CVE-2024-47688

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

driver core: Fix a potential null-ptr-deref in module_add_driver()

Inject fault while probing of-fpga-region, if kasprintf() fails in module_add_driver(), the second sysfs_remove_link() in exit path will cause null-ptr-deref as below because kernfs_name_hash() will call strlen() with NULL driver_name.

Fix it by releasing resources based on the exit path sequence.

 KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007]
 Mem abort info:
   ESR = 0x0000000096000005
   EC = 0x25: DABT (current EL), IL = 32 bits
   SET = 0, FnV = 0
   EA = 0, S1PTW = 0
   FSC = 0x05: level 1 translation fault
 Data abort info:
   ISV = 0, ISS = 0x00000005, ISS2 = 0x00000000
   CM = 0, WnR = 0, TnD = 0, TagAccess = 0
   GCS = 0, Overlay = 0, DirtyBit = 0, Xs = 0
 [dfffffc000000000] address between user and kernel address ranges
 Internal error: Oops: 0000000096000005 [#1] PREEMPT SMP
 Dumping ftrace buffer:
    (ftrace buffer empty)
 Modules linked in: of_fpga_region(+) fpga_region fpga_bridge cfg80211 rfkill 8021q garp mrp stp llc ipv6 [last unloaded: of_fpga_region]
 CPU: 2 UID: 0 PID: 2036 Comm: modprobe Not tainted 6.11.0-rc2-g6a0e38264012 #295
 Hardware name: linux,dummy-virt (DT)
 pstate: 60000005 (nZCv daif -PAN -UAO -TCO -DIT -SSBS BTYPE=--)
 pc : strlen+0x24/0xb0
 lr : kernfs_name_hash+0x1c/0xc4
 sp : ffffffc081f97380
 x29: ffffffc081f97380 x28: ffffffc081f97b90 x27: ffffff80c821c2a0
 x26: ffffffedac0be418 x25: 0000000000000000 x24: ffffff80c09d2000
 x23: 0000000000000000 x22: 0000000000000000 x21: 0000000000000000
 x20: 0000000000000000 x19: 0000000000000000 x18: 0000000000001840
 x17: 0000000000000000 x16: 0000000000000000 x15: 1ffffff8103f2e42
 x14: 00000000f1f1f1f1 x13: 0000000000000004 x12: ffffffb01812d61d
 x11: 1ffffff01812d61c x10: ffffffb01812d61c x9 : dfffffc000000000
 x8 : 0000004fe7ed29e4 x7 : ffffff80c096b0e7 x6 : 0000000000000001
 x5 :...