syzbot


KASAN: out-of-bounds Read in __schedule

Status: auto-closed as invalid on 2019/03/28 23:03
Subsystems: kernel
[Documentation on labels]
Reported-by: syzbot+201e51230785b8b43547@syzkaller.appspotmail.com
First crash: 2032d, last: 2032d

Sample crash report:
page:ffffea0006739000 count:0 mapcount:-128 mapping:0000000000000000 index:0x0
==================================================================
BUG: KASAN: out-of-bounds in schedule_debug kernel/sched/core.c:3285 [inline]
BUG: KASAN: out-of-bounds in __schedule+0x1a18/0x1ed0 kernel/sched/core.c:3395
Read of size 8 at addr ffff88019cd78000 by task syz-executor0/10085

CPU: 0 PID: 10085 Comm: syz-executor0 Not tainted 4.19.0-rc5+ #122
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x1c4/0x2b4 lib/dump_stack.c:113
 print_address_description.cold.8+0x9/0x1ff mm/kasan/report.c:256
 kasan_report_error mm/kasan/report.c:354 [inline]
 kasan_report.cold.9+0x242/0x309 mm/kasan/report.c:412
 __asan_report_load8_noabort+0x14/0x20 mm/kasan/report.c:433
 schedule_debug kernel/sched/core.c:3285 [inline]
 __schedule+0x1a18/0x1ed0 kernel/sched/core.c:3395
 preempt_schedule_common+0x1f/0xd0 kernel/sched/core.c:3597
 preempt_schedule+0x4d/0x60 kernel/sched/core.c:3623
 ___preempt_schedule+0x16/0x18
 __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:161 [inline]
 _raw_spin_unlock_irqrestore+0xbb/0xd0 kernel/locking/spinlock.c:184
 try_to_wake_up+0x10a/0x12f0 kernel/sched/core.c:2055
 wake_up_process kernel/sched/core.c:2123 [inline]
 wake_up_q+0xa4/0x100 kernel/sched/core.c:441
 futex_wake+0x61f/0x760 kernel/futex.c:1556
 do_futex+0x2e4/0x26d0 kernel/futex.c:3533
 __do_sys_futex kernel/futex.c:3589 [inline]
 __se_sys_futex kernel/futex.c:3557 [inline]
 __x64_sys_futex+0x472/0x6a0 kernel/futex.c:3557
 do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x457579
Code: 1d b4 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 eb b3 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007fb9b642dcf8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca
RAX: ffffffffffffffda RBX: 000000000072bf08 RCX: 0000000000457579
RDX: 00000000004c43d5 RSI: 0000000000000081 RDI: 000000000072bf0c
RBP: 000000000072bf00 R08: 0000000000000061 R09: 0000000000000000
R10: ffffffffffffffff R11: 0000000000000246 R12: 000000000072bf0c
R13: 00007ffd732bceef R14: 00007fb9b642e9c0 R15: 0000000000000000

The buggy address belongs to the page:
page:ffffea0006735e00 count:1 mapcount:-1024 mapping:0000000000000000 index:0x0
flags: 0x2fffc0000000000()
raw: 02fffc0000000000 dead000000000100 dead000000000200 0000000000000000
raw: 0000000000000000 ffff8801c3654cb8 00000001fffffbff 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff88019cd77f00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff88019cd77f80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff88019cd78000: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
                      ^
 ffff88019cd78080: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff88019cd78100: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
==================================================================
flags: 0x2fffc0000000000()

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2018/09/29 23:02 net-old 43955a45dc0b 41e4b329 .config console log report ci-upstream-net-this-kasan-gce
* Struck through repros no longer work on HEAD.