Linux kernel source tree for SHARP Brain series (PW-SH1 or later)
Go to file
Desmond Cheong Zhi Xi 0d563020b8 Bluetooth: avoid circular locks in sco_sock_connect
[ Upstream commit 734bc5ff783115aa3164f4e9dd5967ae78e0a8ab ]

In a future patch, calls to bh_lock_sock in sco.c should be replaced
by lock_sock now that none of the functions are run in IRQ context.

However, doing so results in a circular locking dependency:

======================================================
WARNING: possible circular locking dependency detected
5.14.0-rc4-syzkaller #0 Not tainted
------------------------------------------------------
syz-executor.2/14867 is trying to acquire lock:
ffff88803e3c1120 (sk_lock-AF_BLUETOOTH-BTPROTO_SCO){+.+.}-{0:0}, at:
lock_sock include/net/sock.h:1613 [inline]
ffff88803e3c1120 (sk_lock-AF_BLUETOOTH-BTPROTO_SCO){+.+.}-{0:0}, at:
sco_conn_del+0x12a/0x2a0 net/bluetooth/sco.c:191

but task is already holding lock:
ffffffff8d2dc7c8 (hci_cb_list_lock){+.+.}-{3:3}, at:
hci_disconn_cfm include/net/bluetooth/hci_core.h:1497 [inline]
ffffffff8d2dc7c8 (hci_cb_list_lock){+.+.}-{3:3}, at:
hci_conn_hash_flush+0xda/0x260 net/bluetooth/hci_conn.c:1608

which lock already depends on the new lock.

the existing dependency chain (in reverse order) is:

-> #2 (hci_cb_list_lock){+.+.}-{3:3}:
       __mutex_lock_common kernel/locking/mutex.c:959 [inline]
       __mutex_lock+0x12a/0x10a0 kernel/locking/mutex.c:1104
       hci_connect_cfm include/net/bluetooth/hci_core.h:1482 [inline]
       hci_remote_features_evt net/bluetooth/hci_event.c:3263 [inline]
       hci_event_packet+0x2f4d/0x7c50 net/bluetooth/hci_event.c:6240
       hci_rx_work+0x4f8/0xd30 net/bluetooth/hci_core.c:5122
       process_one_work+0x98d/0x1630 kernel/workqueue.c:2276
       worker_thread+0x658/0x11f0 kernel/workqueue.c:2422
       kthread+0x3e5/0x4d0 kernel/kthread.c:319
       ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295

-> #1 (&hdev->lock){+.+.}-{3:3}:
       __mutex_lock_common kernel/locking/mutex.c:959 [inline]
       __mutex_lock+0x12a/0x10a0 kernel/locking/mutex.c:1104
       sco_connect net/bluetooth/sco.c:245 [inline]
       sco_sock_connect+0x227/0xa10 net/bluetooth/sco.c:601
       __sys_connect_file+0x155/0x1a0 net/socket.c:1879
       __sys_connect+0x161/0x190 net/socket.c:1896
       __do_sys_connect net/socket.c:1906 [inline]
       __se_sys_connect net/socket.c:1903 [inline]
       __x64_sys_connect+0x6f/0xb0 net/socket.c:1903
       do_syscall_x64 arch/x86/entry/common.c:50 [inline]
       do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
       entry_SYSCALL_64_after_hwframe+0x44/0xae

-> #0 (sk_lock-AF_BLUETOOTH-BTPROTO_SCO){+.+.}-{0:0}:
       check_prev_add kernel/locking/lockdep.c:3051 [inline]
       check_prevs_add kernel/locking/lockdep.c:3174 [inline]
       validate_chain kernel/locking/lockdep.c:3789 [inline]
       __lock_acquire+0x2a07/0x54a0 kernel/locking/lockdep.c:5015
       lock_acquire kernel/locking/lockdep.c:5625 [inline]
       lock_acquire+0x1ab/0x510 kernel/locking/lockdep.c:5590
       lock_sock_nested+0xca/0x120 net/core/sock.c:3170
       lock_sock include/net/sock.h:1613 [inline]
       sco_conn_del+0x12a/0x2a0 net/bluetooth/sco.c:191
       sco_disconn_cfm+0x71/0xb0 net/bluetooth/sco.c:1202
       hci_disconn_cfm include/net/bluetooth/hci_core.h:1500 [inline]
       hci_conn_hash_flush+0x127/0x260 net/bluetooth/hci_conn.c:1608
       hci_dev_do_close+0x528/0x1130 net/bluetooth/hci_core.c:1778
       hci_unregister_dev+0x1c0/0x5a0 net/bluetooth/hci_core.c:4015
       vhci_release+0x70/0xe0 drivers/bluetooth/hci_vhci.c:340
       __fput+0x288/0x920 fs/file_table.c:280
       task_work_run+0xdd/0x1a0 kernel/task_work.c:164
       exit_task_work include/linux/task_work.h:32 [inline]
       do_exit+0xbd4/0x2a60 kernel/exit.c:825
       do_group_exit+0x125/0x310 kernel/exit.c:922
       get_signal+0x47f/0x2160 kernel/signal.c:2808
       arch_do_signal_or_restart+0x2a9/0x1c40 arch/x86/kernel/signal.c:865
       handle_signal_work kernel/entry/common.c:148 [inline]
       exit_to_user_mode_loop kernel/entry/common.c:172 [inline]
       exit_to_user_mode_prepare+0x17d/0x290 kernel/entry/common.c:209
       __syscall_exit_to_user_mode_work kernel/entry/common.c:291 [inline]
       syscall_exit_to_user_mode+0x19/0x60 kernel/entry/common.c:302
       ret_from_fork+0x15/0x30 arch/x86/entry/entry_64.S:288

other info that might help us debug this:

Chain exists of:
  sk_lock-AF_BLUETOOTH-BTPROTO_SCO --> &hdev->lock --> hci_cb_list_lock

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(hci_cb_list_lock);
                               lock(&hdev->lock);
                               lock(hci_cb_list_lock);
  lock(sk_lock-AF_BLUETOOTH-BTPROTO_SCO);

 *** DEADLOCK ***

The issue is that the lock hierarchy should go from &hdev->lock -->
hci_cb_list_lock --> sk_lock-AF_BLUETOOTH-BTPROTO_SCO. For example,
one such call trace is:

  hci_dev_do_close():
    hci_dev_lock();
    hci_conn_hash_flush():
      hci_disconn_cfm():
        mutex_lock(&hci_cb_list_lock);
        sco_disconn_cfm():
        sco_conn_del():
          lock_sock(sk);

However, in sco_sock_connect, we call lock_sock before calling
hci_dev_lock inside sco_connect, thus inverting the lock hierarchy.

We fix this by pulling the call to hci_dev_lock out from sco_connect.

Signed-off-by: Desmond Cheong Zhi Xi <desmondcheongzx@gmail.com>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2021-09-22 12:26:32 +02:00
arch arm64: dts: qcom: sdm660: use reg value for memory node 2021-09-22 12:26:31 +02:00
block scsi: bsg: Remove support for SCSI_IOCTL_SEND_COMMAND 2021-09-22 12:26:23 +02:00
certs certs: Trigger creation of RSA module signing key if it's not an RSA key 2021-09-15 09:47:29 +02:00
crypto crypto: shash - avoid comparing pointers to exported functions under CFI 2021-07-14 16:53:13 +02:00
Documentation docs: Fix infiniband uverbs minor number 2021-09-22 12:26:23 +02:00
drivers drm/msm: mdp4: drop vblank get/put from prepare/complete_commit 2021-09-22 12:26:32 +02:00
fs userfaultfd: prevent concurrent API initialization 2021-09-22 12:26:26 +02:00
include serial: 8250: Define RX trigger levels for OxSemi 950 devices 2021-09-22 12:26:29 +02:00
init kbuild: add CONFIG_LD_IS_LLD 2021-06-30 08:47:44 -04:00
ipc ipc/util.c: sysvipc_find_ipc() incorrectly updates position index 2020-05-20 08:20:16 +02:00
kernel workqueue: Fix possible memory leaks in wq_numa_init() 2021-09-22 12:26:30 +02:00
lib bpf/tests: Do not PASS tests without actually testing the result 2021-09-22 12:26:29 +02:00
LICENSES LICENSES: Rename other to deprecated 2019-05-03 06:34:32 -06:00
mm mm/page_alloc: speed up the iteration of max_order 2021-09-12 08:56:41 +02:00
net Bluetooth: avoid circular locks in sco_sock_connect 2021-09-22 12:26:32 +02:00
samples samples: bpf: Fix tracex7 error raised on the missing argument 2021-09-22 12:26:30 +02:00
scripts kbuild: Fix 'no symbols' warning when CONFIG_TRIM_UNUSD_KSYMS=y 2021-09-22 12:26:26 +02:00
security Smack: Fix wrong semantics in smk_access_entry() 2021-09-22 12:26:27 +02:00
sound ASoC: Intel: bytcr_rt5640: Move "Platform Clock" routes to the maps for the matching in-/output 2021-09-22 12:26:31 +02:00
tools selftests/bpf: Fix xdp_tx.c prog section name 2021-09-22 12:26:32 +02:00
usr initramfs: restore default compression behavior 2020-04-08 09:08:38 +02:00
virt KVM: Do not leak memory for duplicate debugfs directories 2021-08-12 13:21:03 +02:00
.clang-format clang-format: Update with the latest for_each macro list 2019-08-31 10:00:51 +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: set git diff driver for C source code files 2016-10-07 18:46:30 -07:00
.gitignore Modules updates for v5.4 2019-09-22 10:34:46 -07:00
.mailmap ARM: SoC fixes 2019-11-10 13:41:59 -08:00
COPYING COPYING: use the new text with points to the license files 2018-03-23 12:41:45 -06:00
CREDITS MAINTAINERS: Remove Simon as Renesas SoC Co-Maintainer 2019-10-10 08:12:51 -07:00
Kbuild kbuild: do not descend to ./Kbuild when cleaning 2019-08-21 21:03:58 +09:00
Kconfig docs: kbuild: convert docs to ReST and rename to *.rst 2019-06-14 14:21:21 -06:00
MAINTAINERS Documentation/llvm: add documentation on building w/ Clang/LLVM 2020-08-26 10:40:46 +02:00
Makefile Linux 5.4.147 2021-09-16 12:56:14 +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.