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Daniel Borkmann 23f3770e1a bpf: Fix metadata_dst leak __bpf_redirect_neigh_v{4,6}
Cilium has a BPF egress gateway feature which forces outgoing K8s Pod
traffic to pass through dedicated egress gateways which then SNAT the
traffic in order to interact with stable IPs outside the cluster.

The traffic is directed to the gateway via vxlan tunnel in collect md
mode. A recent BPF change utilized the bpf_redirect_neigh() helper to
forward packets after the arrival and decap on vxlan, which turned out
over time that the kmalloc-256 slab usage in kernel was ever-increasing.

The issue was that vxlan allocates the metadata_dst object and attaches
it through a fake dst entry to the skb. The latter was never released
though given bpf_redirect_neigh() was merely setting the new dst entry
via skb_dst_set() without dropping an existing one first.

Fixes: b4ab314149 ("bpf: Add redirect_neigh helper as redirect drop-in")
Reported-by: Yusuke Suzuki <yusuke.suzuki@isovalent.com>
Reported-by: Julian Wiedmann <jwi@isovalent.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Cc: Martin KaFai Lau <martin.lau@kernel.org>
Cc: Jakub Kicinski <kuba@kernel.org>
Cc: Jordan Rife <jrife@google.com>
Reviewed-by: Simon Horman <horms@kernel.org>
Reviewed-by: Jordan Rife <jrife@google.com>
Reviewed-by: Jakub Kicinski <kuba@kernel.org>
Reviewed-by: Martin KaFai Lau <martin.lau@kernel.org>
Link: https://lore.kernel.org/r/20251003073418.291171-1-daniel@iogearbox.net
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2025-10-06 21:20:10 -07:00
arch IOMMU Updates for Linux v6.18: 2025-10-03 18:00:11 -07:00
block Summary of significant series in this pull request: 2025-10-02 18:18:33 -07:00
certs sign-file,extract-cert: use pkcs11 provider for OPENSSL MAJOR >= 3 2024-09-20 19:52:48 +03:00
crypto Summary of significant series in this pull request: 2025-10-02 18:18:33 -07:00
Documentation soc: build fix for 6.18 2025-10-03 19:36:39 -07:00
drivers SCSI misc on 20251002 2025-10-03 19:17:48 -07:00
fs It has been a relatively busy cycle in docsland, with changes all over: 2025-10-03 17:16:13 -07:00
include bpf: Finish constification of 1st parameter of bpf_d_path() 2025-10-04 09:05:23 -07:00
init Patch series in this pull request: 2025-10-02 18:44:54 -07:00
io_uring Summary of significant series in this pull request: 2025-10-02 18:18:33 -07:00
ipc namespace-6.18-rc1 2025-09-29 11:20:29 -07:00
kernel bpf-fixes 2025-10-03 19:38:19 -07:00
lib Patch series in this pull request: 2025-10-02 18:44:54 -07:00
LICENSES LICENSES: Replace the obsolete address of the FSF in the GFDL-1.2 2025-07-24 11:15:39 +02:00
mm dma-mapping updates for Linux 6.18: 2025-10-03 17:41:12 -07:00
net bpf: Fix metadata_dst leak __bpf_redirect_neigh_v{4,6} 2025-10-06 21:20:10 -07:00
rust dma-mapping updates for Linux 6.18: 2025-10-03 17:41:12 -07:00
samples Summary of significant series in this pull request: 2025-10-02 18:18:33 -07:00
scripts bpf: Finish constification of 1st parameter of bpf_d_path() 2025-10-04 09:05:23 -07:00
security file->f_path constification 2025-10-03 16:32:36 -07:00
sound sound updates for 6.18-rc1 2025-10-02 11:37:19 -07:00
tools libbpf: Fix undefined behavior in {get,put}_unaligned_be32() 2025-10-06 09:16:29 -07:00
usr gen_init_cpio: add -a <data_align> as reflink optimization 2025-08-20 16:02:56 -07:00
virt Merge tag 'kvm-x86-no_assignment-6.17' of https://github.com/kvm-x86/linux into HEAD 2025-07-29 08:36:42 -04:00
.clang-format Linux 6.15-rc5 2025-05-06 16:39:25 +10:00
.clippy.toml rust: clean Rust 1.88.0's warning about clippy::disallowed_macros configuration 2025-05-07 00:11:47 +02:00
.cocciconfig
.editorconfig .editorconfig: remove trim_trailing_whitespace option 2024-06-13 16:47:52 +02:00
.get_maintainer.ignore MAINTAINERS: remove Alyssa Rosenzweig 2025-09-18 21:17:31 +02:00
.gitattributes
.gitignore .gitignore: ignore compile_commands.json globally 2025-08-12 15:53:55 -07:00
.mailmap Patch series in this pull request: 2025-10-02 18:44:54 -07:00
.pylintrc tools: docs: parse-headers.py: move it from sphinx dir 2025-08-29 15:54:42 -06:00
.rustfmt.toml
COPYING
CREDITS MAINTAINERS: Delete inactive maintainers from AF_XDP 2025-09-25 13:18:22 +02:00
Kbuild sched: Make migrate_{en,dis}able() inline 2025-09-25 09:57:16 +02:00
Kconfig io_uring: Rename KConfig to Kconfig 2025-02-19 14:53:27 -07:00
MAINTAINERS SCSI misc on 20251002 2025-10-03 19:17:48 -07:00
Makefile It has been a relatively busy cycle in docsland, with changes all over: 2025-10-03 17:16:13 -07:00
README

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the reStructuredText markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.