[v2,2/2] build: fix crash by disabling AVX512 with binutils 2.31
Checks
Commit Message
On Skylake platform, with native build, KNI kernel module crashes
because of the corrupted values passed to kernel module.
The corruption occurs because the userspace kni library works
unexpectedly. Compiler [1] is using AVX512 instructions and generated
binary is wrong [2].
It turned around gcc does its job correct, but gas is generating binary
wrong. And expected binutils 2.30, 2.31 & 2.31.1 are affected. Issue has
been fixed in binutils 2.32 with:
Commit x86: don't mistakenly scale non-8-bit displacements
AVX512 was already disabled with bintuils 2.30 [3], extending it to
2.31 & 2.31.1 too.
[1] gcc (GCC) 8.3.1 20190223 (Red Hat 8.3.1-2)
[2] gcc bug: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=90028
[3] Bugzilla ID 97 has the details.
Bugzilla ID: 249
Cc: stable@dpdk.org
Signed-off-by: Ferruh Yigit <ferruh.yigit@intel.com>
---
v2:
* Release notes "Known Issues" section updated
---
config/x86/meson.build | 6 ++++++
doc/guides/rel_notes/release_19_05.rst | 6 ++++++
mk/toolchain/gcc/rte.toolchain-compat.mk | 9 ++++++++-
3 files changed, 20 insertions(+), 1 deletion(-)
Comments
On Tue, Apr 16, 2019 at 04:39:32PM +0100, Ferruh Yigit wrote:
> On Skylake platform, with native build, KNI kernel module crashes
> because of the corrupted values passed to kernel module.
>
> The corruption occurs because the userspace kni library works
> unexpectedly. Compiler [1] is using AVX512 instructions and generated
> binary is wrong [2].
>
> It turned around gcc does its job correct, but gas is generating binary
> wrong. And expected binutils 2.30, 2.31 & 2.31.1 are affected. Issue has
> been fixed in binutils 2.32 with:
> Commit x86: don't mistakenly scale non-8-bit displacements
>
> AVX512 was already disabled with bintuils 2.30 [3], extending it to
> 2.31 & 2.31.1 too.
>
> [1] gcc (GCC) 8.3.1 20190223 (Red Hat 8.3.1-2)
>
> [2] gcc bug: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=90028
>
> [3] Bugzilla ID 97 has the details.
>
> Bugzilla ID: 249
> Cc: stable@dpdk.org
>
> Signed-off-by: Ferruh Yigit <ferruh.yigit@intel.com>
> ---
> v2:
> * Release notes "Known Issues" section updated
> ---
> config/x86/meson.build | 6 ++++++
> doc/guides/rel_notes/release_19_05.rst | 6 ++++++
> mk/toolchain/gcc/rte.toolchain-compat.mk | 9 ++++++++-
> 3 files changed, 20 insertions(+), 1 deletion(-)
>
> diff --git a/config/x86/meson.build b/config/x86/meson.build
> index 692aebe7a..9e9d5dc8c 100644
> --- a/config/x86/meson.build
> +++ b/config/x86/meson.build
> @@ -10,6 +10,12 @@ if host_machine.system() != 'windows'
> message('Binutils 2.30 detected, disabling AVX512 support as workaround for bug #97')
> endif
> endif
> + if ldver.contains('2.31')
> + if cc.has_argument('-mno-avx512f')
> + machine_args += '-mno-avx512f'
> + message('Binutils 2.31 detected, disabling AVX512 support as workaround for bug #249')
> + endif
> + endif
Is this not the same as the previous block just with a slightly different
error message? Should we merge the two, and print out both bug numbers?
If not merging, we can reduce the indentation by putting the second
cc.has_argument() condition on the same line as the previous check, i.e.
"if ldver.contains(...) and cc.has_argument(...)"
Apart from this nit:
Acked-by: Bruce Richardson <bruce.richardson@intel.com>
@@ -10,6 +10,12 @@ if host_machine.system() != 'windows'
message('Binutils 2.30 detected, disabling AVX512 support as workaround for bug #97')
endif
endif
+ if ldver.contains('2.31')
+ if cc.has_argument('-mno-avx512f')
+ machine_args += '-mno-avx512f'
+ message('Binutils 2.31 detected, disabling AVX512 support as workaround for bug #249')
+ endif
+ endif
endif
# we require SSE4.2 for DPDK
@@ -338,6 +338,12 @@ Known Issues
Also, make sure to start the actual text at the margin.
=========================================================
+* **On x86 platforms, AVX512 support is disabled with binutils 2.31**
+
+ Because a defect in binutils 2.31 AVX512 support is disabled.
+ DPDK defect: https://bugs.dpdk.org/show_bug.cgi?id=249
+ GCC defect: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=90028
+
* **No software AES-XTS implementation.**
There are currently no cryptodev software PMDs available which implement
@@ -27,7 +27,14 @@ ifneq ($(filter 2.30%,$(LD_VERSION)),)
FORCE_DISABLE_AVX512 := y
# print warning only once for librte_eal
ifneq ($(filter %librte_eal,$(CURDIR)),)
-$(warning AVX512 support disabled because of ld 2.30. See Bug 97)
+$(warning AVX512 support disabled because of binutils 2.30. See Bug 97)
+endif
+endif
+ifneq ($(filter 2.31%,$(LD_VERSION)),)
+FORCE_DISABLE_AVX512 := y
+# print warning only once for librte_eal
+ifneq ($(filter %librte_eal,$(CURDIR)),)
+$(warning AVX512 support disabled because of binutils 2.31. See Bug 249)
endif
endif
endif