[Buildroot] [PATCH] configs/visionfive2_defconfig: bump Linux to 6.18.52

[Buildroot] [PATCH] configs/visionfive2_defconfig: bump Linux to 6.18.52

[Fengwei Tan]

When running iperf3 with Linux 6.18.51 on VisionFive 2, one CPU core
stays at 100% load during the test. The iperf3 server log shows the
throughput is limited to approximately 793 Mbits/sec:

[ ID] Interval           Transfer     Bitrate
[  5]   0.00-10.01  sec   945 MBytes   793 Mbits/sec                  receiver

The regression was introduced in Linux 6.14 by commit df542f669307
("net: stmmac: Switch to zero-copy in non-XDP RX path"). It leads to
misaligned access exceptions when parsing packet headers. During the
iperf3 test, perf stat reported approximately 9.6 million alignment
faults over 5 seconds:

$ perf stat -a -e alignment-faults -- sleep 5

 Performance counter stats for 'system wide':

           9620073      alignment-faults

       5.029337000 seconds time elapsed

The kernel must emulate these unaligned accesses, resulting in
significant overhead.

The Linux kernel CVE team assigned CVE-2026-90059 to this issue [1].

Bump kernel to 6.18.52, which contains the fix for this issue.

[1] https://lore.kernel.org/all/2026091704-CVE-2026-90059-36e6@gregkh

Fixes: 98aa14a186e1 ("configs/visionfive2: bump Linux to 6.18.51, U-Boot to 2026.07, and OpenSBI to 1.8.1")
Assisted-by: Codex:GPT-6.1-Sol
Signed-off-by: Fengwei Tan <tfx2001@outlook.com>
---
Hello all,

This patch fixes a performance issue on the VisionFive 2, caused by
misaligned access when the Linux kernel network stack parses packet
headers.

I noticed this issue while running iperf3 tests on the VisionFive 2
board. I captured perf data [1] and analyzed it with LLM, which
quickly identified the relevant upstream kernel commit and the
corresponding lore archive [2].

I rebuilt Linux 6.18.51 with the fix patch [3] applied and retested; the
issue was resolved. So I am pretty sure this issue was introduced by the
commit identified by the LLM.

[1] https://gist.github.com/tfx2001/f1f10ee1274acb7063ef1def5f2b119a
[2] https://lore.kernel.org/all/2026091704-CVE-2026-90059-36e6@gregkh/
[3] https://git.kernel.org/stable/c/2ea42936416b29cca42b2c7bc7d3d3768f77c199
---
 board/visionfive2/patches/linux/linux.hash | 2 +-
 configs/visionfive2_defconfig              | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/board/visionfive2/patches/linux/linux.hash b/board/visionfive2/patches/linux/linux.hash
index b2cfc9b7e7..1e58cd0b9f 100644
--- a/board/visionfive2/patches/linux/linux.hash
+++ b/board/visionfive2/patches/linux/linux.hash
@@ -1,2 +1,2 @@
 # Locally calculated
-sha256  ba2f60f858bf4d1f929101faa356c93dc8b925b17aaa9f95eabd4627758df613  linux-6.18.51.tar.xz
+sha256  2b69564f7d4fea0c859b1959ba33709ee6e9139bd100e30a853b57159a8221b8  linux-6.18.52.tar.xz
diff --git a/configs/visionfive2_defconfig b/configs/visionfive2_defconfig
index 7ce605b84b..bfe5e42cc5 100644
--- a/configs/visionfive2_defconfig
+++ b/configs/visionfive2_defconfig
@@ -7,7 +7,7 @@ BR2_ROOTFS_OVERLAY="board/visionfive2/overlay"
 BR2_ROOTFS_POST_IMAGE_SCRIPT="board/visionfive2/post-image.sh"
 BR2_LINUX_KERNEL=y
 BR2_LINUX_KERNEL_CUSTOM_VERSION=y
-BR2_LINUX_KERNEL_CUSTOM_VERSION_VALUE="6.18.51"
+BR2_LINUX_KERNEL_CUSTOM_VERSION_VALUE="6.18.52"
 BR2_LINUX_KERNEL_USE_CUSTOM_CONFIG=y
 BR2_LINUX_KERNEL_CUSTOM_CONFIG_FILE="board/visionfive2/linux_defconfig"
 BR2_LINUX_KERNEL_DTS_SUPPORT=y

---
base-commit: 1ab8f8ef5af5a170a1ecbea3209ca39afd49194c
change-id: 20261007-visionfive2-bump-linux-version-0de383d488d3

Best regards,
--  
Fengwei Tan <tfx2001@outlook.com>
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Re: [Buildroot] [PATCH] configs/visionfive2_defconfig: bump Linux to 6.18.52

[Julien Olivain via buildroot]

Hi Fengwei,

On 07/10/2026 19:45, Fengwei Tan wrote:
> When running iperf3 with Linux 6.18.51 on VisionFive 2, one CPU core
> stays at 100% load during the test. The iperf3 server log shows the
> throughput is limited to approximately 793 Mbits/sec:
> 
> [ ID] Interval           Transfer     Bitrate
> [  5]   0.00-10.01  sec   945 MBytes   793 Mbits/sec                  
> receiver
> 
> The regression was introduced in Linux 6.14 by commit df542f669307
> ("net: stmmac: Switch to zero-copy in non-XDP RX path"). It leads to
> misaligned access exceptions when parsing packet headers. During the
> iperf3 test, perf stat reported approximately 9.6 million alignment
> faults over 5 seconds:
> 
> $ perf stat -a -e alignment-faults -- sleep 5
> 
>  Performance counter stats for 'system wide':
> 
>            9620073      alignment-faults
> 
>        5.029337000 seconds time elapsed
> 
> The kernel must emulate these unaligned accesses, resulting in
> significant overhead.
> 
> The Linux kernel CVE team assigned CVE-2026-90059 to this issue [1].
> 
> Bump kernel to 6.18.52, which contains the fix for this issue.
> 
> [1] https://lore.kernel.org/all/2026091704-CVE-2026-90059-36e6@gregkh
> 
> Fixes: 98aa14a186e1 ("configs/visionfive2: bump Linux to 6.18.51, 
> U-Boot to 2026.07, and OpenSBI to 1.8.1")
> Assisted-by: Codex:GPT-6.1-Sol
> Signed-off-by: Fengwei Tan <tfx2001@outlook.com>
> ---
> Hello all,
> 
> This patch fixes a performance issue on the VisionFive 2, caused by
> misaligned access when the Linux kernel network stack parses packet
> headers.
> 
> I noticed this issue while running iperf3 tests on the VisionFive 2
> board. I captured perf data [1] and analyzed it with LLM, which
> quickly identified the relevant upstream kernel commit and the
> corresponding lore archive [2].
> 
> I rebuilt Linux 6.18.51 with the fix patch [3] applied and retested; 
> the
> issue was resolved. So I am pretty sure this issue was introduced by 
> the
> commit identified by the LLM.
> 
> [1] https://gist.github.com/tfx2001/f1f10ee1274acb7063ef1def5f2b119a
> [2] https://lore.kernel.org/all/2026091704-CVE-2026-90059-36e6@gregkh/
> [3] 
> https://git.kernel.org/stable/c/2ea42936416b29cca42b2c7bc7d3d3768f77c199
> ---
>  board/visionfive2/patches/linux/linux.hash | 2 +-
>  configs/visionfive2_defconfig              | 2 +-
>  2 files changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/board/visionfive2/patches/linux/linux.hash 
> b/board/visionfive2/patches/linux/linux.hash
> index b2cfc9b7e7..1e58cd0b9f 100644
> --- a/board/visionfive2/patches/linux/linux.hash
> +++ b/board/visionfive2/patches/linux/linux.hash
> @@ -1,2 +1,2 @@
>  # Locally calculated
> -sha256  
> ba2f60f858bf4d1f929101faa356c93dc8b925b17aaa9f95eabd4627758df613  
> linux-6.18.51.tar.xz
> +sha256  
> 2b69564f7d4fea0c859b1959ba33709ee6e9139bd100e30a853b57159a8221b8  
> linux-6.18.52.tar.xz
> diff --git a/configs/visionfive2_defconfig 
> b/configs/visionfive2_defconfig
> index 7ce605b84b..bfe5e42cc5 100644
> --- a/configs/visionfive2_defconfig
> +++ b/configs/visionfive2_defconfig
> @@ -7,7 +7,7 @@ BR2_ROOTFS_OVERLAY="board/visionfive2/overlay"
>  BR2_ROOTFS_POST_IMAGE_SCRIPT="board/visionfive2/post-image.sh"
>  BR2_LINUX_KERNEL=y
>  BR2_LINUX_KERNEL_CUSTOM_VERSION=y
> -BR2_LINUX_KERNEL_CUSTOM_VERSION_VALUE="6.18.51"
> +BR2_LINUX_KERNEL_CUSTOM_VERSION_VALUE="6.18.52"

Your motivation for this bump is well explained.

Is there any reason to bump to 6.18.52 while there is
the version 6.18.55 already available (which probably
contains many other fixes)?
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?h=v6.18.55

If there is no specific reason, could you send an updated
patch which bumps to the latest 6.18.y series, please?

>  BR2_LINUX_KERNEL_USE_CUSTOM_CONFIG=y
>  
> BR2_LINUX_KERNEL_CUSTOM_CONFIG_FILE="board/visionfive2/linux_defconfig"
>  BR2_LINUX_KERNEL_DTS_SUPPORT=y
> 
> ---
> base-commit: 1ab8f8ef5af5a170a1ecbea3209ca39afd49194c
> change-id: 20261007-visionfive2-bump-linux-version-0de383d488d3
> 
> Best regards,
> --
> Fengwei Tan <tfx2001@outlook.com>

Best regards,

Julien.
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Re: [Buildroot] [PATCH] configs/visionfive2_defconfig: bump Linux to 6.18.52

[Fengwei Tan]

Hi Julien,

在 2026/10/10 04:21, Julien Olivain 写道:
> Is there any reason to bump to 6.18.52 while there is
> the version 6.18.55 already available (which probably
> contains many other fixes)?
> https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?h=v6.18.55
> 
> If there is no specific reason, could you send an updated
> patch which bumps to the latest 6.18.y series, please?

Sure. I will send a v2 after testing.

Thanks,
Fengwei Tan
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