bisecting fixing commit since a844dc4c544291470aa69edbe2434b040794e269 building syzkaller on b31eda3df81f62eb7efde0c5d7a9f24ee7e34e6f testing commit a844dc4c544291470aa69edbe2434b040794e269 with gcc (GCC) 8.1.0 kernel signature: 5134a5336eef5410609b7112c1737796197202802fcae27f7e22f69871047ab7 all runs: crashed: kernel BUG at kernel/time/timer.c:LINE! testing current HEAD 98db2bf27b9ed2d5ed0b6c9c8a4bfcb127a19796 testing commit 98db2bf27b9ed2d5ed0b6c9c8a4bfcb127a19796 with gcc (GCC) 8.1.0 kernel signature: 2cb9bbf7f92068742243679def87a79e34c9e823bf9f41a6cb1b584db9f60111 all runs: crashed: kernel BUG at kernel/time/timer.c:LINE! revisions tested: 2, total time: 34m18.246497241s (build: 18m35.30970118s, test: 14m57.811555156s) the crash still happens on HEAD commit msg: Linux 4.14.171 crash: kernel BUG at kernel/time/timer.c:LINE! sp1: Found TNC sp2: Found TNC sp0: Synchronizing with TNC sp0: Found TNC ------------[ cut here ]------------ kernel BUG at kernel/time/timer.c:1089! invalid opcode: 0000 [#1] PREEMPT SMP KASAN Modules linked in: CPU: 0 PID: 24540 Comm: kworker/u4:10 Not tainted 4.14.171-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: events_unbound flush_to_ldisc sp1: Synchronizing with TNC task: ffff888096310100 task.stack: ffff8880820b0000 RIP: 0010:add_timer+0x5ec/0xab0 kernel/time/timer.c:1089 RSP: 0018:ffff8880820b7b40 EFLAGS: 00010282 RAX: 1ffff1100fbae349 RBX: 1ffff11010416f6f RCX: 0000000000000008 RDX: dffffc0000000000 RSI: ffff8880963109f8 RDI: ffff88807dd71a48 RBP: ffff8880820b7c00 R08: ffff888096310a18 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: dffffc0000000000 R13: ffff8880a8cc0992 R14: ffff8880820b7bd8 R15: ffff88807dd71a40 FS: 0000000000000000(0000) GS:ffff8880aec00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000001f0e000 CR3: 000000008aef4000 CR4: 00000000001406f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: decode_prio_command drivers/net/hamradio/6pack.c:934 [inline] sixpack_decode drivers/net/hamradio/6pack.c:1003 [inline] sixpack_receive_buf+0x8ed/0x1180 drivers/net/hamradio/6pack.c:458 tty_ldisc_receive_buf+0xff/0x1b0 drivers/tty/tty_buffer.c:459 tty_port_default_receive_buf+0x5f/0x90 drivers/tty/tty_port.c:37 receive_buf drivers/tty/tty_buffer.c:475 [inline] flush_to_ldisc+0x197/0x390 drivers/tty/tty_buffer.c:527 sp2: Synchronizing with TNC process_one_work+0x79e/0x16c0 kernel/workqueue.c:2114 worker_thread+0xcc/0xee0 kernel/workqueue.c:2248 kthread+0x338/0x400 kernel/kthread.c:232 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:404 Code: 8b a5 58 ff sp3: Synchronizing with TNC ff ff 48 8b 9d 50 ff ff ff 4c 8b ad 48 ff ff ff 65 ff 0d 44 60 6pack: bad checksum 32 b3 7e 0f 85 e0 fd ff ff e8 7a b1 b1 ff e9 d6 fd ff ff <0f> 0b 0f 0b 6pack: protocol violation 4c 89 a5 68 ff ff ff e9 b2 fd ff ff 65 ff 05 1d 60 RIP: add_timer+0x5ec/0xab0 kernel/time/timer.c:1089 RSP: ffff8880820b7b40 sp2: Synchronizing with TNC 6pack: bad checksum 32 6pack: protocol violation 6pack: protocol violation sp3: Synchronizing with TNC 6pack: protocol violation sp4: Synchronizing with TNC 6pack: protocol violation 6pack: bad checksum 32 6pack: protocol violation 6pack: protocol violation 6pack: protocol violation 6pack: protocol violation 6pack: protocol violation sp5: Synchronizing with TNC 6pack: protocol violation 6pack: protocol violation 6pack: protocol violation 6pack: protocol violation 6pack: protocol violation 6pack: protocol violation 6pack: protocol violation 6pack: protocol violation 6pack: protocol violation 6pack: protocol violation 6pack: protocol violation 6pack: protocol violation 6pack: protocol violation 6pack: protocol violation 6pack: protocol violation 6pack: protocol violation 6pack: protocol violation 6pack: protocol violation 6pack: protocol violation 6pack: protocol violation 6pack: protocol violation 6pack: protocol violation 6pack: protocol violation 6pack: protocol violation 6pack: protocol violation 6pack: protocol violation 6pack: bad checksum 13 6pack: protocol violation 6pack: protocol violation 6pack: protocol violation 6pack: protocol violation 6pack: protocol violation 6pack: protocol violation 6pack: protocol violation 6pack: protocol violation 6pack: protocol violation 6pack: protocol violation 6pack: protocol violation 6pack: bad checksum 13 6pack: protocol violation 6pack: protocol violation 6pack: bad checksum 52 6pack: protocol violation 6pack: protocol violation 6pack: bad checksum 13 6pack: protocol violation 6pack: bad checksum 13 6pack: protocol violation 6pack: protocol violation 6pack: protocol violation 6pack: bad checksum 19 6pack: bad checksum 52 6pack: protocol violation 6pack: protocol violation 6pack: protocol violation 6pack: protocol violation 6pack: protocol violation 6pack: bad checksum 52 6pack: protocol violation 6pack: protocol violation 6pack: bad checksum 19 6pack: protocol violation 6pack: protocol violation 6pack: protocol violation 6pack: protocol violation 6pack: protocol violation 6pack: protocol violation 6pack: bad checksum 19 6pack: protocol violation 6pack: bad checksum 52 6pack: protocol violation 6pack: protocol violation 6pack: protocol violation 6pack: protocol violation 6pack: protocol violation 6pack: protocol violation 6pack: protocol violation 6pack: protocol violation 6pack: protocol violation 6pack: bad checksum 19 6pack: protocol violation 6pack: protocol violation 6pack: protocol violation 6pack: protocol violation 6pack: protocol violation 6pack: bad checksum 13 6pack: protocol violation 6pack: protocol violation 6pack: protocol violation 6pack: protocol violation 6pack: protocol violation 6pack: protocol violation 6pack: protocol violation 6pack: protocol violation 6pack: protocol violation 6pack: protocol violation 6pack: protocol violation 6pack: protocol violation 6pack: protocol violation 6pack: protocol violation 6pack: protocol violation 6pack: protocol violation 6pack: protocol violation 6pack: bad checksum 52 6pack: protocol violation 6pack: protocol violation 6pack: protocol violation 6pack: protocol violation 6pack: bad checksum f6 6pack: protocol violation 6pack: protocol violation 6pack: protocol violation 6pack: protocol violation 6pack: bad checksum 94 6pack: protocol violation 6pack: protocol violation 6pack: protocol violation 6pack: protocol violation 6pack: bad checksum 19 sp2: Found TNC 6pack: protocol violation 6pack: bad checksum f6 6pack: protocol violation 6pack: bad checksum 34 6pack: protocol violation 6pack: protocol violation 6pack: protocol violation 6pack: bad checksum 94 6pack: bad checksum f6 6pack: protocol violation 6pack: protocol violation sp3: Found TNC 6pack: bad checksum 94 6pack: protocol violation 6pack: protocol violation 6pack: bad checksum 34 6pack: protocol violation 6pack: protocol violation 6pack: protocol violation 6pack: protocol violation sp4: Found TNC 6pack: protocol violation 6pack: protocol violation 6pack: protocol violation 6pack: protocol violation 6pack: protocol violation 6pack: protocol violation 6pack: protocol violation 6pack: protocol violation 6pack: protocol violation 6pack: bad checksum 34 6pack: protocol violation 6pack: protocol violation 6pack: bad checksum 13 6pack: protocol violation ---[ end trace aefd93d8c3caa42f ]--- 6pack: protocol violation