Hello, syzbot found the following issue on: HEAD commit: 4b0986a3613c Linux 5.18 git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=14d795e5f00000 kernel config: https://syzkaller.appspot.com/x/.config?x=facb2be252153c68 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 Unfortunately, I don't have any reproducer for this issue yet. IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+5b59d6d459306a556f54@xxxxxxxxxxxxxxxxxxxxxxxxx INFO: task kworker/0:5:29071 blocked for more than 143 seconds. Not tainted 5.18.0-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:kworker/0:5 state:D stack:25080 pid:29071 ppid: 2 flags:0x00004000 Workqueue: usb_hub_wq hub_event Call Trace: <TASK> context_switch kernel/sched/core.c:5073 [inline] __schedule+0xa9a/0x4cc0 kernel/sched/core.c:6388 schedule+0xd2/0x1f0 kernel/sched/core.c:6460 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:6519 __mutex_lock_common kernel/locking/mutex.c:673 [inline] __mutex_lock+0xa32/0x12f0 kernel/locking/mutex.c:733 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:3405 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:3405 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:298 </TASK> Showing all locks held in the system: 1 lock held by khungtaskd/27: #0: ffffffff8bd820e0 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x53/0x260 kernel/locking/lockdep.c:6467 1 lock held by hwrng/755: #0: ffffffff8c81b268 (reading_mutex){+.+.}-{3:3}, at: hwrng_fillfn+0x141/0x370 drivers/char/hw_random/core.c:503 2 locks held by getty/3282: #0: ffff888148d8a098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x22/0x80 drivers/tty/tty_ldisc.c:244 #1: ffffc90002ce62e8 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0xcea/0x1230 drivers/tty/n_tty.c:2075 3 locks held by udevd/19534: #0: ffff88807b230088 (&of->mutex){+.+.}-{3:3}, at: kernfs_file_read_iter fs/kernfs/file.c:198 [inline] #0: ffff88807b230088 (&of->mutex){+.+.}-{3:3}, at: kernfs_fop_read_iter+0x189/0x6f0 fs/kernfs/file.c:237 #1: ffff88801cf57da0 (kn->active#86){++++}-{0:0}, at: kernfs_file_read_iter fs/kernfs/file.c:199 [inline] #1: ffff88801cf57da0 (kn->active#86){++++}-{0:0}, at: kernfs_fop_read_iter+0x1ac/0x6f0 fs/kernfs/file.c:237 #2: ffff8880450c0220 (&dev->mutex){....}-{3:3}, at: device_lock_interruptible include/linux/device.h:772 [inline] #2: ffff8880450c0220 (&dev->mutex){....}-{3:3}, at: read_descriptors+0x3c/0x2c0 drivers/usb/core/sysfs.c:873 6 locks held by kworker/0:5/29071: #0: ffff8880167d4938 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline] #0: ffff8880167d4938 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: arch_atomic_long_set include/linux/atomic/atomic-long.h:41 [inline] #0: ffff8880167d4938 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: atomic_long_set include/linux/atomic/atomic-instrumented.h:1280 [inline] #0: ffff8880167d4938 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: set_work_data kernel/workqueue.c:636 [inline] #0: ffff8880167d4938 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: set_work_pool_and_clear_pending kernel/workqueue.c:663 [inline] #0: ffff8880167d4938 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work+0x87a/0x1610 kernel/workqueue.c:2260 #1: ffffc90005507da8 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work+0x8ae/0x1610 kernel/workqueue.c:2264 #2: ffff88801e5d3220 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:767 [inline] #2: ffff88801e5d3220 (&dev->mutex){....}-{3:3}, at: hub_event+0x1c1/0x4680 drivers/usb/core/hub.c:5693 #3: ffff8880450c0220 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:767 [inline] #3: ffff8880450c0220 (&dev->mutex){....}-{3:3}, at: __device_attach+0x7a/0x4a0 drivers/base/dd.c:945 #4: ffff88801b1351a8 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:767 [inline] #4: ffff88801b1351a8 (&dev->mutex){....}-{3:3}, at: __device_attach+0x7a/0x4a0 drivers/base/dd.c:945 #5: ffffffff8c81b268 (reading_mutex){+.+.}-{3:3}, at: add_early_randomness+0x1a/0x170 drivers/char/hw_random/core.c:69 ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 27 Comm: khungtaskd Not tainted 5.18.0-syzkaller #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:212 [inline] watchdog+0xc1d/0xf50 kernel/hung_task.c:369 kthread+0x2e9/0x3a0 kernel/kthread.c:376 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:298 </TASK> Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 PID: 5271 Comm: kworker/0:6 Not tainted 5.18.0-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: events kfree_rcu_work RIP: 0010:deref_stack_reg arch/x86/kernel/unwind_orc.c:355 [inline] RIP: 0010:unwind_next_frame+0xf70/0x1cc0 arch/x86/kernel/unwind_orc.c:600 Code: 8d 78 20 e8 02 ea ff ff 48 89 c5 49 8d 7d 40 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 80 3c 02 00 0f 85 c4 0a 00 00 <49> 89 6d 40 48 b8 00 00 00 00 00 fc ff df 4c 89 ea 48 c1 ea 03 0f RSP: 0018:ffffc900142b7730 EFLAGS: 00000246 RAX: dffffc0000000000 RBX: 0000000000000001 RCX: 0000000000000001 RDX: 1ffff92002856efc RSI: ffffc900142b7ce8 RDI: ffffc900142b77e0 RBP: ffff8880b9c28118 R08: ffffffff8e39a02a R09: ffffc900142b77d4 R10: fffff52002856eff R11: ffffc900142b7d10 R12: ffffc900142b77d5 R13: ffffc900142b77a0 R14: ffffc900142b7ce8 R15: ffffffff8e39a02e FS: 0000000000000000(0000) GS:ffff8880b9c00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f29cddfe718 CR3: 000000007f592000 CR4: 00000000003526f0 DR0: 0000000000000000 DR1: 000000000000000f DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000ffff0ff0 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+0x21/0x30 mm/kasan/common.c:45 kasan_set_free_info+0x20/0x30 mm/kasan/generic.c:370 ____kasan_slab_free mm/kasan/common.c:366 [inline] ____kasan_slab_free+0x166/0x1a0 mm/kasan/common.c:328 kasan_slab_free include/linux/kasan.h:200 [inline] slab_free_hook mm/slub.c:1728 [inline] slab_free_freelist_hook+0x8b/0x1c0 mm/slub.c:1754 slab_free mm/slub.c:3510 [inline] kmem_cache_free_bulk mm/slub.c:3657 [inline] kmem_cache_free_bulk+0x2c0/0xb60 mm/slub.c:3644 kfree_bulk include/linux/slab.h:437 [inline] kfree_rcu_work+0x51c/0xa10 kernel/rcu/tree.c:3318 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:298 </TASK> ---------------- Code disassembly (best guess): 0: 8d 78 20 lea 0x20(%rax),%edi 3: e8 02 ea ff ff callq 0xffffea0a 8: 48 89 c5 mov %rax,%rbp b: 49 8d 7d 40 lea 0x40(%r13),%rdi f: 48 b8 00 00 00 00 00 movabs $0xdffffc0000000000,%rax 16: fc ff df 19: 48 89 fa mov %rdi,%rdx 1c: 48 c1 ea 03 shr $0x3,%rdx 20: 80 3c 02 00 cmpb $0x0,(%rdx,%rax,1) 24: 0f 85 c4 0a 00 00 jne 0xaee * 2a: 49 89 6d 40 mov %rbp,0x40(%r13) <-- trapping instruction 2e: 48 b8 00 00 00 00 00 movabs $0xdffffc0000000000,%rax 35: fc ff df 38: 4c 89 ea mov %r13,%rdx 3b: 48 c1 ea 03 shr $0x3,%rdx 3f: 0f .byte 0xf --- This report is generated by a bot. It may contain errors. See https://goo.gl/tpsmEJ for more information about syzbot. syzbot engineers can be reached at syzkaller@xxxxxxxxxxxxxxxx. syzbot will keep track of this issue. See: https://goo.gl/tpsmEJ#status for how to communicate with syzbot.
