KASAN: use-after-free Read in do_general

KASAN: use-after-free Read in do_general_protection
Status: upstream: reported C repro on 2018/05/26 09:16
Reported-by: syzbot+a1264132fc103340628f@syzkaller.appspotmail.com
First crash: 776d, last: 747d

Cause bisection: failed (bisect log)

Fix bisection: failed (bisect log)

duplicates (5):
Title	Repro	Count	Last	Reported	Patched	Status
KASAN: use-after-scope Read in vmx_vcpu_run		1	822d	820d	0/17	closed as dup on 2018/05/26 09:26
KASAN: stack-out-of-bounds Read in unwind_next_frame	C	161	14h50m	751d	0/17	closed as dup on 2018/06/20 07:51
KASAN: stack-out-of-bounds Read in do_general_protection	syz	11	710d	776d	0/17	closed as dup on 2018/05/26 09:25
KASAN: slab-out-of-bounds Read in vmx_vcpu_run		1	793d	789d	0/17	closed as dup on 2018/05/26 09:26
KASAN: stack-out-of-bounds Write in notify_die	syz	4	713d	776d	0/17	closed as dup on 2018/05/26 09:26

Sample crash report:

random: sshd: uninitialized urandom read (32 bytes read)
random: sshd: uninitialized urandom read (32 bytes read)
random: sshd: uninitialized urandom read (32 bytes read)
random: sshd: uninitialized urandom read (32 bytes read)
==================================================================
BUG: KASAN: use-after-free in do_general_protection+0x2ac/0x2f0 arch/x86/kernel/traps.c:539
Read of size 8 at addr ffff8801ac11f358 by task syz-executor216/4585

CPU: 1 PID: 4585 Comm: syz-executor216 Not tainted 4.18.0-rc2+ #116
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:

The buggy address belongs to the page:
page:ffffea0006b047c0 count:0 mapcount:0 mapping:0000000000000000 index:0x0
flags: 0x2fffc0000000000()
raw: 02fffc0000000000 0000000000000000 ffffffff06b00101 0000000000000000
raw: 0000000000000000 0000000000000000 00000000ffffffff 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8801ac11f200: 00 00 00 00 00 00 ff ff ff ff ff ff ff ff ff ff
 ffff8801ac11f280: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
>ffff8801ac11f300: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                                                    ^
 ffff8801ac11f380: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff8801ac11f400: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
==================================================================
Kernel panic - not syncing: panic_on_warn set ...

CPU: 1 PID: 4585 Comm: syz-executor216 Tainted: G    B             4.18.0-rc2+ #116
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
Dumping ftrace buffer:
   (ftrace buffer empty)
Kernel Offset: disabled
Rebooting in 86400 seconds..

Crashes (2):
Manager	Time	Kernel	Commit	Syzkaller	Config	Log	Report	Syz repro	C repro
ci-upstream-kasan-gce-root	2018/06/24 20:08	upstream	7daf201d	2064fc5c	.config	log	report	syz	C
ci-upstream-kasan-gce	2018/05/26 06:25	upstream	62d18ecf	f48c20b8	.config	log	report	syz	C