* [Buildroot] [PATCH 1/1] package/ibm-sw-tpm2: fix build with gcc-15.x
@ 2026-09-16 23:12 Bernd Kuhls
2026-09-17 6:37 ` Thomas Petazzoni via buildroot
2026-09-25 14:46 ` Raphaël Mélotte via buildroot
0 siblings, 2 replies; 3+ messages in thread
From: Bernd Kuhls @ 2026-09-16 23:12 UTC (permalink / raw)
To: buildroot; +Cc: Philippe Reynes
Fixes:
https://autobuild.buildroot.net/results/d43/d4364f6e3636c696471bf8cba6d308439130e53a/
In function 'MakeIv',
inlined from 'TestSymmetricAlgorithm' at AlgorithmTests.c:197:25:
AlgorithmTests.c:181:23: error: writing 32 bytes into a region of size
16 [-Werror=stringop-overflow=]
The build error occurs with gcc 15.x on some platforms, gcc 14.x is not
affected.
These defconfigs build without this patch:
BR2_x86_64=y
BR2_GCC_VERSION_14_X=y
BR2_PACKAGE_IBM_SW_TPM2=y
BR2_x86_64=y
BR2_x86_x86_64_v4=y
BR2_GCC_VERSION_14_X=y
BR2_PACKAGE_IBM_SW_TPM2=y
BR2_x86_64=y
BR2_PACKAGE_IBM_SW_TPM2=y
This gcc-15 based defconfig is broken:
BR2_x86_64=y
BR2_x86_x86_64_v4=y
BR2_PACKAGE_IBM_SW_TPM2=y
The build error is not related to the recent bump of the package from
rev183-2024-03-27 to rev183-2026-08-26 because no changes were committed
upstream to AlgorithmTests.c since rev183-2024-03-27:
https://github.com/kgoldman/ibmswtpm2/commits/master/src/AlgorithmTests.c
Signed-off-by: Bernd Kuhls <bernd@kuhls.net>
---
...15-stringop-overflow-error-in-MakeIv.patch | 45 +++++++++++++++++++
1 file changed, 45 insertions(+)
create mode 100644 package/ibm-sw-tpm2/0003-tpm2-fix-GCC-15-stringop-overflow-error-in-MakeIv.patch
diff --git a/package/ibm-sw-tpm2/0003-tpm2-fix-GCC-15-stringop-overflow-error-in-MakeIv.patch b/package/ibm-sw-tpm2/0003-tpm2-fix-GCC-15-stringop-overflow-error-in-MakeIv.patch
new file mode 100644
index 0000000000..9b22522b36
--- /dev/null
+++ b/package/ibm-sw-tpm2/0003-tpm2-fix-GCC-15-stringop-overflow-error-in-MakeIv.patch
@@ -0,0 +1,45 @@
+From b35faee1224f5bccf759464e69f724a03421c8a9 Mon Sep 17 00:00:00 2001
+From: Arthur Gautier <arthur.gautier@arista.com>
+Date: Tue, 9 Jun 2026 21:52:07 -0700
+Subject: [PATCH] tpm2: fix GCC 15 stringop-overflow error in MakeIv
+
+When compiling with GCC 15 using `CFLAGS=-march=x86-64-v4`, the compiler's
+aggressively optimized vectorizer triggers a false-positive
+-Wstringop-overflow error. Because x86-64-v4 enables wide AVX-512 registers,
+the compiler misinterprets the loop unrolling and warns that a 64-byte
+vector write is overflowing the destination buffer:
+```
+ tpm2/TPMCmd/tpm/src/crypt/AlgorithmTests.c:158:17: error:
+ writing 64 bytes into a region of size 15 [-Werror=stringop-overflow=]
+ 158 | *iv = i;
+```
+
+This fixes the warning by marking the `iv` output pointer parameter as
+`volatile`. This inhibits the over-aggressive loop vectorization on this
+specific buffer, silencing the compiler error without changing the
+underlying logic.
+
+Signed-off-by: Arthur Gautier <arthur.gautier@arista.com>
+
+Source: https://github.com/stefanberger/libtpms/commit/2d9b00c4e42677cd0a9b67344f4d873ddc409a21
+Upstream: https://github.com/kgoldman/ibmswtpm2/pull/25
+
+[Bernd: rebased for ibm-sw-tpm2 package]
+Signed-off-by: Bernd Kuhls <bernd@kuhls.net>
+---
+ src/AlgorithmTests.c | 6 +++---
+ 1 file changed, 3 insertions(+), 3 deletions(-)
+
+diff --git a/src/AlgorithmTests.c b/src/AlgorithmTests.c
+index e8549adca..28d8e780a 100644
+--- a/src/AlgorithmTests.c
++++ b/src/AlgorithmTests.c
+@@ -162,7 +162,7 @@
+ // Internal function to make the appropriate IV depending on the mode.
+ static UINT32 MakeIv(TPM_ALG_ID mode, // IN: symmetric mode
+ UINT32 size, // IN: block size of the algorithm
+- BYTE* iv // OUT: IV to fill in
++ volatile BYTE* iv // OUT: IV to fill in
+ )
+ {
+ BYTE i;
--
2.47.3
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^ permalink raw reply related [flat|nested] 3+ messages in thread* Re: [Buildroot] [PATCH 1/1] package/ibm-sw-tpm2: fix build with gcc-15.x
2026-09-16 23:12 [Buildroot] [PATCH 1/1] package/ibm-sw-tpm2: fix build with gcc-15.x Bernd Kuhls
@ 2026-09-17 6:37 ` Thomas Petazzoni via buildroot
2026-09-25 14:46 ` Raphaël Mélotte via buildroot
1 sibling, 0 replies; 3+ messages in thread
From: Thomas Petazzoni via buildroot @ 2026-09-17 6:37 UTC (permalink / raw)
To: Bernd Kuhls; +Cc: buildroot, Philippe Reynes
On Thu, Sep 17, 2026 at 01:12:35AM +0200, Bernd Kuhls wrote:
> Fixes:
> https://autobuild.buildroot.net/results/d43/d4364f6e3636c696471bf8cba6d308439130e53a/
>
> In function 'MakeIv',
> inlined from 'TestSymmetricAlgorithm' at AlgorithmTests.c:197:25:
> AlgorithmTests.c:181:23: error: writing 32 bytes into a region of size
> 16 [-Werror=stringop-overflow=]
>
> The build error occurs with gcc 15.x on some platforms, gcc 14.x is not
> affected.
>
> These defconfigs build without this patch:
>
> BR2_x86_64=y
> BR2_GCC_VERSION_14_X=y
> BR2_PACKAGE_IBM_SW_TPM2=y
>
> BR2_x86_64=y
> BR2_x86_x86_64_v4=y
> BR2_GCC_VERSION_14_X=y
> BR2_PACKAGE_IBM_SW_TPM2=y
>
> BR2_x86_64=y
> BR2_PACKAGE_IBM_SW_TPM2=y
>
> This gcc-15 based defconfig is broken:
>
> BR2_x86_64=y
> BR2_x86_x86_64_v4=y
> BR2_PACKAGE_IBM_SW_TPM2=y
>
> The build error is not related to the recent bump of the package from
> rev183-2024-03-27 to rev183-2026-08-26 because no changes were committed
> upstream to AlgorithmTests.c since rev183-2024-03-27:
> https://github.com/kgoldman/ibmswtpm2/commits/master/src/AlgorithmTests.c
>
> Signed-off-by: Bernd Kuhls <bernd@kuhls.net>
Applied to master, thanks!
Best regards,
Thomas Petazzoni
--
Thomas Petazzoni, co-owner and CEO, Bootlin
Embedded Linux and Kernel engineering and training
https://bootlin.com
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^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [Buildroot] [PATCH 1/1] package/ibm-sw-tpm2: fix build with gcc-15.x
2026-09-16 23:12 [Buildroot] [PATCH 1/1] package/ibm-sw-tpm2: fix build with gcc-15.x Bernd Kuhls
2026-09-17 6:37 ` Thomas Petazzoni via buildroot
@ 2026-09-25 14:46 ` Raphaël Mélotte via buildroot
1 sibling, 0 replies; 3+ messages in thread
From: Raphaël Mélotte via buildroot @ 2026-09-25 14:46 UTC (permalink / raw)
To: buildroot, Bernd Kuhls; +Cc: Raphaël Mélotte
In reply of:
> Fixes:
> https://autobuild.buildroot.net/results/d43/d4364f6e3636c696471bf8cba6d308439130e53a/
>
> In function 'MakeIv',
> inlined from 'TestSymmetricAlgorithm' at AlgorithmTests.c:197:25:
> AlgorithmTests.c:181:23: error: writing 32 bytes into a region of size
> 16 [-Werror=stringop-overflow=]
>
> The build error occurs with gcc 15.x on some platforms, gcc 14.x is not
> affected.
>
> These defconfigs build without this patch:
>
> BR2_x86_64=y
> BR2_GCC_VERSION_14_X=y
> BR2_PACKAGE_IBM_SW_TPM2=y
>
> BR2_x86_64=y
> BR2_x86_x86_64_v4=y
> BR2_GCC_VERSION_14_X=y
> BR2_PACKAGE_IBM_SW_TPM2=y
>
> BR2_x86_64=y
> BR2_PACKAGE_IBM_SW_TPM2=y
>
> This gcc-15 based defconfig is broken:
>
> BR2_x86_64=y
> BR2_x86_x86_64_v4=y
> BR2_PACKAGE_IBM_SW_TPM2=y
>
> The build error is not related to the recent bump of the package from
> rev183-2024-03-27 to rev183-2026-08-26 because no changes were committed
> upstream to AlgorithmTests.c since rev183-2024-03-27:
> https://github.com/kgoldman/ibmswtpm2/commits/master/src/AlgorithmTests.c
>
> Signed-off-by: Bernd Kuhls <bernd@kuhls.net>
Applied to 2026.08.x. Thanks
> ---
> ...15-stringop-overflow-error-in-MakeIv.patch | 45 +++++++++++++++++++
> 1 file changed, 45 insertions(+)
> create mode 100644 package/ibm-sw-tpm2/0003-tpm2-fix-GCC-15-stringop-overflow-error-in-MakeIv.patch
>
> diff --git a/package/ibm-sw-tpm2/0003-tpm2-fix-GCC-15-stringop-overflow-error-in-MakeIv.patch b/package/ibm-sw-tpm2/0003-tpm2-fix-GCC-15-stringop-overflow-error-in-MakeIv.patch
> new file mode 100644
> index 0000000000..9b22522b36
> --- /dev/null
> +++ b/package/ibm-sw-tpm2/0003-tpm2-fix-GCC-15-stringop-overflow-error-in-MakeIv.patch
> @@ -0,0 +1,45 @@
> +From b35faee1224f5bccf759464e69f724a03421c8a9 Mon Sep 17 00:00:00 2001
> +From: Arthur Gautier <arthur.gautier@arista.com>
> +Date: Tue, 9 Jun 2026 21:52:07 -0700
> +Subject: [PATCH] tpm2: fix GCC 15 stringop-overflow error in MakeIv
> +
> +When compiling with GCC 15 using `CFLAGS=-march=x86-64-v4`, the compiler's
> +aggressively optimized vectorizer triggers a false-positive
> +-Wstringop-overflow error. Because x86-64-v4 enables wide AVX-512 registers,
> +the compiler misinterprets the loop unrolling and warns that a 64-byte
> +vector write is overflowing the destination buffer:
> +```
> + tpm2/TPMCmd/tpm/src/crypt/AlgorithmTests.c:158:17: error:
> + writing 64 bytes into a region of size 15 [-Werror=stringop-overflow=]
> + 158 | *iv = i;
> +```
> +
> +This fixes the warning by marking the `iv` output pointer parameter as
> +`volatile`. This inhibits the over-aggressive loop vectorization on this
> +specific buffer, silencing the compiler error without changing the
> +underlying logic.
> +
> +Signed-off-by: Arthur Gautier <arthur.gautier@arista.com>
> +
> +Source: https://github.com/stefanberger/libtpms/commit/2d9b00c4e42677cd0a9b67344f4d873ddc409a21
> +Upstream: https://github.com/kgoldman/ibmswtpm2/pull/25
> +
> +[Bernd: rebased for ibm-sw-tpm2 package]
> +Signed-off-by: Bernd Kuhls <bernd@kuhls.net>
> +---
> + src/AlgorithmTests.c | 6 +++---
> + 1 file changed, 3 insertions(+), 3 deletions(-)
> +
> +diff --git a/src/AlgorithmTests.c b/src/AlgorithmTests.c
> +index e8549adca..28d8e780a 100644
> +--- a/src/AlgorithmTests.c
> ++++ b/src/AlgorithmTests.c
> +@@ -162,7 +162,7 @@
> + // Internal function to make the appropriate IV depending on the mode.
> + static UINT32 MakeIv(TPM_ALG_ID mode, // IN: symmetric mode
> + UINT32 size, // IN: block size of the algorithm
> +- BYTE* iv // OUT: IV to fill in
> ++ volatile BYTE* iv // OUT: IV to fill in
> + )
> + {
> + BYTE i;
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2026-09-16 23:12 [Buildroot] [PATCH 1/1] package/ibm-sw-tpm2: fix build with gcc-15.x Bernd Kuhls
2026-09-17 6:37 ` Thomas Petazzoni via buildroot
2026-09-25 14:46 ` Raphaël Mélotte via buildroot
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