diff options
author | Rafael J. Wysocki <rafael.j.wysocki@intel.com> | 2024-04-26 12:10:10 +0300 |
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committer | Rafael J. Wysocki <rafael.j.wysocki@intel.com> | 2024-04-26 15:57:50 +0300 |
commit | d351eb0ab04c3e8109895fc33250cebbce9c11da (patch) | |
tree | 69d658b6e9ac585c988866c1a4c9406e13d9dbfb /drivers/thermal/thermal_debugfs.c | |
parent | c7f7c37271787a7f77d7eedc132b0b419a76b4c8 (diff) | |
download | linux-d351eb0ab04c3e8109895fc33250cebbce9c11da.tar.xz |
thermal/debugfs: Prevent use-after-free from occurring after cdev removal
Since thermal_debug_cdev_remove() does not run under cdev->lock, it can
run in parallel with thermal_debug_cdev_state_update() and it may free
the struct thermal_debugfs object used by the latter after it has been
checked against NULL.
If that happens, thermal_debug_cdev_state_update() will access memory
that has been freed already causing the kernel to crash.
Address this by using cdev->lock in thermal_debug_cdev_remove() around
the cdev->debugfs value check (in case the same cdev is removed at the
same time in two different threads) and its reset to NULL.
Fixes: 755113d76786 ("thermal/debugfs: Add thermal cooling device debugfs information")
Cc :6.8+ <stable@vger.kernel.org> # 6.8+
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Lukasz Luba <lukasz.luba@arm.com>
Diffstat (limited to 'drivers/thermal/thermal_debugfs.c')
-rw-r--r-- | drivers/thermal/thermal_debugfs.c | 14 |
1 files changed, 11 insertions, 3 deletions
diff --git a/drivers/thermal/thermal_debugfs.c b/drivers/thermal/thermal_debugfs.c index 1fe2914a8853..5693cc8b231a 100644 --- a/drivers/thermal/thermal_debugfs.c +++ b/drivers/thermal/thermal_debugfs.c @@ -505,15 +505,23 @@ void thermal_debug_cdev_add(struct thermal_cooling_device *cdev) */ void thermal_debug_cdev_remove(struct thermal_cooling_device *cdev) { - struct thermal_debugfs *thermal_dbg = cdev->debugfs; + struct thermal_debugfs *thermal_dbg; - if (!thermal_dbg) + mutex_lock(&cdev->lock); + + thermal_dbg = cdev->debugfs; + if (!thermal_dbg) { + mutex_unlock(&cdev->lock); return; + } + + cdev->debugfs = NULL; + + mutex_unlock(&cdev->lock); mutex_lock(&thermal_dbg->lock); thermal_debugfs_cdev_clear(&thermal_dbg->cdev_dbg); - cdev->debugfs = NULL; mutex_unlock(&thermal_dbg->lock); |