401aacd519
[ Upstream commit 1d72f7aec3595249dbb83291ccac041a2d676c57 ] 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: f31871951b38 ("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> Signed-off-by: Sasha Levin <sashal@kernel.org>
Linux kernel ============ This file was moved to Documentation/admin-guide/README.rst Please notice that there are several guides for kernel developers and users. These guides can be rendered in a number of formats, like HTML and PDF. In order to build the documentation, use ``make htmldocs`` or ``make pdfdocs``. There are various text files in the Documentation/ subdirectory, several of them using the Restructured Text markup notation. See Documentation/00-INDEX for a list of what is contained in each file. 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.