From: Jens Axboe axboe@kernel.dk
[ 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@xmission.com Reported-by: Oleg Nesterov oleg@redhat.com Signed-off-by: Jens Axboe axboe@kernel.dk Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- 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); }
/*