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Kuniyuki Iwashima c3369fc5e6 nfc: nci: Fix race between rfkill and nci_unregister_device().
[ Upstream commit d2492688bb ]

syzbot reported the splat below [0] without a repro.

It indicates that struct nci_dev.cmd_wq had been destroyed before
nci_close_device() was called via rfkill.

nci_dev.cmd_wq is only destroyed in nci_unregister_device(), which
(I think) was called from virtual_ncidev_close() when syzbot close()d
an fd of virtual_ncidev.

The problem is that nci_unregister_device() destroys nci_dev.cmd_wq
first and then calls nfc_unregister_device(), which removes the
device from rfkill by rfkill_unregister().

So, the device is still visible via rfkill even after nci_dev.cmd_wq
is destroyed.

Let's unregister the device from rfkill first in nci_unregister_device().

Note that we cannot call nfc_unregister_device() before
nci_close_device() because

  1) nfc_unregister_device() calls device_del() which frees
     all memory allocated by devm_kzalloc() and linked to
     ndev->conn_info_list

  2) nci_rx_work() could try to queue nci_conn_info to
     ndev->conn_info_list which could be leaked

Thus, nfc_unregister_device() is split into two functions so we
can remove rfkill interfaces only before nci_close_device().

[0]:
DEBUG_LOCKS_WARN_ON(1)
WARNING: kernel/locking/lockdep.c:238 at hlock_class kernel/locking/lockdep.c:238 [inline], CPU#0: syz.0.8675/6349
WARNING: kernel/locking/lockdep.c:238 at check_wait_context kernel/locking/lockdep.c:4854 [inline], CPU#0: syz.0.8675/6349
WARNING: kernel/locking/lockdep.c:238 at __lock_acquire+0x39d/0x2cf0 kernel/locking/lockdep.c:5187, CPU#0: syz.0.8675/6349
Modules linked in:
CPU: 0 UID: 0 PID: 6349 Comm: syz.0.8675 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/13/2026
RIP: 0010:hlock_class kernel/locking/lockdep.c:238 [inline]
RIP: 0010:check_wait_context kernel/locking/lockdep.c:4854 [inline]
RIP: 0010:__lock_acquire+0x3a4/0x2cf0 kernel/locking/lockdep.c:5187
Code: 18 00 4c 8b 74 24 08 75 27 90 e8 17 f2 fc 02 85 c0 74 1c 83 3d 50 e0 4e 0e 00 75 13 48 8d 3d 43 f7 51 0e 48 c7 c6 8b 3a de 8d <67> 48 0f b9 3a 90 31 c0 0f b6 98 c4 00 00 00 41 8b 45 20 25 ff 1f
RSP: 0018:ffffc9000c767680 EFLAGS: 00010046
RAX: 0000000000000001 RBX: 0000000000040000 RCX: 0000000000080000
RDX: ffffc90013080000 RSI: ffffffff8dde3a8b RDI: ffffffff8ff24ca0
RBP: 0000000000000003 R08: ffffffff8fef35a3 R09: 1ffffffff1fde6b4
R10: dffffc0000000000 R11: fffffbfff1fde6b5 R12: 00000000000012a2
R13: ffff888030338ba8 R14: ffff888030338000 R15: ffff888030338b30
FS:  00007fa5995f66c0(0000) GS:ffff8881256f8000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f7e72f842d0 CR3: 00000000485a0000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 lock_acquire+0x106/0x330 kernel/locking/lockdep.c:5868
 touch_wq_lockdep_map+0xcb/0x180 kernel/workqueue.c:3940
 __flush_workqueue+0x14b/0x14f0 kernel/workqueue.c:3982
 nci_close_device+0x302/0x630 net/nfc/nci/core.c:567
 nci_dev_down+0x3b/0x50 net/nfc/nci/core.c:639
 nfc_dev_down+0x152/0x290 net/nfc/core.c:161
 nfc_rfkill_set_block+0x2d/0x100 net/nfc/core.c:179
 rfkill_set_block+0x1d2/0x440 net/rfkill/core.c:346
 rfkill_fop_write+0x461/0x5a0 net/rfkill/core.c:1301
 vfs_write+0x29a/0xb90 fs/read_write.c:684
 ksys_write+0x150/0x270 fs/read_write.c:738
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xe2/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fa59b39acb9
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fa5995f6028 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007fa59b615fa0 RCX: 00007fa59b39acb9
RDX: 0000000000000008 RSI: 0000200000000080 RDI: 0000000000000007
RBP: 00007fa59b408bf7 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fa59b616038 R14: 00007fa59b615fa0 R15: 00007ffc82218788
 </TASK>

Fixes: 6a2968aaf5 ("NFC: basic NCI protocol implementation")
Reported-by: syzbot+f9c5fd1a0874f9069dce@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/all/695e7f56.050a0220.1c677c.036c.GAE@google.com/
Signed-off-by: Kuniyuki Iwashima <kuniyu@google.com>
Reviewed-by: Simon Horman <horms@kernel.org>
Link: https://patch.msgid.link/20260127040411.494931-1-kuniyu@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
History 2026-02-06 16:57:32 +01:00
arch arm64: dts: qcom: talos: Correct UFS clocks ordering 2026-01-30 10:32:28 +01:00
block block: zero non-PI portion of auto integrity buffer 2026-01-23 11:21:16 +01:00
certs sign-file,extract-cert: use pkcs11 provider for OPENSSL MAJOR >= 3 2024-09-20 19:52:48 +03:00
crypto crypto: authencesn - reject too-short AAD (assoclen<8) to match ESP/ESN spec 2026-01-30 10:32:12 +01:00
Documentation fou: Don't allow 0 for FOU_ATTR_IPPROTO. 2026-01-30 10:32:12 +01:00
drivers net/mlx5e: Account for netdev stats in ndo_get_stats64 2026-02-06 16:57:32 +01:00
fs btrfs: zlib: fix the folio leak on S390 hardware acceleration 2026-02-06 16:57:29 +01:00
include nfc: nci: Fix race between rfkill and nci_unregister_device(). 2026-02-06 16:57:32 +01:00
init printk changes for 6.18 2025-10-04 11:13:11 -07:00
io_uring io_uring/io-wq: check IO_WQ_BIT_EXIT inside work run loop 2026-01-30 10:32:15 +01:00
ipc namespace-6.18-rc1 2025-09-29 11:20:29 -07:00
kernel tracing: Fix crash on synthetic stacktrace field usage 2026-01-30 10:32:25 +01:00
lib lib/buildid: use __kernel_read() for sleepable context 2026-01-23 11:21:25 +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/vma: enforce VMA fork limit on unfaulted,faulted mremap merge too 2026-01-30 10:32:28 +01:00
net nfc: nci: Fix race between rfkill and nci_unregister_device(). 2026-02-06 16:57:32 +01:00
rust rust: irq: always inline functions using build_assert with arguments 2026-01-30 10:32:26 +01:00
samples samples/ftrace: Adjust LoongArch register restore order in direct calls 2026-01-08 10:17:11 +01:00
scripts kconfig: fix static linking of nconf 2026-01-30 10:32:16 +01:00
security keys/trusted_keys: fix handle passed to tpm_buf_append_name during unseal 2026-01-30 10:32:22 +01:00
sound ALSA: usb-audio: Fix use-after-free in snd_usb_mixer_free() 2026-01-30 10:32:23 +01:00
tools vsock/test: fix seqpacket message bounds test 2026-01-30 10:32:21 +01:00
usr gen_init_cpio: Ignore fsync() returning EINVAL on pipes 2025-10-07 09:53:05 -07:00
virt KVM: Fix last_boosted_vcpu index assignment bug 2026-01-02 12:57:21 +01:00
.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 6.18.8 2026-01-30 10:32:28 +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.