[ OK ] Reached target Graphical Interface. Starting Update UTMP about System Runlevel Changes... Starting Load/Save RF Kill Switch Status... [ OK ] Started Load/Save RF Kill Switch Status. [ OK ] Started Update UTMP about System Runlevel Changes. Debian GNU/Linux 9 syzkaller ttyS0 Warning: Permanently added '10.128.0.38' (ECDSA) to the list of known hosts. executing program executing program syzkaller login: [ 37.229686] [ 37.229691] ============================================ [ 37.229692] WARNING: possible recursive locking detected [ 37.229698] 4.19.172-syzkaller #0 Not tainted [ 37.229700] -------------------------------------------- [ 37.229705] syz-executor806/8072 is trying to acquire lock: [ 37.229708] 000000000863eac4 ((fb_notifier_list).rwsem){++++}, at: blocking_notifier_call_chain+0x6f/0xa0 [ 37.229725] [ 37.229725] but task is already holding lock: [ 37.229727] 000000000863eac4 ((fb_notifier_list).rwsem){++++}, at: blocking_notifier_call_chain+0x6f/0xa0 [ 37.229742] [ 37.229742] other info that might help us debug this: [ 37.229745] Possible unsafe locking scenario: [ 37.229745] [ 37.229747] CPU0 [ 37.229749] ---- [ 37.229751] lock((fb_notifier_list).rwsem); [ 37.229756] lock((fb_notifier_list).rwsem); [ 37.229766] [ 37.229766] *** DEADLOCK *** [ 37.229766] [ 37.229769] May be due to missing lock nesting notation [ 37.229769] [ 37.229776] 3 locks held by syz-executor806/8072: [ 37.229779] #0: 00000000e6c259cd (console_lock){+.+.}, at: do_fb_ioctl+0x772/0xb50 [ 37.229802] #1: 00000000abac736b (&fb_info->lock){+.+.}, at: do_fb_ioctl+0x77c/0xb50 [ 37.229820] #2: 000000000863eac4 ((fb_notifier_list).rwsem){++++}, at: blocking_notifier_call_chain+0x6f/0xa0 [ 37.229832] [ 37.229832] stack backtrace: [ 37.229840] CPU: 0 PID: 8072 Comm: syz-executor806 Not tainted 4.19.172-syzkaller #0 [ 37.229844] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 37.229846] Call Trace: [ 37.229863] dump_stack+0x1fc/0x2ef [ 37.229871] __lock_acquire.cold+0x121/0x57e [ 37.229883] ? mark_held_locks+0xf0/0xf0 [ 37.229891] ? check_preemption_disabled+0x15/0x280 [ 37.229899] ? __sanitizer_cov_trace_pc+0x47/0x50 [ 37.229911] ? check_preemption_disabled+0x41/0x280 [ 37.229918] ? delay_tsc+0x8a/0xb0 [ 37.229931] ? vga16fb_update_fix+0x3a0/0x4a0 [ 37.229939] ? vga16fb_set_par+0x82b/0xa90 [ 37.229946] lock_acquire+0x170/0x3c0 [ 37.229953] ? blocking_notifier_call_chain+0x6f/0xa0 [ 37.229962] down_read+0x36/0x80 [ 37.229969] ? blocking_notifier_call_chain+0x6f/0xa0 [ 37.229977] blocking_notifier_call_chain+0x6f/0xa0 [ 37.229985] fb_set_var+0xc51/0xe20 [ 37.229992] ? fb_set_suspend+0x130/0x130 [ 37.229998] ? cfb_imageblit+0xc0c/0x1040 [ 37.230008] ? __kasan_slab_free+0x186/0x1f0 [ 37.230016] ? vga16fb_imageblit+0x6b4/0x2260 [ 37.230023] ? fb_pad_aligned_buffer+0xf7/0x150 [ 37.230034] ? fb_get_color_depth+0x11a/0x240 [ 37.230041] ? bit_cursor+0x1165/0x1740 [ 37.230047] ? fb_videomode_to_var+0xf/0x610 [ 37.230053] fbcon_switch+0x425/0x1ba0 [ 37.230060] ? bit_update_start+0x1f0/0x1f0 [ 37.230066] ? fbcon_event_notify+0x1d80/0x1d80 [ 37.230077] ? bit_update_start+0x1f0/0x1f0 [ 37.230082] ? fbcon_cursor+0x523/0x700 [ 37.230091] redraw_screen+0x37d/0x870 [ 37.230097] ? vc_init+0x440/0x440 [ 37.230103] ? bit_update_start+0x1f0/0x1f0 [ 37.230108] ? fbcon_cursor+0x523/0x700 [ 37.230117] fbcon_blank+0xae6/0xec0 [ 37.230124] ? con2fb_release_oldinfo.constprop.0+0x5f0/0x5f0 [ 37.230131] ? __lock_acquire+0x6de/0x3ff0 [ 37.230139] ? __lock_acquire+0x6de/0x3ff0 [ 37.230146] ? mark_held_locks+0xf0/0xf0 [ 37.230155] do_unblank_screen+0x241/0x610 [ 37.230161] fbcon_event_notify+0x1a3a/0x1d80 [ 37.230171] notifier_call_chain+0xc0/0x230 [ 37.230179] blocking_notifier_call_chain+0x85/0xa0 [ 37.230186] fb_blank+0x195/0x1d0 [ 37.230192] ? fb_set_logocmap+0x4a0/0x4a0 [ 37.230199] ? lock_acquire+0x170/0x3c0 [ 37.230209] do_fb_ioctl+0x7ec/0xb50 [ 37.230222] ? check_preemption_disabled+0x41/0x280 [ 37.230230] ? register_framebuffer+0x9e0/0x9e0 [ 37.230237] ? is_bpf_text_address+0xfc/0x1b0 [ 37.230246] ? kernel_text_address+0xbd/0xf0 [ 37.230253] ? __kernel_text_address+0x9/0x30 [ 37.230261] ? unwind_get_return_address+0x51/0x90 [ 37.230270] ? entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 37.230277] ? __save_stack_trace+0xaf/0x190 [ 37.230286] ? check_preemption_disabled+0x41/0x280 [ 37.230295] ? trace_hardirqs_off+0x64/0x200 [ 37.230302] ? __kasan_slab_free+0x186/0x1f0 [ 37.230311] ? kmem_cache_free+0x7f/0x260 [ 37.230318] ? putname+0xe1/0x120 [ 37.230324] ? do_sys_open+0x2ba/0x520 [ 37.230331] ? do_syscall_64+0xf9/0x620 [ 37.230337] ? entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 37.230344] ? mark_held_locks+0xf0/0xf0 [ 37.230354] ? debug_check_no_obj_freed+0x201/0x490 [ 37.230364] ? lock_downgrade+0x720/0x720 [ 37.230370] ? lock_acquire+0x170/0x3c0 [ 37.230377] fb_ioctl+0xdd/0x130 [ 37.230383] ? do_fb_ioctl+0xb50/0xb50 [ 37.230389] do_vfs_ioctl+0xcdb/0x12e0 [ 37.230395] ? _raw_spin_unlock_irqrestore+0x66/0xe0 [ 37.230404] ? debug_check_no_obj_freed+0x201/0x490 [ 37.230410] ? ioctl_preallocate+0x200/0x200 [ 37.230417] ? putname+0xe1/0x120 [ 37.230424] ? putname+0xe1/0x120 [ 37.230430] ? rcu_read_lock_sched_held+0x16c/0x1d0 [ 37.230437] ? kmem_cache_free+0x226/0x260 [ 37.230443] ? putname+0xe1/0x120 [ 37.230449] ? do_sys_open+0x2bf/0x520 [ 37.230455] ? filp_open+0x70/0x70 [ 37.230461] ksys_ioctl+0x9b/0xc0 [ 37.230470] __x64_sys_ioctl+0x6f/0xb0 [ 37.230477] ? lockdep_hardirqs_on+0x3a8/0x5c0 [ 37.230482] do_syscall_64+0xf9/0x620 [ 37.230489] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 37.230498] RIP: 0033:0x440029 [ 37.230506] Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 b1 14 00 00 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 c0 ff ff ff f7 d8 64 89 01 48 [ 37.230509] RSP: 002b:00007fffe8d49e18 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 [ 37.230516] RAX: ffffffffffffffda RBX: 00000000000090c5 RCX: 0000000000440029 [ 37.230519] RDX: 0000000000000000 RSI: 0000000000004611 RDI: 0000000000000004 [ 37.230523] RBP: 0000000000000000 R08: 00007fffe8d49fb8 R09: 00007fffe8d49fb8 [ 37.230527] R10: 00007fffe8d49fb8 R11: 0000000000000246 R12: 00007fffe8d49e2c [ 37.230531] R13: 431bde82d7b634db R14: 00000000004ae018 R15: 0000000000400488 executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program