Messages in this thread Patch in this message | | | Date | Fri, 10 Feb 2012 21:00:21 +0100 | From | Oleg Nesterov <> | Subject | [PATCH 1/4] signal: give SEND_SIG_FORCED more power to beat SIGNAL_UNKILLABLE |
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force_sig_info() and friends have the special semantics for synchronous signals, this interface should not be used if the target is not current. And it needs the fixes, in particular the clearing of SIGNAL_UNKILLABLE is not exactly right.
However there are callers which have to use force_ exactly because it clears SIGNAL_UNKILLABLE and thus it can kill the CLONE_NEWPID tasks, although this is almost always is wrong by various reasons.
With this patch SEND_SIG_FORCED ignores SIGNAL_UNKILLABLE, like we do if the signal comes from the ancestor namespace.
This makes the naming in prepare_signal() paths insane, fixed by the next cleanup.
Note: this only affects SIGKILL/SIGSTOP, but this is enough for force_sig() abusers.
Signed-off-by: Oleg Nesterov <oleg@redhat.com> --- kernel/signal.c | 3 ++- 1 files changed, 2 insertions(+), 1 deletions(-)
diff --git a/kernel/signal.c b/kernel/signal.c index c73c428..bfb2b97 100644 --- a/kernel/signal.c +++ b/kernel/signal.c @@ -1059,7 +1059,8 @@ static int __send_signal(int sig, struct siginfo *info, struct task_struct *t, assert_spin_locked(&t->sighand->siglock); - if (!prepare_signal(sig, t, from_ancestor_ns)) + if (!prepare_signal(sig, t, + from_ancestor_ns || (info == SEND_SIG_FORCED))) return 0; pending = group ? &t->signal->shared_pending : &t->pending; -- 1.5.5.1
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