diff options
author | Ingo Molnar <mingo@kernel.org> | 2019-02-11 08:01:50 +0100 |
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committer | Ingo Molnar <mingo@kernel.org> | 2019-02-11 08:01:50 +0100 |
commit | c9ba7560c550fe6c1f4a8f0666bea41d2a349d1d (patch) | |
tree | b15d53e69f73b160b4625e91187cd436c5a3e683 /kernel/locking/rwsem-xadd.c | |
parent | f6783319737f28e4436a69611853a5a098cbe974 (diff) | |
parent | d13937116f1e82bf508a6325111b322c30c85eb9 (diff) |
Merge tag 'v5.0-rc6' into sched/core, to pick up fixes
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'kernel/locking/rwsem-xadd.c')
-rw-r--r-- | kernel/locking/rwsem-xadd.c | 11 |
1 files changed, 9 insertions, 2 deletions
diff --git a/kernel/locking/rwsem-xadd.c b/kernel/locking/rwsem-xadd.c index 09b180063ee1..50d9af615dc4 100644 --- a/kernel/locking/rwsem-xadd.c +++ b/kernel/locking/rwsem-xadd.c @@ -198,15 +198,22 @@ static void __rwsem_mark_wake(struct rw_semaphore *sem, woken++; tsk = waiter->task; - wake_q_add(wake_q, tsk); + get_task_struct(tsk); list_del(&waiter->list); /* - * Ensure that the last operation is setting the reader + * Ensure calling get_task_struct() before setting the reader * waiter to nil such that rwsem_down_read_failed() cannot * race with do_exit() by always holding a reference count * to the task to wakeup. */ smp_store_release(&waiter->task, NULL); + /* + * Ensure issuing the wakeup (either by us or someone else) + * after setting the reader waiter to nil. + */ + wake_q_add(wake_q, tsk); + /* wake_q_add() already take the task ref */ + put_task_struct(tsk); } adjustment = woken * RWSEM_ACTIVE_READ_BIAS - adjustment; |