4.18-stable review patch. If anyone has any objections, please let me know.
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From: Jason Yan yanaijie@huawei.com
commit 2fa4a32613c9182b00e46872755b0662374424a7 upstream.
Commit 2623c7a5f2 ("libata: add refcounting to ata_host") v4.17+ introduced refcounting to ata_host and will increase or decrease the refcount when adding or deleting transport ATA port.
Now the ata host for libsas is embedded in domain_device, and the ->kref member is not initialized. Afer we add ata transport class, ata_host_get() will be called when adding transport ATA port and a warning will be triggered as below:
refcount_t: increment on 0; use-after-free. WARNING: CPU: 2 PID: 103 at lib/refcount.c:153 refcount_inc+0x40/0x48 ...... Call trace: refcount_inc+0x40/0x48 ata_host_get+0x10/0x18 ata_tport_add+0x40/0x120 ata_sas_tport_add+0xc/0x14 sas_ata_init+0x7c/0xc8 sas_discover_domain+0x380/0x53c process_one_work+0x12c/0x288 worker_thread+0x58/0x3f0 kthread+0xfc/0x128 ret_from_fork+0x10/0x18
And also when removing transport ATA port ata_host_put() will be called and another similar warning will be triggered. If the refcount decreased to zero, the ata host will be freed. But this ata host is only part of domain_device, it cannot be freed directly.
So we have to change this embedded static ata host to a dynamically allocated ata host and initialize the ->kref member. To use ata_host_get() and ata_host_put() in libsas, we need to move the declaration of these functions to the public libata.h and export them.
Fixes: b6240a4df018 ("scsi: libsas: add transport class for ATA devices") Signed-off-by: Jason Yan yanaijie@huawei.com CC: John Garry john.garry@huawei.com CC: Taras Kondratiuk takondra@cisco.com CC: Tejun Heo tj@kernel.org Acked-by: Tejun Heo tj@kernel.org Signed-off-by: Martin K. Petersen martin.petersen@oracle.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- drivers/ata/libata-core.c | 3 ++ drivers/ata/libata.h | 2 - drivers/scsi/libsas/sas_ata.c | 40 ++++++++++++++++++++++++------------- drivers/scsi/libsas/sas_discover.c | 2 + include/linux/libata.h | 2 + include/scsi/libsas.h | 2 - 6 files changed, 34 insertions(+), 17 deletions(-)
--- a/drivers/ata/libata-core.c +++ b/drivers/ata/libata-core.c @@ -6424,6 +6424,7 @@ void ata_host_init(struct ata_host *host host->n_tags = ATA_MAX_QUEUE; host->dev = dev; host->ops = ops; + kref_init(&host->kref); }
void __ata_port_probe(struct ata_port *ap) @@ -7391,3 +7392,5 @@ EXPORT_SYMBOL_GPL(ata_cable_80wire); EXPORT_SYMBOL_GPL(ata_cable_unknown); EXPORT_SYMBOL_GPL(ata_cable_ignore); EXPORT_SYMBOL_GPL(ata_cable_sata); +EXPORT_SYMBOL_GPL(ata_host_get); +EXPORT_SYMBOL_GPL(ata_host_put); \ No newline at end of file --- a/drivers/ata/libata.h +++ b/drivers/ata/libata.h @@ -100,8 +100,6 @@ extern int ata_port_probe(struct ata_por extern void __ata_port_probe(struct ata_port *ap); extern unsigned int ata_read_log_page(struct ata_device *dev, u8 log, u8 page, void *buf, unsigned int sectors); -extern void ata_host_get(struct ata_host *host); -extern void ata_host_put(struct ata_host *host);
#define to_ata_port(d) container_of(d, struct ata_port, tdev)
--- a/drivers/scsi/libsas/sas_ata.c +++ b/drivers/scsi/libsas/sas_ata.c @@ -557,34 +557,46 @@ int sas_ata_init(struct domain_device *f { struct sas_ha_struct *ha = found_dev->port->ha; struct Scsi_Host *shost = ha->core.shost; + struct ata_host *ata_host; struct ata_port *ap; int rc;
- ata_host_init(&found_dev->sata_dev.ata_host, ha->dev, &sas_sata_ops); - ap = ata_sas_port_alloc(&found_dev->sata_dev.ata_host, - &sata_port_info, - shost); + ata_host = kzalloc(sizeof(*ata_host), GFP_KERNEL); + if (!ata_host) { + SAS_DPRINTK("ata host alloc failed.\n"); + return -ENOMEM; + } + + ata_host_init(ata_host, ha->dev, &sas_sata_ops); + + ap = ata_sas_port_alloc(ata_host, &sata_port_info, shost); if (!ap) { SAS_DPRINTK("ata_sas_port_alloc failed.\n"); - return -ENODEV; + rc = -ENODEV; + goto free_host; }
ap->private_data = found_dev; ap->cbl = ATA_CBL_SATA; ap->scsi_host = shost; rc = ata_sas_port_init(ap); - if (rc) { - ata_sas_port_destroy(ap); - return rc; - } - rc = ata_sas_tport_add(found_dev->sata_dev.ata_host.dev, ap); - if (rc) { - ata_sas_port_destroy(ap); - return rc; - } + if (rc) + goto destroy_port; + + rc = ata_sas_tport_add(ata_host->dev, ap); + if (rc) + goto destroy_port; + + found_dev->sata_dev.ata_host = ata_host; found_dev->sata_dev.ap = ap;
return 0; + +destroy_port: + ata_sas_port_destroy(ap); +free_host: + ata_host_put(ata_host); + return rc; }
void sas_ata_task_abort(struct sas_task *task) --- a/drivers/scsi/libsas/sas_discover.c +++ b/drivers/scsi/libsas/sas_discover.c @@ -316,6 +316,8 @@ void sas_free_device(struct kref *kref) if (dev_is_sata(dev) && dev->sata_dev.ap) { ata_sas_tport_delete(dev->sata_dev.ap); ata_sas_port_destroy(dev->sata_dev.ap); + ata_host_put(dev->sata_dev.ata_host); + dev->sata_dev.ata_host = NULL; dev->sata_dev.ap = NULL; }
--- a/include/linux/libata.h +++ b/include/linux/libata.h @@ -1111,6 +1111,8 @@ extern struct ata_host *ata_host_alloc(s extern struct ata_host *ata_host_alloc_pinfo(struct device *dev, const struct ata_port_info * const * ppi, int n_ports); extern int ata_slave_link_init(struct ata_port *ap); +extern void ata_host_get(struct ata_host *host); +extern void ata_host_put(struct ata_host *host); extern int ata_host_start(struct ata_host *host); extern int ata_host_register(struct ata_host *host, struct scsi_host_template *sht); --- a/include/scsi/libsas.h +++ b/include/scsi/libsas.h @@ -161,7 +161,7 @@ struct sata_device { u8 port_no; /* port number, if this is a PM (Port) */
struct ata_port *ap; - struct ata_host ata_host; + struct ata_host *ata_host; struct smp_resp rps_resp ____cacheline_aligned; /* report_phy_sata_resp */ u8 fis[ATA_RESP_FIS_SIZE]; };