When the module is removed the led workqueue is destroyed in the remove callback, before the led device is unregistered from the led subsystem.

This leads to a NULL pointer derefence when the led device is unregistered automatically later as part of the module removal cleanup. Bellow is the backtrace showing the problem.

BUG: unable to handle kernel NULL pointer dereference at (null) IP: __queue_work+0x8c/0x410 PGD 0 P4D 0 Oops: 0000 [#1] SMP NOPTI Modules linked in: ccm edac_mce_amd kvm_amd kvm irqbypass crct10dif_pclmul crc32_pclmul ghash_clmulni_intel pcbc aesni_intel aes_x86_64 joydev crypto_simd asus_nb_wmi glue_helper uvcvideo snd_hda_codec_conexant snd_hda_codec_generic snd_hda_codec_hdmi snd_hda_intel asus_wmi snd_hda_codec cryptd snd_hda_core sparse_keymap videobuf2_vmalloc arc4 videobuf2_memops snd_hwdep input_leds videobuf2_v4l2 ath9k psmouse videobuf2_core videodev ath9k_common snd_pcm ath9k_hw media fam15h_power ath k10temp snd_timer mac80211 i2c_piix4 r8169 mii mac_hid cfg80211 asus_wireless(-) snd soundcore wmi shpchp 8250_dw ip_tables x_tables amdkfd amd_iommu_v2 amdgpu radeon chash i2c_algo_bit drm_kms_helper syscopyarea serio_raw sysfillrect sysimgblt fb_sys_fops ahci ttm libahci drm video CPU: 3 PID: 2177 Comm: rmmod Not tainted 4.15.0-5-generic #6+dev94.b4287e5bem1-Endless Hardware name: ASUSTeK COMPUTER INC. X555DG/X555DG, BIOS 5.011 05/05/2015 RIP: 0010:__queue_work+0x8c/0x410 RSP: 0018:ffffbe8cc249fcd8 EFLAGS: 00010086 RAX: ffff992ac6810800 RBX: 0000000000000000 RCX: 0000000000000008 RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffff992ac6400e18 RBP: ffffbe8cc249fd18 R08: ffff992ac6400db0 R09: 0000000000000000 R10: 0000000000000040 R11: ffff992ac6400dd8 R12: 0000000000002000 R13: ffff992abd762e00 R14: ffff992abd763e38 R15: 000000000001ebe0 FS: 00007f318203e700(0000) GS:ffff992aced80000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000000 CR3: 00000001c720e000 CR4: 00000000001406e0 Call Trace: queue_work_on+0x38/0x40 led_state_set+0x2c/0x40 [asus_wireless] led_set_brightness_nopm+0x14/0x40 led_set_brightness+0x37/0x60 led_trigger_set+0xfc/0x1d0 led_classdev_unregister+0x32/0xd0 devm_led_classdev_release+0x11/0x20 release_nodes+0x109/0x1f0 devres_release_all+0x3c/0x50 device_release_driver_internal+0x16d/0x220 driver_detach+0x3f/0x80 bus_remove_driver+0x55/0xd0 driver_unregister+0x2c/0x40 acpi_bus_unregister_driver+0x15/0x20 asus_wireless_driver_exit+0x10/0xb7c [asus_wireless] SyS_delete_module+0x1da/0x2b0 entry_SYSCALL_64_fastpath+0x24/0x87 RIP: 0033:0x7f3181b65fd7 RSP: 002b:00007ffe74bcbe18 EFLAGS: 00000206 ORIG_RAX: 00000000000000b0 RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f3181b65fd7 RDX: 000000000000000a RSI: 0000000000000800 RDI: 0000555ea2559258 RBP: 0000555ea25591f0 R08: 00007ffe74bcad91 R09: 000000000000000a R10: 0000000000000000 R11: 0000000000000206 R12: 0000000000000003 R13: 00007ffe74bcae00 R14: 0000000000000000 R15: 0000555ea25591f0 Code: 01 00 00 02 0f 85 7d 01 00 00 48 63 45 d4 48 c7 c6 00 f4 fa 87 49 8b 9d 08 01 00 00 48 03 1c c6 4c 89 f7 e8 87 fb ff ff 48 85 c0 <48> 8b 3b 0f 84 c5 01 00 00 48 39 f8 0f 84 bc 01 00 00 48 89 c7 RIP: __queue_work+0x8c/0x410 RSP: ffffbe8cc249fcd8 CR2: 0000000000000000 ---[ end trace 7aa4f4a232e9c39c ]---

Unregistering the led device on the remove callback before destroying the workqueue avoids this problem.

https://bugzilla.kernel.org/show_bug.cgi?id=196097

Reported-by: Dun Hum bitter.taste@gmx.com Cc: stable@vger.kernel.org Signed-off-by: João Paulo Rechi Vita jprvita@endlessm.com --- drivers/platform/x86/asus-wireless.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/platform/x86/asus-wireless.c b/drivers/platform/x86/asus-wireless.c index 343e12547660..b8e35a8d65cf 100644 --- a/drivers/platform/x86/asus-wireless.c +++ b/drivers/platform/x86/asus-wireless.c @@ -181,8 +181,10 @@ static int asus_wireless_remove(struct acpi_device *adev) { struct asus_wireless_data *data = acpi_driver_data(adev);

- if (data->wq) + if (data->wq) { + devm_led_classdev_unregister(&adev->dev, &data->led); destroy_workqueue(data->wq); + } return 0; }