Commit 069c8f5a authored by Nikola Z. Ivanov's avatar Nikola Z. Ivanov Committed by Paolo Abeni
Browse files

net: usb: aqc111: Do not perform PM inside suspend callback 



syzbot reports "task hung in rpm_resume"

This is caused by aqc111_suspend calling
the PM variant of its write_cmd routine.

The simplified call trace looks like this:

rpm_suspend()
  usb_suspend_both() - here udev->dev.power.runtime_status == RPM_SUSPENDING
    aqc111_suspend() - called for the usb device interface
      aqc111_write32_cmd()
        usb_autopm_get_interface()
          pm_runtime_resume_and_get()
            rpm_resume() - here we call rpm_resume() on our parent
              rpm_resume() - Here we wait for a status change that will never happen.

At this point we block another task which holds
rtnl_lock and locks up the whole networking stack.

Fix this by replacing the write_cmd calls with their _nopm variants

Reported-by: default avatar <syzbot+48dc1e8dfc92faf1124c@syzkaller.appspotmail.com>
Closes: https://syzkaller.appspot.com/bug?extid=48dc1e8dfc92faf1124c


Fixes: e58ba454 ("net: usb: aqc111: Add support for wake on LAN by MAGIC packet")
Signed-off-by: default avatarNikola Z. Ivanov <zlatistiv@gmail.com>
Link: https://patch.msgid.link/20260313141643.1181386-1-zlatistiv@gmail.com


Signed-off-by: default avatarPaolo Abeni <pabeni@redhat.com>
parent a0671125

drivers/net/usb/aqc111.c

+6 −6
Original line number Diff line number Diff line
@@ -1395,13 +1395,13 @@ static int aqc111_suspend(struct usb_interface *intf, pm_message_t message) 
		aqc111_write16_cmd_nopm(dev, AQ_ACCESS_MAC,

					SFR_MEDIUM_STATUS_MODE, 2, &reg16);



		aqc111_write_cmd(dev, AQ_WOL_CFG, 0, 0,

		aqc111_write_cmd_nopm(dev, AQ_WOL_CFG, 0, 0,

				      WOL_CFG_SIZE, &wol_cfg);

		aqc111_write32_cmd(dev, AQ_PHY_OPS, 0, 0,

		aqc111_write32_cmd_nopm(dev, AQ_PHY_OPS, 0, 0,

					&aqc111_data->phy_cfg);

	} else {

		aqc111_data->phy_cfg |= AQ_LOW_POWER;

		aqc111_write32_cmd(dev, AQ_PHY_OPS, 0, 0,

		aqc111_write32_cmd_nopm(dev, AQ_PHY_OPS, 0, 0,

					&aqc111_data->phy_cfg);



		/* Disable RX path */