[PATCH 0/3] coredump: fix the ancient signal problems

[Oleg Nesterov <oleg@redhat.com>]

Hello.

These problems are really annoying. I reported and tried to fix
them in 2008 (see http://marc.info/?l=linux-kernel&m=121665710711931)
but nobody was interested.

Since then I had a lot of (to some degree contradictory) bug reports:
we do not want the interrupted coredumps (this is what the current code
tries to achieve but the logic is very wrong), but at the same time some
people blame the coredump because it is not interruptible.

And every time the discussion was confusing, it is not clear what should
we actually do to make everyone happy.

Linus, et al, could you please ack/nack the intent? Of course I will
appreciate if you can review the code, but what I am actually worried
about is the user-visible change: the coredumping becomes killable but
only by the _explicit_ SIGKILL, other fatal signals are "ignored".

The changes were not tested at all, I'll try to recheck everything and
test this tomorrow. I am sending this series right now because I strongly
believe that the recent -mm patches in this area are not right and should
be dropped, and I also disagree with the pending v2.

Mandeep, just in case please note that 1/3 alone should fix the problems
with non-fatal signals and wait_dump_helper(). As for the freezer, afaics
we are almost ready for the (slightly modified) fix proposed in
http://marc.info/?l=linux-kernel&m=136103469831268.

Oleg.

 fs/coredump.c         |   33 +++++++++++++++++++--------------
 include/linux/sched.h |    1 +
 kernel/signal.c       |    6 ++++--
 3 files changed, 24 insertions(+), 16 deletions(-)