Affected: Linux

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

iwlwifi: mvm: check debugfs_dir ptr before use

When "debugfs=off" is used on the kernel command line, iwiwifi's mvm module uses an invalid/unchecked debugfs_dir pointer and causes a BUG:

BUG: kernel NULL pointer dereference, address: 000000000000004f #PF: supervisor read access in kernel mode #PF: error_code(0x0000) - not-present page PGD 0 P4D 0 Oops: 0000 [#1] PREEMPT SMP CPU: 1 PID: 503 Comm: modprobe Tainted: G W 5.17.0-rc5 #7 Hardware name: Dell Inc. Inspiron 15 5510/076F7Y, BIOS 2.4.1 11/05/2021 RIP: 0010:iwl_mvm_dbgfs_register+0x692/0x700 [iwlmvm] Code: 69 a0 be 80 01 00 00 48 c7 c7 50 73 6a a0 e8 95 cf ee e0 48 8b 83 b0 1e 00 00 48 c7 c2 54 73 6a a0 be 64 00 00 00 48 8d 7d 8c <48> 8b 48 50 e8 15 22 07 e1 48 8b 43 28 48 8d 55 8c 48 c7 c7 5f 73 RSP: 0018:ffffc90000a0ba68 EFLAGS: 00010246 RAX: ffffffffffffffff RBX: ffff88817d6e3328 RCX: ffff88817d6e3328 RDX: ffffffffa06a7354 RSI: 0000000000000064 RDI: ffffc90000a0ba6c RBP: ffffc90000a0bae0 R08: ffffffff824e4880 R09: ffffffffa069d620 R10: ffffc90000a0ba00 R11: ffffffffffffffff R12: 0000000000000000 R13: ffffc90000a0bb28 R14: ffff88817d6e3328 R15: ffff88817d6e3320 FS: 00007f64dd92d740(0000) GS:ffff88847f640000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000000000000004f CR3: 000000016fc79001 CR4: 0000000000770ee0 PKRU: 55555554 Call Trace: <TASK> ? iwl_mvm_mac_setup_registe…