linux/drivers/leds
Jiri Kosina 9067359faf Revert "leds: convert blink timer to workqueue"
This reverts commit 8b37e1bef5.

It's broken as it changes led_blink_set() in a way that it can now sleep
(while synchronously waiting for workqueue to be cancelled). That's a
problem, because it's possible that this function gets called from atomic
context (tpt_trig_timer() takes a readlock and thus disables preemption).

This has been brought up 3 weeks ago already [1] but no proper fix has
materialized, and I keep seeing the problem since 3.17-rc1.

[1] https://lkml.org/lkml/2014/8/16/128

 BUG: sleeping function called from invalid context at kernel/workqueue.c:2650
 in_atomic(): 1, irqs_disabled(): 0, pid: 2335, name: wpa_supplicant
 5 locks held by wpa_supplicant/2335:
  #0:  (rtnl_mutex){+.+.+.}, at: [<ffffffff814c7c92>] rtnl_lock+0x12/0x20
  #1:  (&wdev->mtx){+.+.+.}, at: [<ffffffffc06e649c>] cfg80211_mgd_wext_siwessid+0x5c/0x180 [cfg80211]
  #2:  (&local->mtx){+.+.+.}, at: [<ffffffffc0817dea>] ieee80211_prep_connection+0x17a/0x9a0 [mac80211]
  #3:  (&local->chanctx_mtx){+.+.+.}, at: [<ffffffffc08081ed>] ieee80211_vif_use_channel+0x5d/0x2a0 [mac80211]
  #4:  (&trig->leddev_list_lock){.+.+..}, at: [<ffffffffc081e68c>] tpt_trig_timer+0xec/0x170 [mac80211]
 CPU: 0 PID: 2335 Comm: wpa_supplicant Not tainted 3.17.0-rc3 #1
 Hardware name: LENOVO 7470BN2/7470BN2, BIOS 6DET38WW (2.02 ) 12/19/2008
  ffff8800360b5a50 ffff8800751f76d8 ffffffff8159e97f ffff8800360b5a30
  ffff8800751f76e8 ffffffff810739a5 ffff8800751f77b0 ffffffff8106862f
  ffffffff810685d0 0aa2209200000000 ffff880000000004 ffff8800361c59d0
 Call Trace:
  [<ffffffff8159e97f>] dump_stack+0x4d/0x66
  [<ffffffff810739a5>] __might_sleep+0xe5/0x120
  [<ffffffff8106862f>] flush_work+0x5f/0x270
  [<ffffffff810685d0>] ? mod_delayed_work_on+0x80/0x80
  [<ffffffff810945ca>] ? mark_held_locks+0x6a/0x90
  [<ffffffff81068a5f>] ? __cancel_work_timer+0x6f/0x100
  [<ffffffff810946ed>] ? trace_hardirqs_on_caller+0xfd/0x1c0
  [<ffffffff81068a6b>] __cancel_work_timer+0x7b/0x100
  [<ffffffff81068b0e>] cancel_delayed_work_sync+0xe/0x10
  [<ffffffff8147cf3b>] led_blink_set+0x1b/0x40
  [<ffffffffc081e6b0>] tpt_trig_timer+0x110/0x170 [mac80211]
  [<ffffffffc081ecdd>] ieee80211_mod_tpt_led_trig+0x9d/0x160 [mac80211]
  [<ffffffffc07e4278>] __ieee80211_recalc_idle+0x98/0x140 [mac80211]
  [<ffffffffc07e59ce>] ieee80211_idle_off+0xe/0x10 [mac80211]
  [<ffffffffc0804e5b>] ieee80211_add_chanctx+0x3b/0x220 [mac80211]
  [<ffffffffc08062e4>] ieee80211_new_chanctx+0x44/0xf0 [mac80211]
  [<ffffffffc080838a>] ieee80211_vif_use_channel+0x1fa/0x2a0 [mac80211]
  [<ffffffffc0817df8>] ieee80211_prep_connection+0x188/0x9a0 [mac80211]
  [<ffffffffc081c246>] ieee80211_mgd_auth+0x256/0x2e0 [mac80211]
  [<ffffffffc07eab33>] ieee80211_auth+0x13/0x20 [mac80211]
  [<ffffffffc06cb006>] cfg80211_mlme_auth+0x106/0x270 [cfg80211]
  [<ffffffffc06ce085>] cfg80211_conn_do_work+0x155/0x3b0 [cfg80211]
  [<ffffffffc06cf670>] cfg80211_connect+0x3f0/0x540 [cfg80211]
  [<ffffffffc06e6148>] cfg80211_mgd_wext_connect+0x158/0x1f0 [cfg80211]
  [<ffffffffc06e651e>] cfg80211_mgd_wext_siwessid+0xde/0x180 [cfg80211]
  [<ffffffffc06e36c0>] ? cfg80211_wext_giwessid+0x50/0x50 [cfg80211]
  [<ffffffffc06e36dd>] cfg80211_wext_siwessid+0x1d/0x40 [cfg80211]
  [<ffffffff81584d0c>] ioctl_standard_iw_point+0x14c/0x3e0
  [<ffffffff810946ed>] ? trace_hardirqs_on_caller+0xfd/0x1c0
  [<ffffffff8158502a>] ioctl_standard_call+0x8a/0xd0
  [<ffffffff81584fa0>] ? ioctl_standard_iw_point+0x3e0/0x3e0
  [<ffffffff81584b76>] wireless_process_ioctl.constprop.10+0xb6/0x100
  [<ffffffff8158521d>] wext_handle_ioctl+0x5d/0xb0
  [<ffffffff814cfb29>] dev_ioctl+0x329/0x620
  [<ffffffff810946ed>] ? trace_hardirqs_on_caller+0xfd/0x1c0
  [<ffffffff8149c7f2>] sock_ioctl+0x142/0x2e0
  [<ffffffff811b0140>] do_vfs_ioctl+0x300/0x520
  [<ffffffff815a67fb>] ? sysret_check+0x1b/0x56
  [<ffffffff810946ed>] ? trace_hardirqs_on_caller+0xfd/0x1c0
  [<ffffffff811b03e1>] SyS_ioctl+0x81/0xa0
  [<ffffffff815a67d6>] system_call_fastpath+0x1a/0x1f
 wlan0: send auth to 00:0b:6b:3c:8c:e4 (try 1/3)
 wlan0: authenticated
 wlan0: associate with 00:0b:6b:3c:8c:e4 (try 1/3)
 wlan0: RX AssocResp from 00:0b:6b:3c:8c:e4 (capab=0x431 status=0 aid=2)
 wlan0: associated
 IPv6: ADDRCONF(NETDEV_CHANGE): wlan0: link becomes ready
 cfg80211: Calling CRDA for country: NA
 wlan0: Limiting TX power to 27 (27 - 0) dBm as advertised by 00:0b:6b:3c:8c:e4

 =================================
 [ INFO: inconsistent lock state ]
 3.17.0-rc3 #1 Not tainted
 ---------------------------------
 inconsistent {SOFTIRQ-ON-W} -> {IN-SOFTIRQ-W} usage.
 swapper/0/0 [HC0[0]:SC1[1]:HE1:SE0] takes:
  ((&(&led_cdev->blink_work)->work)){+.?...}, at: [<ffffffff810685d0>] flush_work+0x0/0x270
 {SOFTIRQ-ON-W} state was registered at:
   [<ffffffff81094dbe>] __lock_acquire+0x30e/0x1a30
   [<ffffffff81096c81>] lock_acquire+0x91/0x110
   [<ffffffff81068608>] flush_work+0x38/0x270
   [<ffffffff81068a6b>] __cancel_work_timer+0x7b/0x100
   [<ffffffff81068b0e>] cancel_delayed_work_sync+0xe/0x10
   [<ffffffff8147cf3b>] led_blink_set+0x1b/0x40
   [<ffffffffc081e6b0>] tpt_trig_timer+0x110/0x170 [mac80211]
   [<ffffffffc081ecdd>] ieee80211_mod_tpt_led_trig+0x9d/0x160 [mac80211]
   [<ffffffffc07e4278>] __ieee80211_recalc_idle+0x98/0x140 [mac80211]
   [<ffffffffc07e59ce>] ieee80211_idle_off+0xe/0x10 [mac80211]
   [<ffffffffc0804e5b>] ieee80211_add_chanctx+0x3b/0x220 [mac80211]
   [<ffffffffc08062e4>] ieee80211_new_chanctx+0x44/0xf0 [mac80211]
   [<ffffffffc080838a>] ieee80211_vif_use_channel+0x1fa/0x2a0 [mac80211]
   [<ffffffffc0817df8>] ieee80211_prep_connection+0x188/0x9a0 [mac80211]
   [<ffffffffc081c246>] ieee80211_mgd_auth+0x256/0x2e0 [mac80211]
   [<ffffffffc07eab33>] ieee80211_auth+0x13/0x20 [mac80211]
   [<ffffffffc06cb006>] cfg80211_mlme_auth+0x106/0x270 [cfg80211]
   [<ffffffffc06ce085>] cfg80211_conn_do_work+0x155/0x3b0 [cfg80211]
   [<ffffffffc06cf670>] cfg80211_connect+0x3f0/0x540 [cfg80211]
   [<ffffffffc06e6148>] cfg80211_mgd_wext_connect+0x158/0x1f0 [cfg80211]
   [<ffffffffc06e651e>] cfg80211_mgd_wext_siwessid+0xde/0x180 [cfg80211]
   [<ffffffffc06e36dd>] cfg80211_wext_siwessid+0x1d/0x40 [cfg80211]
   [<ffffffff81584d0c>] ioctl_standard_iw_point+0x14c/0x3e0
   [<ffffffff8158502a>] ioctl_standard_call+0x8a/0xd0
   [<ffffffff81584b76>] wireless_process_ioctl.constprop.10+0xb6/0x100
   [<ffffffff8158521d>] wext_handle_ioctl+0x5d/0xb0
   [<ffffffff814cfb29>] dev_ioctl+0x329/0x620
   [<ffffffff8149c7f2>] sock_ioctl+0x142/0x2e0
   [<ffffffff811b0140>] do_vfs_ioctl+0x300/0x520
   [<ffffffff811b03e1>] SyS_ioctl+0x81/0xa0
   [<ffffffff815a67d6>] system_call_fastpath+0x1a/0x1f
 irq event stamp: 493416
 hardirqs last  enabled at (493416): [<ffffffff81068a5f>] __cancel_work_timer+0x6f/0x100
 hardirqs last disabled at (493415): [<ffffffff81067e9f>] try_to_grab_pending+0x1f/0x160
 softirqs last  enabled at (493408): [<ffffffff81053ced>] _local_bh_enable+0x1d/0x50
 softirqs last disabled at (493409): [<ffffffff81054c75>] irq_exit+0xa5/0xb0

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

        CPU0
        ----
   lock((&(&led_cdev->blink_work)->work));
   <Interrupt>
     lock((&(&led_cdev->blink_work)->work));

  *** DEADLOCK ***

 2 locks held by swapper/0/0:
  #0:  (((&tpt_trig->timer))){+.-...}, at: [<ffffffff810b4c50>] call_timer_fn+0x0/0x180
  #1:  (&trig->leddev_list_lock){.+.?..}, at: [<ffffffffc081e68c>] tpt_trig_timer+0xec/0x170 [mac80211]

 stack backtrace:
 CPU: 0 PID: 0 Comm: swapper/0 Not tainted 3.17.0-rc3 #1
 Hardware name: LENOVO 7470BN2/7470BN2, BIOS 6DET38WW (2.02 ) 12/19/2008
  ffffffff8246eb30 ffff88007c203b00 ffffffff8159e97f ffffffff81a194c0
  ffff88007c203b50 ffffffff81599c29 0000000000000001 ffffffff00000001
  ffff880000000000 0000000000000006 ffffffff81a194c0 ffffffff81093ad0
 Call Trace:
  <IRQ>  [<ffffffff8159e97f>] dump_stack+0x4d/0x66
  [<ffffffff81599c29>] print_usage_bug+0x1f4/0x205
  [<ffffffff81093ad0>] ? check_usage_backwards+0x140/0x140
  [<ffffffff810944d3>] mark_lock+0x223/0x2b0
  [<ffffffff81094d60>] __lock_acquire+0x2b0/0x1a30
  [<ffffffff81096c81>] lock_acquire+0x91/0x110
  [<ffffffff810685d0>] ? mod_delayed_work_on+0x80/0x80
  [<ffffffffc081e5a0>] ? __ieee80211_get_rx_led_name+0x10/0x10 [mac80211]
  [<ffffffff81068608>] flush_work+0x38/0x270
  [<ffffffff810685d0>] ? mod_delayed_work_on+0x80/0x80
  [<ffffffff810945ca>] ? mark_held_locks+0x6a/0x90
  [<ffffffff81068a5f>] ? __cancel_work_timer+0x6f/0x100
  [<ffffffffc081e5a0>] ? __ieee80211_get_rx_led_name+0x10/0x10 [mac80211]
  [<ffffffff8109469d>] ? trace_hardirqs_on_caller+0xad/0x1c0
  [<ffffffffc081e5a0>] ? __ieee80211_get_rx_led_name+0x10/0x10 [mac80211]
  [<ffffffff81068a6b>] __cancel_work_timer+0x7b/0x100
  [<ffffffff81068b0e>] cancel_delayed_work_sync+0xe/0x10
  [<ffffffff8147cf3b>] led_blink_set+0x1b/0x40
  [<ffffffffc081e6b0>] tpt_trig_timer+0x110/0x170 [mac80211]
  [<ffffffff810b4cc5>] call_timer_fn+0x75/0x180
  [<ffffffff810b4c50>] ? process_timeout+0x10/0x10
  [<ffffffffc081e5a0>] ? __ieee80211_get_rx_led_name+0x10/0x10 [mac80211]
  [<ffffffff810b50ac>] run_timer_softirq+0x1fc/0x2f0
  [<ffffffff81054805>] __do_softirq+0x115/0x2e0
  [<ffffffff81054c75>] irq_exit+0xa5/0xb0
  [<ffffffff810049b3>] do_IRQ+0x53/0xf0
  [<ffffffff815a74af>] common_interrupt+0x6f/0x6f
  <EOI>  [<ffffffff8147b56e>] ? cpuidle_enter_state+0x6e/0x180
  [<ffffffff8147b732>] cpuidle_enter+0x12/0x20
  [<ffffffff8108bba0>] cpu_startup_entry+0x330/0x360
  [<ffffffff8158fb51>] rest_init+0xc1/0xd0
  [<ffffffff8158fa90>] ? csum_partial_copy_generic+0x170/0x170
  [<ffffffff81af3ff2>] start_kernel+0x44f/0x45a
  [<ffffffff81af399c>] ? set_init_arg+0x53/0x53
  [<ffffffff81af35ad>] x86_64_start_reservations+0x2a/0x2c
  [<ffffffff81af36a0>] x86_64_start_kernel+0xf1/0xf4

Cc: Vincent Donnefort <vdonnefort@gmail.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
Signed-off-by: Bryan Wu <cooloney@gmail.com>
2014-09-02 10:02:13 -07:00
..
trigger drivers/leds: Replace __get_cpu_var use through this_cpu_ptr 2014-05-08 14:28:08 +08:00
dell-led.c dell-led: add mic mute led interface 2014-05-08 14:28:07 +08:00
Kconfig ARM: SoC driver changes for 3.17 2014-08-08 11:34:32 -07:00
led-class.c Revert "leds: convert blink timer to workqueue" 2014-09-02 10:02:13 -07:00
led-core.c Revert "leds: convert blink timer to workqueue" 2014-09-02 10:02:13 -07:00
led-triggers.c leds: make sure we unregister a trigger only once 2014-04-07 14:47:25 -07:00
leds-88pm860x.c leds: 88pm860x: Fix missing refcount decrement for parent of_node 2014-05-08 14:28:08 +08:00
leds-adp5520.c leds: Remove duplicated OOM message for individual driver 2014-05-08 14:28:08 +08:00
leds-asic3.c drivers/leds: delete non-required instances of include <linux/init.h> 2014-02-27 09:56:56 -08:00
leds-bd2802.c leds: Remove duplicated OOM message for individual driver 2014-05-08 14:28:08 +08:00
leds-blinkm.c leds: blinkm: remove unnecessary spaces 2014-02-27 10:19:57 -08:00
leds-clevo-mail.c leds: clevo-mail: Make probe function __init 2014-03-13 15:53:31 -07:00
leds-cobalt-qube.c drivers/leds: delete non-required instances of include <linux/init.h> 2014-02-27 09:56:56 -08:00
leds-cobalt-raq.c Merge branch 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/cooloney/linux-leds 2012-12-15 12:52:42 -08:00
leds-da903x.c leds: Remove duplicated OOM message for individual driver 2014-05-08 14:28:08 +08:00
leds-da9052.c leds: Remove duplicated OOM message for individual driver 2014-05-08 14:28:08 +08:00
leds-dac124s085.c leds: dac124s085: Remove redundant spi_set_drvdata 2013-10-22 10:57:34 -07:00
leds-fsg.c drivers/leds: delete non-required instances of include <linux/init.h> 2014-02-27 09:56:56 -08:00
leds-gpio-register.c
leds-gpio.c leds-gpio: of: introduce MODULE_DEVICE_TABLE for module autoloading 2014-03-06 11:56:59 -08:00
leds-hp6xx.c drivers/leds: delete non-required instances of include <linux/init.h> 2014-02-27 09:56:56 -08:00
leds-ipaq-micro.c leds: ipaq-micro: fix sparse non static symbol warning 2014-07-29 10:57:20 -07:00
leds-lm355x.c leds: lm355x: fix attribute-creation race 2014-06-25 15:10:54 -07:00
leds-lm3530.c leds: lm3550: fix attribute-creation race 2014-06-25 15:00:55 -07:00
leds-lm3533.c leds: lm3533: fix attribute-creation race 2014-06-25 15:02:31 -07:00
leds-lm3642.c leds: lm3642: fix attribute-creation race 2014-06-25 15:13:08 -07:00
leds-locomo.c drivers/leds: Add module.h to files using it implicitly 2011-10-31 19:31:49 -04:00
leds-lp55xx-common.c leds: lp55xx-common: fix attribute-creation race 2014-06-27 13:44:05 -07:00
leds-lp55xx-common.h leds: lp55xx: add common macros for device attributes 2013-08-26 17:22:12 -07:00
leds-lp3944.c leds: leds-lp3944, fix "sparse" warning "mixing different enum types" 2013-08-26 17:22:11 -07:00
leds-lp5521.c drivers/leds: delete non-required instances of include <linux/init.h> 2014-02-27 09:56:56 -08:00
leds-lp5523.c leds: lp55xx: add DT bindings for LP55231 2014-05-08 14:28:08 +08:00
leds-lp5562.c leds: lp5562: remove unnecessary parentheses 2014-02-27 10:17:15 -08:00
leds-lp8501.c lp5523, lp8501: comment improvements 2014-01-10 11:44:44 +01:00
leds-lp8788.c leds-lp8788: fix a parent device in _probe() 2013-02-01 17:47:05 -08:00
leds-lt3593.c drivers/leds: delete non-required instances of include <linux/init.h> 2014-02-27 09:56:56 -08:00
leds-max8997.c leds: max8997: fix attribute-creation race 2014-06-25 15:24:03 -07:00
leds-mc13783.c drivers/leds: delete non-required instances of include <linux/init.h> 2014-02-27 09:56:56 -08:00
leds-net48xx.c leds: leds-net48xx: Use linux/io.h instead of asm/io.h 2012-11-27 14:49:28 -08:00
leds-netxbig.c leds: netxbig: fix attribute-creation race 2014-06-25 15:27:37 -07:00
leds-ns2.c leds: ns2: fix attribute-creation race 2014-06-25 15:32:11 -07:00
leds-ot200.c drivers/leds: delete non-required instances of include <linux/init.h> 2014-02-27 09:56:56 -08:00
leds-pca955x.c leds: use dev_get_platdata() 2013-08-26 17:22:11 -07:00
leds-pca963x.c leds:pca963x: Always initialize MODE2 register 2014-07-03 11:55:56 -07:00
leds-pca9532.c leds: use dev_get_platdata() 2013-08-26 17:22:11 -07:00
leds-pwm.c Merge branch 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/cooloney/linux-leds 2014-06-12 13:08:09 -07:00
leds-rb532.c Merge branch 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/cooloney/linux-leds 2012-12-15 12:52:42 -08:00
leds-regulator.c leds: use dev_get_platdata() 2013-08-26 17:22:11 -07:00
leds-s3c24xx.c leds: Remove duplicated OOM message for individual driver 2014-05-08 14:28:08 +08:00
leds-ss4200.c leds: ss4200: fix attribute-creation race 2014-06-25 15:34:24 -07:00
leds-sunfire.c leds: Remove duplicated OOM message for individual driver 2014-05-08 14:28:08 +08:00
leds-tca6507.c drivers: leds: leds-tca6507: check CONFIG_GPIOLIB whether defined for 'gpio_base' 2014-01-27 17:28:49 -08:00
leds-versatile.c ARM/leds: move ARM Versatile LED driver to leds subsystem 2014-03-28 10:54:15 +01:00
leds-wm831x-status.c leds: wm831x-status: fix attribute-creation race 2014-06-25 15:35:11 -07:00
leds-wm8350.c drivers/leds: delete non-required instances of include <linux/init.h> 2014-02-27 09:56:56 -08:00
leds-wrap.c leds: leds-wrap: Use <linux/io.h> instead of <asm/io.h> 2012-11-27 14:49:30 -08:00
leds.h leds: delay led_set_brightness if stopping soft-blink 2012-09-11 18:32:40 +08:00
Makefile ARM: SoC driver changes for 3.17 2014-08-08 11:34:32 -07:00