Accessing files in /sys/kernel/debug/qedf/ can trigger a crash

Issue

When application or user accesses files in /sys/kernel/debug/qedf/, the system might crash with following or similar crash.

[491203.719451] BUG: unable to handle kernel paging request at 00007ffd1d6b43a0
[491203.719695] IP: [<ffffffffaa7a882a>] string.isra.7+0x6a/0xf0
[491203.719900] PGD 9f067067 PUD 7af08067 PMD 3ee52067 PTE 8000000056411867
[491203.720191] Oops: 0003 [#1] SMP 
[491203.785233] CPU: 4 PID: 1187 Comm: aide Kdump: loaded Tainted: G        W  O   ------------ T 3.10.0-1160.90.1.el7.x86_64 #1
[491203.798654] Hardware name: HP Proliant XXX, BIOS XXX XX/XX/XXXX
[491203.812143] task: ffff8a2df3362100 ti: ffff8a26fed2c000 task.ti: ffff8a26fed2c000
[491203.825694] RIP: 0010:[<ffffffffaa7a882a>]  [<ffffffffaa7a882a>] string.isra.7+0x6a/0xf0
[491203.839385] RSP: 0018:ffff8a26fed2fda8  EFLAGS: 00010206
[491203.852988] RAX: 0000000000000005 RBX: 00007ffd1d6b43a0 RCX: 00007ffd1d6b43a5
[491203.866813] RDX: 0000000000000066 RSI: 0000000000000005 RDI: ffffffffc04268af
[491203.880398] RBP: ffff8a26fed2fdd0 R08: 000000000000ffff R09: 000000000000ffff
[491203.893857] R10: 0000000000000000 R11: 0000000000000004 R12: ffffffffc04268af
[491203.907218] R13: 00007ffd9d6b439f R14: 00000000fffffffe R15: 0000000000000000
[491203.920503] FS:  00007f0deca6f840(0000) GS:ffff8a2effb00000(0000) knlGS:0000000000000000
[491203.933953] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[491203.947114] CR2: 00007ffd1d6b43a0 CR3: 000000009e616000 CR4: 00000000007607e0
[491203.960544] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[491203.973896] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[491203.987003] PKRU: 55555554
[491204.000129] Call Trace:
[491204.012928]  [<ffffffffaa7a9f31>] vsnprintf+0x201/0x6a0
[491204.025791]  [<ffffffffaa7aa556>] sprintf+0x56/0x80
[491204.038494]  [<ffffffffc04227ed>] qedf_dbg_stop_io_on_error_cmd_read+0x6d/0x90 [qedf]
[491204.051691]  [<ffffffffaa65bb2f>] vfs_read+0x9f/0x170
[491204.064651]  [<ffffffffaa65cb82>] SyS_pread64+0x92/0xc0
[491204.077667]  [<ffffffffaabc562e>] tracesys+0xa6/0xcc