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Willem de Bruijn d3b7a9c759 net: reenable NETIF_F_IPV6_CSUM offload for BIG TCP packets
[ Upstream commit 68e068cabd ]

The blamed commit disabled hardware offoad of IPv6 packets with
extension headers on devices that advertise NETIF_F_IPV6_CSUM,
based on the definition of that feature in skbuff.h:

 *   * - %NETIF_F_IPV6_CSUM
 *     - Driver (device) is only able to checksum plain
 *       TCP or UDP packets over IPv6. These are specifically
 *       unencapsulated packets of the form IPv6|TCP or
 *       IPv6|UDP where the Next Header field in the IPv6
 *       header is either TCP or UDP. IPv6 extension headers
 *       are not supported with this feature. This feature
 *       cannot be set in features for a device with
 *       NETIF_F_HW_CSUM also set. This feature is being
 *       DEPRECATED (see below).

The change causes skb_warn_bad_offload to fire for BIG TCP
packets.

[  496.310233] WARNING: CPU: 13 PID: 23472 at net/core/dev.c:3129 skb_warn_bad_offload+0xc4/0xe0

[  496.310297]  ? skb_warn_bad_offload+0xc4/0xe0
[  496.310300]  skb_checksum_help+0x129/0x1f0
[  496.310303]  skb_csum_hwoffload_help+0x150/0x1b0
[  496.310306]  validate_xmit_skb+0x159/0x270
[  496.310309]  validate_xmit_skb_list+0x41/0x70
[  496.310312]  sch_direct_xmit+0x5c/0x250
[  496.310317]  __qdisc_run+0x388/0x620

BIG TCP introduced an IPV6_TLV_JUMBO IPv6 extension header to
communicate packet length, as this is an IPv6 jumbogram. But, the
feature is only enabled on devices that support BIG TCP TSO. The
header is only present for PF_PACKET taps like tcpdump, and not
transmitted by physical devices.

For this specific case of extension headers that are not
transmitted, return to the situation before the blamed commit
and support hardware offload.

ipv6_has_hopopt_jumbo() tests not only whether this header is present,
but also that it is the only extension header before a terminal (L4)
header.

Fixes: 04c20a9356 ("net: skip offload for NETIF_F_IPV6_CSUM if ipv6 header contains extension")
Reported-by: syzbot <syzkaller@googlegroups.com>
Reported-by: Eric Dumazet <edumazet@google.com>
Closes: https://lore.kernel.org/netdev/CANn89iK1hdC3Nt8KPhOtTF8vCPc1AHDCtse_BTNki1pWxAByTQ@mail.gmail.com/
Signed-off-by: Willem de Bruijn <willemb@google.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Link: https://patch.msgid.link/20250101164909.1331680-1-willemdebruijn.kernel@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
History 2025-01-09 13:33:41 +01:00
arch perf/x86/intel/ds: Add PEBS format 6 2025-01-02 10:34:23 +01:00
block block: lift bio_is_zone_append to bio.h 2025-01-09 13:33:32 +01:00
certs sign-file,extract-cert: use pkcs11 provider for OPENSSL MAJOR >= 3 2024-09-20 19:52:48 +03:00
crypto crypto: ecdsa - Avoid signed integer overflow on signature decoding 2024-12-14 20:03:36 +01:00
Documentation platform/x86: thinkpad-acpi: Add support for hotkey 0x1401 2025-01-09 13:33:31 +01:00
drivers net: sfc: Correct key_len for efx_tc_ct_zone_ht_params 2025-01-09 13:33:41 +01:00
fs btrfs: use bio_is_zone_append() in the completion handler 2025-01-09 13:33:33 +01:00
include netfilter: nft_set_hash: unaligned atomic read on struct nft_set_ext 2025-01-09 13:33:40 +01:00
init Compiler Attributes: disable __counted_by for clang < 19.1.3 2024-12-05 14:02:45 +01:00
io_uring io_uring/net: always initialize kmsg->msg.msg_inq upfront 2025-01-09 13:33:41 +01:00
ipc ipc: fix memleak if msg_init_ns failed in create_ipc_ns 2024-12-05 14:03:02 +01:00
kernel workqueue: add printf attribute to __alloc_workqueue() 2025-01-09 13:33:40 +01:00
lib timekeeping: Remove CONFIG_DEBUG_TIMEKEEPING 2024-12-14 20:04:16 +01:00
LICENSES LICENSES: add 0BSD license text 2024-09-01 20:43:24 -07:00
mm mm: convert partially_mapped set/clear operations to be atomic 2024-12-27 14:02:20 +01:00
net net: reenable NETIF_F_IPV6_CSUM offload for BIG TCP packets 2025-01-09 13:33:41 +01:00
rust rust: kbuild: set bindgen's Rust target version 2024-12-19 18:13:22 +01:00
samples samples/bpf: Fix a resource leak 2024-12-14 20:03:46 +01:00
scripts setlocalversion: work around "git describe" performance 2024-12-14 20:04:10 +01:00
security selinux: ignore unknown extended permissions 2025-01-09 13:33:32 +01:00
sound ALSA: usb-audio: US16x08: Initialize array before use 2025-01-09 13:33:40 +01:00
tools selftests: net: local_termination: require mausezahn 2025-01-09 13:33:36 +01:00
usr initramfs: shorten cmd_initfs in usr/Makefile 2024-07-16 01:07:52 +09:00
virt KVM: x86: switch hugepage recovery thread to vhost_task 2024-12-05 14:02:43 +01:00
.clang-format clang-format: Update with v6.11-rc1's for_each macro list 2024-08-02 13:20:31 +02:00
.cocciconfig scripts: add Linux .cocciconfig for coccinelle 2016-07-22 12:13:39 +02:00
.editorconfig .editorconfig: remove trim_trailing_whitespace option 2024-06-13 16:47:52 +02:00
.get_maintainer.ignore Add Jeff Kirsher to .get_maintainer.ignore 2024-03-08 11:36:54 +00:00
.gitattributes .gitattributes: set diff driver for Rust source code files 2023-05-31 17:48:25 +02:00
.gitignore Kbuild updates for v6.12 2024-09-24 13:02:06 -07:00
.mailmap mailmap: add entry for Thorsten Blum 2024-11-07 14:14:59 -08:00
.rustfmt.toml rust: add .rustfmt.toml 2022-09-28 09:02:20 +02:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS MAINTAINERS: Remove self from DSA entry 2024-11-03 12:52:38 -08:00
Kbuild Kbuild updates for v6.1 2022-10-10 12:00:45 -07:00
Kconfig kbuild: ensure full rebuild when the compiler is updated 2020-05-12 13:28:33 +09:00
MAINTAINERS MAINTAINERS: update location of media main tree 2024-12-05 14:02:42 +01:00
Makefile Linux 6.12.8 2025-01-02 10:34:26 +01:00
README README: Fix spelling 2024-03-18 03:36:32 -06:00

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.