KMSAN: uninit-value in mii_nway_restart

KMSAN: uninit-value in mii_nway_restart

[syzbot]

Hello,

syzbot found the following crash on:

HEAD commit:    f75e4cfe kmsan: use kmsan_handle_urb() in urb.c
git tree:       kmsan
console output: https://syzkaller.appspot.com/x/log.txt?x=1180360ea00000
kernel config:  https://syzkaller.appspot.com/x/.config?x=602468164ccdc30a
dashboard link: https://syzkaller.appspot.com/bug?extid=1f53a30781af65d2c955
compiler:       clang version 9.0.0 (/home/glider/llvm/clang  
06d00afa61eef8f7f501ebdb4e8612ea43ec2d78)
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=16a2b4f2a00000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=107f4e86a00000

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+1f53a30781af65d2c955@syzkaller.appspotmail.com

ax88179_178a 1-1:0.186 (unnamed net_device) (uninitialized): Failed to  
write reg index 0x000d: -71
ax88179_178a 1-1:0.186 (unnamed net_device) (uninitialized): Failed to  
write reg index 0x000e: -71
ax88179_178a 1-1:0.186 (unnamed net_device) (uninitialized): Failed to  
write reg index 0x000d: -71
ax88179_178a 1-1:0.186 (unnamed net_device) (uninitialized): Failed to  
write reg index 0x000e: -71
ax88179_178a 1-1:0.186 (unnamed net_device) (uninitialized): Failed to read  
reg index 0x0000: -71
==================================================================
BUG: KMSAN: uninit-value in mii_nway_restart+0x141/0x260  
drivers/net/mii.c:467
CPU: 1 PID: 3353 Comm: kworker/1:2 Not tainted 5.1.0+ #1
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS  
Google 01/01/2011
Workqueue: usb_hub_wq hub_event
Call Trace:
  __dump_stack lib/dump_stack.c:77 [inline]
  dump_stack+0x191/0x1f0 lib/dump_stack.c:113
  kmsan_report+0x130/0x2a0 mm/kmsan/kmsan.c:622
  __msan_warning+0x75/0xe0 mm/kmsan/kmsan_instr.c:310
  mii_nway_restart+0x141/0x260 drivers/net/mii.c:467
  ax88179_bind+0xee3/0x1a10 drivers/net/usb/ax88179_178a.c:1329
  usbnet_probe+0x10f5/0x3940 drivers/net/usb/usbnet.c:1728
  usb_probe_interface+0xd66/0x1320 drivers/usb/core/driver.c:361
  really_probe+0xdae/0x1d80 drivers/base/dd.c:513
  driver_probe_device+0x1b3/0x4f0 drivers/base/dd.c:671
  __device_attach_driver+0x5b8/0x790 drivers/base/dd.c:778
  bus_for_each_drv+0x28e/0x3b0 drivers/base/bus.c:454
  __device_attach+0x454/0x730 drivers/base/dd.c:844
  device_initial_probe+0x4a/0x60 drivers/base/dd.c:891
  bus_probe_device+0x137/0x390 drivers/base/bus.c:514
  device_add+0x288d/0x30e0 drivers/base/core.c:2106
  usb_set_configuration+0x30dc/0x3750 drivers/usb/core/message.c:2027
  generic_probe+0xe7/0x280 drivers/usb/core/generic.c:210
  usb_probe_device+0x14c/0x200 drivers/usb/core/driver.c:266
  really_probe+0xdae/0x1d80 drivers/base/dd.c:513
  driver_probe_device+0x1b3/0x4f0 drivers/base/dd.c:671
  __device_attach_driver+0x5b8/0x790 drivers/base/dd.c:778
  bus_for_each_drv+0x28e/0x3b0 drivers/base/bus.c:454
  __device_attach+0x454/0x730 drivers/base/dd.c:844
  device_initial_probe+0x4a/0x60 drivers/base/dd.c:891
  bus_probe_device+0x137/0x390 drivers/base/bus.c:514
  device_add+0x288d/0x30e0 drivers/base/core.c:2106
  usb_new_device+0x23e5/0x2ff0 drivers/usb/core/hub.c:2534
  hub_port_connect drivers/usb/core/hub.c:5089 [inline]
  hub_port_connect_change drivers/usb/core/hub.c:5204 [inline]
  port_event drivers/usb/core/hub.c:5350 [inline]
  hub_event+0x48d1/0x7290 drivers/usb/core/hub.c:5432
  process_one_work+0x1572/0x1f00 kernel/workqueue.c:2269
  worker_thread+0x111b/0x2460 kernel/workqueue.c:2415
  kthread+0x4b5/0x4f0 kernel/kthread.c:254
  ret_from_fork+0x35/0x40 arch/x86/entry/entry_64.S:355

Local variable description: ----buf.i@ax88179_mdio_read
Variable was created at:
  __ax88179_read_cmd drivers/net/usb/ax88179_178a.c:199 [inline]
  ax88179_read_cmd drivers/net/usb/ax88179_178a.c:311 [inline]
  ax88179_mdio_read+0x7b/0x240 drivers/net/usb/ax88179_178a.c:369
  mii_nway_restart+0xcf/0x260 drivers/net/mii.c:465
==================================================================


---
This bug is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
syzbot engineers can be reached at syzkaller@googlegroups.com.

syzbot will keep track of this bug report. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.
syzbot can test patches for this bug, for details see:
https://goo.gl/tpsmEJ#testing-patches

Re: KMSAN: uninit-value in mii_nway_restart

[Alexander Potapenko]

(adding the original recipients back)

On Fri, Aug 26, 2022 at 10:44 AM Alexander Potapenko <glider@google.com> wrote:
>
>
>
> On Tuesday, June 4, 2019 at 12:32:05 PM UTC+2 syzbot wrote:
>>
>> Hello,
>>
>> syzbot found the following crash on:
>>
>> HEAD commit: f75e4cfe kmsan: use kmsan_handle_urb() in urb.c
>> git tree: kmsan
>> console output: https://syzkaller.appspot.com/x/log.txt?x=1180360ea00000
>> kernel config: https://syzkaller.appspot.com/x/.config?x=602468164ccdc30a
>> dashboard link: https://syzkaller.appspot.com/bug?extid=1f53a30781af65d2c955
>> compiler: clang version 9.0.0 (/home/glider/llvm/clang
>> 06d00afa61eef8f7f501ebdb4e8612ea43ec2d78)
>> syz repro: https://syzkaller.appspot.com/x/repro.syz?x=16a2b4f2a00000
>> C reproducer: https://syzkaller.appspot.com/x/repro.c?x=107f4e86a00000
>>
>> IMPORTANT: if you fix the bug, please add the following tag to the commit:
>> Reported-by: syzbot+1f53a3...@syzkaller.appspotmail.com
>>
>> ax88179_178a 1-1:0.186 (unnamed net_device) (uninitialized): Failed to
>> write reg index 0x000d: -71
>> ax88179_178a 1-1:0.186 (unnamed net_device) (uninitialized): Failed to
>> write reg index 0x000e: -71
>> ax88179_178a 1-1:0.186 (unnamed net_device) (uninitialized): Failed to
>> write reg index 0x000d: -71
>> ax88179_178a 1-1:0.186 (unnamed net_device) (uninitialized): Failed to
>> write reg index 0x000e: -71
>> ax88179_178a 1-1:0.186 (unnamed net_device) (uninitialized): Failed to read
>> reg index 0x0000: -71
>> ==================================================================
>> BUG: KMSAN: uninit-value in mii_nway_restart+0x141/0x260
>> drivers/net/mii.c:467
>> CPU: 1 PID: 3353 Comm: kworker/1:2 Not tainted 5.1.0+ #1
>> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
>> Google 01/01/2011
>> Workqueue: usb_hub_wq hub_event
>> Call Trace:
>> __dump_stack lib/dump_stack.c:77 [inline]
>> dump_stack+0x191/0x1f0 lib/dump_stack.c:113
>> kmsan_report+0x130/0x2a0 mm/kmsan/kmsan.c:622
>> __msan_warning+0x75/0xe0 mm/kmsan/kmsan_instr.c:310
>> mii_nway_restart+0x141/0x260 drivers/net/mii.c:467
>> ax88179_bind+0xee3/0x1a10 drivers/net/usb/ax88179_178a.c:1329
>> usbnet_probe+0x10f5/0x3940 drivers/net/usb/usbnet.c:1728
>> usb_probe_interface+0xd66/0x1320 drivers/usb/core/driver.c:361
>> really_probe+0xdae/0x1d80 drivers/base/dd.c:513
>> driver_probe_device+0x1b3/0x4f0 drivers/base/dd.c:671
>> __device_attach_driver+0x5b8/0x790 drivers/base/dd.c:778
>> bus_for_each_drv+0x28e/0x3b0 drivers/base/bus.c:454
>> __device_attach+0x454/0x730 drivers/base/dd.c:844
>> device_initial_probe+0x4a/0x60 drivers/base/dd.c:891
>> bus_probe_device+0x137/0x390 drivers/base/bus.c:514
>> device_add+0x288d/0x30e0 drivers/base/core.c:2106
>> usb_set_configuration+0x30dc/0x3750 drivers/usb/core/message.c:2027
>> generic_probe+0xe7/0x280 drivers/usb/core/generic.c:210
>> usb_probe_device+0x14c/0x200 drivers/usb/core/driver.c:266
>> really_probe+0xdae/0x1d80 drivers/base/dd.c:513
>> driver_probe_device+0x1b3/0x4f0 drivers/base/dd.c:671
>> __device_attach_driver+0x5b8/0x790 drivers/base/dd.c:778
>> bus_for_each_drv+0x28e/0x3b0 drivers/base/bus.c:454
>> __device_attach+0x454/0x730 drivers/base/dd.c:844
>> device_initial_probe+0x4a/0x60 drivers/base/dd.c:891
>> bus_probe_device+0x137/0x390 drivers/base/bus.c:514
>> device_add+0x288d/0x30e0 drivers/base/core.c:2106
>> usb_new_device+0x23e5/0x2ff0 drivers/usb/core/hub.c:2534
>> hub_port_connect drivers/usb/core/hub.c:5089 [inline]
>> hub_port_connect_change drivers/usb/core/hub.c:5204 [inline]
>> port_event drivers/usb/core/hub.c:5350 [inline]
>> hub_event+0x48d1/0x7290 drivers/usb/core/hub.c:5432
>> process_one_work+0x1572/0x1f00 kernel/workqueue.c:2269
>> worker_thread+0x111b/0x2460 kernel/workqueue.c:2415
>> kthread+0x4b5/0x4f0 kernel/kthread.c:254
>> ret_from_fork+0x35/0x40 arch/x86/entry/entry_64.S:355
>>
>> Local variable description: ----buf.i@ax88179_mdio_read
>> Variable was created at:
>> __ax88179_read_cmd drivers/net/usb/ax88179_178a.c:199 [inline]
>> ax88179_read_cmd drivers/net/usb/ax88179_178a.c:311 [inline]
>> ax88179_mdio_read+0x7b/0x240 drivers/net/usb/ax88179_178a.c:369
>> mii_nway_restart+0xcf/0x260 drivers/net/mii.c:465
>> ==================================================================
>>
>
>>
>>
>> ---
>> This bug is generated by a bot. It may contain errors.
>> See https://goo.gl/tpsmEJ for more information about syzbot.
>> syzbot engineers can be reached at syzk...@googlegroups.com.
>>
>> syzbot will keep track of this bug report. See:
>> https://goo.gl/tpsmEJ#status for how to communicate with syzbot.
>> syzbot can test patches for this bug, for details see:
>> https://goo.gl/tpsmEJ#testing-patches
>
>
> This bug is still triggerable by KMSAN (https://syzkaller.appspot.com/bug?id=835562bfa4dd92c72f323f29ad388c9cb4b0e63f):
>
> =====================================================
> BUG: KMSAN: uninit-value in mii_nway_restart+0x117/0x1d0 drivers/net/mii.c:465
>  mii_nway_restart+0x117/0x1d0 drivers/net/mii.c:465
>  dm9601_bind+0xa17/0xb50 drivers/net/usb/dm9601.c:431
>  usbnet_probe+0xebb/0x3cc0 drivers/net/usb/usbnet.c:1747
>  usb_probe_interface+0xc4b/0x11f0 drivers/usb/core/driver.c:396
>  really_probe+0x499/0xf50 drivers/base/dd.c:634
>  __driver_probe_device+0x2fa/0x3d0 drivers/base/dd.c:764
>  driver_probe_device+0x72/0x7a0 drivers/base/dd.c:794
>  __device_attach_driver+0x6f1/0x890 drivers/base/dd.c:917
>  bus_for_each_drv+0x1fc/0x360 drivers/base/bus.c:427
>  __device_attach+0x42a/0x720 drivers/base/dd.c:989
>  device_initial_probe+0x2e/0x40 drivers/base/dd.c:1038
>  bus_probe_device+0x13c/0x3b0 drivers/base/bus.c:487
>  device_add+0x1d4b/0x26c0 drivers/base/core.c:3428
>  usb_set_configuration+0x30f8/0x37e0 drivers/usb/core/message.c:2170
>  usb_generic_driver_probe+0x105/0x290 drivers/usb/core/generic.c:238
>  usb_probe_device+0x288/0x490 drivers/usb/core/driver.c:293
>  really_probe+0x499/0xf50 drivers/base/dd.c:634
>  __driver_probe_device+0x2fa/0x3d0 drivers/base/dd.c:764
>  driver_probe_device+0x72/0x7a0 drivers/base/dd.c:794
>  __device_attach_driver+0x6f1/0x890 drivers/base/dd.c:917
>  bus_for_each_drv+0x1fc/0x360 drivers/base/bus.c:427
>  __device_attach+0x42a/0x720 drivers/base/dd.c:989
>  device_initial_probe+0x2e/0x40 drivers/base/dd.c:1038
>  bus_probe_device+0x13c/0x3b0 drivers/base/bus.c:487
>  device_add+0x1d4b/0x26c0 drivers/base/core.c:3428
>  usb_new_device+0x17a1/0x2360 drivers/usb/core/hub.c:2566
>  hub_port_connect drivers/usb/core/hub.c:5363 [inline]
>  hub_port_connect_change drivers/usb/core/hub.c:5507 [inline]
>  port_event drivers/usb/core/hub.c:5663 [inline]
>  hub_event+0x5559/0x8050 drivers/usb/core/hub.c:5745
>  process_one_work+0xb27/0x13e0 kernel/workqueue.c:2289
>  worker_thread+0x1076/0x1d60 kernel/workqueue.c:2436
>  kthread+0x31b/0x430 kernel/kthread.c:376
>  ret_from_fork+0x1f/0x30
>
> Local variable res created at:
>  dm9601_mdio_read+0x49/0xf0 drivers/net/usb/dm9601.c:226
>  mii_nway_restart+0x84/0x1d0 drivers/net/mii.c:463
>
> CPU: 0 PID: 28 Comm: kworker/0:1 Not tainted 5.19.0-syzkaller-32655-g1b070a5d1a2c #0
> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/22/2022
> Workqueue: usb_hub_wq hub_event
> =====================================================
>
> I believe we should either be always checking the return value of dm_read_shared_word(), or make it unconditionally initialize *value.



-- 
Alexander Potapenko
Software Engineer

Google Germany GmbH
Erika-Mann-Straße, 33
80636 München

Geschäftsführer: Paul Manicle, Liana Sebastian
Registergericht und -nummer: Hamburg, HRB 86891
Sitz der Gesellschaft: Hamburg

Re: KMSAN: uninit-value in mii_nway_restart

[syzbot]

> #syz test

This bug is already marked as fixed. No point in testing.

> diff --git a/drivers/net/usb/dm9601.c b/drivers/net/usb/dm9601.c
> index 48d7d278631e..2e2bb22e60ea 100644
> --- a/drivers/net/usb/dm9601.c
> +++ b/drivers/net/usb/dm9601.c
> @@ -10,6 +10,7 @@
>
>  //#define DEBUG
>
> +#include "net/net_debug.h"
>  #include <linux/module.h>
>  #include <linux/sched.h>
>  #include <linux/stddef.h>
> @@ -222,13 +223,18 @@ static int dm9601_mdio_read(struct net_device
> *netdev, int phy_id, int loc)
>     struct usbnet *dev = netdev_priv(netdev);
>
>     __le16 res;
> +   int err;
>
>     if (phy_id) {
>         netdev_dbg(dev->net, "Only internal phy supported\n");
>         return 0;
>     }
>
> -   dm_read_shared_word(dev, 1, loc, &res);
> +   err = dm_read_shared_word(dev, 1, loc, &res);
> +   if (err < 0) {
> +       netdev_err(dev->net, "MDIO read error: %d\n", err);
> +       return err;
> +   }
>
>     netdev_dbg(dev->net,
>            "dm9601_mdio_read() phy_id=0x%02x, loc=0x%02x, returns=0x%04x\n",

Re: KMSAN: uninit-value in mii_nway_restart

[syzbot]

> #syz test

This bug is already marked as fixed. No point in testing.

Re: KMSAN: uninit-value in mii_nway_restart

[syzbot]

> #syz test:

This bug is already marked as fixed. No point in testing.

> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/ master

Re: KMSAN: uninit-value in mii_nway_restart

[syzbot]

> #syz redo

unknown command "redo"

Re: KMSAN: uninit-value in mii_nway_restart

[syzbot]

> #syz test

This bug is already marked as fixed. No point in testing.

>
>
> -- 
>
> *Eslam Medhat Khafagy*
>
>    *https://www.linkedin.com/in/eslam-khafagy-a8a68159/
>    <https://www.linkedin.com/in/eslam-khafagy-a8a68159/>*

Re: KMSAN: uninit-value in mii_nway_restart

[syzbot]

> #syz test

This bug is already marked as fixed. No point in testing.