From: Luc Van Oostenryck <luc.vanoostenryck@xxxxxxxxx> commit 9e77716a75bc6cf54965e5ec069ba7c02b32251c upstream. pidfd_poll() is defined as returning 'unsigned int' but the .poll method is declared as returning '__poll_t', a bitwise type. Fix this by using the proper return type and using the EPOLL constants instead of the POLL ones, as required for __poll_t. Fixes: b53b0b9d9a61 ("pidfd: add polling support") Cc: Joel Fernandes (Google) <joel@xxxxxxxxxxxxxxxxx> Cc: stable@xxxxxxxxxxxxxxx # 5.3 Signed-off-by: Luc Van Oostenryck <luc.vanoostenryck@xxxxxxxxx> Reviewed-by: Christian Brauner <christian.brauner@xxxxxxxxxx> Link: https://lore.kernel.org/r/20191120003320.31138-1-luc.vanoostenryck@xxxxxxxxx Signed-off-by: Christian Brauner <christian.brauner@xxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- kernel/fork.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) --- a/kernel/fork.c +++ b/kernel/fork.c @@ -1713,11 +1713,11 @@ static void pidfd_show_fdinfo(struct seq /* * Poll support for process exit notification. */ -static unsigned int pidfd_poll(struct file *file, struct poll_table_struct *pts) +static __poll_t pidfd_poll(struct file *file, struct poll_table_struct *pts) { struct task_struct *task; struct pid *pid = file->private_data; - int poll_flags = 0; + __poll_t poll_flags = 0; poll_wait(file, &pid->wait_pidfd, pts); @@ -1729,7 +1729,7 @@ static unsigned int pidfd_poll(struct fi * group, then poll(2) should block, similar to the wait(2) family. */ if (!task || (task->exit_state && thread_group_empty(task))) - poll_flags = POLLIN | POLLRDNORM; + poll_flags = EPOLLIN | EPOLLRDNORM; rcu_read_unlock(); return poll_flags;