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kernel BUG at kernel/time/timer.c:1136!
invalid opcode: 0000 [#1] PREEMPT SMP KASAN
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CPU: 1 PID: 45 Comm: kworker/u4:2 Not tainted 4.20.0+ #2
downgrading a read lock
WARNING: CPU: 0 PID: 9530 at kernel/locking/lockdep.c:3553 __lock_downgrade kernel/locking/lockdep.c:3553 [inline]
WARNING: CPU: 0 PID: 9530 at kernel/locking/lockdep.c:3553 lock_downgrade+0x4d2/0x910 kernel/locking/lockdep.c:3816
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: events_unbound flush_to_ldisc
Kernel panic - not syncing: panic_on_warn set ...
RIP: 0010:add_timer kernel/time/timer.c:1136 [inline]
RIP: 0010:add_timer+0xa81/0x1470 kernel/time/timer.c:1134
Code: 4d 89 7d 40 48 c7 85 70 fe ff ff 00 00 00 00 c7 85 7c fe ff ff ff ff ff ff 48 89 85 90 fe ff ff e9 e6 f7 ff ff e8 cf 42 12 00 <0f> 0b e8 c8 42 12 00 0f 0b e8 c1 42 12 00 4c 89 bd 60 fe ff ff e9
RSP: 0018:ffff8880a96df5a8 EFLAGS: 00010293
RAX: ffff8880a96fc440 RBX: dffffc0000000000 RCX: 0000000000000000
RDX: 0000000000000000 RSI: ffffffff816f3ee1 RDI: ffff88807f48d3b8
RBP: ffff8880a96df760 R08: 0000000000000007 R09: ffff8880a96fcd58
R10: ffff8880a96fc440 R11: 0000000000000000 R12: ffff88807f48d3b8
R13: ffff88807f48d3b8 R14: ffff88807f48d180 R15: 0000000000000010
FS:  0000000000000000(0000) GS:ffff8880ae700000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f54caa71518 CR3: 0000000098648000 CR4: 00000000001406e0
DR0: 000000000000b8c4 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 decode_prio_command drivers/net/hamradio/6pack.c:903 [inline]
 sixpack_decode drivers/net/hamradio/6pack.c:971 [inline]
 sixpack_receive_buf drivers/net/hamradio/6pack.c:457 [inline]
 sixpack_receive_buf+0xf9c/0x1470 drivers/net/hamradio/6pack.c:434
 tty_ldisc_receive_buf+0x164/0x1c0 drivers/tty/tty_buffer.c:465
 tty_port_default_receive_buf+0x114/0x190 drivers/tty/tty_port.c:38
 receive_buf drivers/tty/tty_buffer.c:481 [inline]
 flush_to_ldisc+0x3b2/0x590 drivers/tty/tty_buffer.c:533
 process_one_work+0xd0c/0x1ce0 kernel/workqueue.c:2153
 worker_thread+0x143/0x14a0 kernel/workqueue.c:2296
 kthread+0x357/0x430 kernel/kthread.c:246
 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:352
Modules linked in:
Kernel Offset: disabled
Rebooting in 86400 seconds..