This builds on patches 1-15 of my previous patch posting. As those are
non-controversial I am not posting them again.
I took longer than I had hoped to get this set together because a kernel
testing robot noticed some random corruption with the way I had been
adding to the list. I finally tracked it down to failing to remove the
sigset from the list during fork_idle. So I have made that logic
simpler and use hlist_del_init which will only remove an item from a
list if it was placed on the list in the first place.
I took Oleg's suggesting and moved calculate_sigpending into
schedule_tail where recalc_sigpending an be used directly. Then in
calculate_sigpending I just unconditionally set TIF_SIGPENDING and allow
recalc_sigpending to clear TIF_SIGPENDING if we don't need it.
I also now handle the stop/continue signal magic where we only let one
of stop signals and SIGCONT be pending at a time. Looking at it from
first principles dropping one of SIGTSTP SIGTTIN SIGTTOU or SIGCONT
before calling it's handler feels wrong. I checked and it is our
historical behavior, so I won't even thinking of introducing different
behavior at this point.
Eric W. Biederman (6):
fork: Move and describe why the code examines PIDNS_ADDING
fork: Unconditionally exit if a fatal signal is pending
signal: Add calculate_sigpending()
fork: Skip setting TIF_SIGPENDING in ptrace_init_task
fork: Have new threads join on-going signal group stops
signal: Don't restart fork when signals come in.
include/linux/ptrace.h | 2 --
include/linux/sched/signal.h | 11 ++++++++++
init/init_task.c | 1 +
kernel/fork.c | 49 ++++++++++++++++++++++++++++++--------------
kernel/sched/core.c | 2 ++
kernel/signal.c | 43 ++++++++++++++++++++++++++++++++++++++
6 files changed, 91 insertions(+), 17 deletions(-)
Eric
