bisecting fixing commit since aea8526edf59da3ff5306ca408e13d8f6ab89b34
building syzkaller on 1656845f45f284c574eb4f8bfe85dd7916a47a3a
testing commit aea8526edf59da3ff5306ca408e13d8f6ab89b34 with gcc (GCC) 8.1.0
kernel signature: 93beb18fb02e8a6229f276493fe05cff9250ea5a0167c1b070c1a87ede1903b1
all runs: crashed: WARNING in enqueue_task_dl
testing current HEAD 050272a0423e68207fd2367831ae610680129062
testing commit 050272a0423e68207fd2367831ae610680129062 with gcc (GCC) 8.1.0
kernel signature: c2b51ee1d735de6b5b16ddb362402cb9efecbccc24838576499876e1e7ffed87
all runs: crashed: WARNING in enqueue_task_dl
revisions tested: 2, total time: 26m21.891490479s (build: 18m15.193901067s, test: 6m50.20727128s)
the crash still happens on HEAD
commit msg: Linux 4.14.177
crash: WARNING in enqueue_task_dl
IPv6: ADDRCONF(NETDEV_CHANGE): bridge_slave_1: link becomes ready
bridge0: port 2(bridge_slave_1) entered blocking state
bridge0: port 2(bridge_slave_1) entered forwarding state
device hsr_slave_0 entered promiscuous mode
------------[ cut here ]------------
WARNING: CPU: 1 PID: 7020 at kernel/sched/deadline.c:593 __enqueue_dl_entity kernel/sched/deadline.c:1321 [inline]
WARNING: CPU: 1 PID: 7020 at kernel/sched/deadline.c:593 enqueue_dl_entity kernel/sched/deadline.c:1373 [inline]
WARNING: CPU: 1 PID: 7020 at kernel/sched/deadline.c:593 enqueue_task_dl+0x1b7e/0x28f0 kernel/sched/deadline.c:1441
Kernel panic - not syncing: panic_on_warn set ...

CPU: 1 PID: 7020 Comm: syz-executor.1 Not tainted 4.14.177-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:17 [inline]
 dump_stack+0xf7/0x13b lib/dump_stack.c:58
 panic+0x1b0/0x358 kernel/panic.c:183
 __warn.cold.8+0x25/0x2c kernel/panic.c:547
 report_bug+0x1a4/0x1f3 lib/bug.c:186
 fixup_bug arch/x86/kernel/traps.c:177 [inline]
 do_error_trap+0x1bd/0x310 arch/x86/kernel/traps.c:295
 do_invalid_op+0x1b/0x20 arch/x86/kernel/traps.c:314
 invalid_op+0x1b/0x40 arch/x86/entry/entry_64.S:963
RIP: 0010:setup_new_dl_entity kernel/sched/deadline.c:593 [inline]
RIP: 0010:enqueue_dl_entity kernel/sched/deadline.c:1370 [inline]
RIP: 0010:enqueue_task_dl+0x1b7e/0x28f0 kernel/sched/deadline.c:1441
RSP: 0018:ffff888095247cb8 EFLAGS: 00010002
RAX: 0000000000000000 RBX: ffff8880a5b18300 RCX: ffff8880a5b185cc
RDX: 0000000adb76cf37 RSI: 1ffff11014b630ba RDI: 0000000000000001
RBP: ffff888095247d28 R08: ffff8880a5b185c0 R09: ffff8880aef00000
R10: ffff8880a5b1833c R11: 0000000000000001 R12: ffff8880a5b18578
R13: ffff8880aef2b500 R14: ffffffff87cb4e00 R15: ffff8880aef2b500
 enqueue_task kernel/sched/core.c:763 [inline]
 __sched_setscheduler+0xd97/0x25f0 kernel/sched/core.c:4228
 sched_setattr kernel/sched/core.c:4286 [inline]
 SYSC_sched_setattr kernel/sched/core.c:4457 [inline]
 SyS_sched_setattr+0x22f/0x360 kernel/sched/core.c:4436
 do_syscall_64+0x1c7/0x5b0 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x459819
RSP: 002b:00007f308200ac78 EFLAGS: 00000246 ORIG_RAX: 000000000000013a
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000000459819
RDX: 0000000000000000 RSI: 0000000020000000 RDI: 0000000000000000
RBP: 000000000075bfc8 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f308200b6d4
R13: 00000000004c6d52 R14: 00000000004dc010 R15: 00000000ffffffff

======================================================