin Traynor
2020-03-25 14:18 ` [dpdk-dev] [RFC 0/2] gcc 10 disable stringop-overflow warning Thomas Monjalon
2020-03-31 14:08   ` Kevin Traynor
2020-03-31 14:53     ` Stephen Hemminger
2020-04-01 11:33       ` Kevin Traynor
2020-04-07 16:27 ` [dpdk-dev] [PATCH] build: gcc 10 disable stringop-overflow warnings Kevin Traynor
2020-04-10 10:51   ` Kevin Traynor
2020-04-10 13:23     ` Bruce Richardson
2020-04-16 18:43       ` Kevin Traynor
2020-04-16 18:45   ` [dpdk-dev] [PATCH v2] x86/eal: gcc 10 ignore " Kevin Traynor
2020-04-17  9:33     ` Bruce Richardson
2020-04-17 10:13       ` Thomas Monjalon
2020-04-17 14:50         ` Kevin Traynor
2020-04-17 12:40       ` Kevin Traynor
2020-04-17 15:43     ` [dpdk-dev] [PATCH v3] " Kevin Traynor
2020-05-06  9:20       ` David Marchand

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