Merge branch 'exec-update-lock-for-v5.11' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace

Pull exec-update-lock update from Eric Biederman:
 "The key point of this is to transform exec_update_mutex into a
  rw_semaphore so readers can be separated from writers.

  This makes it easier to understand what the holders of the lock are
  doing, and makes it harder to contend or deadlock on the lock.

  The real deadlock fix wound up in perf_event_open"

* 'exec-update-lock-for-v5.11' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace:
  exec: Transform exec_update_mutex into a rw_semaphore
This commit is contained in:
Linus Torvalds
2020-12-15 19:36:48 -08:00
8 changed files with 44 additions and 43 deletions

View File

@@ -228,12 +228,13 @@ struct signal_struct {
* credential calculations
* (notably. ptrace)
* Deprecated do not use in new code.
* Use exec_update_mutex instead.
*/
struct mutex exec_update_mutex; /* Held while task_struct is being
* updated during exec, and may have
* inconsistent permissions.
* Use exec_update_lock instead.
*/
struct rw_semaphore exec_update_lock; /* Held while task_struct is
* being updated during exec,
* and may have inconsistent
* permissions.
*/
} __randomize_layout;
/*