audit: type=1400 audit(1585518222.562:36): avc: denied { map } for pid=8187 comm="syz-executor874" path="/root/syz-executor874640202" dev="sda1" ino=16484 scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=unconfined_u:object_r:user_home_t:s0 tclass=file permissive=1 ============================================ WARNING: possible recursive locking detected 4.19.113-syzkaller #0 Not tainted -------------------------------------------- syz-executor874/8192 is trying to acquire lock: 000000005b226712 ((fb_notifier_list).rwsem){++++}, at: __blocking_notifier_call_chain kernel/notifier.c:316 [inline] 000000005b226712 ((fb_notifier_list).rwsem){++++}, at: __blocking_notifier_call_chain kernel/notifier.c:304 [inline] 000000005b226712 ((fb_notifier_list).rwsem){++++}, at: blocking_notifier_call_chain kernel/notifier.c:328 [inline] 000000005b226712 ((fb_notifier_list).rwsem){++++}, at: blocking_notifier_call_chain+0x6f/0xa0 kernel/notifier.c:325 but task is already holding lock: 000000005b226712 ((fb_notifier_list).rwsem){++++}, at: __blocking_notifier_call_chain kernel/notifier.c:316 [inline] 000000005b226712 ((fb_notifier_list).rwsem){++++}, at: __blocking_notifier_call_chain kernel/notifier.c:304 [inline] 000000005b226712 ((fb_notifier_list).rwsem){++++}, at: blocking_notifier_call_chain kernel/notifier.c:328 [inline] 000000005b226712 ((fb_notifier_list).rwsem){++++}, at: blocking_notifier_call_chain+0x6f/0xa0 kernel/notifier.c:325 other info that might help us debug this: Possible unsafe locking scenario: CPU0 ---- lock((fb_notifier_list).rwsem); lock((fb_notifier_list).rwsem); *** DEADLOCK *** May be due to missing lock nesting notation 3 locks held by syz-executor874/8192: #0: 000000002f77d622 (console_lock){+.+.}, at: do_fb_ioctl+0x179/0xab0 drivers/video/fbdev/core/fbmem.c:1200 #1: 000000000f2b070c (&fb_info->lock){+.+.}, at: lock_fb_info+0x1a/0x70 drivers/video/fbdev/core/fbmem.c:81 #2: 000000005b226712 ((fb_notifier_list).rwsem){++++}, at: __blocking_notifier_call_chain kernel/notifier.c:316 [inline] #2: 000000005b226712 ((fb_notifier_list).rwsem){++++}, at: __blocking_notifier_call_chain kernel/notifier.c:304 [inline] #2: 000000005b226712 ((fb_notifier_list).rwsem){++++}, at: blocking_notifier_call_chain kernel/notifier.c:328 [inline] #2: 000000005b226712 ((fb_notifier_list).rwsem){++++}, at: blocking_notifier_call_chain+0x6f/0xa0 kernel/notifier.c:325 stack backtrace: CPU: 0 PID: 8192 Comm: syz-executor874 Not tainted 4.19.113-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x188/0x20d lib/dump_stack.c:118 print_deadlock_bug kernel/locking/lockdep.c:1759 [inline] check_deadlock kernel/locking/lockdep.c:1803 [inline] validate_chain kernel/locking/lockdep.c:2399 [inline] __lock_acquire.cold+0x20f/0x4a7 kernel/locking/lockdep.c:3411 lock_acquire+0x170/0x400 kernel/locking/lockdep.c:3903 down_read+0x37/0xb0 kernel/locking/rwsem.c:24 __blocking_notifier_call_chain kernel/notifier.c:316 [inline] __blocking_notifier_call_chain kernel/notifier.c:304 [inline] blocking_notifier_call_chain kernel/notifier.c:328 [inline] blocking_notifier_call_chain+0x6f/0xa0 kernel/notifier.c:325 fb_set_var+0xc39/0xe00 drivers/video/fbdev/core/fbmem.c:1042 fbcon_switch+0x520/0x1970 drivers/video/fbdev/core/fbcon.c:2254 redraw_screen+0x37d/0x870 drivers/tty/vt/vt.c:1008 fbcon_blank+0x9ab/0xf00 drivers/video/fbdev/core/fbcon.c:2392 do_unblank_screen+0x241/0x620 drivers/tty/vt/vt.c:4240 fbcon_fb_blanked drivers/video/fbdev/core/fbcon.c:3256 [inline] fbcon_event_notify+0x1a11/0x1d54 drivers/video/fbdev/core/fbcon.c:3374 notifier_call_chain+0xc0/0x230 kernel/notifier.c:93 __blocking_notifier_call_chain kernel/notifier.c:317 [inline] __blocking_notifier_call_chain kernel/notifier.c:304 [inline] blocking_notifier_call_chain kernel/notifier.c:328 [inline] blocking_notifier_call_chain+0x85/0xa0 kernel/notifier.c:325 fb_blank+0x195/0x1d0 drivers/video/fbdev/core/fbmem.c:1070 do_fb_ioctl+0x1d9/0xab0 drivers/video/fbdev/core/fbmem.c:1206 fb_ioctl+0xdd/0x130 drivers/video/fbdev/core/fbmem.c:1230 vfs_ioctl fs/ioctl.c:46 [inline] file_ioctl fs/ioctl.c:501 [inline] do_vfs_ioctl+0xcda/0x12e0 fs/ioctl.c:688 ksys_ioctl+0x9b/0xc0 fs/ioctl.c:705 __do_sys_ioctl fs/ioctl.c:712 [inline] __se_sys_ioctl fs/ioctl.c:710 [inline] __x64_sys_ioctl+0x6f/0xb0 fs/ioctl.c:710 do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x446179 Code: 8d cd fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 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 0f 83 5b cd fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007ffdb039cfd8 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 0000000000446179 RDX: 0000000000000000 RSI: 0000000000004611 RDI: 0000000000000004 RBP: 000000000000da3d R08: 000000000000da3d R09: 00000000004033f0 R10: 00007ffdb039ceb0 R11: 0000000000000246 R12: 0000000000403360 R13: 00000000004033f0 R14: 0000000000000000 R15: 0000000000000000