diff options
| author | Kent Overstreet <kent.overstreet@linux.dev> | 2023-08-12 17:10:42 -0400 |
|---|---|---|
| committer | Kent Overstreet <kent.overstreet@linux.dev> | 2023-08-14 12:28:45 -0400 |
| commit | 0e474135ce7b8e885e32d0c3adc49b96bad17cd7 (patch) | |
| tree | 8446b58fa9844311a77e5eea7b1d7174a9e00bb3 | |
| parent | 6547d0e7f0d9540434b74d26fac1f45f93e2b2e8 (diff) | |
bcachefs: six locks: Guard against wakee exiting in __six_lock_wakeup()
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
| -rw-r--r-- | fs/bcachefs/six.c | 9 |
1 files changed, 8 insertions, 1 deletions
diff --git a/fs/bcachefs/six.c b/fs/bcachefs/six.c index b6ca53c85249..14cffa68d722 100644 --- a/fs/bcachefs/six.c +++ b/fs/bcachefs/six.c @@ -8,6 +8,7 @@ #include <linux/sched.h> #include <linux/sched/clock.h> #include <linux/sched/rt.h> +#include <linux/sched/task.h> #include <linux/slab.h> #include <trace/events/lock.h> @@ -223,7 +224,12 @@ again: if (ret <= 0) goto unlock; - task = w->task; + /* + * Similar to percpu_rwsem_wake_function(), we need to guard + * against the wakee noticing w->lock_acquired, returning, and + * then exiting before we do the wakeup: + */ + task = get_task_struct(w->task); __list_del(w->list.prev, w->list.next); /* * The release barrier here ensures the ordering of the @@ -234,6 +240,7 @@ again: */ smp_store_release(&w->lock_acquired, true); wake_up_process(task); + put_task_struct(task); } six_clear_bitmask(lock, SIX_LOCK_WAITING_read << lock_type); |