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From:   Aleksandr Nogikh <nogikh@google.com>
Date:   Fri, 14 Jul 2023 11:47:37 +0200
Message-ID: <CANp29Y6P06Hd0x+oovcL480pHmFnkxqDN9AaEnjbdwGrbqzDzg@mail.gmail.com>
Subject: Re: [syzbot] [usb?] memory leak in raw_open
To:     Z qiang <qiang.zhang1211@gmail.com>
Cc:     syzbot <syzbot+feb045d335c1fdde5bf7@syzkaller.appspotmail.com>,
        andreyknvl@gmail.com, gregkh@linuxfoundation.org,
        linux-kernel@vger.kernel.org, linux-usb@vger.kernel.org,
        syzkaller-bugs@googlegroups.com
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Hi,

On Fri, Jul 14, 2023 at 9:12=E2=80=AFAM Z qiang <qiang.zhang1211@gmail.com>=
 wrote:
>
> >
> > Hello,
> >
> > syzbot found the following issue on:
> >
> > HEAD commit:    1c7873e33645 mm: lock newly mapped VMA with corrected o=
rde..
> > git tree:       upstream
> > console output: https://syzkaller.appspot.com/x/log.txt?x=3D1517663ca80=
000
> > kernel config:  https://syzkaller.appspot.com/x/.config?x=3D832b404e095=
b70c0
> > dashboard link: https://syzkaller.appspot.com/bug?extid=3Dfeb045d335c1f=
dde5bf7
> > compiler:       gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binu=
tils for Debian) 2.35.2
> > syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=3D1776519ca=
80000
> > C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=3D117f9778a80=
000
> >
> > Downloadable assets:
> > disk image: https://storage.googleapis.com/syzbot-assets/43b42bd2cf70/d=
isk-1c7873e3.raw.xz
> > vmlinux: https://storage.googleapis.com/syzbot-assets/011ba1b9e8c1/vmli=
nux-1c7873e3.xz
> > kernel image: https://storage.googleapis.com/syzbot-assets/18b349342595=
/bzImage-1c7873e3.xz
> >
> > IMPORTANT: if you fix the issue, please add the following tag to the co=
mmit:
> > Reported-by: syzbot+feb045d335c1fdde5bf7@syzkaller.appspotmail.com
> >
> > BUG: memory leak
> > unreferenced object 0xffff88810b172000 (size 4096):
> >   comm "syz-executor103", pid 5067, jiffies 4294964128 (age 13.070s)
> >   hex dump (first 32 bytes):
> >     01 00 00 00 00 00 00 00 00 bc 96 0e 81 88 ff ff  ................
> >     5d b6 9e 85 ff ff ff ff 03 00 00 00 00 00 00 00  ]...............
> >   backtrace:
> >     [<ffffffff8154bf94>] kmalloc_trace+0x24/0x90 mm/slab_common.c:1076
> >     [<ffffffff8347eb55>] kmalloc include/linux/slab.h:582 [inline]
> >     [<ffffffff8347eb55>] kzalloc include/linux/slab.h:703 [inline]
> >     [<ffffffff8347eb55>] dev_new drivers/usb/gadget/legacy/raw_gadget.c=
:191 [inline]
> >     [<ffffffff8347eb55>] raw_open+0x45/0x110 drivers/usb/gadget/legacy/=
raw_gadget.c:385
> >     [<ffffffff827d1d09>] misc_open+0x1a9/0x1f0 drivers/char/misc.c:165
> >     [<ffffffff8166763b>] chrdev_open+0x11b/0x340 fs/char_dev.c:414
> >     [<ffffffff8165573f>] do_dentry_open+0x30f/0x990 fs/open.c:914
> >     [<ffffffff8167cabb>] do_open fs/namei.c:3636 [inline]
> >     [<ffffffff8167cabb>] path_openat+0x178b/0x1b20 fs/namei.c:3793
> >     [<ffffffff8167e995>] do_filp_open+0xc5/0x1b0 fs/namei.c:3820
> >     [<ffffffff81659453>] do_sys_openat2+0xe3/0x140 fs/open.c:1407
> >     [<ffffffff81659de3>] do_sys_open fs/open.c:1422 [inline]
> >     [<ffffffff81659de3>] __do_sys_openat fs/open.c:1438 [inline]
> >     [<ffffffff81659de3>] __se_sys_openat fs/open.c:1433 [inline]
> >     [<ffffffff81659de3>] __x64_sys_openat+0x83/0xe0 fs/open.c:1433
> >     [<ffffffff84a77ff9>] do_syscall_x64 arch/x86/entry/common.c:50 [inl=
ine]
> >     [<ffffffff84a77ff9>] do_syscall_64+0x39/0xb0 arch/x86/entry/common.=
c:80
> >     [<ffffffff84c0008b>] entry_SYSCALL_64_after_hwframe+0x63/0xcd
> >
> > BUG: memory leak
> > unreferenced object 0xffff88810ad20d60 (size 32):
> >   comm "syz-executor103", pid 5067, jiffies 4294964128 (age 13.070s)
> >   hex dump (first 32 bytes):
> >     72 61 77 2d 67 61 64 67 65 74 2e 30 00 00 00 00  raw-gadget.0....
> >     00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
> >   backtrace:
> >     [<ffffffff8154bf94>] kmalloc_trace+0x24/0x90 mm/slab_common.c:1076
> >     [<ffffffff8347cd2f>] kmalloc include/linux/slab.h:582 [inline]
> >     [<ffffffff8347cd2f>] raw_ioctl_init+0xdf/0x410 drivers/usb/gadget/l=
egacy/raw_gadget.c:460
> >     [<ffffffff8347dfe9>] raw_ioctl+0x5f9/0x1120 drivers/usb/gadget/lega=
cy/raw_gadget.c:1250
> >     [<ffffffff81685173>] vfs_ioctl fs/ioctl.c:51 [inline]
> >     [<ffffffff81685173>] __do_sys_ioctl fs/ioctl.c:870 [inline]
> >     [<ffffffff81685173>] __se_sys_ioctl fs/ioctl.c:856 [inline]
> >     [<ffffffff81685173>] __x64_sys_ioctl+0x103/0x140 fs/ioctl.c:856
> >     [<ffffffff84a77ff9>] do_syscall_x64 arch/x86/entry/common.c:50 [inl=
ine]
> >     [<ffffffff84a77ff9>] do_syscall_64+0x39/0xb0 arch/x86/entry/common.=
c:80
> >     [<ffffffff84c0008b>] entry_SYSCALL_64_after_hwframe+0x63/0xcd
> >
> > BUG: memory leak
> > unreferenced object 0xffff88810e96bc00 (size 128):
> >   comm "syz-executor103", pid 5067, jiffies 4294964128 (age 13.070s)
> >   hex dump (first 32 bytes):
> >     64 75 6d 6d 79 5f 75 64 63 00 00 00 00 00 00 00  dummy_udc.......
> >     00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
> >   backtrace:
> >     [<ffffffff8154bf94>] kmalloc_trace+0x24/0x90 mm/slab_common.c:1076
> >     [<ffffffff8347cd6d>] kmalloc include/linux/slab.h:582 [inline]
> >     [<ffffffff8347cd6d>] raw_ioctl_init+0x11d/0x410 drivers/usb/gadget/=
legacy/raw_gadget.c:468
> >     [<ffffffff8347dfe9>] raw_ioctl+0x5f9/0x1120 drivers/usb/gadget/lega=
cy/raw_gadget.c:1250
> >     [<ffffffff81685173>] vfs_ioctl fs/ioctl.c:51 [inline]
> >     [<ffffffff81685173>] __do_sys_ioctl fs/ioctl.c:870 [inline]
> >     [<ffffffff81685173>] __se_sys_ioctl fs/ioctl.c:856 [inline]
> >     [<ffffffff81685173>] __x64_sys_ioctl+0x103/0x140 fs/ioctl.c:856
> >     [<ffffffff84a77ff9>] do_syscall_x64 arch/x86/entry/common.c:50 [inl=
ine]
> >     [<ffffffff84a77ff9>] do_syscall_64+0x39/0xb0 arch/x86/entry/common.=
c:80
> >     [<ffffffff84c0008b>] entry_SYSCALL_64_after_hwframe+0x63/0xcd
> >
> > BUG: memory leak
> > unreferenced object 0xffff88810e96ba80 (size 128):
> >   comm "syz-executor103", pid 5067, jiffies 4294964128 (age 13.070s)
> >   hex dump (first 32 bytes):
> >     64 75 6d 6d 79 5f 75 64 63 2e 30 00 00 00 00 00  dummy_udc.0.....
> >     00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
> >   backtrace:
> >     [<ffffffff8154bf94>] kmalloc_trace+0x24/0x90 mm/slab_common.c:1076
> >     [<ffffffff8347cdfc>] kmalloc include/linux/slab.h:582 [inline]
> >     [<ffffffff8347cdfc>] raw_ioctl_init+0x1ac/0x410 drivers/usb/gadget/=
legacy/raw_gadget.c:479
> >     [<ffffffff8347dfe9>] raw_ioctl+0x5f9/0x1120 drivers/usb/gadget/lega=
cy/raw_gadget.c:1250
> >     [<ffffffff81685173>] vfs_ioctl fs/ioctl.c:51 [inline]
> >     [<ffffffff81685173>] __do_sys_ioctl fs/ioctl.c:870 [inline]
> >     [<ffffffff81685173>] __se_sys_ioctl fs/ioctl.c:856 [inline]
> >     [<ffffffff81685173>] __x64_sys_ioctl+0x103/0x140 fs/ioctl.c:856
> >     [<ffffffff84a77ff9>] do_syscall_x64 arch/x86/entry/common.c:50 [inl=
ine]
> >     [<ffffffff84a77ff9>] do_syscall_64+0x39/0xb0 arch/x86/entry/common.=
c:80
> >     [<ffffffff84c0008b>] entry_SYSCALL_64_after_hwframe+0x63/0xcd
> >
> > BUG: memory leak
> > unreferenced object 0xffff88810e96bd00 (size 128):
> >   comm "syz-executor103", pid 5067, jiffies 4294964128 (age 13.070s)
> >   hex dump (first 32 bytes):
> >     00 bd 96 0e 81 88 ff ff 00 bd 96 0e 81 88 ff ff  ................
> >     00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
> >   backtrace:
> >     [<ffffffff8154bf94>] kmalloc_trace+0x24/0x90 mm/slab_common.c:1076
> >     [<ffffffff833ecc6a>] kmalloc include/linux/slab.h:582 [inline]
> >     [<ffffffff833ecc6a>] kzalloc include/linux/slab.h:703 [inline]
> >     [<ffffffff833ecc6a>] dummy_alloc_request+0x5a/0xe0 drivers/usb/gadg=
et/udc/dummy_hcd.c:665
> >     [<ffffffff833e9132>] usb_ep_alloc_request+0x22/0xd0 drivers/usb/gad=
get/udc/core.c:196
> >     [<ffffffff8347f13d>] gadget_bind+0x6d/0x370 drivers/usb/gadget/lega=
cy/raw_gadget.c:292
> >     [<ffffffff833e9e83>] gadget_bind_driver+0xe3/0x2e0 drivers/usb/gadg=
et/udc/core.c:1591
> >     [<ffffffff82ba069d>] call_driver_probe drivers/base/dd.c:579 [inlin=
e]
> >     [<ffffffff82ba069d>] really_probe+0x12d/0x430 drivers/base/dd.c:658
> >     [<ffffffff82ba0a61>] __driver_probe_device+0xc1/0x1a0 drivers/base/=
dd.c:798
> >     [<ffffffff82ba0b6a>] driver_probe_device+0x2a/0x120 drivers/base/dd=
.c:828
> >     [<ffffffff82ba0eae>] __driver_attach drivers/base/dd.c:1214 [inline=
]
> >     [<ffffffff82ba0eae>] __driver_attach+0xfe/0x1f0 drivers/base/dd.c:1=
154
> >     [<ffffffff82b9d985>] bus_for_each_dev+0xa5/0x110 drivers/base/bus.c=
:368
> >     [<ffffffff82b9f486>] bus_add_driver+0x126/0x2a0 drivers/base/bus.c:=
673
> >     [<ffffffff82ba25da>] driver_register+0x8a/0x190 drivers/base/driver=
.c:246
> >     [<ffffffff833e7524>] usb_gadget_register_driver_owner+0x64/0x160 dr=
ivers/usb/gadget/udc/core.c:1665
> >     [<ffffffff8347e0e6>] raw_ioctl_run drivers/usb/gadget/legacy/raw_ga=
dget.c:546 [inline]
> >     [<ffffffff8347e0e6>] raw_ioctl+0x6f6/0x1120 drivers/usb/gadget/lega=
cy/raw_gadget.c:1253
> >     [<ffffffff81685173>] vfs_ioctl fs/ioctl.c:51 [inline]
> >     [<ffffffff81685173>] __do_sys_ioctl fs/ioctl.c:870 [inline]
> >     [<ffffffff81685173>] __se_sys_ioctl fs/ioctl.c:856 [inline]
> >     [<ffffffff81685173>] __x64_sys_ioctl+0x103/0x140 fs/ioctl.c:856
> >     [<ffffffff84a77ff9>] do_syscall_x64 arch/x86/entry/common.c:50 [inl=
ine]
> >     [<ffffffff84a77ff9>] do_syscall_64+0x39/0xb0 arch/x86/entry/common.=
c:80
> >
> >
>
>
> #syz test: git://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.=
git
>   master
>
>
> --- a/drivers/usb/gadget/legacy/raw_gadget.c
> +++ b/drivers/usb/gadget/legacy/raw_gadget.c
> @@ -310,12 +310,15 @@ static int gadget_bind(struct usb_gadget *gadget,
>         dev->eps_num =3D i;
>         spin_unlock_irqrestore(&dev->lock, flags);
>

syzbot expects that every line of the git diff patch begins with some
character (unchanged lines with space, added/deleted with + and -
correspondingly). Here you have an empty line and syzbot thinks it's
already the end of the patch. Therefore the patch testing fails.

> -       /* Matches kref_put() in gadget_unbind(). */
> -       kref_get(&dev->count);
> -
>         ret =3D raw_queue_event(dev, USB_RAW_EVENT_CONNECT, 0, NULL);
> -       if (ret < 0)
> +       if (ret < 0) {
>                 dev_err(&gadget->dev, "failed to queue event\n");
> +               set_gadget_data(gadget, NULL);
> +               return ret;
> +       }
> +
> +       /* Matches kref_put() in gadget_unbind(). */
> +       kref_get(&dev->count);
>
>         return ret;
>  }
>
> --
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