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8c76310740
In the error path in ata_tport_add(), when calling put_device(),
ata_tport_release() is called, it will put the refcount of 'ap->host'.
And then ata_host_put() is called again, the refcount is decreased
to 0, ata_host_release() is called, all ports are freed and set to
null.
When unbinding the device after failure, ata_host_stop() 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 : ata_host_stop+0x3c/0x84 [libata]
lr : release_nodes+0x64/0xd0
Call trace:
ata_host_stop+0x3c/0x84 [libata]
release_nodes+0x64/0xd0
devres_release_all+0xbc/0x1b0
device_unbind_cleanup+0x20/0x70
really_probe+0x158/0x320
__driver_probe_device+0x84/0x120
driver_probe_device+0x44/0x120
__driver_attach+0xb4/0x220
bus_for_each_dev+0x78/0xdc
driver_attach+0x2c/0x40
bus_add_driver+0x184/0x240
driver_register+0x80/0x13c
__pci_register_driver+0x4c/0x60
ahci_pci_driver_init+0x30/0x1000 [ahci]
Fix this by removing redundant ata_host_put() in the error path.
Fixes: 2623c7a5f2 ("libata: add refcounting to ata_host")
Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
Signed-off-by: Damien Le Moal <damien.lemoal@opensource.wdc.com>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.