KASAN: stack-out-of-bounds in update_curr

[syzbot]

Hello,

syzbot found the following crash on:

HEAD commit:    645ff1e8e704 Merge branch 'for-linus' of git://git.kernel...
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=10b8c59b400000
kernel config:  https://syzkaller.appspot.com/x/.config?x=20271e14bc1c87f0
dashboard link: https://syzkaller.appspot.com/bug?extid=d959075ee873314ffb9c
compiler:       gcc (GCC) 9.0.0 20181231 (experimental)
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=15b32430c00000

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+d959075ee873314ffb9c@xxxxxxxxxxxxxxxxxxxxxxxxx

IPv6: ADDRCONF(NETDEV_UP): vxcan1: link is not ready
8021q: adding VLAN 0 to HW filter on device batadv0
==================================================================
kasan: CONFIG_KASAN_INLINE enabled
kasan: GPF could be caused by NULL-ptr deref or user memory access
BUG: KASAN: stack-out-of-bounds in calc_delta_fair kernel/sched/fair.c:629  
[inline]
BUG: KASAN: stack-out-of-bounds in update_curr+0x99d/0xbc0  
kernel/sched/fair.c:823
general protection fault: 0000 [#1] PREEMPT SMP KASAN
Read of size 8 at addr ffff8880a94be4c0 by task syz-executor2/8264
CPU: 1 PID: -2015332728 Comm: e Not tainted 4.20.0+ #7

Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS  
Google 01/01/2011
CPU: 0 PID: 8264 Comm: syz-executor2 Not tainted 4.20.0+ #7
RIP: 0010:lookup_object lib/debugobjects.c:156 [inline]
RIP: 0010:debug_object_deactivate lib/debugobjects.c:542 [inline]
RIP: 0010:debug_object_deactivate+0x16c/0x4b0 lib/debugobjects.c:529
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS  
Google 01/01/2011
Code: c1 ea 03 42 80 3c 2a 00 0f 85 49 02 00 00 4d 8b 24 24 4d 85 e4 0f 84  
d1 00 00 00 49 8d 7c 24 18 83 c3 01 48 89 fa 48 c1 ea 03 <42> 80 3c 2a 00  
0f 85 fa 01 00 00 49 3b 4c 24 18 75 c0 49 8d 7c 24
Call Trace:
RSP: 0018:ffff8880ae707b80 EFLAGS: 00010002
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x1db/0x2d0 lib/dump_stack.c:113
RAX: 1ffffffff16d5674 RBX: 0000000000000003 RCX: ffff8880ae726620
RDX: 000000000000000b RSI: 0000000000000004 RDI: 0000000000000058
RBP: ffff8880ae707c70 R08: 1ffff11015ce0f5c R09: ffffffff899ad160
R10: 0000000000000086 R11: 0000000000000003 R12: 0000000000000040
R13: dffffc0000000000 R14: 1ffff11015ce0f74 R15: ffffffff8b6ab3a8
FS:  0000000000000000(0000) GS:ffff8880ae700000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000068 CR3: 000000007f479000 CR4: 00000000001406e0
 print_address_description.cold+0x7c/0x20d mm/kasan/report.c:187
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <IRQ>
 kasan_report.cold+0x1b/0x40 mm/kasan/report.c:317
 __asan_report_load8_noabort+0x14/0x20 mm/kasan/generic_report.c:135
 calc_delta_fair kernel/sched/fair.c:629 [inline]
 update_curr+0x99d/0xbc0 kernel/sched/fair.c:823
 debug_hrtimer_deactivate kernel/time/hrtimer.c:412 [inline]
 debug_deactivate kernel/time/hrtimer.c:462 [inline]
 __run_hrtimer kernel/time/hrtimer.c:1359 [inline]
 __hrtimer_run_queues+0x225/0x1050 kernel/time/hrtimer.c:1451
 enqueue_entity+0x3e5/0x20b0 kernel/sched/fair.c:3880
 hrtimer_interrupt+0x314/0x770 kernel/time/hrtimer.c:1509
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1035 [inline]
 smp_apic_timer_interrupt+0x18d/0x760 arch/x86/kernel/apic/apic.c:1060
 enqueue_task_fair+0x237/0x10c0 kernel/sched/fair.c:5133
 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:807
 enqueue_task kernel/sched/core.c:730 [inline]
 activate_task+0x11d/0x470 kernel/sched/core.c:751
 </IRQ>
 ttwu_activate kernel/sched/core.c:1643 [inline]
 ttwu_do_activate+0xd4/0x1f0 kernel/sched/core.c:1702
Modules linked in:
 ttwu_queue kernel/sched/core.c:1847 [inline]
 try_to_wake_up+0x997/0x1480 kernel/sched/core.c:2057
---[ end trace 5a5c098e51171999 ]---
RIP: 0010:lookup_object lib/debugobjects.c:156 [inline]
RIP: 0010:debug_object_deactivate lib/debugobjects.c:542 [inline]
RIP: 0010:debug_object_deactivate+0x16c/0x4b0 lib/debugobjects.c:529
Code: c1 ea 03 42 80 3c 2a 00 0f 85 49 02 00 00 4d 8b 24 24 4d 85 e4 0f 84  
d1 00 00 00 49 8d 7c 24 18 83 c3 01 48 89 fa 48 c1 ea 03 <42> 80 3c 2a 00  
0f 85 fa 01 00 00 49 3b 4c 24 18 75 c0 49 8d 7c 24
RSP: 0018:ffff8880ae707b80 EFLAGS: 00010002
RAX: 1ffffffff16d5674 RBX: 0000000000000003 RCX: ffff8880ae726620
RDX: 000000000000000b RSI: 0000000000000004 RDI: 0000000000000058
 default_wake_function+0x30/0x50 kernel/sched/core.c:3710
RBP: ffff8880ae707c70 R08: 1ffff11015ce0f5c R09: ffffffff899ad160
R10: 0000000000000086 R11: 0000000000000003 R12: 0000000000000040
 __wake_up_common+0x1d3/0x7d0 kernel/sched/wait.c:92
R13: dffffc0000000000 R14: 1ffff11015ce0f74 R15: ffffffff8b6ab3a8
FS:  0000000000000000(0000) GS:ffff8880ae700000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000068 CR3: 000000007f479000 CR4: 00000000001406e0
 __wake_up_locked+0x11/0x20 kernel/sched/wait.c:154
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
 ep_poll_callback+0x3c5/0x10a0 fs/eventpoll.c:1200
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400


---
This bug is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
syzbot engineers can be reached at syzkaller@xxxxxxxxxxxxxxxxx

syzbot will keep track of this bug report. See:
https://goo.gl/tpsmEJ#bug-status-tracking for how to communicate with  
syzbot.
syzbot can test patches for this bug, for details see:
https://goo.gl/tpsmEJ#testing-patches