kernel: Enable CONFIG_TCP_CONG_BBR3 (#16044)

andrew344c · Andrew Chiang · web-flow · commit 8a4d13495a88 · 2026-03-12T12:40:36.000-07:00
BBR3 (Bottleneck Bandwidth and RTT version 3) is a TCP congestion control algorithm developed by Google, enhancing BBR v1. It was introduced in rolling-lts/mariner-3/6.6.126.1 with the new config option: CONFIG_TCP_CONG_BBR3.

BBR3 is added as a separate kernel module (tcp_bbr3, CONFIG_TCP_CONG_BBR3) alongside the existing BBR v1 (tcp_bbr, CONFIG_TCP_CONG_BBR). The original BBR v1 module remains unchanged, preserving backward compatibility for users with tcp_congestion_control=bbr. BBR3 is opt-in via
sysctl net.ipv4.tcp_congestion_control=bbr3. No behavior changes unless BBR3 is explicitly configured.

Co-authored-by: Andrew Chiang &lt;andrewchiang@microsoft.com&gt;
diff --git a/SPECS-EXTENDED/kernel-ipe/config b/SPECS-EXTENDED/kernel-ipe/config
@@ -1238,7 +1238,7 @@ CONFIG_TCP_CONG_ILLINOIS=m
 CONFIG_TCP_CONG_DCTCP=m
 CONFIG_TCP_CONG_CDG=m
 CONFIG_TCP_CONG_BBR=m
-# CONFIG_TCP_CONG_BBR3 is not set
+CONFIG_TCP_CONG_BBR3=m
 CONFIG_DEFAULT_CUBIC=y
 # CONFIG_DEFAULT_RENO is not set
 CONFIG_DEFAULT_TCP_CONG="cubic"
diff --git a/SPECS-EXTENDED/kernel-ipe/config_aarch64 b/SPECS-EXTENDED/kernel-ipe/config_aarch64
@@ -1249,7 +1249,7 @@ CONFIG_TCP_CONG_ILLINOIS=m
 CONFIG_TCP_CONG_DCTCP=m
 CONFIG_TCP_CONG_CDG=m
 CONFIG_TCP_CONG_BBR=m
-# CONFIG_TCP_CONG_BBR3 is not set
+CONFIG_TCP_CONG_BBR3=m
 CONFIG_DEFAULT_CUBIC=y
 # CONFIG_DEFAULT_RENO is not set
 CONFIG_DEFAULT_TCP_CONG="cubic"
diff --git a/SPECS-EXTENDED/kernel-ipe/kernel-ipe.signatures.json b/SPECS-EXTENDED/kernel-ipe/kernel-ipe.signatures.json
@@ -1,8 +1,8 @@
 {
   "Signatures": {
     "azurelinux-ca-20230216.pem": "d545401163c75878319f01470455e6bc18a5968e39dd964323225e3fe308849b",
-    "config": "33cc973aa1144fb7513c32f8f6c1be9b352b28d30ff1e91925c748c45c88de11",
-    "config_aarch64": "d4c131e815d83b2425b75288ca3d2ad0942bbbac46a4eeba3bbb90419c749936",
+    "config": "6a4f10e2ec6f814e7905bc04289764423e2cf08d5626e461c34a8f66e97c4307",
+    "config_aarch64": "c4837722b817974c4b1cc3fbf122e929b6dfc7cfa1d788ead477de8c9acf8fa9",
     "cpupower": "d7518767bf2b1110d146a49c7d42e76b803f45eb8bd14d931aa6d0d346fae985",
     "cpupower.service": "b057fe9e5d0e8c36f485818286b80e3eba8ff66ff44797940e99b1fd5361bb98",
     "sha512hmac-openssl.sh": "02ab91329c4be09ee66d759e4d23ac875037c3b56e5a598e32fd1206da06a27f",
diff --git a/SPECS-EXTENDED/kernel-ipe/kernel-ipe.spec b/SPECS-EXTENDED/kernel-ipe/kernel-ipe.spec
@@ -33,7 +33,7 @@
 Summary:        Linux Kernel
 Name:           kernel-ipe
 Version:        6.6.126.1
-Release:        1%{?dist}
+Release:        2%{?dist}
 License:        GPLv2
 Vendor:         Microsoft Corporation
 Distribution:   Azure Linux
@@ -460,6 +460,9 @@ echo "initrd of kernel %{uname_r} removed" >&2
 %{_sysconfdir}/bash_completion.d/bpftool
 
 %changelog
+* Fri Feb 27 2026 Andrew Chiang <andrewchiang@microsoft.com> - 6.6.126.1-2
+- Enable CONFIG_TCP_CONG_BBR3=m
+
 * Thu Feb 26 2026 CBL-Mariner Servicing Account <cblmargh@microsoft.com> - 6.6.126.1-1
 - Auto-upgrade to 6.6.126.1
 
diff --git a/SPECS-SIGNED/kernel-64k-signed/kernel-64k-signed.spec b/SPECS-SIGNED/kernel-64k-signed/kernel-64k-signed.spec
@@ -7,7 +7,7 @@
 Summary:        Signed Linux Kernel for %{buildarch} systems
 Name:           kernel-64k-signed-%{buildarch}
 Version:        6.6.126.1
-Release:        1%{?dist}
+Release:        2%{?dist}
 License:        GPLv2
 Vendor:         Microsoft Corporation
 Distribution:   Azure Linux
@@ -105,6 +105,9 @@ echo "initrd of kernel %{uname_r} removed" >&2
 %exclude /module_info.ld
 
 %changelog
+* Fri Feb 27 2026 Andrew Chiang <andrewchiang@microsoft.com> - 6.6.126.1-2
+- Bump release to match kernel
+
 * Thu Feb 26 2026 CBL-Mariner Servicing Account <cblmargh@microsoft.com> - 6.6.126.1-1
 - Auto-upgrade to 6.6.126.1
 
diff --git a/SPECS-SIGNED/kernel-signed/kernel-signed.spec b/SPECS-SIGNED/kernel-signed/kernel-signed.spec
@@ -10,7 +10,7 @@
 Summary:        Signed Linux Kernel for %{buildarch} systems
 Name:           kernel-signed-%{buildarch}
 Version:        6.6.126.1
-Release:        1%{?dist}
+Release:        2%{?dist}
 License:        GPLv2
 Vendor:         Microsoft Corporation
 Distribution:   Azure Linux
@@ -145,6 +145,9 @@ echo "initrd of kernel %{uname_r} removed" >&2
 %exclude /module_info.ld
 
 %changelog
+* Fri Feb 27 2026 Andrew Chiang <andrewchiang@microsoft.com> - 6.6.126.1-2
+- Bump release to match kernel
+
 * Thu Feb 26 2026 CBL-Mariner Servicing Account <cblmargh@microsoft.com> - 6.6.126.1-1
 - Auto-upgrade to 6.6.126.1
 
diff --git a/SPECS-SIGNED/kernel-uki-signed/kernel-uki-signed.spec b/SPECS-SIGNED/kernel-uki-signed/kernel-uki-signed.spec
@@ -6,7 +6,7 @@
 Summary:        Signed Unified Kernel Image for %{buildarch} systems
 Name:           kernel-uki-signed-%{buildarch}
 Version:        6.6.126.1
-Release:        1%{?dist}
+Release:        2%{?dist}
 License:        GPLv2
 Vendor:         Microsoft Corporation
 Distribution:   Azure Linux
@@ -68,6 +68,9 @@ popd
 /boot/efi/EFI/Linux/vmlinuz-uki-%{kernelver}.efi
 
 %changelog
+* Fri Feb 27 2026 Andrew Chiang <andrewchiang@microsoft.com> - 6.6.126.1-2
+- Bump release to match kernel
+
 * Thu Feb 26 2026 CBL-Mariner Servicing Account <cblmargh@microsoft.com> - 6.6.126.1-1
 - Auto-upgrade to 6.6.126.1
 
diff --git a/SPECS/kernel-64k/config_aarch64 b/SPECS/kernel-64k/config_aarch64
@@ -1250,7 +1250,7 @@ CONFIG_TCP_CONG_ILLINOIS=m
 CONFIG_TCP_CONG_DCTCP=m
 CONFIG_TCP_CONG_CDG=m
 CONFIG_TCP_CONG_BBR=m
-# CONFIG_TCP_CONG_BBR3 is not set
+CONFIG_TCP_CONG_BBR3=m
 CONFIG_DEFAULT_CUBIC=y
 # CONFIG_DEFAULT_RENO is not set
 CONFIG_DEFAULT_TCP_CONG="cubic"
diff --git a/SPECS/kernel-64k/kernel-64k.signatures.json b/SPECS/kernel-64k/kernel-64k.signatures.json
@@ -1,7 +1,7 @@
 {
   "Signatures": {
     "azurelinux-ca-20230216.pem": "d545401163c75878319f01470455e6bc18a5968e39dd964323225e3fe308849b",
-    "config_aarch64": "76161cdf871fb1e414f0d6ad97d83bcfa6a5b39eb2c8a1703180114cf114dbf1",
+    "config_aarch64": "f2898226c21ff2b0df59248f100d22e4c78fc41479ac12af6bb82fa583fd7e97",
     "cpupower": "d7518767bf2b1110d146a49c7d42e76b803f45eb8bd14d931aa6d0d346fae985",
     "cpupower.service": "b057fe9e5d0e8c36f485818286b80e3eba8ff66ff44797940e99b1fd5361bb98",
     "sha512hmac-openssl.sh": "02ab91329c4be09ee66d759e4d23ac875037c3b56e5a598e32fd1206da06a27f",
diff --git a/SPECS/kernel-64k/kernel-64k.spec b/SPECS/kernel-64k/kernel-64k.spec
@@ -27,7 +27,7 @@
 Summary:        Linux Kernel
 Name:           kernel-64k
 Version:        6.6.126.1
-Release:        1%{?dist}
+Release:        2%{?dist}
 License:        GPLv2
 Vendor:         Microsoft Corporation
 Distribution:   Azure Linux
@@ -380,6 +380,9 @@ echo "initrd of kernel %{uname_r} removed" >&2
 %{_sysconfdir}/bash_completion.d/bpftool
 
 %changelog
+* Fri Feb 27 2026 Andrew Chiang <andrewchiang@microsoft.com> - 6.6.126.1-2
+- Enable CONFIG_TCP_CONG_BBR3=m
+
 * Thu Feb 26 2026 CBL-Mariner Servicing Account <cblmargh@microsoft.com> - 6.6.126.1-1
 - Auto-upgrade to 6.6.126.1
 
diff --git a/SPECS/kernel-headers/kernel-headers.spec b/SPECS/kernel-headers/kernel-headers.spec
@@ -14,7 +14,7 @@
 Summary:        Linux API header files
 Name:           kernel-headers
 Version:        6.6.126.1
-Release:        1%{?dist}
+Release:        2%{?dist}
 License:        GPLv2
 Vendor:         Microsoft Corporation
 Distribution:   Azure Linux
@@ -75,6 +75,9 @@ done
 %endif
 
 %changelog
+* Fri Feb 27 2026 Andrew Chiang <andrewchiang@microsoft.com> - 6.6.126.1-2
+- Bump release to match kernel
+
 * Thu Feb 26 2026 CBL-Mariner Servicing Account <cblmargh@microsoft.com> - 6.6.126.1-1
 - Auto-upgrade to 6.6.126.1
 
diff --git a/SPECS/kernel/config b/SPECS/kernel/config
@@ -1238,7 +1238,7 @@ CONFIG_TCP_CONG_ILLINOIS=m
 CONFIG_TCP_CONG_DCTCP=m
 CONFIG_TCP_CONG_CDG=m
 CONFIG_TCP_CONG_BBR=m
-# CONFIG_TCP_CONG_BBR3 is not set
+CONFIG_TCP_CONG_BBR3=m
 CONFIG_DEFAULT_CUBIC=y
 # CONFIG_DEFAULT_RENO is not set
 CONFIG_DEFAULT_TCP_CONG="cubic"
diff --git a/SPECS/kernel/config_aarch64 b/SPECS/kernel/config_aarch64
@@ -1249,7 +1249,7 @@ CONFIG_TCP_CONG_ILLINOIS=m
 CONFIG_TCP_CONG_DCTCP=m
 CONFIG_TCP_CONG_CDG=m
 CONFIG_TCP_CONG_BBR=m
-# CONFIG_TCP_CONG_BBR3 is not set
+CONFIG_TCP_CONG_BBR3=m
 CONFIG_DEFAULT_CUBIC=y
 # CONFIG_DEFAULT_RENO is not set
 CONFIG_DEFAULT_TCP_CONG="cubic"
diff --git a/SPECS/kernel/kernel-uki.spec b/SPECS/kernel/kernel-uki.spec
@@ -13,7 +13,7 @@
 Summary:        Unified Kernel Image
 Name:           kernel-uki
 Version:        6.6.126.1
-Release:        1%{?dist}
+Release:        2%{?dist}
 License:        GPLv2
 Vendor:         Microsoft Corporation
 Distribution:   Azure Linux
@@ -70,6 +70,9 @@ cp %{buildroot}/boot/vmlinuz-uki-%{kernelver}.efi %{buildroot}/boot/efi/EFI/Linu
 /boot/efi/EFI/Linux/vmlinuz-uki-%{kernelver}.efi
 
 %changelog
+* Fri Feb 27 2026 Andrew Chiang <andrewchiang@microsoft.com> - 6.6.126.1-2
+- Bump release to match kernel
+
 * Thu Feb 26 2026 CBL-Mariner Servicing Account <cblmargh@microsoft.com> - 6.6.126.1-1
 - Auto-upgrade to 6.6.126.1
 
diff --git a/SPECS/kernel/kernel.signatures.json b/SPECS/kernel/kernel.signatures.json
@@ -1,8 +1,8 @@
 {
   "Signatures": {
     "azurelinux-ca-20230216.pem": "d545401163c75878319f01470455e6bc18a5968e39dd964323225e3fe308849b",
-    "config": "33cc973aa1144fb7513c32f8f6c1be9b352b28d30ff1e91925c748c45c88de11",
-    "config_aarch64": "d4c131e815d83b2425b75288ca3d2ad0942bbbac46a4eeba3bbb90419c749936",
+    "config": "6a4f10e2ec6f814e7905bc04289764423e2cf08d5626e461c34a8f66e97c4307",
+    "config_aarch64": "c4837722b817974c4b1cc3fbf122e929b6dfc7cfa1d788ead477de8c9acf8fa9",
     "cpupower": "d7518767bf2b1110d146a49c7d42e76b803f45eb8bd14d931aa6d0d346fae985",
     "cpupower.service": "b057fe9e5d0e8c36f485818286b80e3eba8ff66ff44797940e99b1fd5361bb98",
     "sha512hmac-openssl.sh": "02ab91329c4be09ee66d759e4d23ac875037c3b56e5a598e32fd1206da06a27f",
diff --git a/SPECS/kernel/kernel.spec b/SPECS/kernel/kernel.spec
@@ -32,7 +32,7 @@
 Summary:        Linux Kernel
 Name:           kernel
 Version:        6.6.126.1
-Release:        1%{?dist}
+Release:        2%{?dist}
 License:        GPLv2
 Vendor:         Microsoft Corporation
 Distribution:   Azure Linux
@@ -440,6 +440,9 @@ echo "initrd of kernel %{uname_r} removed" >&2
 %{_sysconfdir}/bash_completion.d/bpftool
 
 %changelog
+* Fri Feb 27 2026 Andrew Chiang <andrewchiang@microsoft.com> - 6.6.126.1-2
+- Enable CONFIG_TCP_CONG_BBR3=m
+
 * Thu Feb 26 2026 CBL-Mariner Servicing Account <cblmargh@microsoft.com> - 6.6.126.1-1
 - Auto-upgrade to 6.6.126.1
 
diff --git a/toolkit/resources/manifests/package/pkggen_core_aarch64.txt b/toolkit/resources/manifests/package/pkggen_core_aarch64.txt
@@ -1,5 +1,5 @@
 filesystem-1.1-21.azl3.aarch64.rpm
-kernel-headers-6.6.126.1-1.azl3.noarch.rpm
+kernel-headers-6.6.126.1-2.azl3.noarch.rpm
 glibc-2.38-18.azl3.aarch64.rpm
 glibc-devel-2.38-18.azl3.aarch64.rpm
 glibc-i18n-2.38-18.azl3.aarch64.rpm
diff --git a/toolkit/resources/manifests/package/pkggen_core_x86_64.txt b/toolkit/resources/manifests/package/pkggen_core_x86_64.txt
@@ -1,5 +1,5 @@
 filesystem-1.1-21.azl3.x86_64.rpm
-kernel-headers-6.6.126.1-1.azl3.noarch.rpm
+kernel-headers-6.6.126.1-2.azl3.noarch.rpm
 glibc-2.38-18.azl3.x86_64.rpm
 glibc-devel-2.38-18.azl3.x86_64.rpm
 glibc-i18n-2.38-18.azl3.x86_64.rpm
diff --git a/toolkit/resources/manifests/package/toolchain_aarch64.txt b/toolkit/resources/manifests/package/toolchain_aarch64.txt
@@ -158,7 +158,7 @@ intltool-0.51.0-7.azl3.noarch.rpm
 itstool-2.0.7-1.azl3.noarch.rpm
 kbd-2.2.0-2.azl3.aarch64.rpm
 kbd-debuginfo-2.2.0-2.azl3.aarch64.rpm
-kernel-headers-6.6.126.1-1.azl3.noarch.rpm
+kernel-headers-6.6.126.1-2.azl3.noarch.rpm
 kmod-30-1.azl3.aarch64.rpm
 kmod-debuginfo-30-1.azl3.aarch64.rpm
 kmod-devel-30-1.azl3.aarch64.rpm
diff --git a/toolkit/resources/manifests/package/toolchain_x86_64.txt b/toolkit/resources/manifests/package/toolchain_x86_64.txt
@@ -165,8 +165,8 @@ intltool-0.51.0-7.azl3.noarch.rpm
 itstool-2.0.7-1.azl3.noarch.rpm
 kbd-2.2.0-2.azl3.x86_64.rpm
 kbd-debuginfo-2.2.0-2.azl3.x86_64.rpm
-kernel-cross-headers-6.6.126.1-1.azl3.noarch.rpm
-kernel-headers-6.6.126.1-1.azl3.noarch.rpm
+kernel-cross-headers-6.6.126.1-2.azl3.noarch.rpm
+kernel-headers-6.6.126.1-2.azl3.noarch.rpm
 kmod-30-1.azl3.x86_64.rpm
 kmod-debuginfo-30-1.azl3.x86_64.rpm
 kmod-devel-30-1.azl3.x86_64.rpm

Original file line number	Diff line number	Diff line change
`@@ -1,7 +1,7 @@`
`1`	`1`	`{`
`2`	`2`	`"Signatures": {`
`3`	`3`	`"azurelinux-ca-20230216.pem": "d545401163c75878319f01470455e6bc18a5968e39dd964323225e3fe308849b",`
`4`		`- "config_aarch64": "76161cdf871fb1e414f0d6ad97d83bcfa6a5b39eb2c8a1703180114cf114dbf1",`
	`4`	`+ "config_aarch64": "f2898226c21ff2b0df59248f100d22e4c78fc41479ac12af6bb82fa583fd7e97",`
`5`	`5`	`"cpupower": "d7518767bf2b1110d146a49c7d42e76b803f45eb8bd14d931aa6d0d346fae985",`
`6`	`6`	`"cpupower.service": "b057fe9e5d0e8c36f485818286b80e3eba8ff66ff44797940e99b1fd5361bb98",`
`7`	`7`	`"sha512hmac-openssl.sh": "02ab91329c4be09ee66d759e4d23ac875037c3b56e5a598e32fd1206da06a27f",`