kernel/linux
0
Fork 0
mirror of https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ synced 2026-11-10 20:48:12 +00:00
Code Issues Releases Packages Activity
No description
1,399,692 commits 117 branches 5,827 tags 6.3 GiB
  • C 96.8%
  • Assembly 0.9%
  • Rust 0.7%
  • Shell 0.6%
  • Python 0.5%
  • Other 0.3%
Find a file
Paolo Abeni 50f47c02be mptcp: avoid deadlock on fallback while reinjecting 
commit ffb8c27b05 upstream.

Jakub reported an MPTCP deadlock at fallback time:

 WARNING: possible recursive locking detected
 6.18.0-rc7-virtme #1 Not tainted
 --------------------------------------------
 mptcp_connect/20858 is trying to acquire lock:
 ff1100001da18b60 (&msk->fallback_lock){+.-.}-{3:3}, at: __mptcp_try_fallback+0xd8/0x280

 but task is already holding lock:
 ff1100001da18b60 (&msk->fallback_lock){+.-.}-{3:3}, at: __mptcp_retrans+0x352/0xaa0

 other info that might help us debug this:
  Possible unsafe locking scenario:

        CPU0
        ----
   lock(&msk->fallback_lock);
   lock(&msk->fallback_lock);

  *** DEADLOCK ***

  May be due to missing lock nesting notation

 3 locks held by mptcp_connect/20858:
  #0: ff1100001da18290 (sk_lock-AF_INET){+.+.}-{0:0}, at: mptcp_sendmsg+0x114/0x1bc0
  #1: ff1100001db40fd0 (k-sk_lock-AF_INET#2){+.+.}-{0:0}, at: __mptcp_retrans+0x2cb/0xaa0
  #2: ff1100001da18b60 (&msk->fallback_lock){+.-.}-{3:3}, at: __mptcp_retrans+0x352/0xaa0

 stack backtrace:
 CPU: 0 UID: 0 PID: 20858 Comm: mptcp_connect Not tainted 6.18.0-rc7-virtme #1 PREEMPT(full)
 Hardware name: Bochs, BIOS Bochs 01/01/2011
 Call Trace:
  <TASK>
  dump_stack_lvl+0x6f/0xa0
  print_deadlock_bug.cold+0xc0/0xcd
  validate_chain+0x2ff/0x5f0
  __lock_acquire+0x34c/0x740
  lock_acquire.part.0+0xbc/0x260
  _raw_spin_lock_bh+0x38/0x50
  __mptcp_try_fallback+0xd8/0x280
  mptcp_sendmsg_frag+0x16c2/0x3050
  __mptcp_retrans+0x421/0xaa0
  mptcp_release_cb+0x5aa/0xa70
  release_sock+0xab/0x1d0
  mptcp_sendmsg+0xd5b/0x1bc0
  sock_write_iter+0x281/0x4d0
  new_sync_write+0x3c5/0x6f0
  vfs_write+0x65e/0xbb0
  ksys_write+0x17e/0x200
  do_syscall_64+0xbb/0xfd0
  entry_SYSCALL_64_after_hwframe+0x4b/0x53
 RIP: 0033:0x7fa5627cbc5e
 Code: 4d 89 d8 e8 14 bd 00 00 4c 8b 5d f8 41 8b 93 08 03 00 00 59 5e 48 83 f8 fc 74 11 c9 c3 0f 1f 80 00 00 00 00 48 8b 45 10 0f 05 <c9> c3 83 e2 39 83 fa 08 75 e7 e8 13 ff ff ff 0f 1f 00 f3 0f 1e fa
 RSP: 002b:00007fff1fe14700 EFLAGS: 00000202 ORIG_RAX: 0000000000000001
 RAX: ffffffffffffffda RBX: 0000000000000005 RCX: 00007fa5627cbc5e
 RDX: 0000000000001f9c RSI: 00007fff1fe16984 RDI: 0000000000000005
 RBP: 00007fff1fe14710 R08: 0000000000000000 R09: 0000000000000000
 R10: 0000000000000000 R11: 0000000000000202 R12: 00007fff1fe16920
 R13: 0000000000002000 R14: 0000000000001f9c R15: 0000000000001f9c

The packet scheduler could attempt a reinjection after receiving an
MP_FAIL and before the infinite map has been transmitted, causing a
deadlock since MPTCP needs to do the reinjection atomically from WRT
fallback.

Address the issue explicitly avoiding the reinjection in the critical
scenario. Note that this is the only fallback critical section that
could potentially send packets and hit the double-lock.

Reported-by: Jakub Kicinski <kuba@kernel.org>
Closes: https://netdev-ctrl.bots.linux.dev/logs/vmksft/mptcp-dbg/results/412720/1-mptcp-join-sh/stderr
Fixes: f8a1d9b18c ("mptcp: make fallback action and fallback decision atomic")
Cc: stable@vger.kernel.org
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Reviewed-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Link: https://patch.msgid.link/20251205-net-mptcp-misc-fixes-6-19-rc1-v1-4-9e4781a6c1b8@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
History 2026-01-02 12:57:12 +01:00
arch crash: let architecture decide crash memory export to iomem_resource 2026-01-02 12:57:11 +01:00
block block: Remove queue freezing from several sysfs store callbacks 2026-01-02 12:57:11 +01:00
certs sign-file,extract-cert: use pkcs11 provider for OPENSSL MAJOR >= 3 2024-09-20 19:52:48 +03:00
crypto crypto: scatterwalk - Fix memcpy_sglist() to always succeed 2026-01-02 12:57:08 +01:00
Documentation dt-bindings: mmc: sdhci-of-aspeed: Switch ref to sdhci-common.yaml 2026-01-02 12:56:57 +01:00
drivers tpm2-sessions: Fix tpm2_read_public range checks 2026-01-02 12:57:11 +01:00
fs jbd2: use a weaker annotation in journal handling 2026-01-02 12:57:10 +01:00
include mptcp: pm: ignore unknown endpoint flags 2026-01-02 12:57:12 +01:00
init printk changes for 6.18 2025-10-04 11:13:11 -07:00
io_uring io_uring: fix filename leak in __io_openat_prep() 2026-01-02 12:57:06 +01:00
ipc namespace-6.18-rc1 2025-09-29 11:20:29 -07:00
kernel crash: let architecture decide crash memory export to iomem_resource 2026-01-02 12:57:11 +01:00
lib lib/crypto: x86/blake2s: Fix 32-bit arg treated as 64-bit 2026-01-02 12:57:07 +01:00
LICENSES LICENSES: Replace the obsolete address of the FSF in the GFDL-1.2 2025-07-24 11:15:39 +02:00
mm mm/slab: introduce kvfree_rcu_barrier_on_cache() for cache destruction 2026-01-02 12:57:12 +01:00
net mptcp: avoid deadlock on fallback while reinjecting 2026-01-02 12:57:12 +01:00
rust rust: io: add typedef for phys_addr_t 2026-01-02 12:57:05 +01:00
samples samples: rust: fix endianness issue in rust_driver_pci 2026-01-02 12:57:05 +01:00
scripts kbuild: Use objtree for module signing key path 2026-01-02 12:56:40 +01:00
security tpm2-sessions: Fix out of range indexing in name_size 2026-01-02 12:57:11 +01:00
sound ASoC: ops: fix snd_soc_get_volsw for sx controls 2026-01-02 12:56:59 +01:00
tools selftests: mptcp: pm: ensure unknown flags are ignored 2026-01-02 12:57:12 +01:00
usr gen_init_cpio: Ignore fsync() returning EINVAL on pipes 2025-10-07 09:53:05 -07:00
virt KVM: guest_memfd: Remove bindings on memslot deletion when gmem is dying 2025-11-04 09:16:53 -08:00
.clang-format memblock: drop for_each_free_mem_pfn_range_in_zone_from() 2025-09-14 08:49:03 +03:00
.clippy.toml rust: clean Rust 1.88.0's warning about clippy::disallowed_macros configuration 2025-05-07 00:11:47 +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: remove Alyssa Rosenzweig 2025-09-18 21:17:31 +02:00
.gitattributes .gitattributes: set diff driver for Rust source code files 2023-05-31 17:48:25 +02:00
.gitignore .gitignore: ignore compile_commands.json globally 2025-08-12 15:53:55 -07:00
.mailmap 8 hotfixes. 4 are cc:stable, 7 are against mm/. 2025-11-26 12:38:05 -08:00
.pylintrc tools: docs: parse-headers.py: move it from sphinx dir 2025-08-29 15:54:42 -06:00
.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: mark ISDN subsystem as orphan 2025-10-27 17:49:45 -07:00
Kbuild sched: Make migrate_{en,dis}able() inline 2025-09-25 09:57:16 +02:00
Kconfig io_uring: Rename KConfig to Kconfig 2025-02-19 14:53:27 -07:00
MAINTAINERS soc: fixes for 6.18, part 4 2025-11-28 09:57:31 -08:00
Makefile Linux 6.18.2 2025-12-18 14:03:43 +01:00
README README: Fix spelling 2024-03-18 03:36:32 -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 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.