CVE-2024-57913: usb: gadget: f_fs: Remove WARN_ON in functionfs_bind

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

usb: gadget: ffs: Remove WARNON in functionfsbind

This commit addresses an issue related to below kernel panic where paniconwarn is enabled. It is caused by the unnecessary use of WARNON in functionsfsbind, which easily leads to the following scenarios.

1.adbwrite in adbd 2. UDC write via configfs ================= =====================

->usbffsopenthread() ->UDC write ->openfunctionfs() ->configfswriteiter() ->adbopen() ->gadgetdevdescUDCstore() ->adbwrite() ->usbgadgetregisterdriverowner ->driverregister() ->StartMonitor() ->busadddriver() ->adbread() ->gadgetbinddriver() <times-out without BIND event> ->configfscompositebind() ->usbaddfunction() ->openfunctionfs() ->ffsfuncbind() ->adbopen() ->functionfsbind() <ffs->state !=FFSACTIVE>

The adbopen, adbread, and adbwrite operations are invoked from the daemon, but trying to bind the function is a process that is invoked by UDC write through configfs, which opens up the possibility of a race condition between the two paths. In this race scenario, the kernel panic occurs due to the WARNON from functionfsbind when paniconwarn is enabled. This commit fixes the kernel panic by removing the unnecessary WARNON.

Kernel panic - not syncing: kernel: paniconwarn set ... [ 14.542395] Call trace: [ 14.542464] ffsfuncbind+0x1c8/0x14a8 [ 14.542468] usbaddfunction+0xcc/0x1f0 [ 14.542473] configfscompositebind+0x468/0x588 [ 14.542478] gadgetbinddriver+0x108/0x27c [ 14.542483] reallyprobe+0x190/0x374 [ 14.542488] driverprobedevice+0xa0/0x12c [ 14.542492] driverprobedevice+0x3c/0x220 [ 14.542498] driverattach+0x11c/0x1fc [ 14.542502] busforeachdev+0x104/0x160 [ 14.542506] driverattach+0x24/0x34 [ 14.542510] busadddriver+0x154/0x270 [ 14.542514] driverregister+0x68/0x104 [ 14.542518] usbgadgetregisterdriverowner+0x48/0xf4 [ 14.542523] gadgetdevdescUDCstore+0xf8/0x144 [ 14.542526] configfswriteiter+0xf0/0x138