[syzbot] KMSAN: uninit-value in asix_check_host_enable

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 724946410067 x86: kmsan: enable KMSAN builds for x86
git tree: https://github.com/google/kmsan.git master
console output: https://syzkaller.appspot.com/x/log.txt?x=11c85246700000
kernel config: https://syzkaller.appspot.com/x/.config?x=76f99026248b24e4
dashboard link: https://syzkaller.appspot.com/bug?extid=8f5f07bb9d6935e2f8d9
compiler: clang version 14.0.0 (/usr/local/google/src/llvm-git-monorepo 2b554920f11c8b763cd9ed9003f4e19b919b8e1f), GNU ld (GNU Binutils for Debian) 2.35.2
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=11674fe2700000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=1497324c700000

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+8f5f07...@syzkaller.appspotmail.com

asix 1-1:0.0 (unnamed net_device) (uninitialized): Failed to write reg index 0x0000: -71
asix 1-1:0.0 (unnamed net_device) (uninitialized): Failed to enable software MII access
asix 1-1:0.0 (unnamed net_device) (uninitialized): Failed to read reg index 0x0000: -71
=====================================================
BUG: KMSAN: uninit-value in asix_check_host_enable+0x289/0x330 drivers/net/usb/asix_common.c:84
asix_check_host_enable+0x289/0x330 drivers/net/usb/asix_common.c:84
__asix_mdio_write+0x10d/0x5c0 drivers/net/usb/asix_common.c:532
asix_mdio_write+0xad/0xc0 drivers/net/usb/asix_common.c:550
asix_phy_reset+0xd5/0x2e0 drivers/net/usb/asix_devices.c:208
ax88172_bind+0x738/0x9d0 drivers/net/usb/asix_devices.c:275
usbnet_probe+0x1251/0x4160 drivers/net/usb/usbnet.c:1747
usb_probe_interface+0xf19/0x1600 drivers/usb/core/driver.c:396
really_probe+0x653/0x14b0 drivers/base/dd.c:596
__driver_probe_device+0x3e9/0x530 drivers/base/dd.c:752
driver_probe_device drivers/base/dd.c:782 [inline]
__device_attach_driver+0x79f/0x1120 drivers/base/dd.c:899
bus_for_each_drv+0x2d6/0x3f0 drivers/base/bus.c:427
__device_attach+0x593/0x8e0 drivers/base/dd.c:970
device_initial_probe+0x4a/0x60 drivers/base/dd.c:1017
bus_probe_device+0x17b/0x3e0 drivers/base/bus.c:487
device_add+0x1fff/0x26e0 drivers/base/core.c:3405
usb_set_configuration+0x37e9/0x3ed0 drivers/usb/core/message.c:2170
usb_generic_driver_probe+0x13c/0x300 drivers/usb/core/generic.c:238
usb_probe_device+0x309/0x570 drivers/usb/core/driver.c:293
really_probe+0x653/0x14b0 drivers/base/dd.c:596
__driver_probe_device+0x3e9/0x530 drivers/base/dd.c:752
driver_probe_device drivers/base/dd.c:782 [inline]
__device_attach_driver+0x79f/0x1120 drivers/base/dd.c:899
bus_for_each_drv+0x2d6/0x3f0 drivers/base/bus.c:427
__device_attach+0x593/0x8e0 drivers/base/dd.c:970
device_initial_probe+0x4a/0x60 drivers/base/dd.c:1017
bus_probe_device+0x17b/0x3e0 drivers/base/bus.c:487
device_add+0x1fff/0x26e0 drivers/base/core.c:3405
usb_new_device+0x1b8e/0x2950 drivers/usb/core/hub.c:2566
hub_port_connect drivers/usb/core/hub.c:5358 [inline]
hub_port_connect_change drivers/usb/core/hub.c:5502 [inline]
port_event drivers/usb/core/hub.c:5660 [inline]
hub_event+0x58e3/0x89e0 drivers/usb/core/hub.c:5742
process_one_work+0xdb6/0x1820 kernel/workqueue.c:2307
worker_thread+0x10b3/0x21e0 kernel/workqueue.c:2454
kthread+0x3c7/0x500 kernel/kthread.c:377
ret_from_fork+0x1f/0x30

Local variable smsr created at:
asix_check_host_enable+0x66/0x330
__asix_mdio_write+0x10d/0x5c0 drivers/net/usb/asix_common.c:532

CPU: 1 PID: 34 Comm: kworker/1:1 Not tainted 5.17.0-rc4-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: usb_hub_wq hub_event
=====================================================


---
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[Pavel Skripkin]

On 2/23/22 12:30, syzbot wrote:
> Hello,
>
> syzbot found the following issue on:
>
> HEAD commit: 724946410067 x86: kmsan: enable KMSAN builds for x86
> git tree: https://github.com/google/kmsan.git master
> console output: https://syzkaller.appspot.com/x/log.txt?x=11c85246700000
> kernel config: https://syzkaller.appspot.com/x/.config?x=76f99026248b24e4
> dashboard link: https://syzkaller.appspot.com/bug?extid=8f5f07bb9d6935e2f8d9
> compiler: clang version 14.0.0 (/usr/local/google/src/llvm-git-monorepo 2b554920f11c8b763cd9ed9003f4e19b919b8e1f), GNU ld (GNU Binutils for Debian) 2.35.2
> syz repro: https://syzkaller.appspot.com/x/repro.syz?x=11674fe2700000
> C reproducer: https://syzkaller.appspot.com/x/repro.c?x=1497324c700000
>
> IMPORTANT: if you fix the issue, please add the following tag to the commit:
> Reported-by: syzbot+8f5f07...@syzkaller.appspotmail.com
>

Should be fixed by [1], but it's only in next for now.

[1]
https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/commit/?id=920a9fa27e7805499cfe78491b36fed2322c02ec




With regards,
Pavel Skripkin

[syzbot]

Hello,

syzbot has tested the proposed patch and the reproducer did not trigger any issue:

Reported-and-tested-by: syzbot+8f5f07...@syzkaller.appspotmail.com

Tested on:

commit: 72494641 x86: kmsan: enable KMSAN builds for x86

git tree: https://github.com/google/kmsan.git master

kernel config: https://syzkaller.appspot.com/x/.config?x=76f99026248b24e4
dashboard link: https://syzkaller.appspot.com/bug?extid=8f5f07bb9d6935e2f8d9
compiler: clang version 14.0.0 (/usr/local/google/src/llvm-git-monorepo 2b554920f11c8b763cd9ed9003f4e19b919b8e1f), GNU ld (GNU Binutils for Debian) 2.35.2

patch: https://syzkaller.appspot.com/x/patch.diff?x=15ee0569700000

Note: testing is done by a robot and is best-effort only.

[Dmitry Vyukov]

Let's tell syzbot so that it reports new bugs in future:
#syz fix: net: asix: add proper error handling of usb read errors