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authorAlexander Shishkin <alexander.shishkin@linux.intel.com>2020-07-06 19:13:39 +0300
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2020-07-10 16:12:48 +0300
commite78e1fdb282726beaf88aa75943682217e6ded0e (patch)
treee34e04803cbeef608965babb7a1ff0d64e3b3ae0 /drivers/hwtracing
parentfd73d74a32bfaaf259441322cc5a1c83caaa94f2 (diff)
downloadlinux-e78e1fdb282726beaf88aa75943682217e6ded0e.tar.xz
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>
Diffstat (limited to 'drivers/hwtracing')
-rw-r--r--drivers/hwtracing/intel_th/core.c21
-rw-r--r--drivers/hwtracing/intel_th/sth.c4
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)