UBSAN: shift-out-of-bounds in detach

UBSAN: shift-out-of-bounds in detach_tasks
Status: upstream: reported syz repro on 2021/02/23 13:35
Reported-by: syzbot+f9131489729201445f66@syzkaller.appspotmail.com
First crash: 76d, last: 11d

Cause bisection: failed (bisect log)

Sample crash report:

================================================================================
UBSAN: shift-out-of-bounds in kernel/sched/fair.c:7712:14
shift exponent 77 is too large for 64-bit type 'unsigned long'
CPU: 1 PID: 8407 Comm: syz-executor.4 Not tainted 5.12.0-rc6-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 <IRQ>
 __dump_stack lib/dump_stack.c:79 [inline]
 dump_stack+0x176/0x24e lib/dump_stack.c:120
 ubsan_epilogue lib/ubsan.c:148 [inline]
 __ubsan_handle_shift_out_of_bounds+0x42e/0x4d0 lib/ubsan.c:327
 detach_tasks+0xd04/0x1110 kernel/sched/fair.c:7712
 load_balance+0x39f6/0x5a80 kernel/sched/fair.c:9641
 rebalance_domains+0x4ca/0x9c0 kernel/sched/fair.c:10029
 __do_softirq+0x318/0x714 kernel/softirq.c:345
 invoke_softirq kernel/softirq.c:221 [inline]
 __irq_exit_rcu+0x1d8/0x200 kernel/softirq.c:422
 irq_exit_rcu+0x5/0x20 kernel/softirq.c:434
 sysvec_apic_timer_interrupt+0x91/0xb0 arch/x86/kernel/apic/apic.c:1100
 </IRQ>
 asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:632
RIP: 0010:__raw_spin_unlock_irq include/linux/spinlock_api_smp.h:169 [inline]
RIP: 0010:_raw_spin_unlock_irq+0x25/0x40 kernel/locking/spinlock.c:199
Code: b2 fd ff 66 90 53 48 89 fb 48 83 c7 18 48 8b 74 24 08 e8 0e 54 08 f8 48 89 df e8 56 29 0a f8 e8 f1 a4 2a f8 fb bf 01 00 00 00 <e8> 26 39 fe f7 65 8b 05 f7 7c ad 76 85 c0 74 02 5b c3 e8 ab d8 ab
RSP: 0018:ffffc9000187fc70 EFLAGS: 00000282
RAX: eded0b76c3f98d00 RBX: ffff8880b9d34c80 RCX: ffffffff8ff89b03
RDX: 0000000040000000 RSI: 0000000000000002 RDI: 0000000000000001
RBP: ffffc9000187fcd0 R08: ffffffff817f17a0 R09: ffffed10173a6991
R10: ffffed10173a6991 R11: 0000000000000000 R12: ffff8880b9d34c80
R13: ffff88801caeb880 R14: dffffc0000000000 R15: 0000000000000000
 finish_task_switch+0x145/0x620 kernel/sched/core.c:4191
 context_switch kernel/sched/core.c:4325 [inline]
 __schedule+0x9a1/0xe70 kernel/sched/core.c:5073
 schedule+0x14b/0x200 kernel/sched/core.c:5152
 freezable_schedule include/linux/freezer.h:172 [inline]
 do_nanosleep+0x1cd/0x740 kernel/time/hrtimer.c:1896
 hrtimer_nanosleep+0x1b9/0x3a0 kernel/time/hrtimer.c:1949
 __do_sys_clock_nanosleep kernel/time/posix-timers.c:1267 [inline]
 __se_sys_clock_nanosleep kernel/time/posix-timers.c:1245 [inline]
 __x64_sys_clock_nanosleep+0x2f6/0x340 kernel/time/posix-timers.c:1245
 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xae
RIP: 0033:0x48a621
Code: 24 0c 89 3c 24 48 89 4c 24 18 e8 aa e7 ff ff 4c 8b 54 24 18 48 8b 54 24 10 41 89 c0 8b 74 24 0c 8b 3c 24 b8 e6 00 00 00 0f 05 <44> 89 c7 48 89 04 24 e8 e3 e7 ff ff 48 8b 04 24 eb 97 66 2e 0f 1f
RSP: 002b:00007ffd2ecab5c0 EFLAGS: 00000293 ORIG_RAX: 00000000000000e6
RAX: ffffffffffffffda RBX: 0000000000000008 RCX: 000000000048a621
RDX: 00007ffd2ecab600 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 00007ffd2ecab69c R08: 0000000000000000 R09: 0000000000000010
R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000032
R13: 000000000006640a R14: 000000000000000d R15: 00007ffd2ecab700
================================================================================

Crashes (11):
Manager	Time	Kernel	Commit	Syzkaller	Config	Log	Report	Syz repro	VM info	Title
ci-upstream-kasan-gce-smack-root	2021/04/05 07:48	upstream	e49d033b	6a81331a	.config	log	report	syz		UBSAN: shift-out-of-bounds in detach_tasks
ci-upstream-kasan-gce-smack-root	2021/04/28 14:07	upstream	acd3d285	77e2b668	.config	log	report		info	UBSAN: shift-out-of-bounds in detach_tasks
ci-upstream-kasan-gce-smack-root	2021/04/27 14:19	upstream	4a0225c3	805b5003	.config	log	report		info	UBSAN: shift-out-of-bounds in detach_tasks
ci-upstream-kasan-gce-smack-root	2021/04/21 21:44	upstream	16fc44d6	2bc8999a	.config	log	report		info	UBSAN: shift-out-of-bounds in detach_tasks
ci-upstream-kasan-gce-smack-root	2021/04/05 01:15	upstream	e49d033b	6a81331a	.config	log	report		info	UBSAN: shift-out-of-bounds in detach_tasks
ci-upstream-kasan-gce-smack-root	2021/03/29 21:48	upstream	1e43c377	6a81331a	.config	log	report		info	UBSAN: shift-out-of-bounds in detach_tasks
ci-upstream-kasan-gce-smack-root	2021/03/25 00:29	upstream	4ee998b0	607e3baf	.config	log	report		info	UBSAN: shift-out-of-bounds in detach_tasks
ci-upstream-kasan-gce-smack-root	2021/03/03 17:25	upstream	f69d02e3	06ed56cd	.config	log	report		info	UBSAN: shift-out-of-bounds in detach_tasks
ci-upstream-kasan-gce-smack-root	2021/02/28 04:29	upstream	5695e516	4c37c133	.config	log	report		info	UBSAN: shift-out-of-bounds in detach_tasks
ci-upstream-kasan-gce-smack-root	2021/02/22 15:33	upstream	31caf8b2	a659b3f1	.config	log	report		info	UBSAN: shift-out-of-bounds in detach_tasks
ci-upstream-kasan-gce-smack-root	2021/02/22 12:52	upstream	31caf8b2	a659b3f1	.config	log	report		info	UBSAN: shift-out-of-bounds in detach_tasks