CVE-2023-53060

In the Linux kernel, the following vulnerability has been resolved:

igb: revert rtnl_lock() that causes deadlock

The commit 6faee3d4ee8b ("igb: Add lock to avoid data race") adds rtnl_lock to eliminate a false data race shown below

(FREE from device detaching) | (USE from netdev core) igbremove | igbndogetvfconfig igbdisablesriov | vf >= adapter->vfsallocatedcount? kfree(adapter->vfdata) | adapter->vfsallocatedcount = 0 | | memcpy(... adapter->vf_data[vf]

The above race will never happen and the extra rtnl_lock causes deadlock below

[ 141.420169] <TASK> [ 141.420672] _schedule+0x2dd/0x840 [ 141.421427] schedule+0x50/0xc0 [ 141.422041] schedulepreemptdisabled+0x11/0x20 [ 141.422678] _mutexlock.isra.13+0x431/0x6b0 [ 141.423324] unregisternetdev+0xe/0x20 [ 141.423578] igbvfremove+0x45/0xe0 [igbvf] [ 141.423791] pcideviceremove+0x36/0xb0 [ 141.423990] devicereleasedriverinternal+0xc1/0x160 [ 141.424270] pcistopbusdevice+0x6d/0x90 [ 141.424507] pcistopandremovebusdevice+0xe/0x20 [ 141.424789] pciiovremovevirtfn+0xba/0x120 [ 141.425452] sriovdisable+0x2f/0xf0 [ 141.425679] igbdisablesriov+0x4e/0x100 [igb] [ 141.426353] igbremove+0xa0/0x130 [igb] [ 141.426599] pcideviceremove+0x36/0xb0 [ 141.426796] devicereleasedriverinternal+0xc1/0x160 [ 141.427060] driverdetach+0x44/0x90 [ 141.427253] busremovedriver+0x55/0xe0 [ 141.427477] pciunregisterdriver+0x2a/0xa0 [ 141.428296] _x64sysdeletemodule+0x141/0x2b0 [ 141.429126] ? mntputnoexpire+0x4a/0x240 [ 141.429363] ? syscalltraceenter.isra.19+0x126/0x1a0 [ 141.429653] dosyscall64+0x5b/0x80 [ 141.429847] ? exittousermodeprepare+0x14d/0x1c0 [ 141.430109] ? syscallexittousermode+0x12/0x30 [ 141.430849] ? dosyscall64+0x67/0x80 [ 141.431083] ? syscallexittousermodeprepare+0x183/0x1b0 [ 141.431770] ? syscallexittousermode+0x12/0x30 [ 141.432482] ? dosyscall64+0x67/0x80 [ 141.432714] ? excpagefault+0x64/0x140 [ 141.432911] entrySYSCALL64afterhwframe+0x72/0xdc

Since the igbdisablesriov() will call pcidisablesriov() before releasing any resources, the netdev core will synchronize the cleanup to avoid any races. This patch removes the useless rtnl_(un)lock to guarantee correctness.