Avoid that closing /dev/infiniband/umad<n> or /dev/infiniband/issm<n> triggers a use-after-free. __fput() in fs/file_table.c invokes f_op->release() before it invokes cdev_put(). Make sure that the ib_umad_device structure is freed by the cdev_put() call instead of f_op->release(). This avoids that changing the port mode from IB into Ethernet and back to IB followed by restarting opensmd triggers the following kernel oops:
general protection fault: 0000 [#1] PREEMPT SMP RIP: 0010:[<ffffffff810cc65c>] [<ffffffff810cc65c>] module_put+0x2c/0x170 Call Trace: [<ffffffff81190f20>] cdev_put+0x20/0x30 [<ffffffff8118e2ce>] __fput+0x1ae/0x1f0 [<ffffffff8118e35e>] ____fput+0xe/0x10 [<ffffffff810723bc>] task_work_run+0xac/0xe0 [<ffffffff81002a9f>] do_notify_resume+0x9f/0xc0 [<ffffffff814b8398>] int_signal+0x12/0x17 Reference: https://bugzilla.kernel.org/show_bug.cgi?id=75051 Signed-off-by: Bart Van Assche <[email protected]> Cc: <[email protected]> --- drivers/infiniband/core/user_mad.c | 37 ++++++++++++++++++++++++------------- 1 file changed, 24 insertions(+), 13 deletions(-) diff --git a/drivers/infiniband/core/user_mad.c b/drivers/infiniband/core/user_mad.c index 5c67d80..7bec4ca 100644 --- a/drivers/infiniband/core/user_mad.c +++ b/drivers/infiniband/core/user_mad.c @@ -98,7 +98,7 @@ struct ib_umad_port { struct ib_umad_device { int start_port, end_port; - struct kref ref; + struct kobject kobj; struct ib_umad_port port[0]; }; @@ -134,14 +134,18 @@ static DECLARE_BITMAP(dev_map, IB_UMAD_MAX_PORTS); static void ib_umad_add_one(struct ib_device *device); static void ib_umad_remove_one(struct ib_device *device); -static void ib_umad_release_dev(struct kref *ref) +static void ib_umad_release_dev(struct kobject *kobj) { struct ib_umad_device *dev = - container_of(ref, struct ib_umad_device, ref); + container_of(kobj, struct ib_umad_device, kobj); kfree(dev); } +static struct kobj_type ib_umad_dev_ktype = { + .release = ib_umad_release_dev, +}; + static int hdr_size(struct ib_umad_file *file) { return file->use_pkey_index ? sizeof (struct ib_user_mad_hdr) : @@ -783,7 +787,7 @@ static int ib_umad_open(struct inode *inode, struct file *filp) int ret = -ENXIO; port = container_of(inode->i_cdev, struct ib_umad_port, cdev); - kref_get(&port->umad_dev->ref); + kobject_get(&port->umad_dev->kobj); mutex_lock(&port->file_mutex); @@ -812,7 +816,7 @@ out: mutex_unlock(&port->file_mutex); if (ret) - kref_put(&port->umad_dev->ref, ib_umad_release_dev); + kobject_put(&port->umad_dev->kobj); return ret; } @@ -849,7 +853,7 @@ static int ib_umad_close(struct inode *inode, struct file *filp) mutex_unlock(&file->port->file_mutex); kfree(file); - kref_put(&dev->ref, ib_umad_release_dev); + kobject_put(&dev->kobj); return 0; } @@ -877,7 +881,7 @@ static int ib_umad_sm_open(struct inode *inode, struct file *filp) int ret; port = container_of(inode->i_cdev, struct ib_umad_port, sm_cdev); - kref_get(&port->umad_dev->ref); + kobject_get(&port->umad_dev->kobj); if (filp->f_flags & O_NONBLOCK) { if (down_trylock(&port->sm_sem)) { @@ -903,7 +907,7 @@ static int ib_umad_sm_open(struct inode *inode, struct file *filp) fail: if (ret) - kref_put(&port->umad_dev->ref, ib_umad_release_dev); + kobject_put(&port->umad_dev->kobj); return ret; clr_sm_cap: @@ -930,7 +934,7 @@ static int ib_umad_sm_close(struct inode *inode, struct file *filp) up(&port->sm_sem); - kref_put(&port->umad_dev->ref, ib_umad_release_dev); + kobject_put(&port->umad_dev->kobj); return ret; } @@ -998,6 +1002,7 @@ static int find_overflow_devnum(void) } static int ib_umad_init_port(struct ib_device *device, int port_num, + struct ib_umad_device *umad_dev, struct ib_umad_port *port) { int devnum; @@ -1063,6 +1068,11 @@ static int ib_umad_init_port(struct ib_device *device, int port_num, if (device_create_file(port->sm_dev, &dev_attr_port)) goto err_sm_dev; + port->cdev.kobj.parent = &umad_dev->kobj; + kobject_get(&umad_dev->kobj); + port->sm_cdev.kobj.parent = &umad_dev->kobj; + kobject_get(&umad_dev->kobj); + return 0; err_sm_dev: @@ -1141,7 +1151,7 @@ static void ib_umad_add_one(struct ib_device *device) if (!umad_dev) return; - kref_init(&umad_dev->ref); + kobject_init(&umad_dev->kobj, &ib_umad_dev_ktype); umad_dev->start_port = s; umad_dev->end_port = e; @@ -1149,7 +1159,8 @@ static void ib_umad_add_one(struct ib_device *device) for (i = s; i <= e; ++i) { umad_dev->port[i - s].umad_dev = umad_dev; - if (ib_umad_init_port(device, i, &umad_dev->port[i - s])) + if (ib_umad_init_port(device, i, umad_dev, + &umad_dev->port[i - s])) goto err; } @@ -1161,7 +1172,7 @@ err: while (--i >= s) ib_umad_kill_port(&umad_dev->port[i - s]); - kref_put(&umad_dev->ref, ib_umad_release_dev); + kobject_put(&umad_dev->kobj); } static void ib_umad_remove_one(struct ib_device *device) @@ -1175,7 +1186,7 @@ static void ib_umad_remove_one(struct ib_device *device) for (i = 0; i <= umad_dev->end_port - umad_dev->start_port; ++i) ib_umad_kill_port(&umad_dev->port[i]); - kref_put(&umad_dev->ref, ib_umad_release_dev); + kobject_put(&umad_dev->kobj); } static char *umad_devnode(struct device *dev, umode_t *mode) -- 1.8.4.5 -- To unsubscribe from this list: send the line "unsubscribe linux-rdma" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
