Hi,
Just noticed this OOPS in my vanilla 6.8.4 kernel dmesg log. The USB device here is an optical drive, although oddly I wasn't unplugging it at the time. I was actually remounting it as a different user:
$ udisksctl unmount -b /dev/sr1 <SWITCH USER> $ udisksctl mount -b /dev/sr1
[ 7737.972588] usb 2-4: USB disconnect, device number 3 [ 7743.332135] BUG: kernel NULL pointer dereference, address: 0000000000000370 [ 7743.337805] #PF: supervisor write access in kernel mode [ 7743.341730] #PF: error_code(0x0002) - not-present page [ 7743.345569] PGD 0 P4D 0 [ 7743.346830] Oops: 0002 [#1] PREEMPT SMP PTI [ 7743.349711] CPU: 4 PID: 27870 Comm: kworker/4:0 Tainted: G I 6.8.4 #1 [ 7743.356237] Hardware name: Gigabyte Technology Co., Ltd. EX58-UD3R/EX58-UD3R, BIOS FB 05/04/2009 [ 7743.363830] Workqueue: events sg_remove_sfp_usercontext [sg] [ 7743.368196] RIP: 0010:mutex_lock+0x1e/0x2e [ 7743.370997] Code: 90 90 90 90 90 90 90 90 90 90 90 90 0f 1f 44 00 00 51 48 89 3c 24 2e 2e 2e 31 c0 31 c0 48 8b 3c 24 65 48 8b 14 25 40 c2 02 00 <f0> 48 0f b1 17 74 03 5a eb b9 58 c3 cc cc cc cc 90 90 90 90 90 90 [ 7743.388443] RSP: 0018:ffffc90004667e00 EFLAGS: 00010246 [ 7743.392368] RAX: 0000000000000000 RBX: 0000000000000000 RCX: 00000000810000d2 [ 7743.398201] RDX: ffff88805bf30e40 RSI: ffffffffa1bbd20d RDI: 0000000000000370 [ 7743.404034] RBP: 0000000000000370 R08: ffff8881144e2d70 R09: 00000000810000d2 [ 7743.409867] R10: 000000000000023e R11: 000000000000023e R12: ffff8881424039c0 [ 7743.415698] R13: dead000000000100 R14: ffff88826223a000 R15: ffff88826223a030 [ 7743.421522] FS: 0000000000000000(0000) GS:ffff888343d00000(0000) knlGS:0000000000000000 [ 7743.428308] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 7743.432745] CR2: 0000000000000370 CR3: 000000000221a000 CR4: 00000000000006f0 [ 7743.438570] Call Trace: [ 7743.439715] <TASK> [ 7743.440513] ? __die_body+0x1a/0x5c [ 7743.442707] ? page_fault_oops+0x32a/0x377 [ 7743.445504] ? fixup_exception+0x22/0x250 [ 7743.448217] ? exc_page_fault+0x105/0x117 [ 7743.450928] ? asm_exc_page_fault+0x22/0x30 [ 7743.453850] ? __pfx_sg_device_destroy+0x10/0x10 [sg] [ 7743.457602] ? mutex_lock+0x1e/0x2e [ 7743.459839] blk_trace_remove+0x15/0x35 [ 7743.462378] sg_device_destroy+0x1d/0x60 [sg] [ 7743.465438] sg_remove_sfp_usercontext+0xd2/0xe9 [sg] [ 7743.469190] process_scheduled_works+0x198/0x296 [ 7743.472510] worker_thread+0x1c6/0x220 [ 7743.474962] ? __pfx_worker_thread+0x10/0x10 [ 7743.477934] kthread+0xf7/0xff [ 7743.479694] ? __pfx_kthread+0x10/0x10 [ 7743.482146] ret_from_fork+0x24/0x36 [ 7743.484425] ? __pfx_kthread+0x10/0x10 [ 7743.486877] ret_from_fork_asm+0x1b/0x30 [ 7743.489506] </TASK> [ 7743.490397] Modules linked in: udf usb_storage sg algif_hash af_alg snd_seq_dummy rpcrdma rdma_cm iw_cm ib_cm ib_core nf_nat_ftp nf_conntrack_ftp cfg80211 af_packet nf_conntrack_netbios_ns nf_conntrack_broadcast nft_fib_inet nft_fib_ipv4 nft_fib_ipv6 nft_fib nft_reject_inet nf_reject_ipv4 nf_reject_ipv6 nft_reject nft_ct nft_chain_nat nf_tables ebtable_nat ebtable_broute ip6table_nat ip6table_mangle ip6table_raw ip6table_security iptable_nat nf_nat nf_conntrack nf_defrag_ipv6 nf_defrag_ipv4 libcrc32c iptable_mangle iptable_raw iptable_security nfnetlink ebtable_filter ebtables ip6table_filter ip6_tables iptable_filter ip_tables x_tables bnep it87 hwmon_vid binfmt_misc snd_hda_codec_realtek snd_hda_codec_generic snd_hda_codec_hdmi snd_hda_intel uvcvideo intel_powerclamp btusb btintel snd_usb_audio snd_intel_dspcfg coretemp btbcm uvc snd_hda_codec videobuf2_vmalloc kvm_intel snd_virtuoso bluetooth videobuf2_memops snd_oxygen_lib videobuf2_v4l2 snd_hda_core snd_usbmidi_lib videodev snd_mpu401_uart kvm videobuf2_common [ 7743.490474] snd_hwdep snd_rawmidi mc snd_seq ecdh_generic input_leds led_class joydev snd_seq_device snd_pcm rfkill ecc r8169 pktcdvd irqbypass gpio_ich realtek iTCO_wdt intel_cstate snd_hrtimer mdio_devres snd_timer libphy intel_uncore i2c_i801 snd pcspkr psmouse i2c_smbus acpi_cpufreq mxm_wmi soundcore lpc_ich i7core_edac tiny_power_button button nfsd auth_rpcgss nfs_acl lockd grace dm_mod sunrpc fuse configfs loop dax zram zsmalloc ext4 crc32c_generic crc16 mbcache jbd2 amdgpu video amdxcp i2c_algo_bit mfd_core drm_ttm_helper ttm drm_exec gpu_sched sr_mod drm_suballoc_helper drm_buddy drm_display_helper cdrom sd_mod hid_microsoft usbhid drm_kms_helper ahci libahci pata_jmicron drm libata uhci_hcd xhci_pci ehci_pci ehci_hcd scsi_mod xhci_hcd usbcore drm_panel_orientation_quirks cec firewire_ohci crc32c_intel sha512_ssse3 rc_core sha256_ssse3 serio_raw firewire_core sha1_ssse3 usb_common bsg crc_itu_t scsi_common wmi msr [ 7743.659267] CR2: 0000000000000370 [ 7743.661287] ---[ end trace 0000000000000000 ]--- [ 7743.664605] RIP: 0010:mutex_lock+0x1e/0x2e [ 7743.667406] Code: 90 90 90 90 90 90 90 90 90 90 90 90 0f 1f 44 00 00 51 48 89 3c 24 2e 2e 2e 31 c0 31 c0 48 8b 3c 24 65 48 8b 14 25 40 c2 02 00 <f0> 48 0f b1 17 74 03 5a eb b9 58 c3 cc cc cc cc 90 90 90 90 90 90 [ 7743.684850] RSP: 0018:ffffc90004667e00 EFLAGS: 00010246 [ 7743.688767] RAX: 0000000000000000 RBX: 0000000000000000 RCX: 00000000810000d2 [ 7743.694592] RDX: ffff88805bf30e40 RSI: ffffffffa1bbd20d RDI: 0000000000000370 [ 7743.700415] RBP: 0000000000000370 R08: ffff8881144e2d70 R09: 00000000810000d2 [ 7743.706239] R10: 000000000000023e R11: 000000000000023e R12: ffff8881424039c0 [ 7743.712064] R13: dead000000000100 R14: ffff88826223a000 R15: ffff88826223a030 [ 7743.717897] FS: 0000000000000000(0000) GS:ffff888343d00000(0000) knlGS:0000000000000000 [ 7743.724684] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 7743.729129] CR2: 0000000000000370 CR3: 000000000221a000 CR4: 00000000000006f0 [ 7743.734961] note: kworker/4:0[27870] exited with irqs disabled