From: Jens Axboe <axboe@xxxxxxxxx>
[ Upstream commit b16b3855d89fba640996fefdd3a113c0aa0e380d ]
This is racy - move the blocking into when the task is created and
we're marking it as PF_IO_WORKER anyway. The IO threads are now
prepared to handle signals like SIGSTOP as well, so clear that from
the mask to allow proper stopping of IO threads.
Acked-by: "Eric W. Biederman" <ebiederm@xxxxxxxxxxxx>
Reported-by: Oleg Nesterov <oleg@xxxxxxxxxx>
Signed-off-by: Jens Axboe <axboe@xxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
kernel/fork.c | 16 ++++++++--------
1 file changed, 8 insertions(+), 8 deletions(-)
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -1949,8 +1949,14 @@ static __latent_entropy struct task_stru
p = dup_task_struct(current, node);
if (!p)
goto fork_out;
- if (args->io_thread)
+ if (args->io_thread) {
+ /*
+ * Mark us an IO worker, and block any signal that isn't
+ * fatal or STOP
+ */
p->flags |= PF_IO_WORKER;
+ siginitsetinv(&p->blocked, sigmask(SIGKILL)|sigmask(SIGSTOP));
+ }
/*
* This _must_ happen before we call free_task(), i.e. before we jump
@@ -2435,14 +2441,8 @@ struct task_struct *create_io_thread(int
.stack_size = (unsigned long)arg,
.io_thread = 1,
};
- struct task_struct *tsk;
- tsk = copy_process(NULL, 0, node, &args);
- if (!IS_ERR(tsk)) {
- sigfillset(&tsk->blocked);
- sigdelsetmask(&tsk->blocked, sigmask(SIGKILL));
- }
- return tsk;
+ return copy_process(NULL, 0, node, &args);
}
/*
