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John Garry 1d72f7aec3 libata: Remove extra scsi_host_put() in ata_scsi_add_hosts()
If the call to scsi_add_host_with_dma() in ata_scsi_add_hosts() fails,
then we may get use-after-free KASAN warns:

==================================================================
BUG: KASAN: use-after-free in kobject_put+0x24/0x180
Read of size 1 at addr ffff0026b8c80364 by task swapper/0/1
CPU: 1 PID: 1 Comm: swapper/0 Tainted: G        W         5.6.0-rc3-00004-g5a71b206ea82-dirty #1765
Hardware name: Huawei TaiShan 200 (Model 2280)/BC82AMDD, BIOS 2280-V2 CS V3.B160.01 02/24/2020
Call trace:
dump_backtrace+0x0/0x298
show_stack+0x14/0x20
dump_stack+0x118/0x190
print_address_description.isra.9+0x6c/0x3b8
__kasan_report+0x134/0x23c
kasan_report+0xc/0x18
__asan_load1+0x5c/0x68
kobject_put+0x24/0x180
put_device+0x10/0x20
scsi_host_put+0x10/0x18
ata_devres_release+0x74/0xb0
release_nodes+0x2d0/0x470
devres_release_all+0x50/0x78
really_probe+0x2d4/0x560
driver_probe_device+0x7c/0x148
device_driver_attach+0x94/0xa0
__driver_attach+0xa8/0x110
bus_for_each_dev+0xe8/0x158
driver_attach+0x30/0x40
bus_add_driver+0x220/0x2e0
driver_register+0xbc/0x1d0
__pci_register_driver+0xbc/0xd0
ahci_pci_driver_init+0x20/0x28
do_one_initcall+0xf0/0x608
kernel_init_freeable+0x31c/0x384
kernel_init+0x10/0x118
ret_from_fork+0x10/0x18

Allocated by task 5:
save_stack+0x28/0xc8
__kasan_kmalloc.isra.8+0xbc/0xd8
kasan_kmalloc+0xc/0x18
__kmalloc+0x1a8/0x280
scsi_host_alloc+0x44/0x678
ata_scsi_add_hosts+0x74/0x268
ata_host_register+0x228/0x488
ahci_host_activate+0x1c4/0x2a8
ahci_init_one+0xd18/0x1298
local_pci_probe+0x74/0xf0
work_for_cpu_fn+0x2c/0x48
process_one_work+0x488/0xc08
worker_thread+0x330/0x5d0
kthread+0x1c8/0x1d0
ret_from_fork+0x10/0x18

Freed by task 5:
save_stack+0x28/0xc8
__kasan_slab_free+0x118/0x180
kasan_slab_free+0x10/0x18
slab_free_freelist_hook+0xa4/0x1a0
kfree+0xd4/0x3a0
scsi_host_dev_release+0x100/0x148
device_release+0x7c/0xe0
kobject_put+0xb0/0x180
put_device+0x10/0x20
scsi_host_put+0x10/0x18
ata_scsi_add_hosts+0x210/0x268
ata_host_register+0x228/0x488
ahci_host_activate+0x1c4/0x2a8
ahci_init_one+0xd18/0x1298
local_pci_probe+0x74/0xf0
work_for_cpu_fn+0x2c/0x48
process_one_work+0x488/0xc08
worker_thread+0x330/0x5d0
kthread+0x1c8/0x1d0
ret_from_fork+0x10/0x18

There is also refcount issue, as well:
WARNING: CPU: 1 PID: 1 at lib/refcount.c:28 refcount_warn_saturate+0xf8/0x170

The issue is that we make an erroneous extra call to scsi_host_put()
for that host:

So in ahci_init_one()->ata_host_alloc_pinfo()->ata_host_alloc(), we setup
a device release method - ata_devres_release() - which intends to release
the SCSI hosts:

static void ata_devres_release(struct device *gendev, void *res)
{
	...
	for (i = 0; i < host->n_ports; i++) {
		struct ata_port *ap = host->ports[i];

		if (!ap)
			continue;

		if (ap->scsi_host)
			scsi_host_put(ap->scsi_host);

	}
	...
}

However in the ata_scsi_add_hosts() error path, we also call
scsi_host_put() for the SCSI hosts.

Fix by removing the the scsi_host_put() calls in ata_scsi_add_hosts() and
leave this to ata_devres_release().

Fixes: f31871951b ("libata: separate out ata_host_alloc() and ata_host_register()")
Signed-off-by: John Garry <john.garry@huawei.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-03-25 10:29:35 -06:00
arch ARM: SoC fixes 2020-03-08 17:36:22 -07:00
block block, bfq: fix overwrite of bfq_group pointer in bfq_find_set_group() 2020-03-06 07:00:58 -07:00
certs certs: Add wrapper function to check blacklisted binary hash 2019-11-12 12:25:50 +11:00
crypto Merge branch 'next-integrity' of git://git.kernel.org/pub/scm/linux/kernel/git/zohar/linux-integrity 2020-02-20 15:15:16 -08:00
Documentation ARM: SoC fixes 2020-03-08 17:36:22 -07:00
drivers libata: Remove extra scsi_host_put() in ata_scsi_add_hosts() 2020-03-25 10:29:35 -06:00
fs Driver core / debugfs fixes for 5.6-rc5 2020-03-08 10:39:40 -05:00
include libata: drop BPRINTK() 2020-03-12 08:04:00 -06:00
init Tracing updates: 2020-02-26 10:34:42 -08:00
ipc Revert "ipc,sem: remove uneeded sem_undo_list lock usage in exit_sem()" 2020-02-21 11:22:15 -08:00
kernel block-5.6-2020-03-07 2020-03-07 14:14:38 -06:00
lib Tracing updates: 2020-02-26 10:34:42 -08:00
LICENSES LICENSES: Rename other to deprecated 2019-05-03 06:34:32 -06:00
mm mm, hotplug: fix page online with DEBUG_PAGEALLOC compiled but not enabled 2020-03-06 07:06:09 -06:00
net vsock: fix potential deadlock in transport->release() 2020-02-27 12:03:56 -08:00
samples Kbuild updates for v5.6 (2nd) 2020-02-09 16:05:50 -08:00
scripts parse-maintainers: Mark as executable 2020-03-06 16:29:21 -06:00
security Merge branch 'next-integrity' of git://git.kernel.org/pub/scm/linux/kernel/git/zohar/linux-integrity 2020-02-20 15:15:16 -08:00
sound ASoC: Fixes for v5.6 2020-03-07 07:24:36 +01:00
tools for-linus-2020-03-07 2020-03-07 08:01:43 -06:00
usr Kbuild updates for v5.6 (2nd) 2020-02-09 16:05:50 -08:00
virt KVM/arm fixes for 5.6, take #1 2020-02-28 11:50:06 +01:00
.clang-format clang-format: Update with the latest for_each macro list 2019-08-31 10:00:51 +02:00
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.gitattributes .gitattributes: use 'dts' diff driver for dts files 2019-12-04 19:44:11 -08:00
.gitignore selftest/lkdtm: Use local .gitignore 2020-03-02 08:39:39 -07:00
.mailmap A handful of small documentation fixes that wandered in. 2020-02-07 13:03:10 -08:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS MAINTAINERS: Hand MIPS over to Thomas 2020-02-24 22:43:18 -08:00
Kbuild kbuild: rename hostprogs-y/always to hostprogs/always-y 2020-02-04 01:53:07 +09:00
Kconfig docs: kbuild: convert docs to ReST and rename to *.rst 2019-06-14 14:21:21 -06:00
MAINTAINERS ARM: SoC fixes 2020-03-08 17:36:22 -07:00
Makefile Linux 5.6-rc5 2020-03-08 17:44:44 -07:00
README Drop all 00-INDEX files from Documentation/ 2018-09-09 15:08:58 -06:00

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.