ata: libata-core: Fix null pointer dereference on error

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

ata: libata-core: Fix null pointer dereference on error

If the ata_port_alloc() call in ata_host_alloc() fails,

ata_host_release() will get called.

However, the code in ata_host_release() tries to free ata_port struct

members unconditionally, which can lead to the following:

BUG: unable to handle page fault for address: 0000000000003990

PGD 0 P4D 0

Oops: Oops: 0000 [#1] PREEMPT SMP NOPTI

CPU: 10 PID: 594 Comm: (udev-worker) Not tainted 6.10.0-rc5 #44

Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.3-2.fc40 04/01/2014

RIP: 0010:ata_host_release.cold+0x2f/0x6e [libata]

Code: e4 4d 63 f4 44 89 e2 48 c7 c6 90 ad 32 c0 48 c7 c7 d0 70 33 c0 49 83 c6 0e 41

RSP: 0018:ffffc90000ebb968 EFLAGS: 00010246

RAX: 0000000000000041 RBX: ffff88810fb52e78 RCX: 0000000000000000

RDX: 0000000000000000 RSI: ffff88813b3218c0 RDI: ffff88813b3218c0

RBP: ffff88810fb52e40 R08: 0000000000000000 R09: 6c65725f74736f68

R10: ffffc90000ebb738 R11: 73692033203a746e R12: 0000000000000004

R13: 0000000000000000 R14: 0000000000000011 R15: 0000000000000006

FS: 00007f6cc55b9980(0000) GS:ffff88813b300000(0000) knlGS:0000000000000000

CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033

CR2: 0000000000003990 CR3: 00000001122a2000 CR4: 0000000000750ef0

PKRU: 55555554

Call Trace:

<TASK>

? __die_body.cold+0x19/0x27

? page_fault_oops+0x15a/0x2f0

? exc_page_fault+0x7e/0x180

? asm_exc_page_fault+0x26/0x30

? ata_host_release.cold+0x2f/0x6e [libata]

? ata_host_release.cold+0x2f/0x6e [libata]

release_nodes+0x35/0xb0

devres_release_group+0x113/0x140

ata_host_alloc+0xed/0x120 [libata]

ata_host_alloc_pinfo+0x14/0xa0 [libata]

ahci_init_one+0x6c9/0xd20 [ahci]

Do not access ata_port struct members unconditionally.