KASAN: out-of-bounds in update_curr

From: syzbot
Date: Tue Nov 27 2018 - 10:20:08 EST

Hello,

syzbot found the following crash on:

HEAD commit: 4bffc669d624 net: remove unsafe skb_insert()
git tree: net-next
console output: https://syzkaller.appspot.com/x/log.txt?x=1385db83400000
kernel config: https://syzkaller.appspot.com/x/.config?x=c36a72af2123e78a
dashboard link: https://syzkaller.appspot.com/bug?extid=d3bf6aae26942dc9c8dc
compiler: gcc (GCC) 8.0.1 20180413 (experimental)
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=107b426d400000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=11b2e533400000

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+d3bf6aae26942dc9c8dc@xxxxxxxxxxxxxxxxxxxxxxxxx

DEBUG_LOCKS_WARN_ON(!hlock->nest_lock)
------------[ cut here ]------------
Bad or missing usercopy whitelist? Kernel memory overwrite attempt detected to SLAB object 'task_struct' (offset 1432, size 2)!
==================================================================
------------[ cut here ]------------
BUG: KASAN: out-of-bounds in calc_delta_fair kernel/sched/fair.c:630 [inline]
BUG: KASAN: out-of-bounds in update_curr+0x9c0/0xbd0 kernel/sched/fair.c:824
kernel BUG at mm/slab.c:4425!
Read of size 8 at addr ffff8881d9b4a4c0 by task ksoftirqd/0/9
invalid opcode: 0000 [#1] PREEMPT SMP KASAN

CPU: 1 PID: 38 Comm: ïïïÙïïïd ïïïïïï Not tainted 4.20.0-rc3+ #314
CPU: 0 PID: 9 Comm: ksoftirqd/0 Not tainted 4.20.0-rc3+ #314
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:__check_heap_object+0xa7/0xb5 mm/slab.c:4450
Call Trace:
Code: 48 c7 c7 5d df 14 89 e8 97 e3 0a 00 5d c3 41 8b 91 04 01 00 00 48 29 c7 48 39 d7 77 be 48 01 d0 48 29 c8 48 39 f0 72 b3 5d c3 <0f> 0b 48 c7 c7 5d df 14 89 e8 fd eb 0a 00 44 89 e9 48 c7 c7 18 e0
__dump_stack lib/dump_stack.c:77 [inline]
dump_stack+0x244/0x39d lib/dump_stack.c:113
RSP: 0018:ffff8881d9b49ea8 EFLAGS: 00010093
RAX: 00000000000a57eb RBX: 1ffff1103b3693dc RCX: 000000000000000c
RDX: ffff8881d9b4a440 RSI: 0000000000000001 RDI: ffff8881d9b4a088
RBP: ffff8881d9b49ea8 R08: ffff8881d9b4a440 R09: ffff8881da970180
print_address_description.cold.7+0x9/0x1ff mm/kasan/report.c:256
R10: 000000004afd68ef R11: 0000000000000000 R12: ffff8881d9b4a088
kasan_report_error mm/kasan/report.c:354 [inline]
kasan_report.cold.8+0x242/0x309 mm/kasan/report.c:412
R13: 0000000000000001 R14: ffffea000766d280 R15: 0000000000000001
FS: 0000000000000000(0000) GS:ffff8881daf00000(0000) knlGS:0000000000000000
__asan_report_load8_noabort+0x14/0x20 mm/kasan/report.c:433
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
calc_delta_fair kernel/sched/fair.c:630 [inline]
update_curr+0x9c0/0xbd0 kernel/sched/fair.c:824
CR2: 0000000cffc5fa18 CR3: 00000001bfadf000 CR4: 00000000001406e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
Modules linked in:
---[ end trace 04af116ff405efee ]---
RIP: 0010:__check_heap_object+0xa7/0xb5 mm/slab.c:4450
Code: 48 c7 c7 5d df 14 89 e8 97 e3 0a 00 5d c3 41 8b 91 04 01 00 00 48 29 c7 48 39 d7 77 be 48 01 d0 48 29 c8 48 39 f0 72 b3 5d c3 <0f> 0b 48 c7 c7 5d df 14 89 e8 fd eb 0a 00 44 89 e9 48 c7 c7 18 e0
RSP: 0018:ffff8881d9b49ea8 EFLAGS: 00010093
RAX: 00000000000a57eb RBX: 1ffff1103b3693dc RCX: 000000000000000c
enqueue_entity+0x3f5/0x20a0 kernel/sched/fair.c:3871
RDX: ffff8881d9b4a440 RSI: 0000000000000001 RDI: ffff8881d9b4a088
RBP: ffff8881d9b49ea8 R08: ffff8881d9b4a440 R09: ffff8881da970180
R10: 000000004afd68ef R11: 0000000000000000 R12: ffff8881d9b4a088
R13: 0000000000000001 R14: ffffea000766d280 R15: 0000000000000001
FS: 0000000000000000(0000) GS:ffff8881daf00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000cffc5fa18 CR3: 00000001bfadf000 CR4: 00000000001406e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400


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