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intel_th: Fix a NULL dereference when hub driver is not loaded

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Connecting master to an output port when GTH driver module is not loaded
triggers a NULL dereference:

> RIP: 0010:intel_th_set_output+0x35/0x70 [intel_th]
> Call Trace:
>  ? sth_stm_link+0x12/0x20 [intel_th_sth]
>  stm_source_link_store+0x164/0x270 [stm_core]
>  dev_attr_store+0x17/0x30
>  sysfs_kf_write+0x3e/0x50
>  kernfs_fop_write+0xda/0x1b0
>  __vfs_write+0x1b/0x40
>  vfs_write+0xb9/0x1a0
>  ksys_write+0x67/0xe0
>  __x64_sys_write+0x1a/0x20
>  do_syscall_64+0x57/0x1d0
>  entry_SYSCALL_64_after_hwframe+0x44/0xa9

Make sure the module in question is loaded and return an error if not.

Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Fixes: 39f4034693 ("intel_th: Add driver infrastructure for Intel(R) Trace Hub devices")
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reported-by: Ammy Yi <ammy.yi@intel.com>
Tested-by: Ammy Yi <ammy.yi@intel.com>
Cc: stable@vger.kernel.org # v4.4
Link: https://lore.kernel.org/r/20200706161339.55468-5-alexander.shishkin@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Alexander Shishkin 2020-07-06 19:13:39 +03:00 committed by Greg Kroah-Hartman
parent fd73d74a32
commit e78e1fdb28
2 changed files with 19 additions and 6 deletions
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21
drivers/hwtracing/intel_th/core.c
View File

@ -1021,15 +1021,30 @@ int intel_th_set_output(struct intel_th_device *thdev,
{
struct intel_th_device *hub = to_intel_th_hub(thdev);
struct intel_th_driver *hubdrv = to_intel_th_driver(hub->dev.driver);
int ret;
/* In host mode, this is up to the external debugger, do nothing. */
if (hub->host_mode)
return 0;
if (!hubdrv->set_output)
return -ENOTSUPP;
/*
* hub is instantiated together with the source device that
* calls here, so guaranteed to be present.
*/
hubdrv = to_intel_th_driver(hub->dev.driver);
if (!hubdrv || !try_module_get(hubdrv->driver.owner))
return -EINVAL;
return hubdrv->set_output(hub, master);
if (!hubdrv->set_output) {
ret = -ENOTSUPP;
goto out;
}
ret = hubdrv->set_output(hub, master);
out:
module_put(hubdrv->driver.owner);
return ret;
}
EXPORT_SYMBOL_GPL(intel_th_set_output);

4
drivers/hwtracing/intel_th/sth.c
View File

@ -161,9 +161,7 @@ static int sth_stm_link(struct stm_data *stm_data, unsigned int master,
{
struct sth_device *sth = container_of(stm_data, struct sth_device, stm);
intel_th_set_output(to_intel_th_device(sth->dev), master);
return 0;
return intel_th_set_output(to_intel_th_device(sth->dev), master);
}
static int intel_th_sw_init(struct sth_device *sth)