Re: [PATCH 00/15] Rework tty audit

Hi Greg, This patch series overhauls tty audit support. The goal was to simplify and speed up tty auditing, which was a significant performance hit even when disabled. The main features of this series are: * Remove reference counting; the purpose of reference counting the per- process tty_audit_buf was to prevent premature deletion if the buffer was in-use when tty auditing was exited for the process. However, since the process is single-threaded at tty_audit_exit(), the buffer cannot be in-use by another thread. Patch 11/15. * Remove functionally dead code, such as tty_put_user(). Patch 2/15. * Atomically modify tty audit enable/disable flags to support lockless read. Patch 9/15. Cc: Ingo Molnar <mingo(a)redhat.com&gt; Cc: Peter Zijlstra <peterz(a)infradead.org&gt; for patch 9/15 which removes an audit field from the signal_struct. Cc: Oleg Nesterov <oleg(a)redhat.com&gt; to confirm my understanding of the single-threadedness of if (group_dead) tty_audit_exit(), called from do_exit(). Patch 11/15 Requires: "tty: audit: Fix audit source"

Regards, Peter Hurley (15): tty: audit: Early-out pty master reads earlier tty: audit: Never audit packet mode tty: audit: Remove icanon mode from call chain tty: audit: Defer audit buffer association tty: audit: Take siglock directly tty: audit: Ignore current association for audit push tty: audit: Combine push functions tty: audit: Track tty association with dev_t tty: audit: Handle tty audit enable atomically tty: audit: Remove false memory optimization tty: audit: Remove tty_audit_buf reference counting tty: audit: Simplify first-use allocation tty: audit: Check audit enable first tty: audit: Always push audit buffer before TIOCSTI tty: audit: Poison tty_audit_buf while process exits drivers/tty/n_tty.c | 25 ++---- drivers/tty/tty_audit.c | 231 ++++++++++++++---------------------------------- include/linux/audit.h | 4 + include/linux/sched.h | 1 - include/linux/tty.h | 12 +-- kernel/audit.c | 27 +++--- 6 files changed, 97 insertions(+), 203 deletions(-)