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Eric Dumazet 95f1c1e98d netfilter: xt_hashlimit: htable_selective_cleanup() optimization
I have seen syzbot reports hinting at xt_hashlimit abuse:

[  105.783066][ T4331] xt_hashlimit: max too large, truncated to 1048576
[  105.811405][ T4331] xt_hashlimit: size too large, truncated to 1048576

And worker threads using up to 1 second per htable_selective_cleanup() invocation.

[  269.734496][    C1]  [<ffffffff81547180>] ? __local_bh_enable_ip+0x1a0/0x1a0
[  269.734513][    C1]  [<ffffffff817d75d0>] ? lockdep_hardirqs_on_prepare+0x740/0x740
[  269.734533][    C1]  [<ffffffff852e71ff>] ? htable_selective_cleanup+0x25f/0x310
[  269.734549][    C1]  [<ffffffff817dcd30>] ? __lock_acquire+0x2060/0x2060
[  269.734567][    C1]  [<ffffffff817f058a>] ? do_raw_spin_lock+0x14a/0x370
[  269.734583][    C1]  [<ffffffff852e71ff>] ? htable_selective_cleanup+0x25f/0x310
[  269.734599][    C1]  [<ffffffff81547147>] __local_bh_enable_ip+0x167/0x1a0
[  269.734616][    C1]  [<ffffffff81546fe0>] ? _local_bh_enable+0xa0/0xa0
[  269.734634][    C1]  [<ffffffff852e71ff>] ? htable_selective_cleanup+0x25f/0x310
[  269.734651][    C1]  [<ffffffff852e71ff>] htable_selective_cleanup+0x25f/0x310
[  269.734670][    C1]  [<ffffffff815b3cc9>] ? process_one_work+0x7a9/0x1170
[  269.734685][    C1]  [<ffffffff852e57db>] htable_gc+0x1b/0xa0
[  269.734700][    C1]  [<ffffffff815b3cc9>] ? process_one_work+0x7a9/0x1170
[  269.734714][    C1]  [<ffffffff815b3dc9>] process_one_work+0x8a9/0x1170
[  269.734733][    C1]  [<ffffffff815b3520>] ? worker_detach_from_pool+0x260/0x260
[  269.734749][    C1]  [<ffffffff810201c7>] ? _raw_spin_lock_irq+0xb7/0xf0
[  269.734763][    C1]  [<ffffffff81020110>] ? _raw_spin_lock_irqsave+0x100/0x100
[  269.734777][    C1]  [<ffffffff8159d3df>] ? wq_worker_sleeping+0x5f/0x270
[  269.734800][    C1]  [<ffffffff815b53c7>] worker_thread+0xa47/0x1200
[  269.734815][    C1]  [<ffffffff81020010>] ? _raw_spin_lock+0x40/0x40
[  269.734835][    C1]  [<ffffffff815c9f2a>] kthread+0x25a/0x2e0
[  269.734853][    C1]  [<ffffffff815b4980>] ? worker_clr_flags+0x190/0x190
[  269.734866][    C1]  [<ffffffff815c9cd0>] ? kthread_blkcg+0xd0/0xd0
[  269.734885][    C1]  [<ffffffff81027b1a>] ret_from_fork+0x3a/0x50

We can skip over empty buckets, avoiding the lockdep penalty
for debug kernels, and avoid atomic operations on non debug ones.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
2025-01-05 18:41:32 +01:00
arch Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2025-01-03 16:29:29 -08:00
block block: avoid to reuse hctx not removed from cpuhp callback list 2024-12-18 07:25:37 -07:00
certs sign-file,extract-cert: use pkcs11 provider for OPENSSL MAJOR >= 3 2024-09-20 19:52:48 +03:00
crypto crypto: rsassa-pkcs1 - Copy source data for SG list 2024-12-10 13:34:05 +08:00
Documentation Merge tag 'ieee802154-for-net-next-2025-01-03' of git://git.kernel.org/pub/scm/linux/kernel/git/wpan/wpan-next 2025-01-04 17:02:55 -08:00
drivers net: stmmac: TSO: Simplify the code flow of DMA descriptor allocations 2025-01-04 08:23:41 -08:00
fs for-6.13-rc4-tag 2024-12-29 09:34:34 -08:00
include Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2025-01-03 16:29:29 -08:00
init - The series "resource: A couple of cleanups" from Andy Shevchenko 2024-11-25 16:09:48 -08:00
io_uring io_uring/sqpoll: fix sqpoll error handling races 2024-12-26 10:02:40 -07:00
ipc - The series "resource: A couple of cleanups" from Andy Shevchenko 2024-11-25 16:09:48 -08:00
kernel Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2025-01-03 16:29:29 -08:00
lib Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2025-01-03 16:29:29 -08:00
LICENSES LICENSES: add 0BSD license text 2024-09-01 20:43:24 -07:00
mm mm: huge_memory: handle strsep not finding delimiter 2024-12-18 19:04:47 -08:00
net netfilter: xt_hashlimit: htable_selective_cleanup() optimization 2025-01-05 18:41:32 +01:00
rust Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2024-12-19 11:35:07 -08:00
samples BPF fixes: 2024-12-06 15:07:48 -08:00
scripts Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2025-01-03 16:29:29 -08:00
security selinux/stable-6.13 PR 20241217 2024-12-18 12:10:15 -08:00
sound sound fixes for 6.13-rc6 2025-01-03 10:54:51 -08:00
tools Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2025-01-03 16:29:29 -08:00
usr kbuild: Drop support for include/asm-<arch> in headers_check.pl 2024-12-21 11:43:17 +09:00
virt VFIO updates for v6.13 2024-11-27 12:57:03 -08:00
.clang-format clang-format: Update with v6.11-rc1's for_each macro list 2024-08-02 13:20:31 +02:00
.clippy.toml rust: enable Clippy's check-private-items 2024-10-07 21:39:57 +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 MAINTAINERS: Retire Ralf Baechle 2024-11-12 15:48:59 +01:00
.gitattributes .gitattributes: set diff driver for Rust source code files 2023-05-31 17:48:25 +02:00
.gitignore Kbuild updates for v6.13 2024-11-30 13:41:50 -08:00
.mailmap mailmap: add entry for Ying Huang 2024-12-18 19:04:41 -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 cgroup: Changes for v6.13 2024-11-20 09:54:49 -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 Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2025-01-03 16:29:29 -08:00
Makefile Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2025-01-03 16:29:29 -08:00
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.