[PATCH 0/4 v3] seccomp: improve handling of SECCOMP_IOCTL_NOTIF_RECV

[Andrei Vagin <avagin@google.com>]

This patch set addresses two problems with the SECCOMP_IOCTL_NOTIF_RECV
ioctl:
* it doesn't return when the seccomp filter becomes unused (all tasks
  have exited).
* EPOLLHUP is triggered not when a task exits, but rather when its zombie
  is collected.

v2: - Remove unnecessary checks of PF_EXITING.
    - Take siglock with disabling irqs.
    Thanks to Oleg for the review and the help with the first version.
v3: - a few fixes suggested by Kees.
    - add a test to ensure that a dead thread leader doesn't prevent
      installing new filters with SECCOMP_FILTER_FLAG_TSYNC.

Andrei Vagin (3):
  seccomp: interrupt SECCOMP_IOCTL_NOTIF_RECV when all users have exited
  seccomp: release task filters when the task exits
  selftests/seccomp: add test for NOTIF_RECV and unused filters
  selftests/seccomp: check that a zombie leader doesn't affect others

 kernel/exit.c                                 |   3 +-
 kernel/seccomp.c                              |  30 +++-
 tools/testing/selftests/seccomp/seccomp_bpf.c | 131 ++++++++++++++++++
 3 files changed, 157 insertions(+), 7 deletions(-)

-- 
2.45.0.rc1.225.g2a3ae87e7f-goog