diff options
| author | Alexander Shishkin <alexander.shishkin@linux.intel.com> | 2020-07-06 19:13:39 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2020-07-10 15:12:48 +0200 |
| commit | e78e1fdb282726beaf88aa75943682217e6ded0e (patch) | |
| tree | e34e04803cbeef608965babb7a1ff0d64e3b3ae0 | |
| parent | fd73d74a32bfaaf259441322cc5a1c83caaa94f2 (diff) | |
intel_th: Fix a NULL dereference when hub driver is not loaded
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: 39f4034693b7c ("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>
| -rw-r--r-- | drivers/hwtracing/intel_th/core.c | 21 | ||||
| -rw-r--r-- | drivers/hwtracing/intel_th/sth.c | 4 |
2 files changed, 19 insertions, 6 deletions
diff --git a/drivers/hwtracing/intel_th/core.c b/drivers/hwtracing/intel_th/core.c index ca232ec565e8..c9ac3dc65113 100644 --- a/drivers/hwtracing/intel_th/core.c +++ b/drivers/hwtracing/intel_th/core.c @@ -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; + + if (!hubdrv->set_output) { + ret = -ENOTSUPP; + goto out; + } + + ret = hubdrv->set_output(hub, master); - return hubdrv->set_output(hub, master); +out: + module_put(hubdrv->driver.owner); + return ret; } EXPORT_SYMBOL_GPL(intel_th_set_output); diff --git a/drivers/hwtracing/intel_th/sth.c b/drivers/hwtracing/intel_th/sth.c index 3a1f4e650378..a1529f571491 100644 --- a/drivers/hwtracing/intel_th/sth.c +++ b/drivers/hwtracing/intel_th/sth.c @@ -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) |