linux/drivers/leds
Heiner Kallweit fe2b122665 leds: trigger: netdev: fix RTNL handling to prevent potential deadlock
When working on LED support for r8169 I got the following lockdep
warning. Easiest way to prevent this scenario seems to be to take
the RTNL lock before the trigger_data lock in set_device_name().

======================================================
WARNING: possible circular locking dependency detected
6.7.0-rc2-next-20231124+ #2 Not tainted
------------------------------------------------------
bash/383 is trying to acquire lock:
ffff888103aa1c68 (&trigger_data->lock){+.+.}-{3:3}, at: netdev_trig_notify+0xec/0x190 [ledtrig_netdev]

but task is already holding lock:
ffffffff8cddf808 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock+0x12/0x20

which lock already depends on the new lock.

the existing dependency chain (in reverse order) is:

-> #1 (rtnl_mutex){+.+.}-{3:3}:
       __mutex_lock+0x9b/0xb50
       mutex_lock_nested+0x16/0x20
       rtnl_lock+0x12/0x20
       set_device_name+0xa9/0x120 [ledtrig_netdev]
       netdev_trig_activate+0x1a1/0x230 [ledtrig_netdev]
       led_trigger_set+0x172/0x2c0
       led_trigger_write+0xf1/0x140
       sysfs_kf_bin_write+0x5d/0x80
       kernfs_fop_write_iter+0x15d/0x210
       vfs_write+0x1f0/0x510
       ksys_write+0x6c/0xf0
       __x64_sys_write+0x14/0x20
       do_syscall_64+0x3f/0xf0
       entry_SYSCALL_64_after_hwframe+0x6c/0x74

-> #0 (&trigger_data->lock){+.+.}-{3:3}:
       __lock_acquire+0x1459/0x25a0
       lock_acquire+0xc8/0x2d0
       __mutex_lock+0x9b/0xb50
       mutex_lock_nested+0x16/0x20
       netdev_trig_notify+0xec/0x190 [ledtrig_netdev]
       call_netdevice_register_net_notifiers+0x5a/0x100
       register_netdevice_notifier+0x85/0x120
       netdev_trig_activate+0x1d4/0x230 [ledtrig_netdev]
       led_trigger_set+0x172/0x2c0
       led_trigger_write+0xf1/0x140
       sysfs_kf_bin_write+0x5d/0x80
       kernfs_fop_write_iter+0x15d/0x210
       vfs_write+0x1f0/0x510
       ksys_write+0x6c/0xf0
       __x64_sys_write+0x14/0x20
       do_syscall_64+0x3f/0xf0
       entry_SYSCALL_64_after_hwframe+0x6c/0x74

other info that might help us debug this:

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(rtnl_mutex);
                               lock(&trigger_data->lock);
                               lock(rtnl_mutex);
  lock(&trigger_data->lock);

 *** DEADLOCK ***

8 locks held by bash/383:
 #0: ffff888103ff33f0 (sb_writers#3){.+.+}-{0:0}, at: ksys_write+0x6c/0xf0
 #1: ffff888103aa1e88 (&of->mutex){+.+.}-{3:3}, at: kernfs_fop_write_iter+0x114/0x210
 #2: ffff8881036f1890 (kn->active#82){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x11d/0x210
 #3: ffff888108e2c358 (&led_cdev->led_access){+.+.}-{3:3}, at: led_trigger_write+0x30/0x140
 #4: ffffffff8cdd9e10 (triggers_list_lock){++++}-{3:3}, at: led_trigger_write+0x75/0x140
 #5: ffff888108e2c270 (&led_cdev->trigger_lock){++++}-{3:3}, at: led_trigger_write+0xe3/0x140
 #6: ffffffff8cdde3d0 (pernet_ops_rwsem){++++}-{3:3}, at: register_netdevice_notifier+0x1c/0x120
 #7: ffffffff8cddf808 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock+0x12/0x20

stack backtrace:
CPU: 0 PID: 383 Comm: bash Not tainted 6.7.0-rc2-next-20231124+ #2
Hardware name: Default string Default string/Default string, BIOS ADLN.M6.SODIMM.ZB.CY.015 08/08/2023
Call Trace:
 <TASK>
 dump_stack_lvl+0x5c/0xd0
 dump_stack+0x10/0x20
 print_circular_bug+0x2dd/0x410
 check_noncircular+0x131/0x150
 __lock_acquire+0x1459/0x25a0
 lock_acquire+0xc8/0x2d0
 ? netdev_trig_notify+0xec/0x190 [ledtrig_netdev]
 __mutex_lock+0x9b/0xb50
 ? netdev_trig_notify+0xec/0x190 [ledtrig_netdev]
 ? __this_cpu_preempt_check+0x13/0x20
 ? netdev_trig_notify+0xec/0x190 [ledtrig_netdev]
 ? __cancel_work_timer+0x11c/0x1b0
 ? __mutex_lock+0x123/0xb50
 mutex_lock_nested+0x16/0x20
 ? mutex_lock_nested+0x16/0x20
 netdev_trig_notify+0xec/0x190 [ledtrig_netdev]
 call_netdevice_register_net_notifiers+0x5a/0x100
 register_netdevice_notifier+0x85/0x120
 netdev_trig_activate+0x1d4/0x230 [ledtrig_netdev]
 led_trigger_set+0x172/0x2c0
 ? preempt_count_add+0x49/0xc0
 led_trigger_write+0xf1/0x140
 sysfs_kf_bin_write+0x5d/0x80
 kernfs_fop_write_iter+0x15d/0x210
 vfs_write+0x1f0/0x510
 ksys_write+0x6c/0xf0
 __x64_sys_write+0x14/0x20
 do_syscall_64+0x3f/0xf0
 entry_SYSCALL_64_after_hwframe+0x6c/0x74
RIP: 0033:0x7f269055d034
Code: c7 00 16 00 00 00 b8 ff ff ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 f3 0f 1e fa 80 3d 35 c3 0d 00 00 74 13 b8 01 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 54 c3 0f 1f 00 48 83 ec 28 48 89 54 24 18 48
RSP: 002b:00007ffddb7ef748 EFLAGS: 00000202 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 0000000000000007 RCX: 00007f269055d034
RDX: 0000000000000007 RSI: 000055bf5f4af3c0 RDI: 0000000000000001
RBP: 000055bf5f4af3c0 R08: 0000000000000073 R09: 0000000000000001
R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000000007
R13: 00007f26906325c0 R14: 00007f269062ff20 R15: 0000000000000000
 </TASK>

Fixes: d5e01266e7 ("leds: trigger: netdev: add additional specific link speed mode")
Cc: stable@vger.kernel.org
Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Acked-by: Lee Jones <lee@kernel.org>
Link: https://lore.kernel.org/r/fb5c8294-2a10-4bf5-8f10-3d2b77d2757e@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2023-12-06 07:36:55 -08:00
..
blink leds: Convert all platform drivers to return void 2023-11-01 11:28:35 +00:00
flash leds: lm3601x: Convert to use maple tree register cache 2023-11-01 11:29:00 +00:00
rgb pwm: Changes for v6.7-rc1 2023-11-09 13:47:52 -08:00
simple leds: simatic-ipc-leds-gpio: Convert to platform remove callback returning void 2023-11-01 11:28:33 +00:00
trigger leds: trigger: netdev: fix RTNL handling to prevent potential deadlock 2023-12-06 07:36:55 -08:00
Kconfig leds: turris-omnia: Support HW controlled mode via private trigger 2023-11-01 11:28:46 +00:00
led-class-flash.c led-class-flash: fix -Wrestrict warning 2021-09-27 16:09:42 +02:00
led-class-multicolor.c leds: multicolor: Use rounded division when calculating color components 2023-08-17 11:25:03 +01:00
led-class.c leds: class: Don't expose color sysfs entry 2023-11-22 11:46:03 +00:00
led-core.c - Core Frameworks 2023-11-02 14:53:19 -10:00
led-triggers.c leds: Clear LED_INIT_DEFAULT_TRIGGER when clearing current trigger 2023-05-25 12:16:33 +01:00
leds-88pm860x.c leds: Convert all platform drivers to return void 2023-11-01 11:28:35 +00:00
leds-acer-a500.c leds: Add driver for Acer Iconia Tab A500 2020-09-26 21:56:42 +02:00
leds-adp5520.c leds: Convert all platform drivers to return void 2023-11-01 11:28:35 +00:00
leds-an30259a.c leds: Remove redundant of_match_ptr() 2023-08-17 13:28:25 +01:00
leds-apu.c leds: apu: extend support for PC Engines APU1 with newer firmware 2021-02-19 22:15:10 +01:00
leds-ariel.c leds: Explicitly include correct DT includes 2023-07-28 10:02:32 +01:00
leds-aw200xx.c leds: aw200xx: Convert to use maple tree register cache 2023-11-01 11:29:01 +00:00
leds-aw2013.c leds: aw2013: Enable pull-up supply for interrupt and I2C 2023-08-18 16:47:21 +01:00
leds-bcm6328.c leds: bcm6328: Get rid of custom led_init_default_state_get() 2023-01-30 08:03:37 +00:00
leds-bcm6358.c leds: bcm6358: Get rid of custom led_init_default_state_get() 2023-01-30 08:03:38 +00:00
leds-bd2606mvv.c leds: Switch i2c drivers back to use .probe() 2023-05-25 12:16:22 +01:00
leds-bd2802.c leds: Switch i2c drivers back to use .probe() 2023-05-25 12:16:22 +01:00
leds-blinkm.c leds: blinkm: Replace all non-returning strlcpy with strscpy 2023-05-25 12:31:18 +01:00
leds-cht-wcove.c leds: cht-wcove: Remove unneeded semicolon 2023-06-08 18:11:14 +01:00
leds-clevo-mail.c leds: Convert all platform drivers to return void 2023-11-01 11:28:35 +00:00
leds-cobalt-qube.c treewide: Add SPDX license identifier for more missed files 2019-05-21 10:50:45 +02:00
leds-cobalt-raq.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 1 2019-05-21 11:28:39 +02:00
leds-cpcap.c leds: Explicitly include correct DT includes 2023-07-28 10:02:32 +01:00
leds-cr0014114.c leds: cr0014114: Annotate struct cr0014114 with __counted_by 2023-11-01 11:28:26 +00:00
leds-da903x.c leds: Convert all platform drivers to return void 2023-11-01 11:28:35 +00:00
leds-da9052.c leds: Convert all platform drivers to return void 2023-11-01 11:28:35 +00:00
leds-dac124s085.c spi: make remove callback a void function 2022-02-09 13:00:45 +00:00
leds-el15203000.c leds: el15203000: Annotate struct el15203000 with __counted_by 2023-11-01 11:28:28 +00:00
leds-gpio-register.c leds: leds-gpio-register: Supply description for param 'id' 2021-05-28 11:38:54 +02:00
leds-gpio.c leds: gpio: Update headers 2023-11-01 11:29:24 +00:00
leds-hp6xx.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00
leds-ip30.c leds: ip30: Convert to devm_platform_ioremap_resource() 2023-07-28 09:26:21 +01:00
leds-ipaq-micro.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00
leds-is31fl32xx.c leds: Explicitly include correct DT includes 2023-07-28 10:02:32 +01:00
leds-is31fl319x.c leds: Switch i2c drivers back to use .probe() 2023-05-25 12:16:22 +01:00
leds-lm355x.c leds: Switch i2c drivers back to use .probe() 2023-05-25 12:16:22 +01:00
leds-lm3530.c leds: Switch i2c drivers back to use .probe() 2023-05-25 12:16:22 +01:00
leds-lm3532.c leds: Switch i2c drivers back to use .probe() 2023-05-25 12:16:22 +01:00
leds-lm3533.c leds: Convert all platform drivers to return void 2023-11-01 11:28:35 +00:00
leds-lm3642.c leds: Switch i2c drivers back to use .probe() 2023-05-25 12:16:22 +01:00
leds-lm3692x.c leds: lm392x: Convert to use maple tree register cache 2023-11-01 11:29:02 +00:00
leds-lm3697.c leds: lm3697: Annotate struct lm3697 with __counted_by 2023-11-01 11:28:31 +00:00
leds-lm36274.c leds: lm36274: Add missed property.h 2021-05-30 23:03:48 +02:00
leds-locomo.c ARM: pxa: split up mach/hardware.h 2022-04-19 16:27:05 +02:00
leds-lp50xx.c leds: Switch i2c drivers back to use .probe() 2023-05-25 12:16:22 +01:00
leds-lp55xx-common.c leds: lp55xx: Use gpiod_set_value_cansleep() 2023-11-01 11:28:42 +00:00
leds-lp55xx-common.h leds: lp55xx: Add multicolor framework support to lp55xx 2020-07-22 14:42:06 +02:00
leds-lp3944.c leds: Switch i2c drivers back to use .probe() 2023-05-25 12:16:22 +01:00
leds-lp3952.c leds: lp3952: Convert to use maple tree register cache 2023-11-01 11:29:03 +00:00
leds-lp5521.c leds: lp5521: Add an error check in lp5521_post_init_device 2023-11-01 11:29:26 +00:00
leds-lp5523.c leds: Remove redundant of_match_ptr() 2023-08-17 13:28:25 +01:00
leds-lp5562.c leds: Remove redundant of_match_ptr() 2023-08-17 13:28:25 +01:00
leds-lp8501.c leds: Remove redundant of_match_ptr() 2023-08-17 13:28:25 +01:00
leds-lp8788.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00
leds-lp8860.c leds: Switch i2c drivers back to use .probe() 2023-05-25 12:16:22 +01:00
leds-lt3593.c leds: lt3593: Put fwnode in any case during ->probe() 2021-08-03 23:49:31 +02:00
leds-max8997.c leds: max8997: Don't error if there is no pdata 2022-10-22 11:55:03 +02:00
leds-max77650.c leds: parse linux,default-trigger DT property in LED core 2020-09-26 21:56:43 +02:00
leds-mc13783.c leds: Convert all platform drivers to return void 2023-11-01 11:28:35 +00:00
leds-menf21bmc.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 2019-05-30 11:26:32 -07:00
leds-mlxcpld.c leds: leds-mlxcpld: Fix a bunch of kernel-doc formatting issues 2021-05-28 11:39:00 +02:00
leds-mlxreg.c leds: Convert all platform drivers to return void 2023-11-01 11:28:35 +00:00
leds-mt6323.c leds: Convert all platform drivers to return void 2023-11-01 11:28:35 +00:00
leds-net48xx.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00
leds-netxbig.c leds: Use DEVICE_ATTR_{RW, RO, WO} macros 2020-12-30 19:37:13 +01:00
leds-nic78bx.c leds: Convert all platform drivers to return void 2023-11-01 11:28:35 +00:00
leds-ns2.c leds: ns2: Slightly simplify a memory allocation 2023-07-28 11:58:04 +01:00
leds-ot200.c
leds-pca955x.c leds: pca955x: Cleanup OF/ID table terminators 2023-11-01 11:28:55 +00:00
leds-pca963x.c leds: Switch i2c drivers back to use .probe() 2023-05-25 12:16:22 +01:00
leds-pca995x.c leds: pca995x: Fix MODULE_DEVICE_TABLE for OF 2023-08-15 18:30:07 +01:00
leds-pca9532.c leds: Explicitly include correct DT includes 2023-07-28 10:02:32 +01:00
leds-pm8058.c leds: Explicitly include correct DT includes 2023-07-28 10:02:32 +01:00
leds-powernv.c leds: Convert all platform drivers to return void 2023-11-01 11:28:35 +00:00
leds-pwm.c leds: pwm: Don't disable the PWM when the LED should be off 2023-11-01 11:28:50 +00:00
leds-rb532.c leds: Convert all platform drivers to return void 2023-11-01 11:28:35 +00:00
leds-regulator.c leds: Convert all platform drivers to return void 2023-11-01 11:28:35 +00:00
leds-sc27xx-bltc.c leds: sc27xx: Move mutex_init() down 2023-11-01 11:29:15 +00:00
leds-spi-byte.c leds: Explicitly include correct DT includes 2023-07-28 10:02:32 +01:00
leds-ss4200.c leds: ss4200: simplify the return expression of register_nasgpio_led() 2020-12-30 19:37:14 +01:00
leds-sunfire.c leds: Convert all platform drivers to return void 2023-11-01 11:28:35 +00:00
leds-syscon.c leds: Explicitly include correct DT includes 2023-07-28 10:02:32 +01:00
leds-tca6507.c leds: tca6507: Don't use fixed GPIO base 2023-11-01 11:29:04 +00:00
leds-ti-lmu-common.c leds: Explicitly include correct DT includes 2023-07-28 10:02:32 +01:00
leds-tlc591xx.c leds: Explicitly include correct DT includes 2023-07-28 10:02:32 +01:00
leds-tps6105x.c leds: tps6105x: add driver for MFD chip LED mode 2019-12-21 20:10:02 +01:00
leds-turris-omnia.c leds: turris-omnia: Fix brightness setting and trigger activating 2023-11-01 11:29:16 +00:00
leds-wm831x-status.c leds: Convert all platform drivers to return void 2023-11-01 11:28:35 +00:00
leds-wm8350.c leds: Convert all platform drivers to return void 2023-11-01 11:28:35 +00:00
leds-wrap.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00
leds.h leds: Move led_init_default_state_get() to the global header 2023-01-30 08:03:35 +00:00
Makefile leds: pca995x: Add support for PCA995X chips 2023-07-28 09:26:28 +01:00
TODO leds: TODO: Add documentation about possible subsystem improvements 2020-09-30 19:15:33 +02:00
uleds.c leds: uleds: Use module_misc_device macro to simplify the code 2023-08-18 11:42:54 +01:00