Hello, syzbot has tested the proposed patch but the reproducer is still triggering an issue: INFO: task hung in add_early_randomness INFO: task kworker/0:0:6 blocked for more than 143 seconds. Not tainted 5.18.0-syzkaller-11503-gbd8bb9aed56b-dirty #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:kworker/0:0 state:D stack:24728 pid: 6 ppid: 2 flags:0x00004000 Workqueue: usb_hub_wq hub_event Call Trace: <TASK> context_switch kernel/sched/core.c:5116 [inline] __schedule+0xa00/0x4b30 kernel/sched/core.c:6431 schedule+0xd2/0x1f0 kernel/sched/core.c:6503 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:6562 __mutex_lock_common kernel/locking/mutex.c:679 [inline] __mutex_lock+0xa70/0x1350 kernel/locking/mutex.c:747 add_early_randomness+0x1a/0x170 drivers/char/hw_random/core.c:69 hwrng_register+0x399/0x510 drivers/char/hw_random/core.c:599 chaoskey_probe+0x7b5/0xc40 drivers/usb/misc/chaoskey.c:205 usb_probe_interface+0x315/0x7f0 drivers/usb/core/driver.c:396 call_driver_probe drivers/base/dd.c:542 [inline] really_probe+0x23e/0xb20 drivers/base/dd.c:621 __driver_probe_device+0x338/0x4d0 drivers/base/dd.c:752 driver_probe_device+0x4c/0x1a0 drivers/base/dd.c:782 __device_attach_driver+0x20b/0x2f0 drivers/base/dd.c:899 bus_for_each_drv+0x15f/0x1e0 drivers/base/bus.c:427 __device_attach+0x228/0x4a0 drivers/base/dd.c:970 bus_probe_device+0x1e4/0x290 drivers/base/bus.c:487 device_add+0xb83/0x1e20 drivers/base/core.c:3402 usb_set_configuration+0x101e/0x1900 drivers/usb/core/message.c:2170 usb_generic_driver_probe+0xba/0x100 drivers/usb/core/generic.c:238 usb_probe_device+0xd9/0x2c0 drivers/usb/core/driver.c:293 call_driver_probe drivers/base/dd.c:542 [inline] really_probe+0x23e/0xb20 drivers/base/dd.c:621 __driver_probe_device+0x338/0x4d0 drivers/base/dd.c:752 driver_probe_device+0x4c/0x1a0 drivers/base/dd.c:782 __device_attach_driver+0x20b/0x2f0 drivers/base/dd.c:899 bus_for_each_drv+0x15f/0x1e0 drivers/base/bus.c:427 __device_attach+0x228/0x4a0 drivers/base/dd.c:970 bus_probe_device+0x1e4/0x290 drivers/base/bus.c:487 device_add+0xb83/0x1e20 drivers/base/core.c:3402 usb_new_device.cold+0x641/0x1091 drivers/usb/core/hub.c:2566 hub_port_connect drivers/usb/core/hub.c:5363 [inline] hub_port_connect_change drivers/usb/core/hub.c:5507 [inline] port_event drivers/usb/core/hub.c:5665 [inline] hub_event+0x25c6/0x4680 drivers/usb/core/hub.c:5747 process_one_work+0x996/0x1610 kernel/workqueue.c:2289 worker_thread+0x665/0x1080 kernel/workqueue.c:2436 kthread+0x2e9/0x3a0 kernel/kthread.c:376 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:302 </TASK> Showing all locks held in the system: 6 locks held by kworker/0:0/6: #0: ffff88801756a938 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline] #0: ffff88801756a938 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: arch_atomic_long_set include/linux/atomic/atomic-long.h:41 [inline] #0: ffff88801756a938 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: atomic_long_set include/linux/atomic/atomic-instrumented.h:1280 [inline] #0: ffff88801756a938 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: set_work_data kernel/workqueue.c:636 [inline] #0: ffff88801756a938 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: set_work_pool_and_clear_pending kernel/workqueue.c:663 [inline] #0: ffff88801756a938 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work+0x87a/0x1610 kernel/workqueue.c:2260 #1: ffffc900002cfda8 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work+0x8ae/0x1610 kernel/workqueue.c:2264 #2: ffff888147718190 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:762 [inline] #2: ffff888147718190 (&dev->mutex){....}-{3:3}, at: hub_event+0x1c1/0x4680 drivers/usb/core/hub.c:5693 #3: ffff88806a2f0190 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:762 [inline] #3: ffff88806a2f0190 (&dev->mutex){....}-{3:3}, at: __device_attach+0x7a/0x4a0 drivers/base/dd.c:945 #4: ffff88806a270118 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:762 [inline] #4: ffff88806a270118 (&dev->mutex){....}-{3:3}, at: __device_attach+0x7a/0x4a0 drivers/base/dd.c:945 #5: ffffffff8c828728 (reading_mutex){+.+.}-{3:3}, at: add_early_randomness+0x1a/0x170 drivers/char/hw_random/core.c:69 1 lock held by khungtaskd/29: #0: ffffffff8bd840e0 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x53/0x260 kernel/locking/lockdep.c:6491 2 locks held by kworker/u4:5/58: #0: ffff8880b9a39f98 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x2b/0x120 kernel/sched/core.c:544 #1: ffff8880b9a277c8 (&per_cpu_ptr(group->pcpu, cpu)->seq){-.-.}-{0:0}, at: psi_task_switch+0x176/0x4e0 kernel/sched/psi.c:880 1 lock held by hwrng/756: #0: ffffffff8c828728 (reading_mutex){+.+.}-{3:3}, at: hwrng_fillfn+0x141/0x370 drivers/char/hw_random/core.c:503 2 locks held by getty/3281: #0: ffff888022b5a098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x22/0x80 drivers/tty/tty_ldisc.c:244 #1: ffffc90001c382e8 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0xcea/0x1230 drivers/tty/n_tty.c:2075 ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 29 Comm: khungtaskd Not tainted 5.18.0-syzkaller-11503-gbd8bb9aed56b-dirty #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: <TASK> __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106 nmi_cpu_backtrace.cold+0x47/0x144 lib/nmi_backtrace.c:111 nmi_trigger_cpumask_backtrace+0x1e6/0x230 lib/nmi_backtrace.c:62 trigger_all_cpu_backtrace include/linux/nmi.h:146 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:220 [inline] watchdog+0xc22/0xf90 kernel/hung_task.c:378 kthread+0x2e9/0x3a0 kernel/kthread.c:376 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:302 </TASK> Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 PID: 1389 Comm: kworker/u4:7 Not tainted 5.18.0-syzkaller-11503-gbd8bb9aed56b-dirty #0 CPU: 1 PID: 1389 Comm: kworker/u4:7 Not tainted 5.18.0-syzkaller-11503-gbd8bb9aed56b-dirty #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: phy5 ieee80211_iface_work RIP: 0010:unwind_next_frame+0x8c5/0x1cc0 arch/x86/kernel/unwind_orc.c:466 Code: ff 80 3d a8 c0 70 0c 00 0f 85 ee fa ff ff e9 22 54 fb 07 48 b8 00 00 00 00 00 fc ff df 48 8b 54 24 08 48 c1 ea 03 80 3c 02 00 <0f> 85 73 10 00 00 4c 89 c0 4d 8b 75 38 48 ba 00 00 00 00 00 fc ff RSP: 0018:ffffc900059e7528 EFLAGS: 00000246 RAX: dffffc0000000000 RBX: 0000000000000001 RCX: ffffffff8e3c9c1f RDX: 1ffff92000b3ceba RSI: 0000000000000001 RDI: 0000000000000001 RBP: ffffc900059e75e0 R08: ffffffff8e3c9c1a R09: ffffc900059e75cc R10: fffff52000b3cebe R11: 000000000008a07a R12: ffffc900059e75cd R13: ffffc900059e7598 R14: ffffffff81689fbb R15: ffffffff8e3c9c1e FS: 0000000000000000(0000) GS:ffff8880b9b00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f00c3e11110 CR3: 000000000ba8e000 CR4: 00000000003506e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: <TASK> arch_stack_walk+0x7d/0xe0 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0x8c/0xc0 kernel/stacktrace.c:122 kasan_save_stack+0x1e/0x40 mm/kasan/common.c:38 kasan_set_track mm/kasan/common.c:45 [inline] set_alloc_info mm/kasan/common.c:436 [inline] ____kasan_kmalloc mm/kasan/common.c:515 [inline] ____kasan_kmalloc mm/kasan/common.c:474 [inline] __kasan_kmalloc+0xa6/0xd0 mm/kasan/common.c:524 kasan_kmalloc include/linux/kasan.h:234 [inline] kmem_cache_alloc_trace+0x1ea/0x4a0 mm/slab.c:3569 kmalloc include/linux/slab.h:600 [inline] kzalloc include/linux/slab.h:733 [inline] ieee802_11_parse_elems_crc+0xd5/0x1060 net/mac80211/util.c:1502 ieee802_11_parse_elems net/mac80211/ieee80211_i.h:2257 [inline] ieee80211_rx_mgmt_probe_beacon net/mac80211/ibss.c:1605 [inline] ieee80211_ibss_rx_queued_mgmt+0xda5/0x33f0 net/mac80211/ibss.c:1639 ieee80211_iface_process_skb net/mac80211/iface.c:1527 [inline] ieee80211_iface_work+0xa78/0xd10 net/mac80211/iface.c:1581 process_one_work+0x996/0x1610 kernel/workqueue.c:2289 worker_thread+0x665/0x1080 kernel/workqueue.c:2436 kthread+0x2e9/0x3a0 kernel/kthread.c:376 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:302 </TASK> ---------------- Code disassembly (best guess): 0: ff 80 3d a8 c0 70 incl 0x70c0a83d(%rax) 6: 0c 00 or $0x0,%al 8: 0f 85 ee fa ff ff jne 0xfffffafc e: e9 22 54 fb 07 jmpq 0x7fb5435 13: 48 b8 00 00 00 00 00 movabs $0xdffffc0000000000,%rax 1a: fc ff df 1d: 48 8b 54 24 08 mov 0x8(%rsp),%rdx 22: 48 c1 ea 03 shr $0x3,%rdx 26: 80 3c 02 00 cmpb $0x0,(%rdx,%rax,1) * 2a: 0f 85 73 10 00 00 jne 0x10a3 <-- trapping instruction 30: 4c 89 c0 mov %r8,%rax 33: 4d 8b 75 38 mov 0x38(%r13),%r14 37: 48 rex.W 38: ba 00 00 00 00 mov $0x0,%edx 3d: 00 fc add %bh,%ah 3f: ff .byte 0xff Tested on: commit: bd8bb9ae vdpa: ifcvf: set pci driver data in probe git tree: git://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost.git linux-next console output: https://syzkaller.appspot.com/x/log.txt?x=162120bff00000 kernel config: https://syzkaller.appspot.com/x/.config?x=8d4cbb773055caee dashboard link: https://syzkaller.appspot.com/bug?extid=5b59d6d459306a556f54 compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2 patch: https://syzkaller.appspot.com/x/patch.diff?x=141d9e6ff00000