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Liu Jian 33e2168788 net: let net.core.dev_weight always be non-zero
[ Upstream commit d1f9f79fa2 ]

The following problem was encountered during stability test:

(NULL net_device): NAPI poll function process_backlog+0x0/0x530 \
	returned 1, exceeding its budget of 0.
------------[ cut here ]------------
list_add double add: new=ffff88905f746f48, prev=ffff88905f746f48, \
	next=ffff88905f746e40.
WARNING: CPU: 18 PID: 5462 at lib/list_debug.c:35 \
	__list_add_valid_or_report+0xf3/0x130
CPU: 18 UID: 0 PID: 5462 Comm: ping Kdump: loaded Not tainted 6.13.0-rc7+
RIP: 0010:__list_add_valid_or_report+0xf3/0x130
Call Trace:
? __warn+0xcd/0x250
? __list_add_valid_or_report+0xf3/0x130
enqueue_to_backlog+0x923/0x1070
netif_rx_internal+0x92/0x2b0
__netif_rx+0x15/0x170
loopback_xmit+0x2ef/0x450
dev_hard_start_xmit+0x103/0x490
__dev_queue_xmit+0xeac/0x1950
ip_finish_output2+0x6cc/0x1620
ip_output+0x161/0x270
ip_push_pending_frames+0x155/0x1a0
raw_sendmsg+0xe13/0x1550
__sys_sendto+0x3bf/0x4e0
__x64_sys_sendto+0xdc/0x1b0
do_syscall_64+0x5b/0x170
entry_SYSCALL_64_after_hwframe+0x76/0x7e

The reproduction command is as follows:
  sysctl -w net.core.dev_weight=0
  ping 127.0.0.1

This is because when the napi's weight is set to 0, process_backlog() may
return 0 and clear the NAPI_STATE_SCHED bit of napi->state, causing this
napi to be re-polled in net_rx_action() until __do_softirq() times out.
Since the NAPI_STATE_SCHED bit has been cleared, napi_schedule_rps() can
be retriggered in enqueue_to_backlog(), causing this issue.

Making the napi's weight always non-zero solves this problem.

Triggering this issue requires system-wide admin (setting is
not namespaced).

Fixes: e387660545 ("[NET]: Fix sysctl net.core.dev_weight")
Fixes: 3d48b53fb2 ("net: dev_weight: TX/RX orthogonality")
Signed-off-by: Liu Jian <liujian56@huawei.com>
Link: https://patch.msgid.link/20250116143053.4146855-1-liujian56@huawei.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
History 2025-02-08 09:57:24 +01:00
arch arm64: dts: imx93: Use IMX93_CLK_SPDIF_IPG as SPDIF IPG clock 2025-02-08 09:57:09 +01:00
block partitions: ldm: remove the initial kernel-doc notation 2025-02-08 09:56:52 +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 dt-bindings: clock: Add i.MX91 clock support 2025-02-08 09:57:08 +01:00
drivers pwm: stm32: Add check for clk_enable() 2025-02-08 09:57:23 +01:00
fs afs: Fix the fallback handling for the YFS.RemoveFile2 RPC call 2025-02-08 09:56:53 +01:00
include inet: ipmr: fix data-races 2025-02-08 09:57:23 +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/rsrc: require cloned buffers to share accounting contexts 2025-02-01 18:39:40 +01:00
ipc ipc: fix memleak if msg_init_ns failed in create_ipc_ns 2024-12-05 14:03:02 +01:00
kernel cpufreq: schedutil: Fix superfluous updates caused by need_freq_update 2025-02-08 09:57:06 +01:00
lib maple_tree: reload mas before the second call for mas_empty_area 2025-01-09 13:33:50 +01:00
LICENSES LICENSES: add 0BSD license text 2024-09-01 20:43:24 -07:00
mm cachestat: fix page cache statistics permission checking 2025-02-01 18:39:38 +01:00
net net: let net.core.dev_weight always be non-zero 2025-02-08 09:57:24 +01:00
rust rust: kbuild: set bindgen's Rust target version 2024-12-19 18:13:22 +01:00
samples samples/landlock: Fix possible NULL dereference in parse_path() 2025-02-08 09:57:11 +01:00
scripts scripts/sorttable: fix orc_sort_cmp() to maintain symmetry and transitivity 2025-01-09 13:33:50 +01:00
security landlock: Handle weird files 2025-02-08 09:57:16 +01:00
sound ALSA: usb-audio: Add delay quirk for USB Audio Device 2025-02-01 18:39:39 +01:00
tools selftests/landlock: Fix error message 2025-02-08 09:57:23 +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 6.12.12 2025-02-01 18:39:40 +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.