[PATCH 6.12 465/567] drm/xe/oa: Fix potential UAF in xe_oa_add_config_ioctl()

Greg Kroah-Hartman
2026-01-06T17:39:55Z

From: Sanjay Yadav <sanjay.kumar.yadav@intel.com>

commit dcb171931954c51a1a7250d558f02b8f36570783 upstream.

In xe_oa_add_config_ioctl(), we accessed oa_config->id after dropping
metrics_lock. Since this lock protects the lifetime of oa_config, an
attacker could guess the id and call xe_oa_remove_config_ioctl() with
perfect timing, freeing oa_config before we dereference it, leading to
a potential use-after-free.

Fix this by caching the id in a local variable while holding the lock.

v2: (Matt A)
- Dropped mutex_unlock(&oa->metrics_lock) ordering change from
xe_oa_remove_config_ioctl()

Closes: https://gitlab.freedesktop.org/drm/xe/kernel/-/issues/6614
Fixes: cdf02fe1a94a7 ("drm/xe/oa/uapi: Add/remove OA config perf ops")
Cc: <stable@vger.kernel.org> # v6.11+
Suggested-by: Matthew Auld <matthew.auld@intel.com>
Signed-off-by: Sanjay Yadav <sanjay.kumar.yadav@intel.com>
Reviewed-by: Matthew Auld <matthew.auld@intel.com>
Signed-off-by: Matthew Auld <matthew.auld@intel.com>
Link: https://patch.msgid.link/20251118114859.3379952-2-sanjay.kumar.yadav@intel.com
(cherry picked from commit 28aeaed130e8e587fd1b73b6d66ca41ccc5a1a31)
Signed-off-by: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/gpu/drm/xe/xe_oa.c | 8 +++++---
1 file changed, 5 insertions(+), 3 deletions(-)

--- a/drivers/gpu/drm/xe/xe_oa.c
+++ b/drivers/gpu/drm/xe/xe_oa.c
@@ -2378,11 +2378,13 @@ int xe_oa_add_config_ioctl(struct drm_de
goto sysfs_err;
}

- mutex_unlock(&oa->metrics_lock);
+ id = oa_config->id;
+
+ drm_dbg(&oa->xe->drm, "Added config %s id=%i\n", oa_config->uuid, id);

- drm_dbg(&oa->xe->drm, "Added config %s id=%i\n", oa_config->uuid, oa_config->id);
+ mutex_unlock(&oa->metrics_lock);

- return oa_config->id;
+ return id;

sysfs_err:
mutex_unlock(&oa->metrics_lock);