pidfd: getfd should always report ESRCH if a task is exiting

We can get EBADF from pidfd_getfd() if a task is currently exiting,
which might be confusing. Let's check PF_EXITING, and just report ESRCH
if so.

I chose PF_EXITING, because it is set in exit_signals(), which is called
before exit_files(). Since ->exit_status is mostly set after
exit_files() in exit_notify(), using that still leaves a window open for
the race.

Reviewed-by: Oleg Nesterov <[email protected]>
Signed-off-by: Tycho Andersen <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Christian Brauner <[email protected]>

0 files changed, 0 insertions, 0 deletions