KASAN: out-of-bounds Read in unwind_next

KASAN: out-of-bounds Read in unwind_next_frame
Status: upstream: reported syz repro on 2019/01/07 10:01
Reported-by: syzbot+2fdf0ed2b3bc8fc51fc6@syzkaller.appspotmail.com
First crash: 169d, last: 3d11h

Bisection: error (bisect log)
Tree: upstream
Repro: syz .config

similar bugs (2):
Kernel	Title	Repro	Bisected	Count	Last	Reported	Patched	Status
android-49	KASAN: out-of-bounds Read in unwind_next_frame	C		14	257d	73d	0/3	public: reported C repro on 2019/04/13 00:00
android-414	KASAN: out-of-bounds Read in unwind_next_frame			1	249d	72d	0/1	auto-closed as invalid on 2019/04/28 00:03

Sample crash report:

IPv6: ADDRCONF(NETDEV_UP): vxcan1: link is not ready
8021q: adding VLAN 0 to HW filter on device batadv0
==================================================================
BUG: KASAN: out-of-bounds in unwind_next_frame.part.0+0x756/0xa90 arch/x86/kernel/unwind_frame.c:324
Read of size 8 at addr ffff88809476fb68 by task syz-executor1/12572

CPU: 1 PID: 12572 Comm: syz-executor1 Not tainted 5.0.0-rc3+ #44
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+0x1db/0x2d0 lib/dump_stack.c:113
 print_address_description.cold+0x7c/0x20d mm/kasan/report.c:187
 kasan_report.cold+0x1b/0x40 mm/kasan/report.c:317
 __asan_report_load8_noabort+0x14/0x20 mm/kasan/generic_report.c:135
 unwind_next_frame.part.0+0x756/0xa90 arch/x86/kernel/unwind_frame.c:324
 unwind_next_frame+0x3b/0x50 arch/x86/kernel/unwind_frame.c:287
 __save_stack_trace+0x7a/0xf0 arch/x86/kernel/stacktrace.c:44
 save_stack_trace_tsk arch/x86/kernel/stacktrace.c:76 [inline]
 save_stack_trace_tsk+0x9e/0xd0 arch/x86/kernel/stacktrace.c:69
 proc_pid_stack+0x272/0x430 fs/proc/base.c:438
 proc_single_show+0xf6/0x180 fs/proc/base.c:739
 seq_read+0x4db/0x1130 fs/seq_file.c:229
 do_loop_readv_writev fs/read_write.c:700 [inline]
 do_loop_readv_writev fs/read_write.c:687 [inline]
 do_iter_read+0x4a9/0x660 fs/read_write.c:921
 vfs_readv+0x175/0x1c0 fs/read_write.c:983
 do_preadv+0x1c4/0x280 fs/read_write.c:1067
 __do_sys_preadv fs/read_write.c:1117 [inline]
 __se_sys_preadv fs/read_write.c:1112 [inline]
 __x64_sys_preadv+0x9a/0xf0 fs/read_write.c:1112
 do_syscall_64+0x1a3/0x800 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x458099
Code: 6d b7 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 3b b7 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007fedc3d91c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000127
RAX: ffffffffffffffda RBX: 0000000000000004 RCX: 0000000000458099
RDX: 1000000000000156 RSI: 0000000020000480 RDI: 0000000000000004
RBP: 000000000073bf00 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007fedc3d926d4
R13: 00000000004c4b67 R14: 00000000004d82e0 R15: 00000000ffffffff

The buggy address belongs to the page:
page:ffffea000251dbc0 count:0 mapcount:0 mapping:0000000000000000 index:0x0
flags: 0x1fffc0000000000()
raw: 01fffc0000000000 0000000000000000 ffffffff02510101 0000000000000000
raw: 0000000000000000 0000000000000000 00000000ffffffff 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff88809476fa00: 00 f2 f2 00 f2 f2 f2 00 f2 f2 f2 00 f2 f2 f2 f8
 ffff88809476fa80: f3 f3 f3 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff88809476fb00: f1 f1 f1 f1 00 f2 f2 f2 00 f3 f3 f3 00 00 00 00
                                                          ^
 ffff88809476fb80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 f1 f1
 ffff88809476fc00: f1 f1 00 f2 f2 f2 00 00 f2 f2 04 f3 f3 f3 00 00
==================================================================

All crashes (10):
Manager	Time	Kernel	Commit	Syzkaller	Config	Log	Report	Syz repro	Maintainers
ci-upstream-kasan-gce-smack-root	2019/01/26 12:06	upstream	ba606975	c73f090a	.config	log	report	syz	bp@alien8.de, hpa@zytor.com, linux-kernel@vger.kernel.org, mingo@redhat.com, tglx@linutronix.de, x86@kernel.org
ci-upstream-kasan-gce-smack-root	2019/01/31 13:03	upstream	af0c9af1	aa432daf	.config	log	report	syz	bp@alien8.de, hpa@zytor.com, linux-kernel@vger.kernel.org, mingo@redhat.com, tglx@linutronix.de, x86@kernel.org
ci-upstream-kasan-gce-selinux-root	2019/01/06 21:13	upstream	b5aef86e	94f8adb5	.config	log	report		bp@alien8.de, hpa@zytor.com, linux-kernel@vger.kernel.org, mingo@redhat.com, tglx@linutronix.de, x86@kernel.org
ci-upstream-kasan-gce-root	2019/06/21 19:06	upstream	abf02e29	34bf9440	.config	log	report		bp@alien8.de, gregkh@linuxfoundation.org, hpa@zytor.com, jannh@google.com, jpoimboe@redhat.com, linux-kernel@vger.kernel.org, mingo@redhat.com, tglx@linutronix.de, x86@kernel.org
ci-upstream-kasan-gce-selinux-root	2019/03/15 02:04	upstream	3b319ee2	d72db19b	.config	log	report		bp@alien8.de, hpa@zytor.com, jannh@google.com, jpoimboe@redhat.com, linux-kernel@vger.kernel.org, mingo@redhat.com, tglx@linutronix.de, x86@kernel.org
ci-upstream-kasan-gce-root	2019/03/08 11:32	upstream	610cd4ea	12365b99	.config	log	report		bp@alien8.de, hpa@zytor.com, linux-kernel@vger.kernel.org, mingo@redhat.com, tglx@linutronix.de, x86@kernel.org
ci-upstream-kasan-gce-smack-root	2019/01/31 12:19	upstream	af0c9af1	aa432daf	.config	log	report		bp@alien8.de, hpa@zytor.com, linux-kernel@vger.kernel.org, mingo@redhat.com, tglx@linutronix.de, x86@kernel.org
ci-upstream-kasan-gce-selinux-root	2019/01/24 04:14	upstream	30bac164	56558f63	.config	log	report		bp@alien8.de, hpa@zytor.com, linux-kernel@vger.kernel.org, mingo@redhat.com, tglx@linutronix.de, x86@kernel.org
ci-upstream-kasan-gce-smack-root	2019/01/23 05:17	upstream	787a3b43	b1ff06b2	.config	log	report		bp@alien8.de, hpa@zytor.com, linux-kernel@vger.kernel.org, mingo@redhat.com, tglx@linutronix.de, x86@kernel.org
ci-upstream-linux-next-kasan-gce-root	2019/02/13 20:56	linux-next	c4f3ef3e	0a49c954	.config	log	report		bp@alien8.de, hpa@zytor.com, linux-kernel@vger.kernel.org, mingo@redhat.com, tglx@linutronix.de, x86@kernel.org