All of lore.kernel.org
 help / color / mirror / Atom feed
From: syzbot <syzbot+705f4401d5a93a59b87d@syzkaller.appspotmail.com>
To: eesposit@redhat.com, gregkh@linuxfoundation.org,
	kvm@vger.kernel.org, linux-kernel@vger.kernel.org,
	pbonzini@redhat.com, rafael@kernel.org,
	syzkaller-bugs@googlegroups.com
Subject: Re: general protection fault in start_creating
Date: Thu, 04 Jun 2020 05:29:18 -0700	[thread overview]
Message-ID: <0000000000001803d305a7414b66@google.com> (raw)
In-Reply-To: <000000000000e8226505a69ab3c7@google.com>

syzbot has found a reproducer for the following crash on:

HEAD commit:    cb8e59cc Merge git://git.kernel.org/pub/scm/linux/kernel/g..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=170f49de100000
kernel config:  https://syzkaller.appspot.com/x/.config?x=a16ddbc78955e3a9
dashboard link: https://syzkaller.appspot.com/bug?extid=705f4401d5a93a59b87d
compiler:       gcc (GCC) 9.0.0 20181231 (experimental)
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=1367410e100000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=10e07e0e100000

The bug was bisected to:

commit 63d04348371b7ea4a134bcf47c79763d969e9168
Author: Paolo Bonzini <pbonzini@redhat.com>
Date:   Tue Mar 31 22:42:22 2020 +0000

    KVM: x86: move kvm_create_vcpu_debugfs after last failure point

bisection log:  https://syzkaller.appspot.com/x/bisect.txt?x=1366069a100000
final crash:    https://syzkaller.appspot.com/x/report.txt?x=10e6069a100000
console output: https://syzkaller.appspot.com/x/log.txt?x=1766069a100000

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+705f4401d5a93a59b87d@syzkaller.appspotmail.com
Fixes: 63d04348371b ("KVM: x86: move kvm_create_vcpu_debugfs after last failure point")

general protection fault, probably for non-canonical address 0xdffffc000000002a: 0000 [#1] PREEMPT SMP KASAN
KASAN: null-ptr-deref in range [0x0000000000000150-0x0000000000000157]
CPU: 0 PID: 19367 Comm: syz-executor088 Not tainted 5.7.0-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:__lock_acquire+0xe1b/0x4a70 kernel/locking/lockdep.c:4250
Code: 91 0a 41 be 01 00 00 00 0f 86 ce 0b 00 00 89 05 4b 9a 91 0a e9 c3 0b 00 00 48 b8 00 00 00 00 00 fc ff df 4c 89 d2 48 c1 ea 03 <80> 3c 02 00 0f 85 57 2e 00 00 49 81 3a c0 74 c0 8b 0f 84 b0 f2 ff
RSP: 0018:ffffc90004b477b8 EFLAGS: 00010002
RAX: dffffc0000000000 RBX: 0000000000000001 RCX: 0000000000000000
RDX: 000000000000002a RSI: 0000000000000000 RDI: 0000000000000150
RBP: 0000000000000001 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000150 R11: 0000000000000001 R12: 0000000000000000
R13: ffff8880a77c2200 R14: 0000000000000000 R15: 0000000000000000
FS:  00007f9f3c6e5700(0000) GS:ffff8880ae600000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00000000004d5bb0 CR3: 00000000821f9000 CR4: 00000000001426f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 lock_acquire+0x1f2/0x8f0 kernel/locking/lockdep.c:4959
 down_write+0x8d/0x150 kernel/locking/rwsem.c:1531
 inode_lock include/linux/fs.h:799 [inline]
 start_creating+0xa8/0x250 fs/debugfs/inode.c:334
 __debugfs_create_file+0x62/0x400 fs/debugfs/inode.c:383
 kvm_arch_create_vcpu_debugfs+0x9f/0x200 arch/x86/kvm/debugfs.c:52
 kvm_create_vcpu_debugfs arch/x86/kvm/../../../virt/kvm/kvm_main.c:3012 [inline]
 kvm_vm_ioctl_create_vcpu arch/x86/kvm/../../../virt/kvm/kvm_main.c:3089 [inline]
 kvm_vm_ioctl+0x1c0b/0x2440 arch/x86/kvm/../../../virt/kvm/kvm_main.c:3617
 vfs_ioctl fs/ioctl.c:47 [inline]
 ksys_ioctl+0x11a/0x180 fs/ioctl.c:771
 __do_sys_ioctl fs/ioctl.c:780 [inline]
 __se_sys_ioctl fs/ioctl.c:778 [inline]
 __x64_sys_ioctl+0x6f/0xb0 fs/ioctl.c:778
 do_syscall_64+0xf6/0x7d0 arch/x86/entry/common.c:295
 entry_SYSCALL_64_after_hwframe+0x49/0xb3
RIP: 0033:0x44e5d9
Code: e8 7c e6 ff ff 48 83 c4 18 c3 0f 1f 80 00 00 00 00 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 1b 05 fc ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007f9f3c6e4ce8 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00000000006eaa08 RCX: 000000000044e5d9
RDX: 0000000000000000 RSI: 000000000000ae41 RDI: 0000000000000004
RBP: 00000000006eaa00 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000006eaa0c
R13: 00007ffe67678f9f R14: 00007f9f3c6e59c0 R15: 20c49ba5e353f7cf
Modules linked in:
---[ end trace b7d92d5fd0bd5c5f ]---
RIP: 0010:__lock_acquire+0xe1b/0x4a70 kernel/locking/lockdep.c:4250
Code: 91 0a 41 be 01 00 00 00 0f 86 ce 0b 00 00 89 05 4b 9a 91 0a e9 c3 0b 00 00 48 b8 00 00 00 00 00 fc ff df 4c 89 d2 48 c1 ea 03 <80> 3c 02 00 0f 85 57 2e 00 00 49 81 3a c0 74 c0 8b 0f 84 b0 f2 ff
RSP: 0018:ffffc90004b477b8 EFLAGS: 00010002
RAX: dffffc0000000000 RBX: 0000000000000001 RCX: 0000000000000000
RDX: 000000000000002a RSI: 0000000000000000 RDI: 0000000000000150
RBP: 0000000000000001 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000150 R11: 0000000000000001 R12: 0000000000000000
R13: ffff8880a77c2200 R14: 0000000000000000 R15: 0000000000000000
FS:  00007f9f3c6e5700(0000) GS:ffff8880ae600000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00000000004d5bb0 CR3: 00000000821f9000 CR4: 00000000001426f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400


  reply	other threads:[~2020-06-04 12:29 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-05-27  5:44 general protection fault in start_creating syzbot
2020-06-04 12:29 ` syzbot [this message]
2020-06-05 13:38   ` Vitaly Kuznetsov
2020-06-05 13:52     ` Paolo Bonzini

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=0000000000001803d305a7414b66@google.com \
    --to=syzbot+705f4401d5a93a59b87d@syzkaller.appspotmail.com \
    --cc=eesposit@redhat.com \
    --cc=gregkh@linuxfoundation.org \
    --cc=kvm@vger.kernel.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=pbonzini@redhat.com \
    --cc=rafael@kernel.org \
    --cc=syzkaller-bugs@googlegroups.com \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.