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Pablo Neira Ayuso 89e135a36a netfilter: flowtable: fix stuck flows on cleanup due to pending work
[ Upstream commit 9afb4b2734 ]

To clear the flow table on flow table free, the following sequence
normally happens in order:

  1) gc_step work is stopped to disable any further stats/del requests.
  2) All flow table entries are set to teardown state.
  3) Run gc_step which will queue HW del work for each flow table entry.
  4) Waiting for the above del work to finish (flush).
  5) Run gc_step again, deleting all entries from the flow table.
  6) Flow table is freed.

But if a flow table entry already has pending HW stats or HW add work
step 3 will not queue HW del work (it will be skipped), step 4 will wait
for the pending add/stats to finish, and step 5 will queue HW del work
which might execute after freeing of the flow table.

To fix the above, this patch flushes the pending work, then it sets the
teardown flag to all flows in the flowtable and it forces a garbage
collector run to queue work to remove the flows from hardware, then it
flushes this new pending work and (finally) it forces another garbage
collector run to remove the entry from the software flowtable.

Stack trace:
[47773.882335] BUG: KASAN: use-after-free in down_read+0x99/0x460
[47773.883634] Write of size 8 at addr ffff888103b45aa8 by task kworker/u20:6/543704
[47773.885634] CPU: 3 PID: 543704 Comm: kworker/u20:6 Not tainted 5.12.0-rc7+ #2
[47773.886745] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009)
[47773.888438] Workqueue: nf_ft_offload_del flow_offload_work_handler [nf_flow_table]
[47773.889727] Call Trace:
[47773.890214]  dump_stack+0xbb/0x107
[47773.890818]  print_address_description.constprop.0+0x18/0x140
[47773.892990]  kasan_report.cold+0x7c/0xd8
[47773.894459]  kasan_check_range+0x145/0x1a0
[47773.895174]  down_read+0x99/0x460
[47773.899706]  nf_flow_offload_tuple+0x24f/0x3c0 [nf_flow_table]
[47773.907137]  flow_offload_work_handler+0x72d/0xbe0 [nf_flow_table]
[47773.913372]  process_one_work+0x8ac/0x14e0
[47773.921325]
[47773.921325] Allocated by task 592159:
[47773.922031]  kasan_save_stack+0x1b/0x40
[47773.922730]  __kasan_kmalloc+0x7a/0x90
[47773.923411]  tcf_ct_flow_table_get+0x3cb/0x1230 [act_ct]
[47773.924363]  tcf_ct_init+0x71c/0x1156 [act_ct]
[47773.925207]  tcf_action_init_1+0x45b/0x700
[47773.925987]  tcf_action_init+0x453/0x6b0
[47773.926692]  tcf_exts_validate+0x3d0/0x600
[47773.927419]  fl_change+0x757/0x4a51 [cls_flower]
[47773.928227]  tc_new_tfilter+0x89a/0x2070
[47773.936652]
[47773.936652] Freed by task 543704:
[47773.937303]  kasan_save_stack+0x1b/0x40
[47773.938039]  kasan_set_track+0x1c/0x30
[47773.938731]  kasan_set_free_info+0x20/0x30
[47773.939467]  __kasan_slab_free+0xe7/0x120
[47773.940194]  slab_free_freelist_hook+0x86/0x190
[47773.941038]  kfree+0xce/0x3a0
[47773.941644]  tcf_ct_flow_table_cleanup_work

Original patch description and stack trace by Paul Blakey.

Fixes: c29f74e0df ("netfilter: nf_flow_table: hardware offload support")
Reported-by: Paul Blakey <paulb@nvidia.com>
Tested-by: Paul Blakey <paulb@nvidia.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
History 2022-08-31 17:18:07 +02:00
arch parisc: Fix exception handler for fldw and fstw instructions 2022-08-31 17:17:59 +02:00
block blk-mq: run queue no matter whether the request is the last request 2022-08-25 11:45:36 +02:00
certs certs: make system keyring depend on x509 parser 2022-07-24 12:53:55 -07:00
crypto KEYS: asymmetric: enforce SM2 signature use pkey algo 2022-08-17 15:16:17 +02:00
Documentation powerpc/pseries/mobility: set NMI watchdog factor during an LPM 2022-08-25 11:45:51 +02:00
drivers bnxt_en: fix LRO/GRO_HW features in ndo_fix_features callback 2022-08-31 17:18:06 +02:00
fs ntfs: fix acl handling 2022-08-31 17:18:02 +02:00
include netfilter: flowtable: fix stuck flows on cleanup due to pending work 2022-08-31 17:18:07 +02:00
init stack: Declare {randomize_,}kstack_offset to fix Sparse warnings 2022-08-17 15:14:14 +02:00
io_uring io_uring: mem-account pbuf buckets 2022-08-17 15:16:21 +02:00
ipc ipc: Free mq_sysctls if ipc namespace creation failed 2022-06-22 17:47:41 -05:00
kernel kprobes: don't call disarm_kprobe() for disabled kprobes 2022-08-31 17:18:00 +02:00
lib lib/list_debug.c: Detect uninitialized lists 2022-08-25 11:45:48 +02:00
LICENSES LICENSES/LGPL-2.1: Add LGPL-2.1-or-later as valid identifiers 2021-12-16 14:33:10 +01:00
mm mm/hugetlb: support write-faults in shared mappings 2022-08-31 17:18:00 +02:00
net netfilter: flowtable: fix stuck flows on cleanup due to pending work 2022-08-31 17:18:07 +02:00
samples sample: bpf: xdp_router_ipv4: Allow the kernel to send arp requests 2022-08-17 15:14:25 +02:00
scripts kbuild: dummy-tools: avoid tmpdir leak in dummy gcc 2022-08-29 11:07:58 +02:00
security apparmor: Fix memleak in aa_simple_write_to_buffer() 2022-08-25 11:45:11 +02:00
sound Revert "ALSA: hda: Fix page fault in snd_hda_codec_shutdown()" 2022-08-25 11:45:54 +02:00
tools selftests/kprobe: Do not test for GRP/ without event failures 2022-08-25 11:45:46 +02:00
usr Not a lot of material this cycle. Many singleton patches against various 2022-05-27 11:22:03 -07:00
virt KVM: Unconditionally get a ref to /dev/kvm module when creating a VM 2022-08-25 11:45:05 +02:00
.clang-format clang-format: Fix space after for_each macros 2022-05-20 19:27:16 +02:00
.cocciconfig scripts: add Linux .cocciconfig for coccinelle 2016-07-22 12:13:39 +02:00
.get_maintainer.ignore Opt out of scripts/get_maintainer.pl 2019-05-16 10:53:40 -07:00
.gitattributes .gitattributes: use 'dts' diff driver for dts files 2019-12-04 19:44:11 -08:00
.gitignore kbuild: split the second line of *.mod into *.usyms 2022-05-08 03:16:59 +09:00
.mailmap ARM: SoC fixes for 5.19, part 4 2022-07-27 09:43:07 -07:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS MAINTAINERS: mark ARM/PALM TREO SUPPORT orphan 2022-07-07 15:17:00 +02:00
Kbuild kbuild: rename hostprogs-y/always to hostprogs/always-y 2020-02-04 01:53:07 +09:00
Kconfig kbuild: ensure full rebuild when the compiler is updated 2020-05-12 13:28:33 +09:00
MAINTAINERS io_uring: move to separate directory 2022-08-17 15:14:20 +02:00
Makefile Linux 5.19.5 2022-08-29 11:18:05 +02:00
README Drop all 00-INDEX files from Documentation/ 2018-09-09 15:08:58 -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 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.