block: Fix io_context leak after failure of clone with CLONE_IO

With CLONE_IO, parent's io_context->nr_tasks is incremented, but never
decremented whenever copy_process() fails afterwards, which prevents
exit_io_context() from calling IO schedulers exit functions.

Give a task_struct to exit_io_context(), and call exit_io_context() instead of
put_io_context() in copy_process() cleanup path.

Signed-off-by: Louis Rilling <louis.rilling@kerlabs.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>

1 files changed, 2 insertions, 1 deletions

diff --git a/kernel/fork.c b/kernel/fork.c
index 166b8c49257c..607353425bb0 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -1310,7 +1310,8 @@ bad_fork_free_pid:
         if (pid != &init_struct_pid)
                 free_pid(pid);
 bad_fork_cleanup_io:
-        put_io_context(p->io_context);
+        if (p->io_context)
+                exit_io_context(p);
 bad_fork_cleanup_namespaces:
         exit_task_namespaces(p);
 bad_fork_cleanup_mm: