============================================
WARNING: possible recursive locking detected
4.14.295-syzkaller #0 Not tainted
--------------------------------------------
syz-executor.5/1218 is trying to acquire lock:
((fb_notifier_list).rwsem){++++}, at: [<ffffffff8137bdf3>] __blocking_notifier_call_chain kernel/notifier.c:316 [inline]
((fb_notifier_list).rwsem){++++}, at: [<ffffffff8137bdf3>] __blocking_notifier_call_chain kernel/notifier.c:304 [inline]
((fb_notifier_list).rwsem){++++}, at: [<ffffffff8137bdf3>] blocking_notifier_call_chain kernel/notifier.c:328 [inline]
((fb_notifier_list).rwsem){++++}, at: [<ffffffff8137bdf3>] blocking_notifier_call_chain+0x63/0x90 kernel/notifier.c:325
but task is already holding lock:
((fb_notifier_list).rwsem){++++}, at: [<ffffffff8137bdf3>] __blocking_notifier_call_chain kernel/notifier.c:316 [inline]
((fb_notifier_list).rwsem){++++}, at: [<ffffffff8137bdf3>] __blocking_notifier_call_chain kernel/notifier.c:304 [inline]
((fb_notifier_list).rwsem){++++}, at: [<ffffffff8137bdf3>] blocking_notifier_call_chain kernel/notifier.c:328 [inline]
((fb_notifier_list).rwsem){++++}, at: [<ffffffff8137bdf3>] blocking_notifier_call_chain+0x63/0x90 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-executor.5/1218:
#0: (console_lock){+.+.}, at: [<ffffffff83369eba>] do_fb_ioctl+0x81a/0xa70 drivers/video/fbdev/core/fbmem.c:1223
#1: (&fb_info->lock){+.+.}, at: [<ffffffff83369ec4>] lock_fb_info drivers/video/fbdev/core/fbmem.c:82 [inline]
#1: (&fb_info->lock){+.+.}, at: [<ffffffff83369ec4>] do_fb_ioctl+0x824/0xa70 drivers/video/fbdev/core/fbmem.c:1224
#2: ((fb_notifier_list).rwsem){++++}, at: [<ffffffff8137bdf3>] __blocking_notifier_call_chain kernel/notifier.c:316 [inline]
#2: ((fb_notifier_list).rwsem){++++}, at: [<ffffffff8137bdf3>] __blocking_notifier_call_chain kernel/notifier.c:304 [inline]
#2: ((fb_notifier_list).rwsem){++++}, at: [<ffffffff8137bdf3>] blocking_notifier_call_chain kernel/notifier.c:328 [inline]
#2: ((fb_notifier_list).rwsem){++++}, at: [<ffffffff8137bdf3>] blocking_notifier_call_chain+0x63/0x90 kernel/notifier.c:325
stack backtrace:
CPU: 0 PID: 1218 Comm: syz-executor.5 Not tainted 4.14.295-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/11/2022
Call Trace:
__dump_stack lib/dump_stack.c:17 [inline]
dump_stack+0x1b2/0x281 lib/dump_stack.c:58
print_deadlock_bug kernel/locking/lockdep.c:1800 [inline]
check_deadlock kernel/locking/lockdep.c:1847 [inline]
validate_chain kernel/locking/lockdep.c:2448 [inline]
__lock_acquire.cold+0x180/0x97c kernel/locking/lockdep.c:3491
lock_acquire+0x170/0x3f0 kernel/locking/lockdep.c:3998
down_read+0x36/0x80 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+0x63/0x90 kernel/notifier.c:325
fb_set_var+0xbc8/0xdc0 drivers/video/fbdev/core/fbmem.c:1065
fbcon_switch+0x3d9/0x19e0 drivers/video/fbdev/core/fbcon.c:2066
redraw_screen+0x32c/0x790 drivers/tty/vt/vt.c:689
fbcon_blank+0x986/0xd50 drivers/video/fbdev/core/fbcon.c:2204
do_unblank_screen+0x1fd/0x4e0 drivers/tty/vt/vt.c:3954
fbcon_fb_blanked drivers/video/fbdev/core/fbcon.c:2933 [inline]
fbcon_event_notify+0x1445/0x1760 drivers/video/fbdev/core/fbcon.c:3051
notifier_call_chain+0x108/0x1a0 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+0x79/0x90 kernel/notifier.c:325
fb_blank+0x14c/0x190 drivers/video/fbdev/core/fbmem.c:1093
do_fb_ioctl+0x894/0xa70 drivers/video/fbdev/core/fbmem.c:1229
fb_ioctl+0xdd/0x130 drivers/video/fbdev/core/fbmem.c:1253
vfs_ioctl fs/ioctl.c:46 [inline]
file_ioctl fs/ioctl.c:500 [inline]
do_vfs_ioctl+0x75a/0xff0 fs/ioctl.c:684
SYSC_ioctl fs/ioctl.c:701 [inline]
SyS_ioctl+0x7f/0xb0 fs/ioctl.c:692
do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292
entry_SYSCALL_64_after_hwframe+0x46/0xbb
RIP: 0033:0x7f40ee89f5f9
RSP: 002b:00007f40ed212168 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f40ee9bff80 RCX: 00007f40ee89f5f9
RDX: 0000000000000000 RSI: 0000000000004611 RDI: 0000000000000003
RBP: 00007f40ee8fa7b0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ffe490729ff R14: 00007f40ed212300 R15: 0000000000022000