random bluetoothd crashes

```
[ 2903.917746] WARNING: CPU: 0 PID: 4695 at /opt/kernel-builder_repos/Re4son/re4son-raspberrypi-linux/all/fs/sysfs/group.c:255 sysfs_remove_group+0x98/0xa4
[ 2903.917753] sysfs group 'byte_queue_limits' not found for kobject 'tx-0'
[ 2903.917757] Modules linked in: evdev uinput bnep hci_uart btbcm serdev bluetooth ecdh_generic fuse spidev brcmfmac brcmutil raspberrypi_hwmon snd_bcm2835(C) hwmon cfg80211 snd_pcm snd_timer rfkill snd bcm2835_codec(C) v4l2_mem2mem bcm2835_v4l2(C) i2c_bcm2835 bcm2835_mmal_vchiq(C) spi_bcm2835aux v4l2_common videobuf2_dma_contig videobuf2_vmalloc videobuf2_memops videobuf2_v4l2 videobuf2_common spi_bcm2835 videodev media vc_sm_cma(C) fixed uio_pdrv_genirq uio i2c_dev usb_f_ecm g_ether usb_f_rndis u_ether libcomposite dwc2 udc_core ip_tables x_tables ipv6
[ 2903.917930] CPU: 0 PID: 4695 Comm: kbnepd bnep0 Tainted: G C 4.19.66-Re4son+ #1
[ 2903.917935] Hardware name: BCM2835
[ 2903.917969] [] (unwind_backtrace) from [] (show_stack+0x20/0x24)
[ 2903.917992] [] (show_stack) from [] (dump_stack+0x20/0x28)
[ 2903.918075] [] (dump_stack) from [] (__warn+0xf0/0x118)
[ 2903.918092] [] (__warn) from [] (warn_slowpath_fmt+0x50/0x70)
[ 2903.918112] [] (warn_slowpath_fmt) from [] (sysfs_remove_group+0x98/0xa4)
[ 2903.918131] [] (sysfs_remove_group) from [] (netdev_queue_update_kobjects+0xc0/0x178)
[ 2903.918146] [] (netdev_queue_update_kobjects) from [] (netdev_unregister_kobject+0x60/0x80)
[ 2903.918169] [] (netdev_unregister_kobject) from [] (rollback_registered_many+0x1ec/0x508)
[ 2903.918185] [] (rollback_registered_many) from [] (unregister_netdevice_queue+0x9c/0x130)
[ 2903.918199] [] (unregister_netdevice_queue) from [] (unregister_netdev+0x28/0x30)
[ 2903.918237] [] (unregister_netdev) from [] (bnep_session+0x4d4/0x888 [bnep])
[ 2903.918288] [] (bnep_session [bnep]) from [] (kthread+0x120/0x160)
[ 2903.918305] [] (kthread) from [] (ret_from_fork+0x14/0x28)
[ 2903.918312] Exception stack(0xd67affb0 to 0xd67afff8)
[ 2903.918321] ffa0: 00000000 00000000 00000000 00000000
[ 2903.918332] ffc0: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
[ 2903.918340] ffe0: 00000000 00000000 00000000 00000000 00000013 00000000
[ 2903.918347] ---[ end trace cfb2c6995ec3c276 ]---
...
[ 2903.918482] WARNING: CPU: 0 PID: 4695 at /opt/kernel-builder_repos/Re4son/re4son-raspberrypi-linux/all/fs/sysfs/group.c:255 sysfs_remove_group+0x98/0xa4
[ 2903.918488] sysfs group 'power' not found for kobject 'bnep0'
[ 2903.918492] Modules linked in: evdev uinput bnep hci_uart btbcm serdev bluetooth ecdh_generic fuse spidev brcmfmac brcmutil raspberrypi_hwmon snd_bcm2835(C) hwmon cfg80211 snd_pcm snd_timer rfkill snd bcm2835_codec(C) v4l2_mem2mem bcm2835_v4l2(C) i2c_bcm2835 bcm2835_mmal_vchiq(C) spi_bcm2835aux v4l2_common videobuf2_dma_contig videobuf2_vmalloc videobuf2_memops videobuf2_v4l2 videobuf2_common spi_bcm2835 videodev media vc_sm_cma(C) fixed uio_pdrv_genirq uio i2c_dev usb_f_ecm g_ether usb_f_rndis u_ether libcomposite dwc2 udc_core ip_tables x_tables ipv6
[ 2903.918652] CPU: 0 PID: 4695 Comm: kbnepd bnep0 Tainted: G WC 4.19.66-Re4son+ #1
[ 2903.918657] Hardware name: BCM2835
[ 2903.918682] [] (unwind_backtrace) from [] (show_stack+0x20/0x24)
[ 2903.918701] [] (show_stack) from [] (dump_stack+0x20/0x28)
[ 2903.918722] [] (dump_stack) from [] (__warn+0xf0/0x118)
[ 2903.918738] [] (__warn) from [] (warn_slowpath_fmt+0x50/0x70)
[ 2903.918756] [] (warn_slowpath_fmt) from [] (sysfs_remove_group+0x98/0xa4)
[ 2903.918781] [] (sysfs_remove_group) from [] (dpm_sysfs_remove+0x58/0x60)
[ 2903.918798] [] (dpm_sysfs_remove) from [] (device_del+0x7c/0x360)
[ 2903.918813] [] (device_del) from [] (netdev_unregister_kobject+0x7c/0x80)
[ 2903.918832] [] (netdev_unregister_kobject) from [] (rollback_registered_many+0x1ec/0x508)
[ 2903.918847] [] (rollback_registered_many) from [] (unregister_netdevice_queue+0x9c/0x130)
[ 2903.918861] [] (unregister_netdevice_queue) from [] (unregister_netdev+0x28/0x30)
[ 2903.918891] [] (unregister_netdev) from [] (bnep_session+0x4d4/0x888 [bnep])
[ 2903.918919] [] (bnep_session [bnep]) from [] (kthread+0x120/0x160)
[ 2903.918933] [] (kthread) from [] (ret_from_fork+0x14/0x28)
[ 2903.918940] Exception stack(0xd67affb0 to 0xd67afff8)
[ 2903.918949] ffa0: 00000000 00000000 00000000 00000000
[ 2903.918959] ffc0: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
[ 2903.918968] ffe0: 00000000 00000000 00000000 00000000 00000013 00000000
[ 2903.918973] ---[ end trace cfb2c6995ec3c277 ]---
...
[ 2903.919015] WARNING: CPU: 0 PID: 4695 at /opt/kernel-builder_repos/Re4son/re4son-raspberrypi-linux/all/fs/sysfs/group.c:255 sysfs_remove_group+0x98/0xa4
[ 2903.919021] sysfs group 'statistics' not found for kobject 'bnep0'
[ 2903.919024] Modules linked in: evdev uinput bnep hci_uart btbcm serdev bluetooth ecdh_generic fuse spidev brcmfmac brcmutil raspberrypi_hwmon snd_bcm2835(C) hwmon cfg80211 snd_pcm snd_timer rfkill snd bcm2835_codec(C) v4l2_mem2mem bcm2835_v4l2(C) i2c_bcm2835 bcm2835_mmal_vchiq(C) spi_bcm2835aux v4l2_common videobuf2_dma_contig videobuf2_vmalloc videobuf2_memops videobuf2_v4l2 videobuf2_common spi_bcm2835 videodev media vc_sm_cma(C) fixed uio_pdrv_genirq uio i2c_dev usb_f_ecm g_ether usb_f_rndis u_ether libcomposite dwc2 udc_core ip_tables x_tables ipv6
[ 2903.919178] CPU: 0 PID: 4695 Comm: kbnepd bnep0 Tainted: G WC 4.19.66-Re4son+ #1
[ 2903.919182] Hardware name: BCM2835
[ 2903.919201] [] (unwind_backtrace) from [] (show_stack+0x20/0x24)
[ 2903.919219] [] (show_stack) from [] (dump_stack+0x20/0x28)
[ 2903.919237] [] (dump_stack) from [] (__warn+0xf0/0x118)
[ 2903.919252] [] (__warn) from [] (warn_slowpath_fmt+0x50/0x70)
[ 2903.919269] [] (warn_slowpath_fmt) from [] (sysfs_remove_group+0x98/0xa4)
[ 2903.919284] [] (sysfs_remove_group) from [] (sysfs_remove_groups+0x34/0x44)
[ 2903.919310] [] (sysfs_remove_groups) from [] (device_remove_attrs+0x4c/0x7c)
[ 2903.919326] [] (device_remove_attrs) from [] (device_del+0x148/0x360)
[ 2903.919339] [] (device_del) from [] (netdev_unregister_kobject+0x7c/0x80)
[ 2903.919357] [] (netdev_unregister_kobject) from [] (rollback_registered_many+0x1ec/0x508)
[ 2903.919372] [] (rollback_registered_many) from [] (unregister_netdevice_queue+0x9c/0x130)
[ 2903.919386] [] (unregister_netdevice_queue) from [] (unregister_netdev+0x28/0x30)
[ 2903.919414] [] (unregister_netdev) from [] (bnep_session+0x4d4/0x888 [bnep])
[ 2903.919440] [] (bnep_session [bnep]) from [] (kthread+0x120/0x160)
[ 2903.919455] [] (kthread) from [] (ret_from_fork+0x14/0x28)
[ 2903.919461] Exception stack(0xd67affb0 to 0xd67afff8)
[ 2903.919469] ffa0: 00000000 00000000 00000000 00000000
[ 2903.919480] ffc0: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
[ 2903.919488] ffe0: 00000000 00000000 00000000 00000000 00000013 00000000
...
[ 2942.007241] WARNING: CPU: 0 PID: 492 at /opt/kernel-builder_repos/Re4son/re4son-raspberrypi-linux/all/lib/refcount.c:153 refcount_inc_checked+0x40/0x50
[ 2942.007249] refcount_t: increment on 0; use-after-free.
[ 2942.007254] Modules linked in: evdev uinput bnep hci_uart btbcm serdev bluetooth ecdh_generic fuse spidev brcmfmac brcmutil raspberrypi_hwmon snd_bcm2835(C) hwmon cfg80211 snd_pcm snd_timer rfkill snd bcm2835_codec(C) v4l2_mem2mem bcm2835_v4l2(C) i2c_bcm2835 bcm2835_mmal_vchiq(C) spi_bcm2835aux v4l2_common videobuf2_dma_contig videobuf2_vmalloc videobuf2_memops videobuf2_v4l2 videobuf2_common spi_bcm2835 videodev media vc_sm_cma(C) fixed uio_pdrv_genirq uio i2c_dev usb_f_ecm g_ether usb_f_rndis u_ether libcomposite dwc2 udc_core ip_tables x_tables ipv6
[ 2942.007500] CPU: 0 PID: 492 Comm: bluetoothd Tainted: G WC 4.19.66-Re4son+ #1
[ 2942.007506] Hardware name: BCM2835
[ 2942.007552] [] (unwind_backtrace) from [] (show_stack+0x20/0x24)
[ 2942.007583] [] (show_stack) from [] (dump_stack+0x20/0x28)
[ 2942.007619] [] (dump_stack) from [] (__warn+0xf0/0x118)
[ 2942.007641] [] (__warn) from [] (warn_slowpath_fmt+0x50/0x70)
[ 2942.007670] [] (warn_slowpath_fmt) from [] (refcount_inc_checked+0x40/0x50)
[ 2942.007695] [] (refcount_inc_checked) from [] (kobject_get+0x2c/0x5c)
[ 2942.007715] [] (kobject_get) from [] (device_add+0xc0/0x608)
[ 2942.007737] [] (device_add) from [] (netdev_register_kobject+0x7c/0x160)
[ 2942.007771] [] (netdev_register_kobject) from [] (register_netdevice+0x390/0x568)
[ 2942.007794] [] (register_netdevice) from [] (register_netdev+0x2c/0x44)
[ 2942.007848] [] (register_netdev) from [] (bnep_add_connection+0x214/0x30c [bnep])
[ 2942.007897] [] (bnep_add_connection [bnep]) from [] (bnep_sock_ioctl+0x220/0x358 [bnep])
[ 2942.007933] [] (bnep_sock_ioctl [bnep]) from [] (sock_ioctl+0x1e0/0x454)
[ 2942.007967] [] (sock_ioctl) from [] (do_vfs_ioctl+0xac/0x798)
[ 2942.007992] [] (do_vfs_ioctl) from [] (ksys_ioctl+0x44/0x68)
[ 2942.008012] [] (ksys_ioctl) from [] (sys_ioctl+0x18/0x1c)
[ 2942.008033] [] (sys_ioctl) from [] (ret_fast_syscall+0x0/0x28)
[ 2942.008043] Exception stack(0xd8b27fa8 to 0xd8b27ff0)
[ 2942.008059] 7fa0: 00000000 000f1828 0000000a 400442c8 bec1e458 00000001
[ 2942.008075] 7fc0: 00000000 000f1828 002a9ae6 00000036 00000014 00000000 b6e59448 00000000
[ 2942.008087] 7fe0: 000f1c5c bec1e454 0003ba58 b6bb951c
[ 2942.008096] ---[ end trace cfb2c6995ec3c279 ]---
[ 2942.008120] ------------[ cut here ]------------
[ 2942.008149] WARNING: CPU: 0 PID: 492 at /opt/kernel-builder_repos/Re4son/re4son-raspberrypi-linux/all/lib/refcount.c:187 refcount_sub_and_test_checked+0x9c/0xb0
[ 2942.008156] refcount_t: underflow; use-after-free.
[ 2942.008161] Modules linked in: evdev uinput bnep hci_uart btbcm serdev bluetooth ecdh_generic fuse spidev brcmfmac brcmutil raspberrypi_hwmon snd_bcm2835(C) hwmon cfg80211 snd_pcm snd_timer rfkill snd bcm2835_codec(C) v4l2_mem2mem bcm2835_v4l2(C) i2c_bcm2835 bcm2835_mmal_vchiq(C) spi_bcm2835aux v4l2_common videobuf2_dma_contig videobuf2_vmalloc videobuf2_memops videobuf2_v4l2 videobuf2_common spi_bcm2835 videodev media vc_sm_cma(C) fixed uio_pdrv_genirq uio i2c_dev usb_f_ecm g_ether usb_f_rndis u_ether libcomposite dwc2 udc_core ip_tables x_tables ipv6
[ 2942.008379] CPU: 0 PID: 492 Comm: bluetoothd Tainted: G WC 4.19.66-Re4son+ #1
[ 2942.008386] Hardware name: BCM2835
[ 2942.008416] [] (unwind_backtrace) from [] (show_stack+0x20/0x24)
[ 2942.008441] [] (show_stack) from [] (dump_stack+0x20/0x28)
[ 2942.008466] [] (dump_stack) from [] (__warn+0xf0/0x118)
[ 2942.008488] [] (__warn) from [] (warn_slowpath_fmt+0x50/0x70)
[ 2942.008516] [] (warn_slowpath_fmt) from [] (refcount_sub_and_test_checked+0x9c/0xb0)
[ 2942.008541] [] (refcount_sub_and_test_checked) from [] (refcount_dec_and_test_checked+0x18/0x1c)
[ 2942.008562] [] (refcount_dec_and_test_checked) from [] (kobject_put+0x2c/0xd8)
[ 2942.008581] [] (kobject_put) from [] (kobject_add_internal+0xcc/0x2e4)
[ 2942.008599] [] (kobject_add_internal) from [] (kobject_add+0x60/0xc0)
[ 2942.008636] [] (kobject_add) from [] (get_device_parent+0x104/0x198)
[ 2942.008657] [] (get_device_parent) from [] (device_add+0xd0/0x608)
[ 2942.008676] [] (device_add) from [] (netdev_register_kobject+0x7c/0x160)
[ 2942.008701] [] (netdev_register_kobject) from [] (register_netdevice+0x390/0x568)
[ 2942.008723] [] (register_netdevice) from [] (register_netdev+0x2c/0x44)
[ 2942.008764] [] (register_netdev) from [] (bnep_add_connection+0x214/0x30c [bnep])
[ 2942.008812] [] (bnep_add_connection [bnep]) from [] (bnep_sock_ioctl+0x220/0x358 [bnep])
[ 2942.008846] [] (bnep_sock_ioctl [bnep]) from [] (sock_ioctl+0x1e0/0x454)
[ 2942.008872] [] (sock_ioctl) from [] (do_vfs_ioctl+0xac/0x798)
[ 2942.008895] [] (do_vfs_ioctl) from [] (ksys_ioctl+0x44/0x68)
[ 2942.008915] [] (ksys_ioctl) from [] (sys_ioctl+0x18/0x1c)
[ 2942.008936] [] (sys_ioctl) from [] (ret_fast_syscall+0x0/0x28)
[ 2942.008945] Exception stack(0xd8b27fa8 to 0xd8b27ff0)
[ 2942.008960] 7fa0: 00000000 000f1828 0000000a 400442c8 bec1e458 00000001
[ 2942.008976] 7fc0: 00000000 000f1828 002a9ae6 00000036 00000014 00000000 b6e59448 00000000
[ 2942.008988] 7fe0: 000f1c5c bec1e454 0003ba58 b6bb951c
[ 2942.008997] ---[ end trace cfb2c6995ec3c27a ]---
...
[ 3631.191041] WARNING: CPU: 0 PID: 492 at /opt/kernel-builder_repos/Re4son/re4son-raspberrypi-linux/all/lib/kobject.c:612 kobject_get+0x50/0x5c
[ 3631.199607] Unable to handle kernel paging request at virtual address 6d756e5f
[ 3631.199613] pgd = fe9bf8fb
[ 3631.199617] [6d756e5f] *pgd=00000000
[ 3631.199623] Internal error: Oops: 5 [#1] ARM
[ 3631.199625] Modules linked in: evdev uinput bnep hci_uart btbcm serdev bluetooth ecdh_generic fuse spidev brcmfmac brcmutil raspberrypi_hwmon snd_bcm2835(C) hwmon cfg80211 snd_pcm snd_timer rfkill snd bcm2835_codec(C) v4l2_mem2mem bcm2835_v4l2(C) i2c_bcm2835 bcm2835_mmal_vchiq(C) spi_bcm2835aux v4l2_common videobuf2_dma_contig videobuf2_vmalloc videobuf2_memops videobuf2_v4l2 videobuf2_common spi_bcm2835 videodev media vc_sm_cma(C) fixed uio_pdrv_genirq uio i2c_dev usb_f_ecm g_ether usb_f_rndis u_ether libcomposite dwc2 udc_core ip_tables x_tables ipv6
[ 3631.199708] CPU: 0 PID: 492 Comm: bluetoothd Tainted: G WC 4.19.66-Re4son+ #1
[ 3631.199711] Hardware name: BCM2835
[ 3631.199713] PC is at string+0x34/0xb8
[ 3631.199715] LR is at 0xfffffffe
[ 3631.199719] pc : [] lr : [] psr: a0000093
[ 3631.199722] sp : d8b27b00 ip : d8b27b28 fp : d8b27b1c
[ 3631.199725] r10: d8b27b3c r9 : 00000002 r8 : c08eec32
[ 3631.199728] r7 : c0b0bd38 r6 : d8b27cdc r5 : c08eec30 r4 : c0b0bd38
[ 3631.199732] r3 : ffffffff r2 : 6d756e5f r1 : c0b0bd38 r0 : c0b0b964
[ 3631.199735] Flags: NzCv IRQs off FIQs on Mode SVC_32 ISA ARM Segment user
[ 3631.199738] Control: 00c5387d Table: 17124008 DAC: 00000055
[ 3631.199742] Process bluetoothd (pid: 492, stack limit = 0xb880c5fe)
[ 3631.199745] Stack: (0xd8b27b00 to 0xd8b28000)
[ 3631.199749] 7b00: c0af99e8 00000003 0000e094 c0b0b964 d8b27b74 d8b27b28 c0707fcc c0704994
[ 3631.199753] 7b20: c0707ec4 ffffff04 ffff0a00 c0ae9528 c0b0b958 000003e0 c00d6394 ffffff04
[ 3631.199757] 7b40: ffff0a00 d7af6de9 00000270 000003e0 00000000 00000000 ffffffff c0b0af90
[ 3631.199761] 7b60: 00000000 00000000 d8b27b8c d8b27b78 c070823c c0707e64 c0b0b950 00000000
[ 3631.199766] 7b80: d8b27bdc d8b27b90 c0065d9c c0708234 c00f1d60 c00f1b94 ffffffff c006621c
[ 3631.199770] 7ba0: 00000000 00000000 00000000 00000000 d8b27bdc ffffffff 00000000 00000000
[ 3631.199774] 7bc0: 00000000 00000000 c06f7c74 60000013 d8b27c24 d8b27be0 c0066244 c0065d68
[ 3631.199778] 7be0: c08eec24 d8b27cdc 00000009 00000264 c06f7c74 d7bf3cc0 d8b27c1c d8b27cac
[ 3631.199782] 7c00: c08eec74 00000000 00000009 00000264 c06f7c74 d7bf3cc0 d8b27c3c d8b27c28
[ 3631.199786] 7c20: c00666c8 c00661b4 c08eec24 d8b27cdc d8b27c5c d8b27c40 c006716c c0066694
[ 3631.199791] 7c40: d8b27c64 d7af6de9 c00d6394 d8b27cac d8b27c6c d8b27c60 c0063df4 c0067130
[ 3631.199795] 7c60: d8b27c9c d8b27c70 c00245b0 c0063de8 00000264 c06f7c74 c0a43028 c08eec24
[ 3631.199799] 7c80: d7af6de9 d7bf3ad0 c0a43028 00000000 d8b27cd4 d8b27ca0 c002469c c0024540
[ 3631.199803] 7ca0: 00000000 d8b27cac d8864a60 c08eec24 d8b27cdc d7af6de9 d8b27cfc cf219588
[ 3631.199808] 7cc0: cf219580 d7bf3ad0 d8b27cfc d8b27ce0 c06f7c74 c002465c c08eec24 6d756e5f
[ 3631.199812] 7ce0: cf219588 c0a43028 00000000 d7bf3ad8 d8b27d4c d8b27d00 c049438c c06f7c30
[ 3631.199816] 7d00: c06f859c c015173c c0a43028 d7bf3c38 d7bf3ad0 d7bf3c30 d8b27d40 d7af6de9
[ 3631.199820] 7d20: c0492c78 d7bf3800 d7bf3c38 d7bf3ad0 d7bf3c30 10000001 00000000 d7bf3cc0
[ 3631.199824] 7d40: d8b27d74 d8b27d50 c0613614 c04942d8 d7bf3800 c0ac3e48 c0a43028 00000000
[ 3631.199828] 7d60: 10000001 00000000 d8b27dbc d8b27d78 c05ebb8c c06135a4 d8b27d94 d8b27d88
[ 3631.199833] 7d80: 00000000 00000000 d8b27dac d7bf3800 00000000 d7af6de9 d7bf3800 d14ad900
[ 3631.199837] 7da0: d8b27e34 c0a43028 bf5f34a8 bf5f34b8 d8b27dd4 d8b27dc0 c05ebd90 c05eb808
[ 3631.199841] 7dc0: d7bf3800 d14ad900 d8b27e1c d8b27dd8 bf5f1f20 c05ebd70 00000001 00000001
[ 3631.199845] 7de0: d31e868c 27b8ab95 f0f735eb d7af6de9 c01b8494 bec1e458 c0a43028 ffffe000
[ 3631.199849] 7e00: d14ad900 00000000 0000000a 00000000 d8b27e7c d8b27e20 bf5f256c bf5f1d18
[ 3631.199853] 7e20: d8b27eb8 00000001 bf595004 d14ad900 d7b2a140 00000014 00000001 6e621115
[ 3631.199857] 7e40: 64257065 00000000 00000000 00000000 00000000 d7af6de9 00000004 400442c8
[ 3631.199861] 7e60: c0a43028 bec1e458 c0ac3e48 d8f08da0 d8b27ed4 d8b27e80 c05c39fc bf5f2358
[ 3631.199866] 7e80: d889e460 d7b2a140 000001ff c0a59a48 c0028f60 c0a43028 00000014 d14ad900
[ 3631.199870] 7ea0: d8b27ed4 d8b27eb0 c00d6394 d7af6de9 000001ff c0a43028 bec1e458 d7b2ea00
[ 3631.199874] 7ec0: 400442c8 d8f08da0 d8b27f6c d8b27ed8 c01adf0c c05c3828 cf219000 00000000
[ 3631.199878] 7ee0: d8b27f04 d8b27ef0 c05ca94c c0028ef4 cf219000 00000000 d8b27f64 d8b27f08
[ 3631.199882] 7f00: c05cae50 c05ca8cc d14ad920 00000000 00000004 0000069a d8b27f54 d8b27f28
[ 3631.199886] 7f20: c019a4bc c01e120c 00000000 c01b8a10 d8b27f4c d7af6de9 c01b8a10 d7af6de9
[ 3631.199891] 7f40: 00000008 d7b2ea00 d7b2ea00 0000000a 400442c8 bec1e458 d8b26000 00000000
[ 3631.199895] 7f60: d8b27f94 d8b27f70 c01ae63c c01ade6c 00000000 000f1828 002af556 00000036
[ 3631.199899] 7f80: c00091a4 d8b26000 d8b27fa4 d8b27f98 c01ae678 c01ae604 00000000 d8b27fa8
[ 3631.199903] 7fa0: c0009000 c01ae66c 00000000 000f1828 0000000a 400442c8 bec1e458 00000001
[ 3631.199907] 7fc0: 00000000 000f1828 002af556 00000036 00000014 00000000 b6e59448 00000000
[ 3631.199911] 7fe0: 000f1c5c bec1e454 0003ba58 b6bb951c 40000010 0000000a 00000000 00000000
[ 3631.199915] [] (string) from [] (vsnprintf+0x174/0x3d0)
[ 3631.199919] [] (vsnprintf) from [] (vscnprintf+0x14/0x2c)
[ 3631.199922] [] (vscnprintf) from [] (vprintk_store+0x40/0x1fc)
[ 3631.199926] [] (vprintk_store) from [] (vprintk_emit+0x9c/0x340)
[ 3631.199930] [] (vprintk_emit) from [] (vprintk_default+0x40/0x74)
[ 3631.199934] [] (vprintk_default) from [] (vprintk_func+0x48/0xb0)
[ 3631.199938] [] (vprintk_func) from [] (vprintk+0x18/0x1c)
[ 3631.199941] [] (vprintk) from [] (__warn+0x7c/0x118)
[ 3631.199945] [] (__warn) from [] (warn_slowpath_fmt+0x50/0x70)
[ 3631.199949] [] (warn_slowpath_fmt) from [] (kobject_get+0x50/0x5c)
[ 3631.199953] [] (kobject_get) from [] (device_add+0xc0/0x608)
[ 3631.199957] [] (device_add) from [] (netdev_register_kobject+0x7c/0x160)
[ 3631.199961] [] (netdev_register_kobject) from [] (register_netdevice+0x390/0x568)
[ 3631.199966] [] (register_netdevice) from [] (register_netdev+0x2c/0x44)
[ 3631.199970] [] (register_netdev) from [] (bnep_add_connection+0x214/0x30c [bnep])
[ 3631.199975] [] (bnep_add_connection [bnep]) from [] (bnep_sock_ioctl+0x220/0x358 [bnep])
[ 3631.199979] [] (bnep_sock_ioctl [bnep]) from [] (sock_ioctl+0x1e0/0x454)
[ 3631.199982] [] (sock_ioctl) from [] (do_vfs_ioctl+0xac/0x798)
[ 3631.199986] [] (do_vfs_ioctl) from [] (ksys_ioctl+0x44/0x68)
[ 3631.199990] [] (ksys_ioctl) from [] (sys_ioctl+0x18/0x1c)
[ 3631.199994] [] (sys_ioctl) from [] (ret_fast_syscall+0x0/0x28)
[ 3631.199997] Exception stack(0xd8b27fa8 to 0xd8b27ff0)
[ 3631.200001] 7fa0: 00000000 000f1828 0000000a 400442c8 bec1e458 00000001
[ 3631.200005] 7fc0: 00000000 000f1828 002af556 00000036 00000014 00000000 b6e59448 00000000
[ 3631.200008] 7fe0: 000f1c5c bec1e454 0003ba58 b6bb951c
[ 3631.200011] Code: 3a000019 e3530000 e243e001 0a00001b (e5d2c000)
[ 3631.200014] ---[ end trace cfb2c6995ec3c27b ]---
```

The report provides kernel 4.19.66 traces rather than repository files or tests. Start by investigating the bnep_session and bnep_add_connection paths, along with sysfs_remove_group and the refcount warnings, then reproduce the bluetoothd failure on the reported BCM2835 hardware. Done requires identifying the crash cause and verifying a correction without the reported warnings or use-after-free symptoms.

Written by the indexing model from the issue text.