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: syzbot+48dc1e8dfc92faf1124c@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=48dc1e8dfc92faf1124c
Fixes: e58ba4544c77 ("net: usb: aqc111: Add support for wake on LAN by MAGIC packet")
Signed-off-by: Nikola Z. Ivanov <zlatistiv@gmail.com>
Link: https://patch.msgid.link/20260313141643.1181386-1-zlatistiv@gmail.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

diff --git a/drivers/net/usb/aqc111.c b/drivers/net/usb/aqc111.c
index cbffa9ae1bb6ba47de02c9a5fa4080c8b95c0a7b..dd53f413c38f6035c18f9922fd4e90d66a73ae53 100644 (file)
--- a/drivers/net/usb/aqc111.c
+++ b/drivers/net/usb/aqc111.c
@@ -1395,14 +1395,14 @@ 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,
-                                WOL_CFG_SIZE, &wol_cfg);
-               aqc111_write32_cmd(dev, AQ_PHY_OPS, 0, 0,
-                                  &aqc111_data->phy_cfg);
+               aqc111_write_cmd_nopm(dev, AQ_WOL_CFG, 0, 0,
+                                     WOL_CFG_SIZE, &wol_cfg);
+               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_data->phy_cfg);
+               aqc111_write32_cmd_nopm(dev, AQ_PHY_OPS, 0, 0,
+                                       &aqc111_data->phy_cfg);
 
                /* Disable RX path */
                aqc111_read16_cmd_nopm(dev, AQ_ACCESS_MAC,