CVE-2022-49826

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

ata: libata-transport: fix double atahostput() in atatportadd()

In the error path in atatportadd(), when calling putdevice(), atatport_release() is called, it will put the refcount of 'ap->host'.

And then atahostput() is called again, the refcount is decreased to 0, atahostrelease() is called, all ports are freed and set to null.

When unbinding the device after failure, atahoststop() is called to release the resources, it leads a null-ptr-deref(), because all the ports all freed and null.

Unable to handle kernel NULL pointer dereference at virtual address 0000000000000008 CPU: 7 PID: 18671 Comm: modprobe Kdump: loaded Tainted: G E 6.1.0-rc3+ #8 pstate: 80400009 (Nzcv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--) pc : atahoststop+0x3c/0x84 [libata] lr : releasenodes+0x64/0xd0 Call trace: atahoststop+0x3c/0x84 [libata] releasenodes+0x64/0xd0 devresreleaseall+0xbc/0x1b0 deviceunbindcleanup+0x20/0x70 really_probe+0x158/0x320 __driverprobedevice+0x84/0x120 driverprobedevice+0x44/0x120 __driverattach+0xb4/0x220 busforeachdev+0x78/0xdc driverattach+0x2c/0x40 busadddriver+0x184/0x240 driverregister+0x80/0x13c _pciregisterdriver+0x4c/0x60 ahcipcidriverinit+0x30/0x1000 [ahci]

Fix this by removing redundant atahostput() in the error path.