Received-SPF: pass (google.com: domain of linux-kernel+bounces-139954-linux.lists.archive=gmail.com@vger.kernel.org designates 2604:1380:4601:e00::3 as permitted sender) client-ip=2604:1380:4601:e00::3;
Precedence: bulk
MIME-Version: 1.0
References: <CAEkJfYON+ry7xPx=AiLR9jzUNT+i_Va68ACajOC3HoacOfL1ig@mail.gmail.com>
 <2024041125-anemic-decorated-52aa@gregkh>
In-Reply-To: <2024041125-anemic-decorated-52aa@gregkh>
From: Sam Sun <samsun1006219@gmail.com>
Date: Thu, 11 Apr 2024 15:19:25 +0800
Message-ID: <CAEkJfYPBjBbHX0Nt4Pxg3orPfZzRGjYhgZKGphoO5+Pskso7hQ@mail.gmail.com>
Subject: Re: [Linux kernel bug] general protection fault in disable_store
To: Greg KH <gregkh@linuxfoundation.org>
Cc: linux-kernel@vger.kernel.org, linux-usb@vger.kernel.org, 
	Alan Stern <stern@rowland.harvard.edu>, swboyd@chromium.org, ricardo@marliere.net, 
	hkallweit1@gmail.com, heikki.krogerus@linux.intel.com, 
	mathias.nyman@linux.intel.com, royluo@google.com, 
	syzkaller-bugs@googlegroups.com, xrivendell7@gmail.com
Content-Type: text/plain; charset="UTF-8"
Content-Transfer-Encoding: quoted-printable

On Thu, Apr 11, 2024 at 2:58=E2=80=AFPM Greg KH <gregkh@linuxfoundation.org=
> wrote:
>
> On Thu, Apr 11, 2024 at 02:52:27PM +0800, Sam Sun wrote:
> > Dear developers and maintainers,
> >
> > We encountered a general protection fault in function disable_store.
> > It is tested against the latest upstream linux (tag 6.9-rc3). C repro
> > and kernel config are attached to this email. Kernel crash log is
> > listed below.
> > ```
> > general protection fault, probably for non-canonical address
> > 0xdffffc0000000000: 0000 [#1] PREEMPT SMP KASAN
> > KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007]
> > CPU: 1 PID: 9459 Comm: syz-executor414 Not tainted 6.7.0-rc7 #2
> > Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.15.0-1 04=
/01/2014
> > RIP: 0010:disable_store+0xd0/0x3d0 drivers/usb/core/port.c:88
> > Code: 02 00 00 4c 8b 75 40 4d 8d be 58 ff ff ff 4c 89 ff e8 a4 20 fa
> > ff 48 89 c2 48 89 c5 48 b8 00 00 00 00 00 fc ff df 48 c1 ea 03 <80> 3c
> > 02 00 0f 85 b0 02 00 00 48 8b 45 00 48 8d bb 34 05 00 00 48
> > RSP: 0018:ffffc90006e3fc08 EFLAGS: 00010246
> > RAX: dffffc0000000000 RBX: ffff88801d4d4008 RCX: ffffffff86706be8
> > RDX: 0000000000000000 RSI: ffffffff86706c4d RDI: 0000000000000005
> > RBP: 0000000000000000 R08: 0000000000000005 R09: 0000000000000000
> > R10: 0000000000000000 R11: 0000000000000000 R12: 1ffff92000dc7f85
> > R13: ffff88810f4bfb18 R14: ffff88801d4d10a8 R15: ffff88801d4d1000
> > FS:  00007fa0af71b640(0000) GS:ffff888135c00000(0000) knlGS:00000000000=
00000
> > CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> > CR2: 00007fa0af71a4b8 CR3: 0000000022f5f000 CR4: 0000000000750ef0
> > DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
> > DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
> > PKRU: 55555554
> > Call Trace:
> >  <TASK>
> >  dev_attr_store+0x54/0x80 drivers/base/core.c:2366
> >  sysfs_kf_write+0x114/0x170 fs/sysfs/file.c:136
> >  kernfs_fop_write_iter+0x337/0x500 fs/kernfs/file.c:334
> >  call_write_iter include/linux/fs.h:2020 [inline]
> >  new_sync_write fs/read_write.c:491 [inline]
> >  vfs_write+0x96a/0xd80 fs/read_write.c:584
> >  ksys_write+0x122/0x250 fs/read_write.c:637
> >  do_syscall_x64 arch/x86/entry/common.c:52 [inline]
> >  do_syscall_64+0x40/0x110 arch/x86/entry/common.c:83
> >  entry_SYSCALL_64_after_hwframe+0x63/0x6b
> > RIP: 0033:0x7fa0aff9ee1f
> > Code: 89 54 24 18 48 89 74 24 10 89 7c 24 08 e8 a9 f4 02 00 48 8b 54
> > 24 18 48 8b 74 24 10 41 89 c0 8b 7c 24 08 b8 01 00 00 00 0f 05 <48> 3d
> > 00 f0 ff ff 77 31 44 89 c7 48 89 44 24 08 e8 ec f4 02 00 48
> > RSP: 002b:00007fa0af71a460 EFLAGS: 00000293 ORIG_RAX: 0000000000000001
> > RAX: ffffffffffffffda RBX: 00000000ffffffff RCX: 00007fa0aff9ee1f
> > RDX: 0000000000000004 RSI: 00007fa0af71acc0 RDI: 0000000000000005
> > RBP: 0000000000000005 R08: 0000000000000000 R09: 00007fffdb6af2cf
> > R10: 0000000000000000 R11: 0000000000000293 R12: 00007fa0af71acc0
> > R13: 000000000000006e R14: 00007fa0aff613d0 R15: 00007fa0af6fb000
> >  </TASK>
> > Modules linked in:
> > ---[ end trace 0000000000000000 ]---
> > RIP: 0010:disable_store+0xd0/0x3d0 drivers/usb/core/port.c:88
> > Code: 02 00 00 4c 8b 75 40 4d 8d be 58 ff ff ff 4c 89 ff e8 a4 20 fa
> > ff 48 89 c2 48 89 c5 48 b8 00 00 00 00 00 fc ff df 48 c1 ea 03 <80> 3c
> > 02 00 0f 85 b0 02 00 00 48 8b 45 00 48 8d bb 34 05 00 00 48
> > RSP: 0018:ffffc90006e3fc08 EFLAGS: 00010246
> > RAX: dffffc0000000000 RBX: ffff88801d4d4008 RCX: ffffffff86706be8
> > RDX: 0000000000000000 RSI: ffffffff86706c4d RDI: 0000000000000005
> > RBP: 0000000000000000 R08: 0000000000000005 R09: 0000000000000000
> > R10: 0000000000000000 R11: 0000000000000000 R12: 1ffff92000dc7f85
> > R13: ffff88810f4bfb18 R14: ffff88801d4d10a8 R15: ffff88801d4d1000
> > FS:  00007fa0af71b640(0000) GS:ffff888063a00000(0000) knlGS:00000000000=
00000
> > CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> > CR2: 000055d23050c460 CR3: 0000000022f5f000 CR4: 0000000000750ef0
> > DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
> > DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
> > PKRU: 55555554
> > ----------------
> > Code disassembly (best guess):
> >    0:    02 00                    add    (%rax),%al
> >    2:    00 4c 8b 75              add    %cl,0x75(%rbx,%rcx,4)
> >    6:    40                       rex
> >    7:    4d 8d be 58 ff ff ff     lea    -0xa8(%r14),%r15
> >    e:    4c 89 ff                 mov    %r15,%rdi
> >   11:    e8 a4 20 fa ff           call   0xfffa20ba
> >   16:    48 89 c2                 mov    %rax,%rdx
> >   19:    48 89 c5                 mov    %rax,%rbp
> >   1c:    48 b8 00 00 00 00 00     movabs $0xdffffc0000000000,%rax
> >   23:    fc ff df
> >   26:    48 c1 ea 03              shr    $0x3,%rdx
> > * 2a:    80 3c 02 00              cmpb   $0x0,(%rdx,%rax,1) <--
> > trapping instruction
> >   2e:    0f 85 b0 02 00 00        jne    0x2e4
> >   34:    48 8b 45 00              mov    0x0(%rbp),%rax
> >   38:    48 8d bb 34 05 00 00     lea    0x534(%rbx),%rdi
> >   3f:    48                       rex.W
> > ```
> > We analyzed the root cause of this bug. When calling disable_store()
> > in drivers/usb/core/port.c, if function authorized_store() is calling
> > usb_deauthorized_device() concurrently, the usb_interface will be
> > removed by usb_disable_device. However, in function disable_store,
> > usb_hub_to_struct_hub() would try to deref interface, causing
> > nullptr-deref. We also tested other functions in
> > drivers/usb/core/port.c. So far we haven't found a similar problem.
> >
> > If you have any questions, please contact us.
> >
> > Reported by Yue Sun <samsun1006219@gmail.com>
> > Reported by xingwei lee <xrivendell7@gmail.com>
>
> Do you have a proposed patch to fix this as you have a way to easily
> test this?
>
> thanks,
>
> greg k-h

I am glad to help, but I am afraid I don't have a proposed patch
currently. This bug is a bit tricky, since the child device (usb port)
is trying to get its parent device (usb interface) while its
grandparent device (usb device) is trying to delete it (usb
interface). I need to further look into the locks to see which lock
should I grab to avoid deadlock or introducing other problems. I will
try my best but there is no guarantee. Hope someone who knows usb
subsystem better could fix this.

Best Regards,
Yue