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Florian Westphal 56a6ea76dd netfilter: nf_tables: nft_set_rbtree: fix spurious insertion failure
[ Upstream commit 087388278e ]

nft_rbtree_gc_elem() walks back and removes the end interval element that
comes before the expired element.

There is a small chance that we've cached this element as 'rbe_ge'.
If this happens, we hold and test a pointer that has been queued for
freeing.

It also causes spurious insertion failures:

$ cat test-testcases-sets-0044interval_overlap_0.1/testout.log
Error: Could not process rule: File exists
add element t s {  0 -  2 }
                   ^^^^^^
Failed to insert  0 -  2 given:
table ip t {
        set s {
                type inet_service
                flags interval,timeout
                timeout 2s
                gc-interval 2s
        }
}

The set (rbtree) is empty. The 'failure' doesn't happen on next attempt.

Reason is that when we try to insert, the tree may hold an expired
element that collides with the range we're adding.
While we do evict/erase this element, we can trip over this check:

if (rbe_ge && nft_rbtree_interval_end(rbe_ge) && nft_rbtree_interval_end(new))
      return -ENOTEMPTY;

rbe_ge was erased by the synchronous gc, we should not have done this
check.  Next attempt won't find it, so retry results in successful
insertion.

Restart in-kernel to avoid such spurious errors.

Such restart are rare, unless userspace intentionally adds very large
numbers of elements with very short timeouts while setting a huge
gc interval.

Even in this case, this cannot loop forever, on each retry an existing
element has been removed.

As the caller is holding the transaction mutex, its impossible
for a second entity to add more expiring elements to the tree.

After this it also becomes feasible to remove the async gc worker
and perform all garbage collection from the commit path.

Fixes: c9e6978e27 ("netfilter: nft_set_rbtree: Switch to node list walk for overlap detection")
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-10-10 22:00:43 +02:00
Documentation arm64: errata: Add Cortex-A520 speculative unprivileged load workaround 2023-10-10 22:00:39 +02:00
LICENSES LICENSES/LGPL-2.1: Add LGPL-2.1-or-later as valid identifiers 2021-12-16 14:33:10 +01:00
arch perf/x86/amd: Do not WARN() on every IRQ 2023-10-10 22:00:41 +02:00
block block: fix use-after-free of q->q_usage_counter 2023-10-10 22:00:37 +02:00
certs certs: Fix build error when PKCS#11 URI contains semicolon 2023-02-09 11:28:11 +01:00
crypto crypto: lrw,xts - Replace strlcpy with strscpy 2023-09-23 11:11:01 +02:00
drivers ibmveth: Remove condition to recompute TCP header checksum. 2023-10-10 22:00:43 +02:00
fs NFSv4: Fix a nfs4_state_manager() race 2023-10-10 22:00:41 +02:00
include netfilter: handle the connecting collision properly in nf_conntrack_proto_sctp 2023-10-10 22:00:43 +02:00
init sched/psi: Select KERNFS as needed 2023-09-13 09:42:28 +02:00
io_uring io_uring/fs: remove sqe->rw_flags checking from LINKAT 2023-10-06 14:57:02 +02:00
ipc ipc: fix memory leak in init_mqueue_fs() 2022-12-31 13:32:01 +01:00
kernel ring-buffer: Fix bytes info in per_cpu buffer stats 2023-10-10 22:00:36 +02:00
lib kobject: Add sanity check for kset->kobj.ktype in kset_register() 2023-09-23 11:11:07 +02:00
mm mm: page_alloc: fix CMA and HIGHATOMIC landing on the wrong buddy list 2023-10-10 22:00:36 +02:00
net netfilter: nf_tables: nft_set_rbtree: fix spurious insertion failure 2023-10-10 22:00:43 +02:00
rust rust: allocator: Prevent mis-aligned allocation 2023-08-11 12:08:18 +02:00
samples samples/hw_breakpoint: fix building without module unloading 2023-09-23 11:11:09 +02:00
scripts modpost: add missing else to the "of" check 2023-10-10 22:00:41 +02:00
security ima: rework CONFIG_IMA dependency block 2023-10-10 22:00:41 +02:00
sound ASoC: tegra: Fix redundant PLLA and PLLA_OUT0 updates 2023-10-10 22:00:34 +02:00
tools netfilter: nf_tables: Deduplicate nft_register_obj audit logs 2023-10-10 22:00:43 +02:00
usr usr/gen_init_cpio.c: remove unnecessary -1 values from int file 2022-10-03 14:21:44 -07:00
virt kvm/vfio: ensure kvg instance stays around in kvm_vfio_group_add() 2023-09-13 09:42:46 +02:00
.clang-format inet: ping: use hlist_nulls rcu iterator during lookup 2022-12-01 12:42:46 +01:00
.cocciconfig
.get_maintainer.ignore get_maintainer: add Alan to .get_maintainer.ignore 2022-08-20 15:17:44 -07:00
.gitattributes .gitattributes: use 'dts' diff driver for dts files 2019-12-04 19:44:11 -08:00
.gitignore Kbuild: add Rust support 2022-09-28 09:02:20 +02:00
.mailmap 9 hotfixes. 6 for MM, 3 for other areas. Four of these patches address 2022-12-10 17:10:52 -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 Michal Marek from Kbuild maintainers 2022-11-16 14:53:00 +09:00
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 devlink: move code to a dedicated directory 2023-08-30 16:11:00 +02:00
Makefile Linux 6.1.56 2023-10-06 14:57:07 +02:00
README Drop all 00-INDEX files from Documentation/ 2018-09-09 15:08:58 -06:00

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 Restructured Text 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.