KASAN: vmalloc-out-of-bounds Read in srcu_invoke_callbacks

[syzbot]

Hello,

syzbot found the following crash on:

HEAD commit:    6398b9fc Merge tag 'char-misc-5.5-rc3' of git://git.kernel..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=140da2b9e00000
kernel config:  https://syzkaller.appspot.com/x/.config?x=1b59a3066828ac4c
dashboard link: https://syzkaller.appspot.com/bug?extid=e8574d6a7b2172d6d2a6
compiler:       gcc (GCC) 9.0.0 20181231 (experimental)
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=152f4a49e00000

The bug was bisected to:

commit 9121923c457d1d8667a6e3a67302c29e5c5add6b
Author: Jim Mattson <jmattson@xxxxxxxxxx>
Date:   Thu Oct 24 23:03:26 2019 +0000

    kvm: Allocate memslots and buses before calling kvm_arch_init_vm

bisection log:  https://syzkaller.appspot.com/x/bisect.txt?x=15bf9ac1e00000
final crash:    https://syzkaller.appspot.com/x/report.txt?x=17bf9ac1e00000
console output: https://syzkaller.appspot.com/x/log.txt?x=13bf9ac1e00000

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+e8574d6a7b2172d6d2a6@xxxxxxxxxxxxxxxxxxxxxxxxx
Fixes: 9121923c457d ("kvm: Allocate memslots and buses before calling  
kvm_arch_init_vm")

==================================================================
BUG: KASAN: vmalloc-out-of-bounds in __read_once_size  
include/linux/compiler.h:199 [inline]
BUG: KASAN: vmalloc-out-of-bounds in rcu_seq_current kernel/rcu/rcu.h:99  
[inline]
BUG: KASAN: vmalloc-out-of-bounds in srcu_invoke_callbacks+0x338/0x360  
kernel/rcu/srcutree.c:1169
Read of size 8 at addr ffffc90004c18c78 by task kworker/0:2/9307

CPU: 0 PID: 9307 Comm: kworker/0:2 Not tainted 5.5.0-rc2-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS  
Google 01/01/2011
Workqueue: rcu_gp srcu_invoke_callbacks
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x197/0x210 lib/dump_stack.c:118
 print_address_description.constprop.0.cold+0x5/0x30b mm/kasan/report.c:374
 __kasan_report.cold+0x1b/0x41 mm/kasan/report.c:506
 kasan_report+0x12/0x20 mm/kasan/common.c:639
 __asan_report_load8_noabort+0x14/0x20 mm/kasan/generic_report.c:135
 __read_once_size include/linux/compiler.h:199 [inline]
 rcu_seq_current kernel/rcu/rcu.h:99 [inline]
 srcu_invoke_callbacks+0x338/0x360 kernel/rcu/srcutree.c:1169
 process_one_work+0x9af/0x1740 kernel/workqueue.c:2264
 worker_thread+0x98/0xe40 kernel/workqueue.c:2410
 kthread+0x361/0x430 kernel/kthread.c:255
 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352


Memory state around the buggy address:
 ffffc90004c18b00: f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9
 ffffc90004c18b80: f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9
> ffffc90004c18c00: f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9
                                                                ^
 ffffc90004c18c80: f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9
 ffffc90004c18d00: f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9
==================================================================


---
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