[syzbot] KASAN: vmalloc-out-of-bounds Read in kvm_put_kvm

From: syzbot
Date: Sat Aug 20 2022 - 11:58:40 EST


Hello,

syzbot found the following issue on:

HEAD commit: 7ebfc85e2cd7 Merge tag 'net-6.0-rc1' of git://git.kernel.o..
git tree: upstream
console+strace: https://syzkaller.appspot.com/x/log.txt?x=124e1715080000
kernel config: https://syzkaller.appspot.com/x/.config?x=924833c12349a8c0
dashboard link: https://syzkaller.appspot.com/bug?extid=ee478a0237db20ef61f1
compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=1403627b080000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=1672d823080000

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+ee478a0237db20ef61f1@xxxxxxxxxxxxxxxxxxxxxxxxx

L1TF CPU bug present and SMT on, data leak possible. See CVE-2018-3646 and https://www.kernel.org/doc/html/latest/admin-guide/hw-vuln/l1tf.html for details.
==================================================================
BUG: KASAN: vmalloc-out-of-bounds in __list_del_entry_valid+0xf2/0x110 lib/list_debug.c:59
Read of size 8 at addr ffffc900039da340 by task syz-executor260/3614

CPU: 0 PID: 3614 Comm: syz-executor260 Not tainted 5.19.0-syzkaller-13930-g7ebfc85e2cd7 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/22/2022
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106
print_address_description mm/kasan/report.c:317 [inline]
print_report.cold+0x59/0x719 mm/kasan/report.c:433
kasan_report+0xb1/0x1e0 mm/kasan/report.c:495
__list_del_entry_valid+0xf2/0x110 lib/list_debug.c:59
__list_del_entry include/linux/list.h:134 [inline]
list_del include/linux/list.h:148 [inline]
kvm_destroy_vm arch/x86/kvm/../../../virt/kvm/kvm_main.c:1290 [inline]
kvm_put_kvm+0x130/0xb70 arch/x86/kvm/../../../virt/kvm/kvm_main.c:1352
kvm_vm_release+0x3f/0x50 arch/x86/kvm/../../../virt/kvm/kvm_main.c:1375
__fput+0x277/0x9d0 fs/file_table.c:320
task_work_run+0xdd/0x1a0 kernel/task_work.c:177
exit_task_work include/linux/task_work.h:38 [inline]
do_exit+0xad5/0x29b0 kernel/exit.c:795
do_group_exit+0xd2/0x2f0 kernel/exit.c:925
__do_sys_exit_group kernel/exit.c:936 [inline]
__se_sys_exit_group kernel/exit.c:934 [inline]
__x64_sys_exit_group+0x3a/0x50 kernel/exit.c:934
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd
RIP: 0033:0x7fd7dbdc3d39
Code: Unable to access opcode bytes at RIP 0x7fd7dbdc3d0f.
RSP: 002b:00007ffce9fd1d88 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7
RAX: ffffffffffffffda RBX: 00007fd7dbe383f0 RCX: 00007fd7dbdc3d39
RDX: 000000000000003c RSI: 00000000000000e7 RDI: 0000000000000000
RBP: 0000000000000000 R08: ffffffffffffffc0 R09: 0000000000000001
R10: 0000000000000000 R11: 0000000000000246 R12: 00007fd7dbe383f0
R13: 0000000000000001 R14: 0000000000000000 R15: 0000000000000001
</TASK>

Memory state around the buggy address:
ffffc900039da200: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8
ffffc900039da280: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8
>ffffc900039da300: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8
^
ffffc900039da380: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8
ffffc900039da400: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8
==================================================================


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