From: kernel test robot <oliver.sang@intel.com>
To: Max Staudt <max@enpas.org>
Cc: <oe-lkp@lists.linux.dev>, <lkp@intel.com>,
<linux-kernel@vger.kernel.org>, <linux-serial@vger.kernel.org>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Jiri Slaby <jirislaby@kernel.org>, Max Staudt <max@enpas.org>,
<oliver.sang@intel.com>
Subject: Re: [PATCH v1] tty: Register device *after* creating the cdev for a tty
Date: Wed, 28 May 2025 15:06:19 +0800 [thread overview]
Message-ID: <202505281412.8c836cb7-lkp@intel.com> (raw)
In-Reply-To: <20250526112523.23122-1-max@enpas.org>
Hello,
kernel test robot noticed "WARNING:possible_circular_locking_dependency_detected" on:
commit: c8190da3d46a287a5fe76c9f92ee041564c06236 ("[PATCH v1] tty: Register device *after* creating the cdev for a tty")
url: https://github.com/intel-lab-lkp/linux/commits/Max-Staudt/tty-Register-device-after-creating-the-cdev-for-a-tty/20250526-192806
base: https://git.kernel.org/cgit/linux/kernel/git/gregkh/tty.git tty-testing
patch link: https://lore.kernel.org/all/20250526112523.23122-1-max@enpas.org/
patch subject: [PATCH v1] tty: Register device *after* creating the cdev for a tty
in testcase: boot
config: i386-randconfig-011-20250527
compiler: gcc-12
test machine: qemu-system-i386 -enable-kvm -cpu SandyBridge -smp 2 -m 4G
(please refer to attached dmesg/kmsg for entire log/backtrace)
+-------------------------------------------------------------------------------------------------------------------------------------------------------+------------+------------+
| | b495021a97 | c8190da3d4 |
+-------------------------------------------------------------------------------------------------------------------------------------------------------+------------+------------+
| WARNING:possible_circular_locking_dependency_detected | 0 | 6 |
| WARNING:possible_circular_locking_dependency_detected_swapper_is_trying_to_acquire_lock:at:tty_port_open_but_task_is_already_holding_lock:at:tty_lock | 0 | 6 |
+-------------------------------------------------------------------------------------------------------------------------------------------------------+------------+------------+
If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <oliver.sang@intel.com>
| Closes: https://lore.kernel.org/oe-lkp/202505281412.8c836cb7-lkp@intel.com
[ 6.990953][ T1] WARNING: possible circular locking dependency detected
[ 6.991958][ T1] 6.15.0-rc4-00107-gc8190da3d46a #1 Tainted: G T
[ 6.993098][ T1] ------------------------------------------------------
[ 6.994053][ T1] swapper/1 is trying to acquire lock:
[ 6.994811][ T1] b40b31ac (&port->mutex){+.+.}-{4:4}, at: tty_port_open (kbuild/obj/consumer/i386-randconfig-011-20250527/arch/x86/include/asm/bitops.h:206 kbuild/obj/consumer/i386-randconfig-011-20250527/arch/x86/include/asm/bitops.h:238 kbuild/obj/consumer/i386-randconfig-011-20250527/include/asm-generic/bitops/instrumented-non-atomic.h:142 kbuild/obj/consumer/i386-randconfig-011-20250527/include/linux/tty_port.h:211 kbuild/obj/consumer/i386-randconfig-011-20250527/drivers/tty/tty_port.c:761)
[ 6.995978][ T1]
[ 6.995978][ T1] but task is already holding lock:
[ 6.997087][ T1] ed9fbc48 (&tty->legacy_mutex){+.+.}-{4:4}, at: tty_lock (kbuild/obj/consumer/i386-randconfig-011-20250527/drivers/tty/tty_mutex.c:19)
[ 7.002405][ T1]
[ 7.002405][ T1] which lock already depends on the new lock.
[ 7.002405][ T1]
[ 7.003949][ T1]
[ 7.003949][ T1] the existing dependency chain (in reverse order) is:
[ 7.005246][ T1]
[ 7.005246][ T1] -> #2 (&tty->legacy_mutex){+.+.}-{4:4}:
[ 7.006388][ T1] __lock_acquire (kbuild/obj/consumer/i386-randconfig-011-20250527/kernel/locking/lockdep.c:5235)
[ 7.007155][ T1] lock_acquire (kbuild/obj/consumer/i386-randconfig-011-20250527/kernel/locking/lockdep.c:472 kbuild/obj/consumer/i386-randconfig-011-20250527/kernel/locking/lockdep.c:5868)
[ 7.007870][ T1] __mutex_lock (kbuild/obj/consumer/i386-randconfig-011-20250527/arch/x86/include/asm/atomic.h:23 kbuild/obj/consumer/i386-randconfig-011-20250527/include/linux/atomic/atomic-arch-fallback.h:457 kbuild/obj/consumer/i386-randconfig-011-20250527/include/linux/jump_label.h:262 kbuild/obj/consumer/i386-randconfig-011-20250527/include/trace/events/lock.h:95 kbuild/obj/consumer/i386-randconfig-011-20250527/kernel/locking/mutex.c:603 kbuild/obj/consumer/i386-randconfig-011-20250527/kernel/locking/mutex.c:746)
[ 7.008582][ T1] mutex_lock_nested (kbuild/obj/consumer/i386-randconfig-011-20250527/kernel/locking/mutex.c:799)
[ 7.009322][ T1] tty_lock (kbuild/obj/consumer/i386-randconfig-011-20250527/drivers/tty/tty_mutex.c:19)
[ 7.010008][ T1] tty_init_dev (kbuild/obj/consumer/i386-randconfig-011-20250527/drivers/tty/tty_io.c:1295 kbuild/obj/consumer/i386-randconfig-011-20250527/drivers/tty/tty_io.c:1407)
[ 7.010739][ T1] tty_open (kbuild/obj/consumer/i386-randconfig-011-20250527/drivers/tty/tty_io.c:2073 kbuild/obj/consumer/i386-randconfig-011-20250527/drivers/tty/tty_io.c:2120)
[ 7.011435][ T1] chrdev_open (kbuild/obj/consumer/i386-randconfig-011-20250527/fs/char_dev.c:414)
[ 7.012161][ T1] do_dentry_open (kbuild/obj/consumer/i386-randconfig-011-20250527/fs/open.c:956)
[ 7.012939][ T1] vfs_open (kbuild/obj/consumer/i386-randconfig-011-20250527/fs/open.c:1086)
[ 7.013641][ T1] do_open (kbuild/obj/consumer/i386-randconfig-011-20250527/fs/namei.c:3880)
[ 7.014340][ T1] path_openat (kbuild/obj/consumer/i386-randconfig-011-20250527/fs/namei.c:4039)
[ 7.015052][ T1] do_filp_open (kbuild/obj/consumer/i386-randconfig-011-20250527/fs/namei.c:4066)
[ 7.015775][ T1] file_open_name (kbuild/obj/consumer/i386-randconfig-011-20250527/fs/open.c:1374)
[ 7.016565][ T1] filp_open (kbuild/obj/consumer/i386-randconfig-011-20250527/fs/open.c:1393)
[ 7.017247][ T1] console_on_rootfs (kbuild/obj/consumer/i386-randconfig-011-20250527/init/main.c:1528)
[ 7.018070][ T1] kernel_init_freeable (kbuild/obj/consumer/i386-randconfig-011-20250527/init/main.c:1578)
[ 7.018887][ T1] kernel_init (kbuild/obj/consumer/i386-randconfig-011-20250527/init/main.c:1459)
[ 7.019589][ T1] ret_from_fork (kbuild/obj/consumer/i386-randconfig-011-20250527/arch/x86/kernel/process.c:159)
[ 7.020334][ T1] ret_from_fork_asm (kbuild/obj/consumer/i386-randconfig-011-20250527/arch/x86/entry/entry_32.S:737)
[ 7.021115][ T1] entry_INT80_32 (kbuild/obj/consumer/i386-randconfig-011-20250527/arch/x86/entry/entry_32.S:942)
[ 7.021884][ T1]
[ 7.021884][ T1] -> #1 (tty_mutex){+.+.}-{4:4}:
[ 7.022934][ T1] __lock_acquire (kbuild/obj/consumer/i386-randconfig-011-20250527/kernel/locking/lockdep.c:5235)
[ 7.023681][ T1] lock_acquire (kbuild/obj/consumer/i386-randconfig-011-20250527/kernel/locking/lockdep.c:472 kbuild/obj/consumer/i386-randconfig-011-20250527/kernel/locking/lockdep.c:5868)
[ 7.024418][ T1] __mutex_lock (kbuild/obj/consumer/i386-randconfig-011-20250527/arch/x86/include/asm/atomic.h:23 kbuild/obj/consumer/i386-randconfig-011-20250527/include/linux/atomic/atomic-arch-fallback.h:457 kbuild/obj/consumer/i386-randconfig-011-20250527/include/linux/jump_label.h:262 kbuild/obj/consumer/i386-randconfig-011-20250527/include/trace/events/lock.h:95 kbuild/obj/consumer/i386-randconfig-011-20250527/kernel/locking/mutex.c:603 kbuild/obj/consumer/i386-randconfig-011-20250527/kernel/locking/mutex.c:746)
[ 7.025137][ T1] mutex_lock_nested (kbuild/obj/consumer/i386-randconfig-011-20250527/kernel/locking/mutex.c:799)
[ 7.025908][ T1] tty_register_device_attr (kbuild/obj/consumer/i386-randconfig-011-20250527/drivers/tty/tty_io.c:3250)
[ 7.026751][ T1] tty_port_register_device_attr_serdev (kbuild/obj/consumer/i386-randconfig-011-20250527/drivers/tty/tty_port.c:199)
[ 7.027724][ T1] serial_core_add_one_port (kbuild/obj/consumer/i386-randconfig-011-20250527/drivers/tty/serial/serial_core.c:3184)
[ 7.028574][ T1] serial_core_register_port (kbuild/obj/consumer/i386-randconfig-011-20250527/drivers/tty/serial/serial_core.c:3388)
[ 7.029416][ T1] serial_ctrl_register_port (kbuild/obj/consumer/i386-randconfig-011-20250527/drivers/tty/serial/serial_ctrl.c:42)
[ 7.030245][ T1] uart_add_one_port (kbuild/obj/consumer/i386-randconfig-011-20250527/drivers/tty/serial/serial_port.c:144)
[ 7.031025][ T1] serial8250_register_8250_port (kbuild/obj/consumer/i386-randconfig-011-20250527/drivers/tty/serial/8250/8250_core.c:822)
[ 7.031940][ T1] serial_pnp_probe (kbuild/obj/consumer/i386-randconfig-011-20250527/drivers/tty/serial/8250/8250_pnp.c:480)
[ 7.032707][ T1] pnp_device_probe (kbuild/obj/consumer/i386-randconfig-011-20250527/drivers/pnp/driver.c:111)
[ 7.033455][ T1] really_probe (kbuild/obj/consumer/i386-randconfig-011-20250527/drivers/base/dd.c:579 kbuild/obj/consumer/i386-randconfig-011-20250527/drivers/base/dd.c:657)
[ 7.038357][ T1] __driver_probe_device (kbuild/obj/consumer/i386-randconfig-011-20250527/drivers/base/dd.c:799)
[ 7.039198][ T1] driver_probe_device (kbuild/obj/consumer/i386-randconfig-011-20250527/drivers/base/dd.c:829)
[ 7.040004][ T1] __driver_attach (kbuild/obj/consumer/i386-randconfig-011-20250527/drivers/base/dd.c:1216)
[ 7.040773][ T1] bus_for_each_dev (kbuild/obj/consumer/i386-randconfig-011-20250527/drivers/base/bus.c:370)
[ 7.041556][ T1] driver_attach (kbuild/obj/consumer/i386-randconfig-011-20250527/drivers/base/dd.c:1234)
[ 7.042088][ T1] bus_add_driver (kbuild/obj/consumer/i386-randconfig-011-20250527/drivers/base/bus.c:678)
[ 7.042585][ T1] driver_register (kbuild/obj/consumer/i386-randconfig-011-20250527/drivers/base/driver.c:249)
[ 7.043090][ T1] pnp_register_driver (kbuild/obj/consumer/i386-randconfig-011-20250527/drivers/pnp/driver.c:281)
[ 7.043609][ T1] serial8250_pnp_init (kbuild/obj/consumer/i386-randconfig-011-20250527/drivers/tty/serial/8250/8250_pnp.c:531)
[ 7.044115][ T1] serial8250_init (kbuild/obj/consumer/i386-randconfig-011-20250527/drivers/tty/serial/8250/8250_platform.c:315)
[ 7.044602][ T1] do_one_initcall (kbuild/obj/consumer/i386-randconfig-011-20250527/init/main.c:1257)
[ 7.045089][ T1] do_initcalls (kbuild/obj/consumer/i386-randconfig-011-20250527/init/main.c:1318 kbuild/obj/consumer/i386-randconfig-011-20250527/init/main.c:1335)
[ 7.045549][ T1] kernel_init_freeable (kbuild/obj/consumer/i386-randconfig-011-20250527/init/main.c:1569)
[ 7.046075][ T1] kernel_init (kbuild/obj/consumer/i386-randconfig-011-20250527/init/main.c:1459)
[ 7.046531][ T1] ret_from_fork (kbuild/obj/consumer/i386-randconfig-011-20250527/arch/x86/kernel/process.c:159)
[ 7.047000][ T1] ret_from_fork_asm (kbuild/obj/consumer/i386-randconfig-011-20250527/arch/x86/entry/entry_32.S:737)
[ 7.047494][ T1] entry_INT80_32 (kbuild/obj/consumer/i386-randconfig-011-20250527/arch/x86/entry/entry_32.S:942)
[ 7.047972][ T1]
[ 7.047972][ T1] -> #0 (&port->mutex){+.+.}-{4:4}:
[ 7.048668][ T1] check_prev_add (kbuild/obj/consumer/i386-randconfig-011-20250527/kernel/locking/lockdep.c:3167)
[ 7.049154][ T1] validate_chain (kbuild/obj/consumer/i386-randconfig-011-20250527/kernel/locking/lockdep.c:3286 kbuild/obj/consumer/i386-randconfig-011-20250527/kernel/locking/lockdep.c:3909)
[ 7.049652][ T1] __lock_acquire (kbuild/obj/consumer/i386-randconfig-011-20250527/kernel/locking/lockdep.c:5235)
[ 7.050147][ T1] lock_acquire (kbuild/obj/consumer/i386-randconfig-011-20250527/kernel/locking/lockdep.c:472 kbuild/obj/consumer/i386-randconfig-011-20250527/kernel/locking/lockdep.c:5868)
[ 7.050609][ T1] __mutex_lock (kbuild/obj/consumer/i386-randconfig-011-20250527/arch/x86/include/asm/atomic.h:23 kbuild/obj/consumer/i386-randconfig-011-20250527/include/linux/atomic/atomic-arch-fallback.h:457 kbuild/obj/consumer/i386-randconfig-011-20250527/include/linux/jump_label.h:262 kbuild/obj/consumer/i386-randconfig-011-20250527/include/trace/events/lock.h:95 kbuild/obj/consumer/i386-randconfig-011-20250527/kernel/locking/mutex.c:603 kbuild/obj/consumer/i386-randconfig-011-20250527/kernel/locking/mutex.c:746)
[ 7.051064][ T1] mutex_lock_nested (kbuild/obj/consumer/i386-randconfig-011-20250527/kernel/locking/mutex.c:799)
[ 7.051547][ T1] tty_port_open (kbuild/obj/consumer/i386-randconfig-011-20250527/arch/x86/include/asm/bitops.h:206 kbuild/obj/consumer/i386-randconfig-011-20250527/arch/x86/include/asm/bitops.h:238 kbuild/obj/consumer/i386-randconfig-011-20250527/include/asm-generic/bitops/instrumented-non-atomic.h:142 kbuild/obj/consumer/i386-randconfig-011-20250527/include/linux/tty_port.h:211 kbuild/obj/consumer/i386-randconfig-011-20250527/drivers/tty/tty_port.c:761)
[ 7.052005][ T1] uart_open (kbuild/obj/consumer/i386-randconfig-011-20250527/drivers/tty/serial/serial_core.c:1974)
[ 7.052433][ T1] tty_open (kbuild/obj/consumer/i386-randconfig-011-20250527/drivers/tty/tty_io.c:2137)
[ 7.052862][ T1] chrdev_open (kbuild/obj/consumer/i386-randconfig-011-20250527/fs/char_dev.c:414)
[ 7.053311][ T1] do_dentry_open (kbuild/obj/consumer/i386-randconfig-011-20250527/fs/open.c:956)
[ 7.053798][ T1] vfs_open (kbuild/obj/consumer/i386-randconfig-011-20250527/fs/open.c:1086)
[ 7.054220][ T1] do_open (kbuild/obj/consumer/i386-randconfig-011-20250527/fs/namei.c:3880)
[ 7.054647][ T1] path_openat (kbuild/obj/consumer/i386-randconfig-011-20250527/fs/namei.c:4039)
[ 7.055093][ T1] do_filp_open (kbuild/obj/consumer/i386-randconfig-011-20250527/fs/namei.c:4066)
[ 7.055548][ T1] file_open_name (kbuild/obj/consumer/i386-randconfig-011-20250527/fs/open.c:1374)
[ 7.056027][ T1] filp_open (kbuild/obj/consumer/i386-randconfig-011-20250527/fs/open.c:1393)
[ 7.056453][ T1] console_on_rootfs (kbuild/obj/consumer/i386-randconfig-011-20250527/init/main.c:1528)
[ 7.056933][ T1] kernel_init_freeable (kbuild/obj/consumer/i386-randconfig-011-20250527/init/main.c:1578)
[ 7.057447][ T1] kernel_init (kbuild/obj/consumer/i386-randconfig-011-20250527/init/main.c:1459)
[ 7.057904][ T1] ret_from_fork (kbuild/obj/consumer/i386-randconfig-011-20250527/arch/x86/kernel/process.c:159)
[ 7.058365][ T1] ret_from_fork_asm (kbuild/obj/consumer/i386-randconfig-011-20250527/arch/x86/entry/entry_32.S:737)
[ 7.058843][ T1] entry_INT80_32 (kbuild/obj/consumer/i386-randconfig-011-20250527/arch/x86/entry/entry_32.S:942)
[ 7.059302][ T1]
[ 7.059302][ T1] other info that might help us debug this:
[ 7.059302][ T1]
[ 7.060225][ T1] Chain exists of:
[ 7.060225][ T1] &port->mutex --> tty_mutex --> &tty->legacy_mutex
[ 7.060225][ T1]
[ 7.061811][ T1] Possible unsafe locking scenario:
The kernel config and materials to reproduce are available at:
https://download.01.org/0day-ci/archive/20250528/202505281412.8c836cb7-lkp@intel.com
--
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki
next prev parent reply other threads:[~2025-05-28 7:07 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-05-26 11:25 [PATCH v1] tty: Register device *after* creating the cdev for a tty Max Staudt
2025-05-28 7:06 ` kernel test robot [this message]
2025-05-28 8:23 ` Greg Kroah-Hartman
2025-05-28 13:31 ` Max
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