From: John Garry john.garry@huawei.com
[ 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 --- drivers/ata/libata-scsi.c | 9 +++------ 1 file changed, 3 insertions(+), 6 deletions(-)
diff --git a/drivers/ata/libata-scsi.c b/drivers/ata/libata-scsi.c index 58e09ffe8b9cb..5af34a3201ed2 100644 --- a/drivers/ata/libata-scsi.c +++ b/drivers/ata/libata-scsi.c @@ -4553,22 +4553,19 @@ int ata_scsi_add_hosts(struct ata_host *host, struct scsi_host_template *sht) */ shost->max_host_blocked = 1;
- rc = scsi_add_host_with_dma(ap->scsi_host, - &ap->tdev, ap->host->dev); + rc = scsi_add_host_with_dma(shost, &ap->tdev, ap->host->dev); if (rc) - goto err_add; + goto err_alloc; }
return 0;
- err_add: - scsi_host_put(host->ports[i]->scsi_host); err_alloc: while (--i >= 0) { struct Scsi_Host *shost = host->ports[i]->scsi_host;
+ /* scsi_host_put() is in ata_devres_release() */ scsi_remove_host(shost); - scsi_host_put(shost); } return rc; }